Aircooled 3.8 race engine hits 400bhp...
Discussion
Just thought some of you may be interested in the recent power test of our new 3.82 litre 964/993 race engine, as tested in GT Purely Porsche in Adrian's 964RS but now fitted with our pukka race cams and in my 993RSR. [I'll post the image properly when I can a) remember how and b) reduce the size slightly]
www.9mracing.co.uk/articles/images/28_100.jpg
The fairly basic specification is:
Windage ported crankcases
standard 993 crank & oil pump
9m 103mm piston/barrel & long rod assembly
9m ported standard heads
9m race cams, valve springs & titanium retainers
Individual throttle body induction system
standard (!) 993 headers
100 cell cats, std 993RS silencers (100dBa @ 4000)
Motec M48 PRO ecu
I calculated the peak torque at 411Nm at 5700, with more than 350Nm all the way from 3700 to 7800rpm. Hopefully with a little more work we will have it over 400bhp soon (I suppose if we disconnected the power steering it may save the 8bhp required), I suspect that intake revisions alone may give the desired result although a set of our own equal length headers are on the way.
Any comments would be appreciated, if Ted or the boys want to come and drive it let me know, until then you will just have to believe me when I say that it starts and idles perfectly from cold, has more torque through the mid range than a standard 993RS and FLIES up to the self imposed 7800 limit like you would not believe, pulling strong right up to the red line.
www.9mracing.co.uk/articles/images/28_100.jpg
The fairly basic specification is:
Windage ported crankcases
standard 993 crank & oil pump
9m 103mm piston/barrel & long rod assembly
9m ported standard heads
9m race cams, valve springs & titanium retainers
Individual throttle body induction system
standard (!) 993 headers
100 cell cats, std 993RS silencers (100dBa @ 4000)
Motec M48 PRO ecu
I calculated the peak torque at 411Nm at 5700, with more than 350Nm all the way from 3700 to 7800rpm. Hopefully with a little more work we will have it over 400bhp soon (I suppose if we disconnected the power steering it may save the 8bhp required), I suspect that intake revisions alone may give the desired result although a set of our own equal length headers are on the way.
Any comments would be appreciated, if Ted or the boys want to come and drive it let me know, until then you will just have to believe me when I say that it starts and idles perfectly from cold, has more torque through the mid range than a standard 993RS and FLIES up to the self imposed 7800 limit like you would not believe, pulling strong right up to the red line.
) perhaps someone like Clubsport with a standard 993RS or Dom with a near standard 964RS would care to also make the trip for a little comparison? 
Yeah, I would love to pop up in the Baron soon. I'm sure either myself or Dr Alex could word a suitable article for release on PH etc.
Dunno how 9m finds the time! Colin - I have been following your racing in porsche post - well done - I see some urchin has knocked you off top spot tho'. Hope you get the lead back.
Cheers
Domster
Dunno how 9m finds the time! Colin - I have been following your racing in porsche post - well done - I see some urchin has knocked you off top spot tho'. Hope you get the lead back.
Cheers
Domster
Yeah, I dunno either. The bottom line is that I was knocked off the top spot because I was racing a 1352kg standard RSR (including me!) against both a 3.8 litre 911SC (300bhp/1150kg) and PH's modified 993RS with 360bhp/1212kg with JRZ suspension. To save you the trouble, that's my 229bhp/tonne against 260 & 297 respectively. Even though I have a JRZ package to fit I just have not had enough hours in a week (due to the 9m expansion programme currently underway) so when the opportunity arose to drop in the new engine since it was out for a cam change I just had to make the time to take the quantum leap forward.
I think it's fair to say we achieved our desired objective, seeing as how on the first event, whilst still mapping it between the runs, it went through the MIRA speed trap at 123mph compared to PH 993RS at 120, Skutter's 964RSR at 118 and the 3.8SC at 115. This was with 382bhp, subsequent remapping on the rollers saw this increase to a 392.6 peak (although the dyno runs shown were the later ones that had a flatter torque curve). As for demo's I'm sure that John C will tell you that the road is no place to play with this beastie, the car is ridiculously fast with relentless push to the redline in any gear, maybe someone could organise a track day somewhere sensible (Oulton Park please?) for late August or early September?
Erm, as for price, the bottom line will be around £20k + VAT which I think is realistic. This price reflects just the cost of the parts and the labour to modify and build the engine, there are no heavy mark-ups for development. The key costs in there for converting say a 964RS engine are: piston/cylinder/rod set £5000, induction system £2500, cams/springs/retainers £1250, Motec £3000, labour £5000 (100 hours minimum). In theory it should be possible for me to supply the engine as a kit, but that prospect seems a long, long way off at present.
Subsequent exhaust development should bring about a bit more power, but since 400 has to be possible with the standard exhaust and cats, it begs the question as to how much power do we need to be interesting enough? My computer model predicts 420-430bhp with the cylinder heads we have now and equal length headers, but with a brand new head design on the cards we should easily see 450bhp at the same rpms.
My only concern is that I may develop the engine out of most people's price range, but since the knock-on effect of the work will be much better upgrades for standard engines the project will still be a success. In any case, other people have talked about doing it, but we have actually done it which is good enough for me.
I think it's fair to say we achieved our desired objective, seeing as how on the first event, whilst still mapping it between the runs, it went through the MIRA speed trap at 123mph compared to PH 993RS at 120, Skutter's 964RSR at 118 and the 3.8SC at 115. This was with 382bhp, subsequent remapping on the rollers saw this increase to a 392.6 peak (although the dyno runs shown were the later ones that had a flatter torque curve). As for demo's I'm sure that John C will tell you that the road is no place to play with this beastie, the car is ridiculously fast with relentless push to the redline in any gear, maybe someone could organise a track day somewhere sensible (Oulton Park please?) for late August or early September?
Erm, as for price, the bottom line will be around £20k + VAT which I think is realistic. This price reflects just the cost of the parts and the labour to modify and build the engine, there are no heavy mark-ups for development. The key costs in there for converting say a 964RS engine are: piston/cylinder/rod set £5000, induction system £2500, cams/springs/retainers £1250, Motec £3000, labour £5000 (100 hours minimum). In theory it should be possible for me to supply the engine as a kit, but that prospect seems a long, long way off at present.
Subsequent exhaust development should bring about a bit more power, but since 400 has to be possible with the standard exhaust and cats, it begs the question as to how much power do we need to be interesting enough? My computer model predicts 420-430bhp with the cylinder heads we have now and equal length headers, but with a brand new head design on the cards we should easily see 450bhp at the same rpms.
My only concern is that I may develop the engine out of most people's price range, but since the knock-on effect of the work will be much better upgrades for standard engines the project will still be a success. In any case, other people have talked about doing it, but we have actually done it which is good enough for me.
9m as wonderful as it sounds would it not be more cost effective to achieve 400 approx bhp with a supercharger for road use..many thanks for posting this,as you say the off shoots of the development work should pay didvidends down the line.
one thing I was suprised at was the fitment of standard 993 Rs exhausts...I was under the impression that these were more restrictive than regular 993 boxes to supress the extra noise due to the enlargement of capacity to 3.8L Do the 100 cell cats with std RS boxes give advantage over the many sports exhausts available? i always thought 993Rs had fun at emmision test time and 100 cellcats could make this even more borderline...cheers.
one thing I was suprised at was the fitment of standard 993 Rs exhausts...I was under the impression that these were more restrictive than regular 993 boxes to supress the extra noise due to the enlargement of capacity to 3.8L Do the 100 cell cats with std RS boxes give advantage over the many sports exhausts available? i always thought 993Rs had fun at emmision test time and 100 cellcats could make this even more borderline...cheers.
Supercharging is an easy option, but it is just not the same when it comes down the the purity of the driving experience of either a 964RS or 993RS, neither is it as light or as easy to drive on the limit. Let's wait 'till the boys test it, then you will have an independent view whether it is worth the effort (and price).
As for the silencers/cats etc, yes the 100 cells are marginal at MOT time with standard 993RS engines, but I think you may be missing the point. This is a no-compromise race engine that could be driven on the road, with these cams I doubt that it could pass emissions even with standard cats, but since you mentioned it I will look into the emissions performance although I will be building them on a track use basis.
As for the silencers/cats etc, yes the 100 cells are marginal at MOT time with standard 993RS engines, but I think you may be missing the point. This is a no-compromise race engine that could be driven on the road, with these cams I doubt that it could pass emissions even with standard cats, but since you mentioned it I will look into the emissions performance although I will be building them on a track use basis.
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