6.0 Litre V8 Ls2 into 944 Turbo
- Thread starter andye
- Start date
422hp944
New member
Andrew - I think it's great that you are offering this conversion and i'm sure when people see the finished car and even more so...drive it...a lot of guys on here will be converted to the idea if not already. The peace of mind having the chevy engine as the chosen powerplant is very tempting. I lived in the States for 3 years and have seen firsthand the positives of these great engines..i.e...power and reliability! Even assuming the V8 went " Bang " at the track from serious abuse the cost of internal parts are peanuts compared to porsche items....I've seen 8 racing rods for chevy engines supplied brand new for less than a third of the price for comparable 944 rods ( and you only get 4 of them! ). All in all the LS2 route is the way to go for serious power thats unburstable in my view. The only thing that would concern me would be the drivetrain. I'm running 420 bhp as you know and having ( only 420 bhp ) power under my right foot I mangled my torque tube...it literally shredded itself at the gearbox end!!... Now....Am I just the unlucky one or will this be a regular event with that kind of power and upwards with the potential the LS2 has to produce? Would the drive train be beefed up in anyway?
AndrewS
Member
Hi John,
Nice to read from you again! Rather than beef up the components, the plan is to program the PCM to limit the torque in specific gears at certain points to ensure that no component suffers any undue torsional stress when the throttle is mashed to the floor.
This is preferable to changing the properties of some components, but ultimately some components may need to be changed (testing on the track will provide that information). Your torque tube is almost certainly original, hence has done over 200,000 + miles and all the track days I did from 1997 to 2004 (at least 30).
In my experience, the running gear components of the 944 Turbo are very tough. Both my last 944 Turbos have done loads of track action and I have never suffered any drive or running gear related issues. The weakest point has always been the engine. As some may know, my cars are generally tracked on slicks and don't get an easy time. [
]Regards,
Andrew
422hp944
New member
Hi Andrew - I'm glad you confirmed the torque tube is the original. It makes sense now and considering the mileage, track days and power it's well past its best....It has got 220K on it so cant really complain
Jonny944CS
New member
IIRC, I read somewhere that the factory retained the standard Ø25 drive shaft for the 924 Le Mans prototypes (16v 400+hp), thereby retaining the std bearings and keeping weight to a minimum.
How did it survive? Rubber donuts - integral to the drive shafts between the diff and the wheels to absorb impulse loadings.
How did it survive? Rubber donuts - integral to the drive shafts between the diff and the wheels to absorb impulse loadings.
Andrew, excuse my ignorance but what is this PCM you refer to? Porsche 'C' Mgmt...
Are you installing some sort of traction control too? So for 20k you get the LS2 installed drive away and with a warranty? What other 'refurbishments' are included? Does this not include the cost of the car as well or is the customer to provide their vehicle?
Oh, not sure about the actual torque tube design of the 924 Le Mans racers, but here's the transmission and axles. Note how much beefier they are from stock. Makes you think....
Are you installing some sort of traction control too? So for 20k you get the LS2 installed drive away and with a warranty? What other 'refurbishments' are included? Does this not include the cost of the car as well or is the customer to provide their vehicle?
Oh, not sure about the actual torque tube design of the 924 Le Mans racers, but here's the transmission and axles. Note how much beefier they are from stock. Makes you think....
AndrewS
Member
The PCM (Power Control Module) is a function of the GM central ECM (nearest equivalent on a 944 is the ECU). Comparing the GM PCM to a near 30 year old ECU is like comparing a modern high performance PC to the original 8086 IBM PC - things have moved on (a lot). Traction control could be installed - but that would be optional. The GM PCM has the capability to manage traction control.
The 20k GBP cost is for a complete car. not for an LS2 installed in a customer car. A warranty could only be offered for a complete vehicle. Hence, the package would be a drive away 944 Turbo V8 with 450bhp (all subject to confirmation - see post at beginning of thread by andye). Power would be dyno verified.
Also, by offering the complete car package, it avoids any risks associated with somebody's car becoming a long term project (becuase of issues with their own car). If anybody wants to discuss in detail, get in touch with andye.
Regards,
Andrew
Ummm, why would this help? Given that the component giving concern is the torque tube, and this is between the engine and the gearbox, limiting the engine torque in any one gear won't help. It is subjected to the full torque output of the engine (at full throttle, naturally), no matter which gear the transmission is in ...
(Please feel free to correct me if I am missing something! [
] ) Oli.
AndrewS
Member
ORIGINAL: zcacogp
Ummm, why would this help? Given that the component giving concern is the torque tube, and this is between the engine and the gearbox, limiting the engine torque in any one gear won't help. It is subjected to the full torque output of the engine (at full throttle, naturally), no matter which gear the transmission is in ...
(Please feel free to correct me if I am missing something! [
Oli.
Hi Oli,
Best way to explain is as follows:
Imagine you have a wooden shaft with a handle at one end and a large heavy weight at the other end. The wooden shaft is supported at both ends by mounts and will turn freely (see picture)
If you violently turn the handle, the shaft may snap. If you turn it more gently and then gradually increase the speed and force with which you are turning it, the weight will turn and the speed of the weight turning will increase. When the weight is turning quickly and you increase the force at which you are turning the handle - the shaft will not be as stressed as if you attempt to turn it with great force when the weight was stationary.
This is the principle of torque management which can be achieved electronically.
Regards,
Andrew
AndrewS
Member
I would also add (apart from my little picture looking a bit like a K9) that's why drive shafts get such a hard time when racing (and why big rubber donuts are sometime used to absorb the twisting forces applied to them).
In the Porsche Cup (when the 944 Turbo was racing), drive shaft fauilure was common from the start line (hence the need for beefed up driveshafts from GKN).
Regards,
Andrew
In the Porsche Cup (when the 944 Turbo was racing), drive shaft fauilure was common from the start line (hence the need for beefed up driveshafts from GKN).
Regards,
Andrew
Essentially are you limiting how much work is done on the shaft itself? So to take your handle with the fixed mass analogy, when you spin it quickly a lot of the work you do is twisting the shaft rather than spinning the mass due to overcoming the inertia of the mass (it doesnt want to move to start with).
AndrewS
Member
I should also have added that limiting torque in specific gears could safe guard the driveshafts. Specific RPM torque limitations could be required to possibly reduce the stress on the torque tube assembly.
However, I think the torque tube is probably more than capable of handling the power. MarkK's car (which was dyno tested in 2006 with 440+ bhp) is still runing well with it's original torque tube and driveshafts. The car's done many track days and shows no signs of any stress related issues when it's brought in for inspections.
John Daly's car (422bhp 2.8 Stroker 944 turbo) has done 220,000 miles - 30,000+ with 422bhp and well over 30 track days! Again, torque tube failure is very rare and this is the first case I have read about.
Regards,
Andrew
However, I think the torque tube is probably more than capable of handling the power. MarkK's car (which was dyno tested in 2006 with 440+ bhp) is still runing well with it's original torque tube and driveshafts. The car's done many track days and shows no signs of any stress related issues when it's brought in for inspections.
John Daly's car (422bhp 2.8 Stroker 944 turbo) has done 220,000 miles - 30,000+ with 422bhp and well over 30 track days! Again, torque tube failure is very rare and this is the first case I have read about.
Regards,
Andrew
Andrew,
Thanks for the explanation.
I *think* I *may* understand it. (Alternatively, I may just sigh, recall that I failed a mech.eng. degree many years ago and accept both that there are people who know more - much more - about these things and the wisdom that such people dispense!) [&:]
Oli.
Thanks for the explanation.
I *think* I *may* understand it. (Alternatively, I may just sigh, recall that I failed a mech.eng. degree many years ago and accept both that there are people who know more - much more - about these things and the wisdom that such people dispense!) [&:]
Oli.
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