Pete Silcock's Sabre Turbo
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Pete Silcock's Sabre Turbo
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08/31/08 |
     
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This is Pete's own write-up on the somewhat extensive and very well thought out modifications to the prototype Sabre.DET into Sabre -16 valve road car
Purpose of the conversion – Why did the Idiot do it?
The Start The engine as lifted out of the 200sx will fit well into the engine bay and looks immediately as if it should be there. The mountings and clearances are all fine.
The two hockey stick curved engine to gearbox braces need to be removed. This leaves two other brackets plus the block bolts to hold the engine to the gearbox so I am happy to simply omit these. The lower inlet manifold brace was also forgotten. For a straight replacement ET to DET then three points need to be addressed
My solutions to these items follow plus the other changes I made I fitted a scrap DET and got emerald working before fitting the new engine. Manifold I bought an aftermarket stainless manifold from E-bay. I then cut at the block flange and turned the pipery upside-down and re-welded. While cheap and beautifully curved the quality of the mating of pipes to flanges was awful - before cutting off and turning around. A die grinder is needed to both clean off inside and mate to the block and turbo. This gives me a top mounted Turbo with enough space for a 2 ½” downpipe (just)
Wiring Loom I stripped out the Sabre wiring keeping only the leads to various sensors as I have rewired for Emerald management. The wiring to the alternator, starter and oil pressure are the same. The DET has two or three air bypass valves and a tickover stepper sprouting out around the inlet manifold. These were junked as not required, but the stepper for cold tickover may be re- installed. I have also been able to junk the mass airflow meter which is not used with the Emerald system. Emerald uses a crankshaft sensor rather than the Nissan cam sensor. This was machined into the original front pulley, but the sensor was later moved to the cam pulley due to misfiring problems about 6200rpm. Pipework I have fitted an intercooler from a Volvo 740. This is fitted at an angle roughly where the original radiator sat. It has been slightly shortened to fit between the chassis rails and the end capping re- glassed into place. Convenient tapped holes exist in the chassis within the spare wheel bay that I have used for holding the radiator, behind the intercooler. I now have a can in the boot rather than a spare wheel and the battery also sits in the boot.
Other bits With the top mount Turbo the inner wing needed alteration (hack out and re- glass into place) for the header tank and a direct pipe led to the void under the headlight for the air cleaner – watch and protect from water dripping around the headlight. What I should have done. 1. Most definite – stripped out and thrown away all of the original wiring including in the cockpit. Only keeping the wiring to the rear lights. –15+year old Reliant wiring is specifically designed to make you utter profanity at loud volume and throw things at the wall. 2. Duct the airflow to the radiator - now done and no cooling problems. The radiator is standard size SS1 with a triple rather than double gallery core – less cost than a new standard radiator from our specialist suppliers. 3. The crankshaft has a vibration at 6200rpm which knocked out the engine speed signal – I have re-located the engine speed sensor from the crankshaft to the cam and no further problems (see above) Turbo
I have a variable nozzle turbo from Turbo Technics. This has vanes operated by a second actuator. The vanes are ‘closed’ at no boost and open fully at .6bar. The ‘closed’ vanes squirt the exhaust gas giving a very early spool up of the Turbo Boost is seen at 1650rpm building to the .6bar at 2100rpm and then up to wastegate pressure, or above, at 3200rpm. The car does not feel that quick with a thump of torque as the turbo progressively winds up – but the corners come very quick. At wastegate pressure of .8 bar I have 250 bhp and will have around 320bhp when the boost is upped. The only time there is any lag is when booting to flat out from a low throttle angle - which is still very smooth as the vanes feed the power in. I have had problems with the Turbo – no boost at large throttle angles but these have all been resolved – but I don’t know why some problems have disappeared. The ‘official’ Turbo Technics distributor local to me when ‘correcting’ my fitting of the turbo turned my recirculation dump valve backwards and then played with the boost valve map to again ‘correct’ the boost– leaking away from the backwards dump valve --- and then --- gave me a big bill!!! – paid as the excellent work done was only discovered later. Warning --- Go only to tuning people who you know and have unblemished reputations ----- Turbo Technics have been helpful – but have not so far accepted any responsibility for their – frankly incompetent distributor and agent (or paid the £250 bill) Final turbo point is that both the actuator for the wastegate and the vanes vibrate badly. I put rubber pipe on the wastegate rod and was advised to weld a weight onto the vanes actuator rod - I attached lead with a jubilee clip – more needed soon to damp the vibration – this fell off and is now epoxied – more to come? Cooling I initially had overheating. This may have been in part due to incomplete mapping having weak mixtures giving excessive heat. The intercooler is completely in front of the radiator - the best place but restricting and heating the airflow I fitted an air scoop to feed air from under the car and a flare to the rear of the bonnet to remove air – fitting both together I have no idea which of both works but the cooling is now fine. The underbonnet temperature while driving is 10degrees above ambient – but gets quickly to 60 when stopped. The scoop had to be strengthened as at over 90mph it hit the ground due to the downforce it generated – more than me standing on the centre of the scoop – at 75mm from the ground it also collects the tops of sleeping policemen - and where I live it scoops the tops from horse poo left in the centre of the road.
Emerald and programmable ECUs The control over all aspects of the engine is superb, with a few extra comments. First – if the car is fast then mapping on the road is not possible – 90 mph + playing with a laptop + watching lambda readouts = dead – the car can be driven by someone else and some work done the speeds needed will affect the license of the driver very quickly. The only option is a rolling road with a good operator who also knows the management system being used well – otherwise you either have a Muppet who knows nothing about tuning – or someone who will charge xxxx per hour to learn the management computer program. A big difficulty is to make sure the new engine is all working correctly before paying for the rolling road – but how can you do that without bad mapping destroying the new engine? Second – A wideband lambda either plumbed in or temporary is essential to alter the fuelling accurately the information is essential for power area of the map to prevent weak mixtures melting things and for the cruise area to sip fuel. This piece of kit added to ears listening for the dreaded detonation (pinking) will enable the engine to be run safely – get some miles and checking done before the expensive rolling road. This control over every aspect of the engine gives a very smooth and easy drive with none of the spitting animal like behavior expected with tuned engines. The DIY Megasquirt systems do deserve a good look as with a wideband Lambda they can tune themselves - keeping down the rolling road costs. I am currently looking further at this option. They are also not expensive
Engine Spec. Engine from scrap 200sx 1860cc with Wiseco forged pistons. Rebuilt engine complete– no crankshaft grind needed Grooves for a wire machined into the block
Balanced - the crank unusually for Nissan was way out. The rods were fine. Flywheel – gurt great chunks of metal removed but still a big chunk of metal. 444cc injectors – available from Skylines upgrading to bigger – enough for 300+ bhp Inlet and head – smoothed off to ensure all stepping in the right direction – 3mm needed removing from Plenum to injector housing. Lumps around valves reduced. Headgasket – Nissan original – I would rather the gasket gave up than anything else – so far ok. Clutch – Nippon Autoparts standard – said to be 30% uprated from original Nissan – with a light car should be ok –again so far so good – better clutches are very expensive and some are undriveable on the road Manifold. – E-bay special – cheap, nice curves, bad internal finish – Exhaust – 2.5” straight thru with one small box – does not go over the axle –very quiet until the Turbo vanes go to full boost then makes a nice racket. Worth it?? Yes – but fraught at times during the ‘sort the problems phase’ The engine is very different than the ET – in comparison, smooth almost turbine like, free revving but with no stress, loads of power off boost – on the road very rarely will boost be needed unless playing. When challenged – just go – and smile. The power is delivered in an unobtrusive fashion, it does not give the Turbo ‘kick in the back’ – I do think that this is also partly the variable nozzle Turbo. As it is so smooth it is easy to be doing very silly speeds and a car in front doing 40 – scrubbing off the speed can increase the heart rate. The doc says that increasing the heart rate and sweating every day is good for you??? Do you think this is what he had in mind? Next Steps Finalise the mapping and turn up the boost ------------------ 320+ here we come Brakes Phil Howard’s Carlton/Volvo large vented discs – A Must. Sierra estate rear wheel cylinders Problems at present with variable pedal – tandem master cylinders being looked at Suspension Front Coil over conversion to the front. – Strengthened wishbones and uprated springs.
Polybushes and Avo adjustable shocks – adjustable seat height fir ride height adjustment Rear Strengthened hub carrier, shortened avos and stiffer springs. Tyres 205/15/50 Toyo 888s – Great sticky tyres – needed the inside of the wheel arches to be ‘lightened’ to give clearance. Parking needs muscles Dash ETB DigiDash – Brilliant information and programmable alarms – i.e. oil pressure below 35psi at 200o rpm = alarm – The oil light is a laugh by showing the engine has just been destroyed. It also has data logging (not programmed yet) and loads of readouts for G- force etc. Seatbelts I have the standard leather seats – the first time on the track was very slippy bum to seat. I now use CG lock which I find very good – See group buy--- Still I am upset at removing the classic Metro dash of course it has upset the quality and ambience carefully crafted by Reliant of the standard car Body Scruffy original paint. Mk 2 front – because it is pretty.
Flare to the rear of the bonnet to allow heat out.
I can't help adding this quote from Pete the first time the Sabre ran with its new heart... "Drove up our narrow, bumpy lane - as the pedal is pressed and boost comes in - car pours smoke off tyres and squats enough to file the bottom off the exhaust - I crap myself and grin like a moron." Pete has just given me another one of his quotes which also demonstrates the power that's now there: Last week - slightly damp here - I was driving to Kingsbridge- at Aveton Gifford there is a very steep mile of hill - I eased up the first bit in third past 15 - 20 cars - changed to 4th - 90 plus - and decided that I could floor the throttle. -- Spun up both wheels and snaked - backed off --!!!!-- looking to have a set of Toyo T1s for the wet as the Road Slick 888s caused another cardio vascular workout. That should keep the doctor happy..but he might need to look at your bowels next if you keep that up!
This site was last updated 11/26/06 |
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