Ex works Vauxhall Astra BTCC track car
Discussion
, yup, it's definitely a race car 
What a sound!!! 
It’s been a while - sorry for the slow updates but I’ve been carefully considering all the engine options for use as a track car.
It makes sense to keep the original engine architecture (GM L850) so that it installs with the original mounts & is compatible with the Xtrac sequential gearbox. With this in mind I found 4 options….
1. Use the existing Sodemo 2.0NA unit, I spoke with Swindon engines (they can fully support this engine) they reckon £15k to refresh the engine and it’s will last approx 500 race mls before rebuild.
2. Use a current BTCC 2.0 turbo engine, these are about 370 bhp & only need refreshing each season and start at £6k for a used unit.
3. Use a Saab B207 2.0 turbo and 'off the shelf' performance parts, engines are only £1k new!!
4. Build myself a 2.4NA engine raiding the Vauxhall parts bin & use aftermarket tuning parts.
Option 1 – No way, too expensive for a track car. I will save the original so that it meets historic touring car technical regs should I want to race it in the future.
Options 2&3 – Although they will mount to gearbox, the rev limit is lower (7k) and the torque is much higher (400NM) than the original. The max speed for longest available Xtrac ratio @7k is only 125mph & the gearbox is only rated to 300NM.
Option 4 – Reasonable build cost (£3-4k), estimated power similar to Sodemo original, gearbox will handle the torque and it should rev to 8k. So should be similar to drive to the original with hopefully much more life. It will have the same head design therefore will mount to the original exhaust / intake / fuel / ECU systems. If it ever goes bang, I can fix it.
So decided on option 4 and am now sourcing parts to build myself a 2.4NA engine

Gearbox is going to a specialist to be stripped & checked next week.
Any recommendations for somebody to service the shocks?
It makes sense to keep the original engine architecture (GM L850) so that it installs with the original mounts & is compatible with the Xtrac sequential gearbox. With this in mind I found 4 options….
1. Use the existing Sodemo 2.0NA unit, I spoke with Swindon engines (they can fully support this engine) they reckon £15k to refresh the engine and it’s will last approx 500 race mls before rebuild.
2. Use a current BTCC 2.0 turbo engine, these are about 370 bhp & only need refreshing each season and start at £6k for a used unit.
3. Use a Saab B207 2.0 turbo and 'off the shelf' performance parts, engines are only £1k new!!
4. Build myself a 2.4NA engine raiding the Vauxhall parts bin & use aftermarket tuning parts.
Option 1 – No way, too expensive for a track car. I will save the original so that it meets historic touring car technical regs should I want to race it in the future.
Options 2&3 – Although they will mount to gearbox, the rev limit is lower (7k) and the torque is much higher (400NM) than the original. The max speed for longest available Xtrac ratio @7k is only 125mph & the gearbox is only rated to 300NM.
Option 4 – Reasonable build cost (£3-4k), estimated power similar to Sodemo original, gearbox will handle the torque and it should rev to 8k. So should be similar to drive to the original with hopefully much more life. It will have the same head design therefore will mount to the original exhaust / intake / fuel / ECU systems. If it ever goes bang, I can fix it.
So decided on option 4 and am now sourcing parts to build myself a 2.4NA engine
Gearbox is going to a specialist to be stripped & checked next week.
Any recommendations for somebody to service the shocks?
Hi OP. I hate to disagree...
You have something of value here, a car which was very competitive at the time, won races and could have taken the crown. The engine is the heart of every race car and sticking a parts bin VX lump really isn’t doing the car justice. These cars represent the pinnacle of UK tin top racing at the time and I it would be such a shame to lose the engine from the car. These are only going to go up in value form now and it will be worth so much more with the original engine and go faster bits. It may cost more to rebuild it but be worth it in the long run.
Secondly, please re-consider competing with this car. If you don’t fancy door to door action, then do sprints and hill climbs. The car is wasted poncing around a track on a Javelin day (no offence to Javelin who put on great events!). It was built to race and it will be so much more rewarding than overtaking production cars on road tyres going very slowly around a track.
Finally, whatever route you take, have you found a good fabricator to make new parts for you?
You have something of value here, a car which was very competitive at the time, won races and could have taken the crown. The engine is the heart of every race car and sticking a parts bin VX lump really isn’t doing the car justice. These cars represent the pinnacle of UK tin top racing at the time and I it would be such a shame to lose the engine from the car. These are only going to go up in value form now and it will be worth so much more with the original engine and go faster bits. It may cost more to rebuild it but be worth it in the long run.
Secondly, please re-consider competing with this car. If you don’t fancy door to door action, then do sprints and hill climbs. The car is wasted poncing around a track on a Javelin day (no offence to Javelin who put on great events!). It was built to race and it will be so much more rewarding than overtaking production cars on road tyres going very slowly around a track.
Finally, whatever route you take, have you found a good fabricator to make new parts for you?
Thurbs said:
Hi OP. I hate to disagree...
You have something of value here, a car which was very competitive at the time, won races and could have taken the crown. The engine is the heart of every race car and sticking a parts bin VX lump really isn’t doing the car justice. These cars represent the pinnacle of UK tin top racing at the time and I it would be such a shame to lose the engine from the car. These are only going to go up in value form now and it will be worth so much more with the original engine and go faster bits. It may cost more to rebuild it but be worth it in the long run.
Secondly, please re-consider competing with this car. If you don’t fancy door to door action, then do sprints and hill climbs. The car is wasted poncing around a track on a Javelin day (no offence to Javelin who put on great events!). It was built to race and it will be so much more rewarding than overtaking production cars on road tyres going very slowly around a track.
Finally, whatever route you take, have you found a good fabricator to make new parts for you?
was he not looking to remove the original engine and keep it tucked away in the garage instead of wasting it driving around on track days and keep the value in the car by having the original engine to slot back in? You have something of value here, a car which was very competitive at the time, won races and could have taken the crown. The engine is the heart of every race car and sticking a parts bin VX lump really isn’t doing the car justice. These cars represent the pinnacle of UK tin top racing at the time and I it would be such a shame to lose the engine from the car. These are only going to go up in value form now and it will be worth so much more with the original engine and go faster bits. It may cost more to rebuild it but be worth it in the long run.
Secondly, please re-consider competing with this car. If you don’t fancy door to door action, then do sprints and hill climbs. The car is wasted poncing around a track on a Javelin day (no offence to Javelin who put on great events!). It was built to race and it will be so much more rewarding than overtaking production cars on road tyres going very slowly around a track.
Finally, whatever route you take, have you found a good fabricator to make new parts for you?
sounds like an ideal plan to me. Yep, this isn't going anywhere other than under the bench until needed. i.e. when tech regs require it.
Perhaps this one day...... http://www.supertcc.com/2-litre-touring--st4.html
Walk around vid of the PT on the subframe (dullest thing on youtube according to my 10yr old daughter)
https://www.youtube.com/watch?v=OsfqZyZY6ns
Perhaps this one day...... http://www.supertcc.com/2-litre-touring--st4.html
Walk around vid of the PT on the subframe (dullest thing on youtube according to my 10yr old daughter)
https://www.youtube.com/watch?v=OsfqZyZY6ns
If you put some less aggresive cams in that (i.e. ones where the lobe stays in contact with what it's driving for the full rotation - S2000 only specified the max lift at the cam not the max lift that the valve ended up at) and turned the revs down a touch it would do WAY more than 500 miles and still make 250bhp odd.
Is this on the Sodemo ECU or a Pectel? I might still have some of the configs and maps for it somewhere......
Is this on the Sodemo ECU or a Pectel? I might still have some of the configs and maps for it somewhere......
poppopbangbang said:
If you put some less aggresive cams in that (i.e. ones where the lobe stays in contact with what it's driving for the full rotation - S2000 only specified the max lift at the cam not the max lift that the valve ended up at) and turned the revs down a touch it would do WAY more than 500 miles and still make 250bhp odd.
Is this on the Sodemo ECU or a Pectel? I might still have some of the configs and maps for it somewhere......
It's a BTC-T spec with a EFI type ECU as per TOCA regs at the time. You wouldn't have maps for this would you??? That would be awesome. Is this on the Sodemo ECU or a Pectel? I might still have some of the configs and maps for it somewhere......
I'm told that the cams are very aggressive (square) I've got newman cams lined up to measure the profiles and make me something less so. The 2.4 bottom end I'm getting from the states will marry to any L850 head including original (lost foam cast) and the saab B207 (sand cast). Only cost buttons too.
VX BlackRat said:
It's a BTC-T spec with a EFI type ECU as per TOCA regs at the time. You wouldn't have maps for this would you??? That would be awesome.
I'm told that the cams are very aggressive (square) I've got newman cams lined up to measure the profiles and make me something less so. The 2.4 bottom end I'm getting from the states will marry to any L850 head including original (lost foam cast) and the saab B207 (sand cast). Only cost buttons too.
The reason for the square cams is to get around the maximum valve lift specified in the regulations. If the regs say 12mm lift and you grind your cam so when measured it has a lift of 11.99mm then you're legal, however if you design this cam with a hugely aggresive ramp angle and pair it with a valve spring of a suitable rate (this is the bit which takes a lot of work) then during valve opening events the valve and it's associated valve train bits leave the end of the cam due to the very high ramp angle which gets you precious extra valve lift over and above what the cam measures at. The downside is you have fairly large wear on cam and followers and likely valve life and valve seat life is reduced as the valve can clatter back into the seat rather than being returned back to the seat by the cam lobe in a controlled way in extreme cases (although really your ramp out wouldn't be that harsh in practice). If you have a series with spec max revs and valve lift but OEM budgets then it's a good option to explore and many used it in BTCC at various points. I'm told that the cams are very aggressive (square) I've got newman cams lined up to measure the profiles and make me something less so. The 2.4 bottom end I'm getting from the states will marry to any L850 head including original (lost foam cast) and the saab B207 (sand cast). Only cost buttons too.
I won't have the EFI maps unfortunately but it's likely you can read the maps that are in there off the chip if the current ECU isn't on an open developer and then with a bit of work get these into a standard spec open EFI ecu so you have an ECU that plugs right in but you can access. If it's the one with a big red TOCA on the front and a single Amphenol connector then it's a Euro 6 - have you tried talking to it with just the boggo EFI CAN interface to see if it's open?
OP - nothing to say really other than listening to that idle made me smile! Whilst not professing any real expertise and knowledge of the pro engine builders here - i would also add that often race engine life between rebuilds is deliberately conservative and assumes you are using it flat chat all the time. say this as i have a full spec alloy 2.0 cosworth bda in a trackcar which easily exceeds rebuild time without adverse effects although gets well maintained and periodically a leak down test etc. this is probably because it's not used for racing now constantly at 8500 rpm and life in trackday land with me and my mates driving is a bit more sedentary - btw the guy i share my 7 with did the exhausts for these vx btcc models - although you obviously have more pressing stuff to get involved with at moment
Anyway whatever you do with the motor - what a wonderful toy to own - best of luck and look forward to seeing in-car video when you get out on track!
Anyway whatever you do with the motor - what a wonderful toy to own - best of luck and look forward to seeing in-car video when you get out on track!
poppopbangbang said:
The reason for the square cams is to get around the maximum valve lift specified in the regulations. If the regs say 12mm lift and you grind your cam so when measured it has a lift of 11.99mm then you're legal, however if you design this cam with a hugely aggresive ramp angle and pair it with a valve spring of a suitable rate (this is the bit which takes a lot of work) then during valve opening events the valve and it's associated valve train bits leave the end of the cam due to the very high ramp angle which gets you precious extra valve lift over and above what the cam measures at. The downside is you have fairly large wear on cam and followers and likely valve life and valve seat life is reduced as the valve can clatter back into the seat rather than being returned back to the seat by the cam lobe in a controlled way in extreme cases (although really your ramp out wouldn't be that harsh in practice). If you have a series with spec max revs and valve lift but OEM budgets then it's a good option to explore and many used it in BTCC at various points.
I won't have the EFI maps unfortunately but it's likely you can read the maps that are in there off the chip if the current ECU isn't on an open developer and then with a bit of work get these into a standard spec open EFI ecu so you have an ECU that plugs right in but you can access. If it's the one with a big red TOCA on the front and a single Amphenol connector then it's a Euro 6 - have you tried talking to it with just the boggo EFI CAN interface to see if it's open?
Fantastic info. thanks! Love finding out about the work-around tricks of the day.I won't have the EFI maps unfortunately but it's likely you can read the maps that are in there off the chip if the current ECU isn't on an open developer and then with a bit of work get these into a standard spec open EFI ecu so you have an ECU that plugs right in but you can access. If it's the one with a big red TOCA on the front and a single Amphenol connector then it's a Euro 6 - have you tried talking to it with just the boggo EFI CAN interface to see if it's open?
You put up a really strong argument for running the Sodemo but I think I’m going to stick with the 2.4NA build, I currently don’t have anywhere near the funds for the initial engine refresh of the Sodemo and if I did it would still carry some risk running it….I’d hate to blow something so valuable just doing track days. I’ve already got some parts for the 2.4 build too.
I’m essentially building a replica Sodemo head for my 2.4NA build with less aggressive cams using a better cast Saab head. This will be skimmed & ported by a specialist (not decided who yet), can’t see why I shouldn’t see similar flow rates? The std valves are just shy (-0.15mm) of the tech reg sizes so will probably leave them alone or consider custom later. Up the spring rates to allow extra rpm. Bolt up a forged & balanced 2.4 bottom end.
The ECU is a Euro 6, I don’t have a cable, they are quite pricy so was looking for a tuner to sort all of that when it goes for set up on a dyno. Do you know somebody local (I’m in Beds too) who could do this?
Cheers!
Running the thing and footing the periodic refreshes is one thing, repairing it after an unexpected mechanical failure (always a risk with a race engine no matter how well built) is quite another. I think you're doing the right thing putting it under the bench for now. You've a risky period coming up where you have to put the thing back together, learn to run, maintain and set it up properly, and learn to drive it, without the constant worry of an engine which could end your season if it felt like it.
As others have said, I'd run the original engine but to a lower rpm, perhaps changing the cams if necessary. This should give many multiples of the quoted 500 miles engine life.
Also do you need a full 15k rebuild? Surely the 15k quote is to rebuild everything to perfect specification, like it would be prior to a full BTCC weekend. I would have thought it would be possible to strip down and rebuild only what is necessary, e.g. replacing bearings and gaskets etc.
IMO the value in these cars is running them in original specification, doing otherwise is a bodge.
Also do you need a full 15k rebuild? Surely the 15k quote is to rebuild everything to perfect specification, like it would be prior to a full BTCC weekend. I would have thought it would be possible to strip down and rebuild only what is necessary, e.g. replacing bearings and gaskets etc.
IMO the value in these cars is running them in original specification, doing otherwise is a bodge.
Olivera said:
As others have said, I'd run the original engine but to a lower rpm, perhaps changing the cams if necessary. This should give many multiples of the quoted 500 miles engine life.
Also do you need a full 15k rebuild? Surely the 15k quote is to rebuild everything to perfect specification, like it would be prior to a full BTCC weekend. I would have thought it would be possible to strip down and rebuild only what is necessary, e.g. replacing bearings and gaskets etc.
IMO the value in these cars is running them in original specification, doing otherwise is a bodge.
Would not be at all surprised to hear that £15k was the cost of a periodic refresh. And even if properly refreshed, you are only ever one oil leak, overheat or random failure away from a needing a new block, head, crank, piston type scenario which could cost multiples. Also do you need a full 15k rebuild? Surely the 15k quote is to rebuild everything to perfect specification, like it would be prior to a full BTCC weekend. I would have thought it would be possible to strip down and rebuild only what is necessary, e.g. replacing bearings and gaskets etc.
IMO the value in these cars is running them in original specification, doing otherwise is a bodge.
IMO the value in these cars is best protected by ensuring that it can be returned to race finishing spec as the OP is doing, whereas running the car in race spec, having a catastrophic engine failure and then having to remortgage the house to have it put right or ending up with a box full of shrapnel instead of an engine would be far worse.
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