9m 993RS 3.8 race engine hits 415bhp
Discussion
Well, I've talked about it for long enough but we have finally achieved our objective of building a 400+bhp normally aspirated aircooled 911 engine.
The new motor hit the dyno last night with its Mk2 9m pre-production machined-from-solid (billet) cylinder heads & the latest variation of our 103mm upset billet piston and posted the following data (6th gear, uncorrected)
Peak power 414.8bhp @ 7400
Power @ tyres 355bhp at 192mph
Peak Torque 326.3lbft 442Nm @ 5400
Torque spread over 300lbft from 4000 to 7000rpm
Specific power 109bhp/litre (3.820 capacity)
Next on the cards will be to replace the standard heat exchangers with a set of custom designed headers (yes, it made this power on stock heat exchangers & 100 cell cats!) and then to finish designing & test the new 9m high injector carbon intake system. Following on from there revised high lift cams & followers could possibly see us approach 440bhp or more.
I'll post the dyno curves on our website soon.
The new motor hit the dyno last night with its Mk2 9m pre-production machined-from-solid (billet) cylinder heads & the latest variation of our 103mm upset billet piston and posted the following data (6th gear, uncorrected)
Peak power 414.8bhp @ 7400
Power @ tyres 355bhp at 192mph
Peak Torque 326.3lbft 442Nm @ 5400
Torque spread over 300lbft from 4000 to 7000rpm
Specific power 109bhp/litre (3.820 capacity)
Next on the cards will be to replace the standard heat exchangers with a set of custom designed headers (yes, it made this power on stock heat exchangers & 100 cell cats!) and then to finish designing & test the new 9m high injector carbon intake system. Following on from there revised high lift cams & followers could possibly see us approach 440bhp or more.
I'll post the dyno curves on our website soon.
If you atarted from scratch with a standard 993RS (or 993/964/964RS for that matter) including Motec engine management but excluding exhaust mods, the turnkey engine would cost around £20k +VAT to build.
We know that at this price it will not be suitable for everyone, but in race engine terms it represents good value for money against something like the GT3RS-R engine at circa 45,000 euros. However the spin-off from the development are cylinder heads that will fit the standard 993RS engine and finally allow us to achieve tangible performance gains for a sensible cost (9m heads £750 each with valves, Porsche 993RS head £790 each bare), indeed we already have plans for a 360bhp 993RS engine that costs less than £10k to build.
The target lifespan "flat to the board" is 30 hours for the top end which exceeds the expectation for the factory GT3RS & Cup engines. I was once told that 24hrs racing is equivalent to 100,000 miles on the road, I'm not sure about that but I would guess that if the engine was used for trackdays with a sympathetic driver you would be looking at around 50-100hrs or possibly 2 yrs between builds.
We know that at this price it will not be suitable for everyone, but in race engine terms it represents good value for money against something like the GT3RS-R engine at circa 45,000 euros. However the spin-off from the development are cylinder heads that will fit the standard 993RS engine and finally allow us to achieve tangible performance gains for a sensible cost (9m heads £750 each with valves, Porsche 993RS head £790 each bare), indeed we already have plans for a 360bhp 993RS engine that costs less than £10k to build.
The target lifespan "flat to the board" is 30 hours for the top end which exceeds the expectation for the factory GT3RS & Cup engines. I was once told that 24hrs racing is equivalent to 100,000 miles on the road, I'm not sure about that but I would guess that if the engine was used for trackdays with a sympathetic driver you would be looking at around 50-100hrs or possibly 2 yrs between builds.
Probably thanks to all the development we have been doing at 9m I think it is pretty much common knowledge that the 964 heads have performance advantages over the 993 & 993RS heads due to the intake port profile. As a result, finding power in a 993 & 993RS engine is not as easy as our Motec/Motec +1 package for the 964 due to the head design. The solution is therefore to change the heads first.
You may suggest (rightly) that we shoudl fit used 964 heads, but it is not as simple as it seems because the heads are not truly interchangeable. The 993 heat exchangers are made symetrically and therefore will not fit on the RHS bank of a 964 headed engine because of the exhaust manifold studs of the 964 are asymetrical when built.
Thus for 993/RS owners these heads represent the first stage of real engine development beyond the limitations of the standard engine since they are a bolt on solution. I would guess that with a set of the 9m heads on a 993RS with a non-VR manifold, 9m sport cams & a remap we should see around 350bhp.
For 964 owners the 9m heads offer some advantages (better material, stonger design, precision CNC ports, etc.) but are not as critical, therefore for most the engine management will be the first priority in terms of upgrades. However it will not be too much longer before the original heads are cream crackered, so faced with buying a new set I guess it will be cheaper to buy 9m heads than buy new factory items.
You may suggest (rightly) that we shoudl fit used 964 heads, but it is not as simple as it seems because the heads are not truly interchangeable. The 993 heat exchangers are made symetrically and therefore will not fit on the RHS bank of a 964 headed engine because of the exhaust manifold studs of the 964 are asymetrical when built.
Thus for 993/RS owners these heads represent the first stage of real engine development beyond the limitations of the standard engine since they are a bolt on solution. I would guess that with a set of the 9m heads on a 993RS with a non-VR manifold, 9m sport cams & a remap we should see around 350bhp.
For 964 owners the 9m heads offer some advantages (better material, stonger design, precision CNC ports, etc.) but are not as critical, therefore for most the engine management will be the first priority in terms of upgrades. However it will not be too much longer before the original heads are cream crackered, so faced with buying a new set I guess it will be cheaper to buy 9m heads than buy new factory items.
Technically a 4.0 litre engine is possible but not desirable. We have specifically designed the heads to suit a 103mm barrel as we saw this size as the best compromise between running a larger bore with a stiff liner that maintains sufficient head gasket sealing area. The 104mm barrels of the 4 litre engines compromise reliability & strength too much for our liking.
Besides, since I have yet to see any other aircooled normally aspirated engine producing this kind of power, my guess is that a 4.0 litre package will be as effective as a 3.8 conversion on a standard 993.
Besides, since I have yet to see any other aircooled normally aspirated engine producing this kind of power, my guess is that a 4.0 litre package will be as effective as a 3.8 conversion on a standard 993.
MOD500 said:
Sounds like a great engine, Colin.
Though after putting £20k into the engine, then having a rebuild cost of £5-10k (?) every few years, surely it would be a better bet to buy a GT 2 / 3 to start with and use re-build funds to improve them?
....just wondering!
Thanks
Martyn.
Good point, not all of us have the facilities to rebuild/upgrade our cars at cost.
Please remember that this is a race engine.
Therefore:
1. Has anyone asked about the longevity of a GT3RS engine modified to 425bhp and then thrashed constantly on a track? Probably not. A GT3 race engine refresh will be due at less hours than our aircooled engine and cost double typically quoted in excess of £10k a time. The 9m engine will be less than £5k.
2. Practically everyone with a spanner (certainly every UK specialist) can rebuild a 964/993 engine in 40 hours with next to no special tools. Our race engine will need no extra expertise, the parts are all off the shelf. Very few specialists can build a GT3 engine (even when they have the tools!).
3. the 993RS is a way cheaper car to run than a GT3RS
4. The 993RS is a cheaper car to buy than the GT3RS (ignoring the sub 400bhp GT3's, the're not worthy) and it does not depreciate.
5. 993RS with 415bhp is just as fast as GT3RS.
6. 964RS with 415bhp will be insane (sounds perfect).
7. Ruf build fast limo's, not track cars.
Therefore:
1. Has anyone asked about the longevity of a GT3RS engine modified to 425bhp and then thrashed constantly on a track? Probably not. A GT3 race engine refresh will be due at less hours than our aircooled engine and cost double typically quoted in excess of £10k a time. The 9m engine will be less than £5k.
2. Practically everyone with a spanner (certainly every UK specialist) can rebuild a 964/993 engine in 40 hours with next to no special tools. Our race engine will need no extra expertise, the parts are all off the shelf. Very few specialists can build a GT3 engine (even when they have the tools!).
3. the 993RS is a way cheaper car to run than a GT3RS
4. The 993RS is a cheaper car to buy than the GT3RS (ignoring the sub 400bhp GT3's, the're not worthy) and it does not depreciate.
5. 993RS with 415bhp is just as fast as GT3RS.
6. 964RS with 415bhp will be insane (sounds perfect).
7. Ruf build fast limo's, not track cars.
ninemeister said:
7. Ruf build fast limo's, not track cars.
Mostly
, but not all of them 
. Mine is ok on track
and so are the RGT and RGT RSR (which was in the 24hrs Nurburgring race this year). Some pics here.
www.6speedonline.com/forums/showthread.php?s=&threadid=16374
That said they are all very expensive.
Guy
Colin,
We have discussed this before, but I have forgotten what you said, so here goes!
My car has RS Tuning bits on: throttle bodies and fancy intake system/uprated valve springs/cams (?cup cams?)/Cargraphic manifolds and exhaust with 100 cell cats. As you know, you got the car making a good but peaky 348 BHP, and 300 lb/ft torque, but the torque curve isn't as beefy as you like 'em.
My Cargraphic manifolds need replacing soon and you said I should replace them with standard 993 manifolds because their narrow diameter increases torque, so this I plan to do. The way I see it, the major limiting factor for my engine to produce a bit more power and much better torque is the head design.
Now I know you would love me to buy your own throttle bodies/intake/cams but this could cost me a lot, even if I do sell my own present hardware on Ebay or whatever. Perhaps by buying a second hand set of 993 manifolds and your own bespoke 9M heads.....I could have a nice solution on something like a reasonable budget?
So what might I be looking at for labour for the above reasonbly conservative modifications including mapping and VAT? What sort of power and torque could I get? (and I know you don't like the Euro-throttle bodies/cams etc on my car!!) and finally, is all this modifying limiting the life of my engine by much? Surely if I come away with, say, 355-360 BHP and 330 lb/ft torque I won't be looking at rebuilds every 5 minutes?
PS.....if you did do the head and manifolds only on my car, what other mandatory work would you do (and me have to budget for) whilst the engine is in bits?.....I'm thinking about valves/injectors, that sort of thing....oh yes...and then there's the obvious stuff like the gaskets and 10L of oil to put in the bloody thing!!
We have discussed this before, but I have forgotten what you said, so here goes!
My car has RS Tuning bits on: throttle bodies and fancy intake system/uprated valve springs/cams (?cup cams?)/Cargraphic manifolds and exhaust with 100 cell cats. As you know, you got the car making a good but peaky 348 BHP, and 300 lb/ft torque, but the torque curve isn't as beefy as you like 'em.
My Cargraphic manifolds need replacing soon and you said I should replace them with standard 993 manifolds because their narrow diameter increases torque, so this I plan to do. The way I see it, the major limiting factor for my engine to produce a bit more power and much better torque is the head design.
Now I know you would love me to buy your own throttle bodies/intake/cams but this could cost me a lot, even if I do sell my own present hardware on Ebay or whatever. Perhaps by buying a second hand set of 993 manifolds and your own bespoke 9M heads.....I could have a nice solution on something like a reasonable budget?
So what might I be looking at for labour for the above reasonbly conservative modifications including mapping and VAT? What sort of power and torque could I get? (and I know you don't like the Euro-throttle bodies/cams etc on my car!!) and finally, is all this modifying limiting the life of my engine by much? Surely if I come away with, say, 355-360 BHP and 330 lb/ft torque I won't be looking at rebuilds every 5 minutes?
PS.....if you did do the head and manifolds only on my car, what other mandatory work would you do (and me have to budget for) whilst the engine is in bits?.....I'm thinking about valves/injectors, that sort of thing....oh yes...and then there's the obvious stuff like the gaskets and 10L of oil to put in the bloody thing!!
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