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For normal road use in anything but the 1800Ti format, the std brakes are OK. For ‘spirited’ driving they can be improved. Firstly, the front brake pads need changing for some of the excellent EBC ‘Greenstuff’ versions. They have the initial bite of standard road pads, but have excellent fade resistance, even with standard non-vented discs. Another bonus is the reduction of brake dust on your expensive alloy wheels. I have used the famous Mintex competition compound M171 pads too, but whilst offering better fade resistance and hot stopping power, they were plain horrible for everyday use. They were bordering on dangerous when cold as they had little retardation (akin to brand new pads) and zero ‘feel’ and could ‘grab’ the disc and lock a wheel if forced into an emergency stop situation. They wrecked discs too, 2 sets of pads seeing off a pair of discs. The later (and current) compound is the M1144. These are asbestos free and much better than the M171s but at nearly twice the price of EBCs, still expensive and still not as much feel to the brake pedal. 

For any 1800Ti models, the vented discs from a Metro Turbo along with the wider spaced calipers from the same model are pretty well essential. I have faded the standard set up when in a hurry, let alone driving hard! Graham Walker Ltd and Queensberry Road Garage both offer complete conversions, including discs, pads, new calipers and wheels spacers (required for std Reliant wheels) for 300+, great value when compared with using trees and ditches for deceleration!!

If you intend on Sprinting your SS1 or are uprating the engines performance significantly, I would suggest buying the new Metro turbo vented calipers, but using grooved and/or drilled aftermarket discs to further improve the braking (NOTE:- this currently isn’t allowed in all RSSOC classes—please check regs). The drilled ‘holes’ disperse the gasses that build up between pad and disc during heavy braking, and the grooves ‘de-glaze’ the pad surfaces. The glazing causes the pad surface to harden and become like granite, thus reducing the braking performance (just try taking a file to a glazed pad surface and tell me it ain’t hard!). Again the excellent EBC Greenstuff pads will take some beating under most driving conditions.

Another part of the braking set up which is often overlooked is the brake fluid. Replace the fluid with top DOT 5.1 quality fluid, preferably every two years max. Avoid the full race silicone fluids for a road car because they need regular (read constant!) bleeding and they cost the earth. AP Racing AP600 is good stuff and not too dear (see BG Developments). Always buy more than you need, and flush the system fully before finally bleeding the brakes. I normally re-bleed the brakes again a after weeks use, just to be sure.

The rear brakes are pretty good anyway as they are sourced from the Ford parts bin (Escort van and various Sierras). Although not the trendier disc brake variety, the car only weighs 850kg soaking wet so you don’t need too much at the rear or it will swap ends under heavy braking. That said, keeping them in tip-top condition will help to avoid expensive bodywork repairs. Use only top branded brake shoes (Ferodo, Mintex etc) as at least you are getting a known standard of material rather than something that will last 200,000 miles or 3months and down-to-the-rivets. For those of you that really want to max the performance of the engine, you can change the rear wheel cylinders to the ‘larger’ diameter piston variants from a Sierra estate. These are 22mm pistons (If I remember correctly) as opposed to the 19mm versions fitted to the SS1 as std. This will give slightly improved braking but should only really be used with the vented disc conversion on the front or else it may ‘un-balance’ the cars braking set up. Rear discs are really overkill on an SS1 unless it’s an out-and-out racer with huge front discs. Raiding a disc equipped Sierra will do the trick, but stick with the smaller Sierra non vented variants, rather than the Cosworth variety. Mods are required to the rear wishbone to mount the calipers and the handbrake will require some thought too. The Sierra rear hubs will also need to re-drilled to the SS1s Vauxhall/VW 100mm PCD wheel stud pattern, rather than the Sierras 104mm (I think).

Last but not least, change the flexible rubber brake lines to the much better Goodridge Aeroquip stainless steel braided hoses. These will ‘firm’ up the brake pedal feel and just give a little more confidence in the cars stopping ability, especially for track work. As most SS1s are now 15years+ old, new hoses should be seen as good housekeeping anyway, and the braided versions aren’t much more expensive than original equipment Reliant versions anyway ( if you can find ‘em). Seejoc will help on the braided hoses, discs etc.

Buzz words    safety, balance   



The SS1 is blessed with very good handling as standard so long as the components are still in good nick, so its really down to the individual as to how far they go to improve the handling further. In my opinion, the improvements should be balanced against what you are going to use your beloved SS1 for. If its your daily driver (as one of mine was for 11 years and 192,000miles!), then you will soon get fed up with a ‘full race’ set up, whereas a sprint racer/track day warrior wont be interested in a silky smooth ride.      

The front shocks are usually where most people find the biggest problems. The factory std Monroe-made shocks are junk and should be used as paperweights or door stops but shouldn’t be fitted to any car that will be driven in anger (or just driven really!!). A piece of Reliant parts bin economics I suspect. Speak to any of the marque specialists and they will back me up on this one ,and probably sell you either Spax or Avo adjustable damping versions. At the last count, they were only a couple of quid more than the nasty Monroes. Both makes are very popular, with the Spax variants the best known. For a road car, there’s little to choose between the two makes, but for sprinting, I prefer the AVO’s. They seem to be a little more competition orientated in the valving, and if you call the factory in Northampton, the ladies on the end of the phone are really helpful, not to mention pretty in the flesh too (Ah, the joys of the Autosport show at the NEC!!).

Setting of the damping adjustment is really a matter of personal preference, but road type, tyre size, grip levels, and other suspension mods will also affect your choice. Personally, I can put up with a little ‘scuttle’ shake and a slightly firmer ride than std to give that sharper steering feel and extra stability under braking. Start at about damping of the given settings (no 4 of 16 positions, 6 of 22 etc) and work your way stiffer until ‘your’ settings are arrived at. Too soft and the car will pitch too much under heavy braking, and too hard and the front of the car will feel ‘vague’ and ‘push wide’ (understeer) in the corners. Try to balance the car front to rear. If adjustable rear dampers are fitted, then greater front damping settings are possible than with std rear shocks. Too much, or too little damping at one end or the other, makes the car twitchy and unpleasant when driven briskly. Playing with shock settings is free and will enlighten the driver as to the cars handling characteristics, which is always useful when that idiot pulls out on you and evasive manoeuvres are required.

Rear shocks on the SS1 were again sourced from Monroe but actually seem quite good for an unmodified road car. They work well with adjustable fronts if in good condition, but for those into spirited driving, then adjustable rears are required too. Always get the adjustable spring seat versions as these can be used with a wider range of rear springs including the SS1s originals (NOTE:- adj spring seat shocks aren’t permitted in all RSSOC Sprint classes---check the regs). The shock bodies are threaded with a collar that allows the spring to be raised or lowered, which raises or lowers the cars rear ride height accordingly. This is useful if you live in city centre London with the GLC traffic calming (or driver enraging) speed bumps, or you tour in your SS1 with the boot full of bags and tent. As with the fronts, damping rates will depend on your driving requirements, but remember the suspension mantra-‘Balance’.

For the fast road enthusiasts/sprinters out there, more can be done to improve the handling further, although we do start to sacrifice ride quality a little.

Changing the suspensions bushes on the lower front suspension arms for Superflex poly bushes will certainly tighten up the cars response and steering a little although their use on the upper wishbones is nice, its not as necessary as the lower arms. Std lower bushes on a racer with uprated brakes and stickier tyres will wear out std bushes in a couple of months.

A cheap trick with the front anti-roll bar is to tighten the nut on the top of the long drop link bolt ( about 6" long) which links the anti-roll bar to the lower wishbone until about 15mm to20mm of thread is visible poking out above the nut itself (a couple of threads is factory std). This compresses the 4 (2 upper,2 lower) rubber spacer bushes and removes any ‘give’ before the bar starts to resist the chassis roll. This has the effect of sharpening steering response, a bit like quality tyres as opposed to remoulds. It does have a downside though. The long bolts that run through the links themselves have a habit of breaking anyway (common on the Vauxhall Chevettes and Mantas that the suspension is based upon too), so checking them every month or so is required. This involves winding the car onto full left hand steering lock and reaching into the wheel arch and pulling the anti roll bar upwards. Repeat for the other side. Check that the link is still attached. No need for a jack, just 30 seconds per side. Simple.

The next area for attention, are the spring rates. The front suspension is based upon Vauxhall Chevette components,  and this is where the problems start. Although uprated Chevette springs are available, they are too long, and increase the ride height too much, so custom made springs are required. For normal fast road use though, you can get away with cutting the standard springs down a little though, especially if you have the adj. spring seat rear shocks to ensure correct ride height front and rear. Now before you all moan and groan about cutting down the front springs as a ‘bodge’, I’m only suggesting 1.5 coils from the overall length. This will drop the ride height by approx. 15mm, and as shortening any spring for the same given wire gauge actually increases the rate slightly, it actually has the effect of ‘stiffening’ the ride by about 5% too. And it’s free. Win, win in my book. You can also remove the very hard rubber ‘top hat’ from above the spring that seats the spring to the chassis cup. This spacer helps to isolate the chassis and cabin from a lot of vibration and ‘noise’, so not ideal for a daily driver.

The next stage is to have custom made front springs made. If you supply the cars original spring rate (180lbs/in), their ‘free’ length as removed from the car, their ‘weighted’ length at rest as fitted to the car and the cars existing ride height at rest, then a spring specialist (see supplier list for details), will be able to create a custom spring giving whatever rate and ride height you require. As the cars have a reasonably low ride height anyway, don’t go overboard on the lowering side if the cars going to be a daily driver, but dropping the car 25mm-35mm for fast road/track use will improve things no end.

The spring rate is the next thing that you need to decide upon. The std rate is (I believe) 180lbs/in, which means that to compress the ‘free’ length of the spring by 1”, you need a load of 180lbs. On one of my sprint racers, I have used front springs with a rate of 400lbs/in. It radically improves the handling, but is too stiff for ‘Ol Blightys ‘B’ roads. I would suggest approximately 275-300lbs/in for a fast road spec car would be fine. Its your call, and again depends on what you require from your SS1.

Another consideration is the model of SS1 too. The 1300/1400/1600 SS1s are the lightest with the front end of an 1800Ti approx. 30kgs heavier due to the turbo and all its ancillaries. The SSTs and Sabres however, are significantly heavier due to their one-piece fibreglass bodyshell construction. These cars can be 100kg (yes apparently!!) heavier, so again this will affect the spring rate required. Most of the extra weight is biased towards the front of the car though.

The rear spring rates are much easier to sort out, because the cars use the ‘coil over’ design of shock absorber. This allows the spring to be mounted over the outside of the body of the shock itself. The rear springs are of an industry standard 1.9” internal diameter and are readily available from any motorsport supplier in 1” increments. I would suggest 8” or 9” 200lb/in rears on spring seat adj. shocks for road cars is about ideal. Most sprinters have used 200lb/in on the rear too, reasoning that slightly uprated springs aid traction away from the start line. This is true of course, especially as the SS1s never came from the factory with an LSD (limited slip differential), but if your car uses wider tyres and or has an LSD, my preference is for between 240lb-275lb/in rears. It may reduce traction off the line due to the reduction of weight transfer, (the cars natural nose high/tail low stance when launching hard from a standstill), but personally I prefer to trade a little off the line for greater chassis control in the corners. No races are won at the start line, but plenty are lost in the corners.

The rear of the car uses a single trailing arm each side along with the aforementioned coil over shocks. It’s a commonly used setup and can be found on lots Blackpool Scimitars too (TVRs). The trailing arms themselves are over-engineered for such a little car, so no worries there, but just check them for corrosion. The metal that ‘folds’ around the bearing hub maust be checked carefully, as corrosion here can cause the welds to fail disasterously. An hour with a wire brush and some Hammerite paint will keep them tip-top. They are each mounted to the chassis with two large bushes. I have never seen one worn out, although I’m sure they must degrade with time. Give them a good check over, and replace if necessary. I believe that Superflex will be offering these in polyurethane soon.

Both the front and rear anti roll bars have rubber bushes that mount the bars to the chassis. Again our friends at Superflex offer polyurethane alternatives, although a little modification with a sharp knife is required for the rears. Both ends are quick and simple to replace.

I believe that the front tracking should be set at straight ahead (no toe in or out) as it was from the factory, certainly for road use anyway. If you want to improve the cars turn-in on the track though, I favour a little toe-out. It makes the car wander a little in a straight line if the steering wheel isn’t held tight and tramlines, but does make the steering a little sharper. Some people have suggested that a little toe-in does the same thing, but I haven’t found that to be the case.

The camber of the wheels has quite a large effect on the cars handling. Camber means the amount that the top of the tyre ‘leans’ in or out relative to the bottom of the tyre. We are only concerned with negative camber (tyre leaning in at the top) as it improves the tyres ‘contact patch’ with the road during cornering. In real terms most cars have to 1 degree of negative camber on the front wheels to aid turn-in and grip under load in the corners.

The front suspension, as mentioned earlier, is based on Vauxhall Chevette components. This allows us to use a trick developed by Bill Blydenstein who prepared the ‘works’ Vauxhalls for rallying and the track too. The front upper wishbone balljoints mount through the wishbones via two bolts. The balljoints themselves are eliptical in their design, and as such can be mounted either way around. If they are turned through 180degrees, it increases the negative camber by about to of a degree. For more camber increase, slot the mounting holes in the wishbone which will allow more still.  For the track, more camber can be used on the front wheels, but it really depends on what tyres you are using, road tyres, race tyres or slicks. The cars ride height and the amount of chassis roll will also have an effect. More camber, with a little toe-out and race tyres will make the steering very heavy too, and effect its ‘self centring’ tendencies.

The rear of the cars camber is fixed from the factory due to the trailing arm design, but some roll induced camber is built into the design due to the chassis mountings for the trailing arm being of different heights inboard and outboard. Reducing the rear ride height of the car with adjustable spring seat shocks naturally increases the negative camber. Check that both left and right rear wheels have the same amount of camber.

A 10-15 year old Scimitar will probably be out as compared to how it left the factory anyway, so get it checked out at a decent tyre specialist. Try to pick  a garage that has 4 wheel laser alignment equipment and pick the old boy rather than his spotty YTS assistant. He will probably be more sympathetic to your cause, and more experienced too (Boy don’t I sound like an old fart?!). 

The front upper wishbones were the subject of a factory update at some point. The wishbones are std chevette with the addition of the ‘pushrod’ bracketry which gives the SS1 its distinctive front suspension layout. These brackets are welded to the steel wishbone pressing and operate through the inner wings into the engine compartment and onto the shock absorbers. Unfortunately the pushrod is only attached to the forward facing part of the wishbone. This causes the wishbone to twist and can cause the wishbone to break around the balljoint area. Reliant beefed up the underside of the wishbone pressing at some point. Check the wishbones fitted to the car, if they aren’t beefed up, then modify or replace them with later ones at least. In my opinion this should be done to all SS1s and not just those used for enthusiastic driving (I’ve broken two on different cars on the road!! Not nice).

The next stage of modification for the front wishbones, is to brace the wishbones further. Run 30mm x 18mm box section steel from the rearward upper bushing mount up to the point that the shock mounts to and weld in place. This triangulates the load from the damper into the whole wishbone assembly. It’s standard race car engineering practice. This last trick also allows the use of coilover front shocks too.

By using 1.9” adj. spring seat coilover front shocks with 8” 1.9” ID springs, you can bin the std. front springs and have a huge range of spring rates available to you. I’ve used this method on my racers and it works a treat. Ride height can be adjusted in seconds (yes really) and simplifies things too. If your going to buy new shocks anyway, why not try this method.  The only thing to note though, is that to achieve the same suspension spring rate at the wheel (known as the wheel rate) as a setup with the springs in the original position, you must use a slightly lower poundage spring. As an example, I used 400lb/in springs on a sprinter in the original factory position between the wisbones, but to achieve the same rate when using the inboard coilover design, I needed 350lb/in springs. The reasons for this is due to the slightly different lengths of the wishbone pushrod relative to the mounting point on the lower wishbone. I used the excellent information in the book Race and Rally Car Data Source Book by Allan Staniforth. This guy is the absolute guru when it comes to race car chassis and suspension design, and luckily for me his personal area of expertise is sprints and hillclimbs. 


Buzz words  balance, adjustment




Ford 4 & 5 speed

Most of the SS1s use Ford gearboxes from Sierras, either of the 4 speed or 5 speed variety. The 4 speed is generally fitted to the 1300s and as such is unlikely to be used as a fast road car, although uprated clutches and gearshifts are available. We will concentrate on the 5 speeder. It is the Ford Type 9 variety and is fitted to many competition-based cars. It’s very cheap, strong and reliable with a decent gear change action too. There’s no real need to modify it in anyway for anything other than track use unless you’ve have really upped the power output of the engine. If you experience a sloppy change, remove the gear stick and check out the strange shaped black plastic moulding that fits between the ‘fork’ of the gear lever and the selector rods. They cost about 85pence and ensure that change is accurate. A damaged one can lead to selector fork damage leading to the entire gearbox needing to be removed.


For those wishing to get the most from their gearbox with an uprated engine power output, then an uprated clutch will be in order. Helix Autosport will advise you, or mixing and matching clutch covers and plates from the Ford range of more powerful cars using the Type 9 will do too. Whilst the clutch is being replaced, take time to have the engine flywheel re-faced and lightened and balanced too. Ensure that a specialist does this ( such as Burton Power, Autosprint in Birmingham) as too much material machined away, or incorrect balancing, will cause the flywheel to shatter at high RPM with dangerous results. Ask anyone that has had a flywheel lightened though, and they will confirm what a difference it makes. It makes the car feel snappier and more aggressive during hard acceleration as 1kg from the flywheel, is like 50kg removed from the chassis.

Another fast road/track only mod is to replace the gear lever with one from the transmission wizards at Quaife Engineering. At about 60 its not cheap, although I picked mine up for 30 from the classifieds in Motorsport News. It’s a quality piece of engineering using a rosejoint to replace the ‘ball and cup’ arrangement of the standard. It reduces the required throw of the lever between gears dramatically and removes any vagueness from the shift. It is a ‘no grey area’ shift, its in or out of gear, no more missed shifts mid corner.

Quaife and Tran X are really the main protaganists for a full blown competition Ford based box. Both do ranges of gear ratios for all sorts of applications, generally giving a ‘longer’ first gear, and closer ratios thereafter. They are often of the straight cut gear variety too (rather than the road car helically cut versions) which offers greater strength but makes them very noisy and promotes transmission ‘shunt’ at low speeds. Not pleasant for a road car.

Nissan 5 speed


The other gearbox used in the cars, is the Nissan 5 speeder from the Nissan Silvia turbo. This unit is pretty bulletproof and will handle 300bhp with ease. The only weak point for a fast road car is the clutch unit. If your turbo engines is putting out 165-180bhp, then the clutch will almost certainly complain. Again, clutches don’t last forever, and if you like to be away first at the traffic light Grand Prix, then replace it with one from the S13 Nissan 200SX coupe. This car used a 16v twin cam variant of the 1800 engine which put out 167bhp as std, but used the same gearbox. Don’t scrimp on the clutch unit, fit the plate, cover and thrust bearing from the S13, and don’t buy some brand you’ve never heard of, buy nissan or a recognised brand. For further hi-power output engines then Helix Autosport can supply uprated covers and trick organic plates. If you are going to sprint the car with 200-300bhp, then AP Racing produce a 4-paddle plate which will take real abuse, but isnt that great in terms of smoothness of take up in traffic. It would soon annoy with its juddery low speed antics. Having spoken to AP, they make two versions of the 4 paddle clutch, one with a 6 spring centre and a fixed centre. The fixed centre isn’t ideal for sprinting as all the transmission shocks from the ‘tyre warming’ and constant hard standing starts would put even more strain on the diff and propshaft. The sprung centre is still very harsh compared to a stock clutch plate, but may stop you needing new driveshafts every year!

The other clutch component to be looked at is the clutch cover. This only really needs changing to an S13 item for up to 250bhp for road use, but for sprinting Helix offer an uprated cover that’s rated to 289lb/ft of torque (part no 60-4656) and is available from Mardi Gras Motorsport at the Silverstone Circuit industrial estate  at 189-92+vat. Its probably ideal as a bullet proof road cover too. The ultimate cover though comes again from Nissans own competition department, Nismo. This beastie is available from Apex Performance and is said to be ideal even when running up to 450bhp when used in conjunction with an AP Racing paddle clutch plate whilst drag racing on slicks! I have one fitted to my sprinter but haven’t used it yet. I suspect it may be a little heavy in operation.

Gear shifters

The aren’t many decent gear shifts available for the Nissan ’box, and they tend to cost the earth! 165 is a lot of bread for the Nismo version (Nissans factory tuning department). I haven’t used one, but Bren from Apex Performance in Bradford will take your money of you if you feel the need.  There are alternatives made by B&M Shifters from the USA and an OBX version (Apex Performance, Bradford for both). The S13 guys tend to rate the B&M but the OBX is little better than a good nick stock setup. Eddie Ratley at DatMan has some very cheap B&M replicas that are under 40 and seem to be the business. Cheap and slick.

At the other end of the scale is the Ikeya.F1 Sequential Shifter which converts the std nissan box to a full race car sequential shift. This means that instead of the std ‘H’patern gate, its just push away to go up a gear and pull back for down a cog. Cool eh? Theres an optional digital gear indicator which tells you which gear you are in too. The down sides are that for a road car it’s a bit bulky and would spoil the look of the interior. It stands about 8” high plus the short stubby gear lever, putting it high up and near the steering wheel as is the current vogue in the race and rally world. Great for a racer but at odds with a road car interior. The other slight problem is the price tag of 120,000 japanese yen. At current exchange rates, that’s about 680!! Nuff said…..  

One last thought on the Nissan Gearboxes, later 200SX’s, called Silvias too, use a 6 speed gearbox which is of similar dimensions and attached to the later SR20ET 250bhp turbo engine. These cars aren’t widely available in the UK, being import only I believe, but various companies bring them in at not unreasonable prices. From the research I have done so far, it seems to be of similar dimensions, but a slightly different ‘shape’. I have no idea whether it would fit in the SS1s transmission tunnel, but a few hours with a tape measure and a few calculations may get you a unique 6 speed SS1 Turbo!


All  SS1s use the Ford 7” differential from a Sierra estate. It uses tri-lobe CV joints and Reliant’s own driveshafts. They are pretty well bullet proof, and maintenance free, even with 250+ bhp.

Back to the diff, it came from the factory as an ‘open’ (non-Limited slip variety) with a 3.9:1 ratio. With the Ford 5 speed gearbox and 1600cc CVH engine, it gives a lovely set of ratios, that suits a small sports car really well. With the Nissan 1800 engine, the ratios aren’t quite so good, but this more to do with the gearbox ratios being a little poor but the torque of the engine when the turbo is spooled up overcomes the gearbox ratios shortcomings. It does make 1st gear feel a little ‘short’ though.

The diff will go on an on, with little chance of damage. They tend to whine a little when 100,000miles plus, but will never break. Breakers yards are full of Sierras, so replacements are cheap and plentiful.

For road use the std ‘open’ diff is fine, giving the car an easy to drive quality, with the car spinning an inside rear wheel in a turn if too much throttle is applied. One wheel spinning in the wet from the lights  is again common. If the car gets tail happy again the diff comes to the rescue and ‘diffs-out’, spins one wheel harmlessly and stops or limits the slide. That’s all very well and safe but for serious application o the loud pedal, a limited slip diff is required. The guys and girls at Quaife Engineering again come to the rescue with one of their world famous Automatic Torque Biasing (ATB) diffs. There are various sorts of LSDs on the market, and they all have their own merits. The Quaife is of the Torsen (torque –sensing) variety. Unlike some LSD’s  (Tran X etc) they don’t have plates to wear or need occasional re-shimming, but use spirally cut gears. The theory is that it operates as ‘freely’ as an open diff during normal cornering, but wont allow the inside wheel in a turn spooling out of control. It will allow some wheelspin across the axle, but not too much. Its just as usable on the road as the track. At 500ish its not too bad price wise, given that its not likely to ever need replacing and only the occasional oil top up.

Tran X make ramp and plate style diffs which is the traditional method of LSDs. They are really a competition only style unit, but do have the advantage of being able to be stripped and re-shimmed to give varying rates of ‘lock-up’ and tension. Looser diffs are progressive in terms of lock up but my still allow a little too much ‘diffing-out’ on the exit of tight turns when hard on the throttle. A tight diff makes the car odd at low speeds and makes the car rather tail happy out of corners. 

The other alternative is a real ‘parts bin’ special. Ford never produced a 7” LSD that accepts the tri-pod driveshafts for any of their road cars cars, so a little lateral thinking is required. Steve Kent was the pioneer of this conversion which uses a Ford Viscous Coupling LSD. A VC diff uses a fluid filled ‘cartridge’ inside the diff to add the pre-load to the sun and planet gears in a similar way a plated diff. Its ‘tighter’ in its action than the Quaife, and does ‘lock’ during high loads (it doesn’t actually lock but to all intents and purposes it does. On the road you will notice an instant difference, with the car feeling tighter at the rear at parking speeds, you can hear the tyres ‘chirp’ on gravel car park as the VC resists the diff action. Under hard acceleration it really does its stuff, transferring equal torque to both sides of the axle. This will drive the car forward with more urgency, but does make the car more tail happy in the wet.  I have used it on sprinters since with excellent results. Its possible to alter the diff lsd action by recharging the viscous cartridge, but theres not many places that can do it. Dome Motorsport, now part of the TAL Group are experts in this field. They can also supply uprated internal gears too, although these aren’t likely to be needed on SS1s as they are designed for 300+bhp Group A Escort Cosworth Rally cars.

Fitting a Sierra Viscous LSD

Find yourself a sierra 2.0 XR4x4 car and remove the diff from its cradle, along with its inboard driveshaft CV joints and  assorted E rings. Remove the SS1 diff by removing the boot floor liner, and one side trailing arm assembly (not as big a job as it sounds with the boot floor out for access). Drop the diff cradle and slide out both tripod driveshafts from the diff case (it may be easier to also remove the fuel tank straps and turn the tank through 90degrees to allow access to the single rear cradle mounting bolt ). Turn your attention to the driveshafts of the SS1 now. Cut away the rubber gaiter, and use tin snips to open up and peel back the tin shroud for the tripod CV. Don’t worry because you are going to throw them away anyway. Remove the cup and finally the C rings that hold the tripod centre to the splines of the shaft itself. Try not to damage these rings because you will need them later. Keep hold of the 1” stiff springs too as these will also be reused. By now you will be sick of black molybdenum CV grease and the smell of EP90 diff oil, but it will be worth it.

Now for the Sierra XR4x4 diff and shafts. Remove the CV joints from the shafts, again keeping hold of the C rings, bolts, lock tab plates etc. A Haynes manual is useful for re-fitting the CV joint in the correct sequence. Ensure that the components are all cleaned thoroughly and packed with the correct spec CV grease. Essentially the later CV joints fit onto the driveshaft splines in the same manner as the original. Use whichever C rings allow the fitment of the CV onto the driveshaft (some are ‘thicker’ than others). Once the CVs are assembled onto the driveshafts, the short, stiff springs can then be inserted between the CV joint and the diff flanges. The long cap head Allen bolts can then be tightened up. One tip it to dispense with the paper gasket between the diff flange and the CV joint, as they compress with time and allow the bolts to become slack. Once tightened correctly, the whole diff assembly can be bolted back into the cradle, and raised back up into the chassis. A smear of silicone sealant around the joint of the diff flange and the CV joint will take the place of the discarded paper gasket and stop the CV grease seeping out. A bit of red paint on each cap head bolt to lock plate will ensure that you can tell at a glance if any of them are coming loose (due to the paint marks no longer lining up).

Once the diff is installed, top up the oil level and its ready to use.


Which ever type you decide on is up to you and your requirements obviously. I have used both for sprinting, and cant fail to be impressed by the quality of the Quaife and its smoothness of operation, but feel that the agressiveness of the VC suits the ‘press on, tail happy’ driver better. The Quaife is easier in the wet to master, but may lack the ultimate in traction in the dry if you are running a really powerful car. Your call.



Buzz words  strength, reliability



 The biggest change to the way the car looks will also be one of the biggest changes to the handling too. A decent set of 6.5” x 15” alloys using 195/50 x15 tyres will endow the SS1 with modern day handling and vastly improved looks with the only down side being a little more road noise and slightly harsher ride. Unless you need limo-like ride quality, forget 13” or 14” wheels. Performance tyres are ten a penny in 15” and very cheap too. I pay approx. 34 per tyre for Yokohama A539 V rated tyres fitted. Now as these tyres are the leaders in road race tyres with most sprinters that cant be bad. As a comparison, the 14” variants are 2 dearer! Most car accessory dealers offer ‘packages’ of 4 new wheels and 4 tyres. Expect to pay 299 to 350 for a complete new set with Yokohama or Toyo tyres. Avoid cheap branded tyres, they really have no place on a sports car. For any SS1, any wheels that will fit a Volkswagen Golf GTi  Mk 2 with an offset of ET35 and no more than 6.5” width will be fine. That said 7” wide will fit with a little “adjustment” of the rear wings and inner arches. This is pretty easy as the inner arches are riveted to the wings themselves, but bolt to the boot floor liner rather than the chassis. If you open the boot and check the boot corners, you will see a single bolt that fits through the floor and into the inner arch moulding. If you remove this bolt and then pull the wing outwards and re-drill the hole and re-insert the bolt, the rear wings can be ‘flared’ by approx. 25mm+. For more than this an extension bracket will have to be made up. This mod produces a lovely subtle flare that’s barely noticeable unless your SS1 is parked next to a stock version.

If further clearance is required for competition purposes, then its possible to remove the wings from the steel box section frame and then space them away with wood or plastic box section and re-attach with longer bolts. It doesn’t really do a lot for the panel shut lines, but then how many SS1s have got decent shut lines from the factory anyway? Its not a problem for a racer though.




1300/1400/1600 Ford CVH

The Ford CVH engine was chosen by Reliant as a relatively light and compact unit to power their SS1 cars from its inception. The 1400 version is a later type of the ‘lean burn’ variety, which isnt much different in terms of performance to the 1300, but had improved emissions, efficiency etc. The 1600 is the version as commonly found in the Fiesta XR2 and produces 96hp, not exactly likely to worry a Ferrari, but definitely enough to put a big grin on the drivers face.

For those wishing to improve the performance of the venerable CVH, my first suggestion is to ensure you are starting with a 1600. If you have a 1300, get a 1600 engine from the breakers yard and fit that. The bhp gain over the smaller engines is significant, whilst the impact on your wallet isn’t huge. That said, all CVHs are essentially tuneable in the same manner, larger carb(s), modified heads, hotter camshafts etc, but lack of tuning parts made specifically for the smaller capacity engines makes them an unrealistic proposition.

Haynes, the famous ‘manual’ publishers, produce an invaluable book detailing all areas of CVH tuning, and for those intending  on uprating their engine, its an essential read.

The first place to start is to ensure that the engine is in good condition. Any form of increased performance is only possible on a good engine. Hard earned money spent tuning a clapped out engine is pointless.

The engine should be treated to good quality semi-synthetic oil and regular oil filter changes too. Always use ‘engine oil flush’ at each oil change too, as the CVH is particularly susceptible to problems with dirty oil primarily due to the cams hydraulic lifters. Clean, quality oil will keep your engine in tip-top condition.

Ok, so your engine is good to go, so what’s first to play with? Pretty traditional stuff really, but the air filter can be replaced with something ‘sporty’. Replacement elements are available that fit into the original pancake style housing. The more popular route though, is to use an aftermarket ‘pancake’ filter. These replace the original filter and its plastic housing. K&N’s offering wont need replacing for 100,000 miles, is more efficient and produces a lovely induction roar.


A Weber 34DMTL is a more performance orientated carb, that can cope with the fuelling requirements of an engine that can produce up to 140bhp. Weber and I think even Ford dealers used to sell them at one time as a conversion with the corresponding manifold. These are probably rare or even discontinued now, but help is at hand. The carb was fitted as std to some Lancias and even Land Rovers, and by using a manifold from a XR3 and spacer plate you can achieve the same thing. The spacer plate is a hard, non-metallic gasket approx. 20mm thick that isolates the carb from the heat of the engine, which could be transmitted up through the engine into the inlet manifold and then up to the carb. This unwanted heat transfer can cause problems with fuel vapourisation especially in hot weather, or hot starting. The spacer helps to stop the heat soak.

Next up in the fuelling stakes would be to ditch the single carb for twin carbs. A popular set up is twin 40 DCNF carbs. These are of the downdraught variety and fit straight on with a suitable manifold from Demon Tweeks or Burton Power. Some modification to the throttle/choke linkages will be required. The DCNFs are getting rare too now, but a common source is the MG Montego which had them as standard. Re-jetting may be required depending on the engine spec. The 40’s give a lot more grunt at midrange through to the top end. They are capable of fuelling to 160bhpish.

Finally sidedraught DCOE carbs are required. In an SS1 there are clearance issues with the bulkhead and brake servo, but these can be overcome if necessary. On a full race engine 180bhp is possible, revving to 8,500rpm, but this is VERY expensive to achieve and virtually un-driveable on anything other than a track.

For outputs above about 120bhp a better fuel supply is needed. This will require an uprated electric fuel pump to replace the std mechanically driven one (which will need to be remove and a blanking plate fitted to the head from Burton Power). Facet make a whole range from solid state pumps for fast road use to full competition specs that will require a fuel pressure regulator. This is required to stop the pump from flooding the carbs and float chambers at idle/low throttle applications. The Malpassi Filter king acts as a regulator and quality fuel filter.


The engine can now draw more air via the filter, and add sufficient fuel to it, so a performance camshaft is now called for. A performance cam generally has increased valve lift and duration. This opens the valves more, and for longer. Cam choice is a little complicated because you have really got to decide what you expect from the engine and what its going to be used for. You don’t want a full race cam with a power band from 5,500rpm to 8,500rpm if the rest of the engine is stock, and you want good fuel mileage. Conversely a std cam in a wild spec engine wont realise the maximum bhp potential. Piper and Kent offer cams and cam kits ( recommended as they include new length/uprated and valve springs etc) in a variety of specs to suit all needs.

The CVHs come with maintenance-free hydraulic cam followers. There are two types of these depending on the head. At high rpm (6,000+) the oil in the follower ‘bucket’ can become aerated and froth. This causes the follower to not do its job properly and cam or valve damage is likely. Later followers are known as ‘anti-pump’ followers, and they reduce they likelihood of this. They are safe to 6,500rpm. Using decent quality engine oil and changing it every 5,000 miles or less if the cars used hard, will safeguard against this too.

 For full race or high rev engines, use solid lifters instead of the original hydraulic ones. These are available from your Ford dealer as a spare for the rare Escort RS1600i  car or from Kent/Piper/Burton Power.

Cylinder head

Cylinder head modifications are next on your shopping list. As with cams, these need to be matched to the final spec of your engine and its intended purpose. Stage 1 tuning generally consists of opening up the inlet and exhaust ports a little and smoothing the passage of the fuel/air mixture through the head. Stage 2 is bigger valves with more porting and preferably 3 point valve seats. Stage 3 is full race with huge valves and porting.

An uprated oil pump is good idea too. Burton Power supply these quite cheaply.

An oil cooler is required at stage 2 levels and above. As the output of the engine goes up, so does the workload for the lubricant. The original oil filter is removed and a sandwich plate put in its place. Use a thermostatically controlled sandwich plate so that the oil cooler is bypassed until its required.  Due to the chassis rail proximity, the original filter wont fit as its now too long. A shorter filter is required, I have used the filter from the SS1 1800Ti. Mount the cooler somewhere where they will be air flow, but not where it’s likely to get damaged. In front of the radiator behind the mesh panel is ideal. Fast road spec engines will require a 10 row cooler with more rows for full race motors.


Nissan 1800 turbo engine


Reliant were forced into fitting a more powerful engine into the SS1 after the car was universally criticised in the motoring press for being rather lethargic with even the 1600CVH engine let alone the 1300. It was a little unfair as they were after producing a spiritual successor to the MG Midget etc rather than a high performance sports car a la Lotus etc. The excellent chassis balance also begged for more grunt.

The story goes that the R&D guys at Reliant looked at dropping the turbocharged and fuel injected  1600CVH from the Escort RS Turbo into the SS1. Although the logical choice, the inlet manifold and plenum of the turbo’d 1600 was rather large and would have required major surgery to the bulkhead and tub costing money I suspect Reliant didn’t have, so an alternative was needed. Oddly, it was Nissan that proved the solution.

The Nissan 1800 turbocharged and fuel injected CA18ET engine from the Silvia ZX Turbo came to the rescue. The engine fitted with minimal hassle, being of similar dimensions to the Ford engine and gearbox. It produced 135bhp with a Garrett T2 turbo which was the same as the Ford Turbo but with a bigger turbo(T3 ). All this at only 6psi of boost. With Nissan legendary build quality and longevity, it proved an ideal choice.

Fast road spec tuning

All improvements to the engines performance are only to be attempted if the original engine is in tip-top condition. Ensure that the engine is treated to top quality oil and filters changed at 3,000 mile intervals irrespective of what the spotty youth in Halfords tells you. Always use a fully synthetic oil of reputable make as turbo engines are notorious for giving their oil a hard time. Mobil 1 0/40w is ideal for engines that are under say 90,000 miles, but for higher mileage or competition engines, the 15/50w Mobil 1 or Castrol RS 10/60w are better. Never scrimp on the oil, the Nissan CA18 bearings are about the only things that routine fail on high mileage, neglected Nissan cars, but regular oil changes will prevent this. I ran an SS1 for 142,000miles with no wear problems at all. 

As far as modifications are concerned to improve the performance, its all pretty basic stuff.

Stage 1, involves a K+N filter panel to replace the stock paper panel, removal of the std Nissan ‘pop-off’ valve,  a turbo boost bleed valve, some colder spark plugs and a turbo boost gauge. The bleed valve is fitted in the rubber hose from the turbo compressor housing to the wastegate actuator. It essentially “ cheats” the wastegate into thinking that it is only seeing the standard 6psi of boost (6psi above atmospheric pressure). The boost gauge is necessary to ensure that no more than 10psi of boost is used at this level of modification. The fitting of “colder” spark plugs stops detonation (pre ignition) which could easily damage the engines internal components. The final job is to remove or weld up the pop off valve. This valve is fitted to the inlet plenum and releases excess turbo pressure into the atmosphere as asafety measure. It is set to pop off at 7psi which without its removal, deems all the other mods useless. Its possible to unscrew it from the manifold casting, and screw in a std brass plumbing ‘blanking’ plug. This could be drilled and tapped to take the boost gauge take off if you wish. These few simple and cheap mods (approx 100), will add approx. 20-30  horsepower. This will make your SS1 1800Ti more than a match for the hottest MX5s, Porsche 924s, 944s, virtually all but the hottest hatches etc, etc, and will give you hours of fun in the traffic light Grand Prix! 

Stage 2 mods get a bit more involved in terms of parts, hassle and money, but the performance gains are even more impressive. At Stage 2, approx 180-200hp is the aim. All the Stage 1 mods are used (and in fact required) but the additions of an intercooler, more boost (approx 14.5psi) and retarded ignition are required. The std CA18ET engine was never fitted with an intercooler due its relatively low boost (6psi), relatively low compression ratio (8.5:1) and tiny turbo (Garrett T2), but for our purposes we will require one. The  basic problem with any turbocharged engine is that as the turbo forces the air into the engine, it compresses the air which heats it considerably. The hotter the inlet air, the greater the chances of detonation (extreme ‘pinking) which can bend conrods, blow holes in pistons etc. Its probably the biggest cause of engine failure in tweaked turbo cars. The intercooler is essentially an ‘air-to-air’ radiator which is fitted between the turbo and inlet manifold throttle body. The compressed ‘heated’ air from the turbo passes through the intercooler radiator matrix which then cools the air back to a more acceptable temperature before it enters the throttle body and then the combustion chamber. The intercooler is normally fitted in the front of the car as it requires a fair amount of high velocity air flow to keep the matrix, and thus the air charge, cool. In the case of the SS1 the choice of the type and dimensions of the intercooler you are going to use, will largely depend on what you want and need from  your particular car. An intercooler such as the ones fitted to the Ford Sierra Cosworth 2 and 4 wheel drive cars are very good in terms of design, they are alloy in construction, very low pressure loss and readily available. They could be fitted below the number plate in front of the mesh grille in front of the radiator for maximum air flow, but it does spoil the cars ‘original’ form somewhat and blanks off some of the radiators air flow  a more modern radiator fan such as the types that fit directly to the rad core from Pacet etc (see any kit car magazine for a huge choice) will overcome this.

Secondly and probably more practical, is to fit it in the engine bay where the spare wheel is fitted normally, fed with cold air from a bonnet mounted air scoop (think Subaru Impreza Turbo for inspiration). It does mean that the spare wheel will be lost, but then most Scimitar owners have some form of AA or RAC breakdown cover anyway don’t they!! or a can of that ‘Run flat’ tyre inflator aerosol can be used to get you home in the event of a puncture ( many TVRs and Lotuses don’t have spare wheels a std and just rely on this stuff, so it must work ok). The intercooler must then be plumbed between the turbo outlet and the throttle body. For the majority of the plumbing runs you should use steel or alloy tubing, with silicone rubber hoses for any joints or angle changes (Samco etc make huge ranges for the DIY turbo tinkerer available from Demon Tweeks catalogue).

The third method will suit the Scimitar purist and RSSOC Modified class competitor down to the ground. Fitting an intercooler again where the spare wheel is, but this time really low down, in fact between the chassis rails and fed with lovely cold air by a home ‘scoop’ from under the nose of the car. This may be a bit of pain to get it all in neatly, but it will ensure that the bodywork of your car stays untouched. The Cossie intercooler wont fit between the chassis rails without mods to the end caps but there is a Peugeot version which will fit. Again silicone hoses and metal tubing will complete the installation. So we can now keep the air charge cool, so we can turn the boost up to 14ish psi. Again this is set up on the road under load with your boost gauge. Re-setting the ignition timing to 15degrees BTDC should ensure its all A-OK on the spark front.   


Competition spec engine tuning

If you want the ultimate in performance then the car will cease to be as user friendly on the road and for every further 5bhp gained over the initial tuning stages, a lot more money is required. The law of diminishing returns Im afraid, but for those that are interested, read on……..

Block and head gasket

The CA18ET engine as fitted to the SS1 is the 8v forerunner of the CA18DET 16v engine as fitted to Nissan 200SX coupes. The blocks are very, very similar, but the DET has a few nicer features such as thicker, stronger conrods and oil spray jets that are fitted into the main oil galleries and ‘squirt’ oil onto the underside of the piston crown and conrod little end too. The thicker rods are good for 250-280bhp, after which steel forged rods will be required. The piston spray jets perform two important functions. Firstly, extra lubrication just where its needed, and secondly the oil cools the little end bearing and piston crown. The cooling of the piston crown also affects the combustion chamber temperature, which in turn reduces the onset of detonation of the fuel/air charge.

The other feature of the DET block, is its crank girdle. These are also known as  crank braces and essentially stop the block from flexing under very high power applications. The brace basically attaches all of the crank bearing caps toghether. If building an ultimate spec SS1 then its probably worth buying a second hand DET short block and using your original head etc. The crank is a little different than that of the ET so you will need to use the 8 hole flywheel of the DET and probably change the alterantor pulley to suit the wider flat crank pulley form of the DET too. The stronger rods, piston jets and crank bearing brace makes a cheap and simple basis for a 250bhp engine.

If, however you intend to race the car in the RSSOC sprint and hillclimb championship, then the DET block is out as is out of bounds in any class other than the full competition non-road car category. For the std and modified classes a crank brace is also illegal, but could be used for super modified class. For super mod, 200SX rods should be used, along with the crank brace, and the block machined to take the oil squirt jets. A lot of hassle but the only way to stay within the super mod regs.

The block of any engine that intends to run 18+ps1 boost, should also have the head surface wire ringed. This involves machining a tiny groove on the deck of the block (where the head gasket is fitted) around each bore, approximately 2mm greater diameter than the bore itself. This groove then takes a ring of mig welding wire into it. The groove should be only half the depth of the thickness of the mig wire, resulting in the wire protruding proud of the block deck. When the head gasket is fitted and then the head torqued down, the protruding mig wire exerts extra clamping force on the head gasket around the bore firing rings without having to increase the torque figure of the head bolt tension. The head bolts are of the ‘stretch’ variety and a s such should not be re-used on a serious engine build. Don’t over tighten the head bolts down thinking that they will stop the head gasket failing, because it wont. Use a mig wired block, new NISSAN head gasket not some cheaper pattern variety end new head bolts carefully torqued down. The head bolt threads should be carefully cleaned and dried, as should the internal head threads, then a small amount of engine oil applied to the threads. They shouldn’t be wet but just a little shiny. Excess liquid will stop the bolts from torquing down properly. A small amount of anti-seize compound applied only to the underside of the bolt head will stop the head underside from ‘picking up’ on the cylinder head and giving a false torque setting.

The Japanese tuners all favour metal head gaskets which do not require wire ringing of the block. These on the face of it are perfect because they don’t need any machining of the block to fit them and also come in varying thicknesses to lower the engines compression ratio. The only down side id the cost, 250+ for a head gasket seems a bit expensive to me when the mig wire methods have been used for years on race and rally engines in europe.

One more thing regarding head bolts is that if using the DET bottom end, you will need to use DET bolts which are too long when used in conjunction with the ET head. Don’t attempt to shorten them, but measure each bolt and get machined spacers to fit under each bolt head as required (this is due to parts of the DET head being ‘thicker’ than the ET 8v version).


Pistons and conrods

As mentioned previously the 200SX rods from the DET engine will be required for  serious engine, and you might as well use the pistons too as the little end arrangement is different from that of the ET. The ceiling for these components is 250-270bhp depending on who you talk to. After this it’s the pistons that will need looking at first. In fact for a race engine, forged pistons really ought to be used from 220 onwards really. Most forged pistons are rated at 400+bhp.

There are two easily available makes of forged pistons on the market in the UK. The first are JE pistons and these are available from Silvia Engineering (now called Nisstek I believe) in Maldon in Essex. They are designed as an overbore piston, the theory being that if your engine is 10+ years old, it will need a re-bore anyway. The JEs are usually supplied with a lower compression ratio (8:1)  which is ideal for running more boost too (std 8.5:1). They cost around 700 a set and include new piston rings.

The other make are Wiseco pistons. They are available from Apex Performance in Bradford for 329 for a set and again will require and overbore to 84mm (gives capacity of 1860cc instead of std 1809cc). They are the std comp ratio but do have deeper valve recesses for use with higher lift cams. The piston crown can be machined easily to drop the comp ratio if required.

All forgies as they are known tend to have a reputation for being noisy on start up. This noise is usually piston slap and is usually associated with old, worn out engines, but in this case it is more to do with the bore tolerances used and special  alloys used to make them.

Both the JEs and Wisecos will require DET rods or forged steel rods. If using DET rods, then ensure they aren’t bent and have them balanced along with all the other bits before using the engine (balancing covered later). Forged steel rods are the ultimate way to go, but as usual aren’t cheap either. Apex sell Pauter rods which are mega strong, suit the forged pistons, but cost 550 a set. Cheaper than the Nismo ones though, as they cost 800+!! The Pauter rods are rated at 500bhp+ and come with expensive ARP competition rod bolts as standard (normally 80-100 a set).



The flywheels as fitted by Nissan are very heavy by modern standards. This is due, I suspect, to the fact the CA18 in its normally aspirated form is used in many mundane saloons and even vans. For our purposes its too heavy causing the engine to be sluggish in spinning up and down in accordance with the throttle pedal. It needs to be lightened by machining excess material from the casting but it’s a job for experts rather than just any machine shop. Poorly modified flywheels are very dangerous because if machined badly or not balanced properly they can shatter, destroying engine and gearbox and possibly injuring the driver too. The flywheels should be lightened though from a performance point of view, but just ensure its done correctly. There are a couple of japanese manufacturers of alloy flywheels with steel clutch surface inserts, but expect to pay 450+ for these.

The flywheel to crank bolts should be replaced with new really and degreased and fitted with a little threadock too.



The crank should be checked for wear and being straight and true. A bent crank should be discarded, but a worn crank can be re-ground undersize and new oversize crank bearings (pref heavy duty—see Apex Performance) can be fitted. It must be dynamically balanced along with the other components before the engine is finished.



The CA18 ETs and DETs are renowned in Nissan circles for eating crank and conrod bearings. This may be true but is rarely the case with those used in SS1s. I believe that this is due to Scimitars being an enthusiasts car, and is more likely to be serviced religiously and using decent oil. A Nissan rust bucket is more likely to have its oil change intervals stretched and then probably have only cheap oil lavished upon it. This isn’t too much of a worry though as the bearings seem rather soft anyway, so if caught early enough, replacement of the bearings is often all that’s required, the crank often surviving the need for a re-grind. This good news in a way, as minter Nissans can be picked up for next to nothing with rattling shells, and make an ideal engine donor for us. The rest of the car can be broken and sold off to Nissan enthusiasts to cover the purchase cost of the car. Win, win I would say.



To my knowledge only Piper Cams offer a performance cam for the ET. This is part no. 446 and is of the 268 degrees variety, costing approx 139 as an exchange re-grind. As with most turbocharged engines, the camshaft profile isnt quite as important to the engines breathing capability as the fuel and air mixture is being shoved in under pressure by the turbo, but for a race spec engine it should be fitted anyway.


Camshaft vernier pulley

The purpose of the vernier pulley is to allow the camshafts timing to be altered relative to the pistons. This is of little use on a std engine, but is beneficial on a hot spec motor with a Piper cam so that the cam operating the valves can be set fractions of a tooth ‘out’ on the timing belt to give maximum power.

These pulleys used to be available off the shelf as an exchange item, but I’m not sure they are now. Myself and others have had them made by a machine shop relatively easily.


Cylinder head

As with cams, the head isn’t quite as important as a normally aspirated head where small changes in the head shaping make a big difference to power, but never the less, some work should be done. The basic head tidying can be accomplished by the competant DIYer with a high speed drill fitted with a flexi drive, some tungsten carbide grinding bits of various shapes and sizes, and some sanding/polishing drums too. The ET had was a multi purpose casting, being used in all manner of cars and vans, and as such was offered with 2 spark plugs per cylinder in some guises. This was more for emissions rather than power considerations, allowing the second spark to ignite any unburnt fuel in the chamber, and therefore cleaning up the emissions from the exhaust pipe. The idea is to remove the ‘lump’ in the combustion chamber where the second spark plug in each chamber would be and smooth and polish the chamber. Further polishing and tidying of the ports is possible without taking a lot of material away, but just removing casting burrs, lines and seams will all help, as will polishing out the rough casting surfaces in the alloy. Don’t go too mad as the head isn’t that thick in places, but cleaning up is perfectly safe to do.

Careful matching of the exhaust and inlet manifolds to the head itself is also easy to do and will only cost time on your part not money. On an engine that has been used, its easy to see the marks on the manifolds and head where they don’t quite match up properly. A little time and patience with the flexi drive in the drill will see this sorted out. Don’t forget to ensure that after all your hard work, you don’t forget to do the gaskets too. No use flowing the manifolds to the head, and then partially blocking the gases passage again with an ill fitting gasket.

For further levels of head work, its really best left to then experts. I believe that GBH Motorsport in Chesterfield have done some really good work on the ET head for someone that has a 400bhp 8v ET in a Nissan Silvia!! Now that’s gotta be fun! Head work at this level requires specialist flow bench equipment to ensure that each of the four chambers flows the same, as well as some sort of experience and skill too I suspect. I believe that GBH take out so much material in one particular area, that the head has to have a steel sleeve fitted where one of the head studs passes through the head in order to stop the gasses escaping into the head. Not for the DIY’er……



The engines reciprocating parts will need to be dynamically balanced to ensure that the motor runs smoother at normal revs and stays together at higher revs! Engine specialists will strap the block to a vibration bench, fitted with the crank, front dampener pulley, flywheel and clutch cover. The engine is turned over at approx 1,500rpm by an electric motor and a computer plots where any imbalance lies. Then tiny amounts of metal can be machined away from the components to ensure a smooth running engine.

Each piston and rod should be assembled and weighed, and small amounts of material ground away from the little end of the rod, until all 4 piston/rod assemblies weigh the same as the lightest one.


Exhaust manifold

The exhaust manifold on the SS1 is a mirror image of Nissans Silvia version. It was made by Beans Engineering that ended up owning Reliant at one point! The internal design essentially splits the passage of the gasses in two to keep the velocity of the gasses up. This allows the turbo to spool up quicker. It can however cause a few problems, the first of which is that being cast iron and getting red hot every day, it can start to break up internally which can wreck your precious turbo. Out with drill and flexi drive again and smooth or remove any frail looking internal webbing. In theory this will drop the velocity of the gasses passing through, but as we expect to be running a lot more boot than the std 6psi, its not a problem. In fact the very features that make it a clever, quick spool design at 6psi, make it very restrictive at high boost. Modifying it is essential, or better still replacement.

There are no commercially avaialble trick manifolds for the SS1, so its down to good old ingenuity Im afraid. Get some 10-12mm thick steel flanges made. Flame cutting is much cheaper for one offs than CNC machining, but will need a bit of tidying up with a file etc. These flanges then need to be welded to tubular runners arriving at the turbo flange. The runners can be made from 3mm thick walled ‘weld-els’ angles which are used in the steam/high pressure gas industry. Try and get all 4 runners to the same length if you can. This design may not be as good at low gas speeds (low, off boost rpm) but will allow more power at higher boost levels. Make sure your manifold is nice and robust as with the extreme heat cycles, it will need to be. Think about bracing it to the head or block too.


Inlet manifold

The std ET inlet manifold does a pretty good job for most applications but can be improved when big power is your aim.

Its almost certain that you will be running some kind of front mounted intercooler (FMIC) at this level and probably pretty high boost pressures too, so the inlet manifold could be a source of restriction in the system. As previously mentioned, making sure the inlet manifold matches the head ports is the first thing [V1] to do. The next is probably the throttle body. The throttle body has an internal bore of approx 38mm if I remember correctly. As with carbs, the bigger the bore, the more air flow. Its really a case of going around the breakers yard and finding a throttle body with a larger bore and a bolt pattern that is suitable too. Easier said than done. Generally its going to be a case of  welding up the 4 mounting holes in the face of the manifold and re-drilling and tapping it to suit your new found throttle body. Most TBs have industry std spindles to take your throttle position switch. A popular choice is pinched from the Sierra Cosworth. It’s about 52mm and pretty simple in its design.

OK, now the TB is sorted, the next thing to look at is the design of the plenum chamber itself. The later DET engine uses a forward facing plenum that would be nicer for our front mounted intercoolers, but it doesn’t fit easily due to different head port spacing. The idea is good though, and a lot of Nissan tuners tend to copy the design, but make up their own plenum. The idea is to chop the plenum chamber off the 4 inlet runners and weld on a thick, flat alloy plate. Then a plenum chamber ‘box’ can be created and welded in place, with a new front flange to suit whichever TB you have chosen. The std idle valve etc will need to be made to fit too. For the ultimate spec engines, a fabricated plenum is probably essential. If you intend to use a stand alone ECU (more of these later, Omex, Motec, Emerald etc), then its even easier with a fabricated plenum as most of them don’t require all the idle and emissions gubbins, just requiring water temperature sensor and air temp sensor. Take-offs for a MAP (Manifold Absolute Pressure) sensor and boost gauge will be needed too.



For more power, we are going to need more fuel. The std ecu isn’t adjustable via a chip or reprogramming, so we have to improvise. The std injectors run at pretty well full capacity at 5,500rpm so we need to supplement their contributions. We cant fit greater flow injectors because without being able to alter the ecus inbuilt fuel map, they would supply the required extra fuel at high revs and high boost, but would over-fuel everywhere else. What we need is extra fuel, just at high boost. The answer is simple, if a little crude, but does seem to work ok. It should be noted that as with all mods, a rolling road session will ensure that all the modifications are doing their job, and show up any areas of concern that need to be addressed. We need a ‘fifth injector’ setup to assist the current four injectors. The injector needs to supply extra fuel triggered by boost pressure. A pressure switch set at 6 or 7psi tapped into the plenum chamber is needed. A brake line pressure or oil pressure switch, are cheap and can be checked for their switching pressure by connecting a multimeter to the switch and a length of rubber hose to the threaded part of the switch and then pressurised by a tyre pump fitted with a pressure gauge. Once the switch has been chosen, it needs to be fitted to the plenum chamber. The ideal place is the blanking plug fitted where the std Nissan ‘blow-off’ was fitted. Drill and tap the blanking plug and hey presto, job done. Now for the injector and its fuel supply. The most commonly used injector is the cold start injector from the Ford Escort XR3i. This will need a ‘boss’ welding to the boost transfer pipe from the turbo to the plenum. Try to fit as near to the TB as is practical. Once the boss and the injector have been fitted, we then need to cut the fuel rail (input side from the pump) and fit a metal ‘T’ piece into the line. Then connect the ‘T’ piece to the injector via rubber fuel hose. Make sure its fuel injection spec hose rather than hose for use with carbs (injection systems often run at 20 times the pressure of carbs). The injector will need to be wired up via the pressure switch to ignition-on supply. Its not a bad idea to wire in a light/lamp/LED etc to fit to the dash to show when the injectors working. A further refinement would be a more expensive adjustable pressure switch to give greater control of when the extra fuelling comes in.

Bigger injectors (stand-alone ECUs only)

Bigger, or more accurately, greater flow injectors are the real answer, but again the ecu is the problem. Assuming that a stand alone ecu is being used, then which injectors do we need? There is an easy rule-of-thumb method for injector selection. Take the flow rate i.e. 440cc, divide it by 5, multiply it by the numbers of cylinders in the engine (4), which will then give your target BHP, = 352bhp. Using this method, if you know what power your engine is going to make, its possible to work out what injectors will suit your purpose. The above equation rates the injectors at 85% duty which should be considered the maximum ( running the injectors at higher than 85% duty cycle rarely increases fuel flow at all). As a guide, std S13 DET injectors are 370cc flow, std Skyline injectors are 440cc and Sierra Cosworth dark greens are approx 450cc too. Basically large capacity saloons with few cylinders are ideal breakers yard targets.


Fuel pumps and fuel regulators

Although I have no flow rates to back this up, I suspect the std SS1 pump is pretty good. It seems to supply enough fuel for 250ish bhp. A pump from a Sierra 2.9 V6 or Capri V6 will flow enough for up to 350bhp apparently.

The std fuel pressure regulator is ideal for most applications as its simple light and typically Nissan-reliable. The only thing it doesn’t offer is any adjustability of the fuel line pressure. FSE offer lots of adj regulators at about 70, so its not a major problem anyway. Certain cars have adjustable regulators as std, so again a trip to the breakers may well turn up a suitable replacement. The fuel pressure should be set on a rolling road.

Spark plugs

The plugs should be chosen on the rolling road really. Start with a plug 1 or 2 ranges colder than the stock NGK 6s. Use a V grooved or race spec if available. The std ET plug gaps of  1mm ( 39 thou) will need to be narrowed for high boost applications. This is because the higher boost pressures will ‘blow out’ the spark. Try 25-28 thou and work from there on the rolling road. My personal preference is for NGK plugs.

Air Flow Meter (AFM).

The std AFM is fine for most applications, but becomes restrictive on really high power engines due to its relatively small bore. The AFM looks a reasonable diameter until you realise that the actual bore is much smaller due to the hot wire sensor hole also being in the AFM intake. It is possible to fit a larger AFM but this wrecks the airflow readings to the ecu as the engine is actually seeing more air than the airflow meter says its seeing. This can lead to extremely lean mixtures, which can wreck the engine. The answer is to fit a trick piece of electronics that interpret the AFM readings and make then make sense of them for the ecu. These units aren’t cheap, and are all Japanese. Look for units by APEXi, Greddy, Trust etc. Many are 200-300. Personally I would put the money to a fully programmable ecu and then you don’t even need the AFM as the airflow is sensed by the MAP sensor and TPS (throttle position sensor) instead. Your call.

Stand alone programmable ECU

This is, as it suggests, a stand alone replacement ECU that is programmable via a laptop. It controls every aspect of the engine’s health and performance, but is so capable that almost anything can be accomplished. It also gives you total control of every aspect of performance and the ability to use and integrate other manufacturers components and configure them in a way that’s just not possible with any std ecu.

As an example, its possible to get rid of the AFM, use a different make of throttle body, remove all the emissions crap from the inlet manifold and use any make, type and size of turbo and injectors out there.

The ecus made by Omex and Emerald are the two most likely to tick all the boxes for your SS1. There are guys with Nissans out there with these fitted, and it may be possible to track someone down (try SXOC.CO.UK) who has one and get a copy of their ‘map’ as a starting point and then just refine it on the rolling road or even the open road ( private land of course……). You don’t need to be a computer genius to be able to do it either, but some understanding of both computers and what the engine is experiencing is necessary. The Emerald system is the one I know most about, so forgive me if most of the info is based on their system. Many of the features are similar on the Omex though.

The ecu has total control of the engine via various sensors. It takes air and water temperatures, manifold pressures including boost (above atmospheric pressure), throttle butterfly position, and crank position (usually triggered by a crank pulley or flywheel mounted multi-toothed disc). It can then fire the spark at the right time, supply the correct fuelling via the injectors which can be altered to take into account throttle opening and load. Pretty much what most OE ecus do really, but tuned solely to your engine spec. Std OE ecus have to take into account the car being used on poor quality 2 star fuel in some countries, or the heat of the desert or cold of Siberia, so have really wide parameters in their maps. You can ensure with your ecu programming, that those are much ‘tighter’ therefore having less margin for error and therefore produce more power.

The Emerald also allows two maps to be stored in the ecu, which are switchable via a dash mounted switch. This gives you a nice, sensible, good MPG map for daily driving, and then a real rip-snorting, fire breathing map for track use. It has a user selectable rev limiter to safeguard your engine, a user selectable ‘shift-light’ to tell you that the rev limit is approaching and that you need to shift into the next gear. It can also support anti-lag which is the system used by top rally teams that sounds like cannon fire in between gear changes! This isn’t really suitable for most turbos as it tends to wreck them pretty quickly but the option is there. It also has the ability of full 4 wheel traction control if sensors are fitted to each wheel. These can be very simple and cheap sensors as the ecu configures the information itself. Then what it does is read both of the front wheels and compares them to the two rear wheels independently. It then works out if either of the rear wheels are turning faster than the undriven fronts (wheelspin) and then cuts the engines power accordingly to stop the wheelspin. What’s even cleverer is the ability to adjust via a dash mounted knob, the amount of ‘slip’. For a performance vehicle some wheelspin is acceptable, in fact in sprint and hillclimbing, it’s actually desirable. I read somewhere (I think one of the Allan Staniforth books) that 24% wheelspin makes the perfect start. It allows the rear tyres to spin stopping the engine from ‘bogging’ off the line, it allows the turbo to spool up quicker and puts some traction-enhancing heat into the tyres too. By playing with the traction settings feature, the car can be made faster and safer in slippy conditions on both the road and track.    

Craig Hughes & 2005


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