Peckster

This is a joke, right?

Dave951M

I think BoostGuy is serious if somewhat misguided. There are those who persist in attempting to make drag cars out of the 951. To me that's on par with doing it to an E type Jag. It's just not what the car was designed for, but with enough money and determination, anybody can build about anything.

billgot

Boostguy951 I have been dealing with this CV problem for a while now.I dred going to the drag strip because I know I walk the line with the CV joints.I have 3 broken CV at the track to my credit.I know you have to first stop any wheel hop you have because that will break a CV quicker then power will.I have Drag radials on my car currently and busted a CV joint with them.I also busted my orig Tranny input shaft.All this destruction and the only thing I can tell you is keep fighting the good fight.You want to run the 1/4 mile do it.I have upgraded my butt off to get better times.The one thing that always comes back is the dam launch I am up to about 115 MPH threw the traps but my times are High 12s breaks my heart.I am just looking for the one magical run where the wheels hook up nothing breaks and I hit the low 12's high 11's I might be dreaming but I am not goona give up.I say you keep looking for the solution I know I am.The only good thing is I never broke a CV on the street.Corvette's use a similar designed axel and the can hold 600+ HP We just need the right people and money to do it.

BoostGuy951

Keep fightin, Brother!





If you guys want to start a drag race bashing thead, by all means go ahead. But do it on another thread. You can look down your nose at this form of motorsport, that is your opinion, and I respect that. I can not remember how many times I have been told not to drag race my 951. I AM going to do it. There are alot of us that are going to do it. So nay sayers, your opinion is noted, and disregarded.

Yup... and we will.


Again, true. It was not designed to be a drag car. But neither was it designed to be a track car either. It was designed to be a street car, and yet in the name of "Track race preparation", people rip them apart to the bare metal interior. People install highly modified engines that were never "Meant" to be in there (ie the 104mm block and crank). They replace every single body panel with fiberglass. A properly prepared track car is worlds away from how it rolled out of the factory, and this is totally acceptable. But if someone wants to strengthen the drivetrain for drag racing, they are Misguided.

DaveM, I resent your comment. Who in the hell are you to call me misguided? When are we going to have some tolerance on this *$&@ing board?

Tomas L

The reason Porsche owners don't like drag racing is because we get our *** kicked :-( But insted of admitting it it's easier to find other excuses...

I don't think welding is an alternative. If you can keep the axle straight after welding it, which is not very easy, you probably can not line up the suspension to fit the axels. My guess is that the gearbox axles are a bit fore or aft of the wheel centreline. If its possible to line up everything you have to replace the shock with stiff bars to kill all suspension movement which probably makes the car impossible to drive even on a flat dragstrip. If you do succed with this chances are high that you still will break something because the unability to flex, my guess is on the welded cv joints. To weld a heat treated component is not a good idea.

I think the best way to handle this would be if it is possible to find parts from another car that can be machined to fit. What about 930? Or big Mercedeses or BMWs? IIRC there are some big engined fwd US cars?

Tomas

Dave951M

In addition, the CV joints not only flex as they rotate, but as the axle swings with the suspension movement, the distance center to center of the CV joints changes as well. It's not much, but enough that welding is not possible. Back to the solid rear unless you can adapt a beefier part.

And Boost- no need to get huffy about dragging. The fact of automotive life is that there are very, very few in the Porsche world that really care about it. I don't know if it's a sports car thing or whatever, just that you don't see many Porsches on the drag strip. The preferred venue for sports cars is road courses, pure and simple. That would also bring up a debate on just what constitues a sports car. So take it for what it's worth. Lots of sports car types (fill in the marque) don't care too much about the 1/4 except as a tool to compare acceleration rates. That's just the way it is. But like I said before, it's your car and your money and modifications that might make you quicker in the 1/4 are not compatible with road courses.

Tomas L

Why is a more powerful engine not compatible with a road corse?

Tomas

rage2

The stock tranny is fine if you don't launch it. I was on street tires, and Autothority chipped car (270hp) when I broke 2 CV's a year, and chipped 1st gear after a year or two. I'm currently running GKN OEM's (not motorsports), street tires, and stock tranny. It holds up fine as long as there's no powershift from 1st to 2nd, and no huge launches (I feather the clutch).

If you were to use slicks, I'd expect you to lose 1st gear after a night of runs... that's if the CV's don't break .

Peckster

I'm afraid not.

Maybe our friend is planning to weld the rear suspension too. Even then, it doesn't make sense to weld the CV.

Matt H

I dont think it has much to do with whether or not it was designed for it, plain and simple it just costs to much f*ckin money. If you trash a Ford V-8 rear end who cares, go get another one out of the junk yard for 200 bucks, trash your 951 gearbox and you are talking 1000 bucks give or take.

You can run slicks, or at least it isnt wise to as you will break trans parts or worse still torch the clutch, so you cant maximize your times.

I commend you for doing something different but I just cant see the economy of it. If you want to go real fast like that then I know plenty of 9.0 sec Mustangs for sale.

Why is a more powerful engine not compatible with a road corse?

It will need 1000 lb rear springs or more in order to keep the rear end from squatting to get a launch worth a damn. Much different damping on the rear shocks (really need a very heavy duty coilover, which presents an entirely different set of problems, mostly that the mounting point for the rear coilovers should not really be subjected to launching as I am sure they will eventually break), and we are not now nor have we ever in this thread discussed the power of said car. No one has said he cant make it fast enough, they have said that it is impractical (which it is).

Boostguy - if I were you and you are serious about doing this then I would contact any of the axle makers and have them make you a set, it is gonna cost you a bunch but it is the right thing to do. Someone else already pointed out that after CVs something else will break, you can make that part stronger or continue to replace it. My concern would be toasting clutches (we all know how much fun dropping the exaust is) and trashing transaxles (they are not real cheap).
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FSAEracer03

...whoa... 1000lb or more?? Jeesh!! Is that much stiffness seriously necessary? Personally, I'd be wary of driving a car that stiff...

For toasting clutches... I know Performace Products sells CenterForce clutches/pressure plates that claim to hold up to 90% more power... though they're $1500... they might last longer

H2Opumpr

Have you considered custom made universal joints with custom shafts like the older vettes run? I believe that idea had been mentioned earlier in this thread.
I had a buddy who dragged his older vette into the 11's and from what I remember those older universal style rear suspensions dont like to much flex, but seemed to be strong. A stiff rear spring and good geometry help with 60 foots on an IRS. Seems as though there is a trade off with IRS, but Ford seemed to find a way to make the '03 supercharged mustang handle and hook better than the '01 and previous years with some geometry mods.


I commend you on your dragging a 951. Now, do you wanna find an auto trannie so you can torque brake and build boost off the line and realize the E.T's you can really make...Oh and the consistency too...
Always wondered about a 928 trannie?

GMS

You would not be able to run U-joints unless you either a) redesign the rear suspension or b) had a splined joint in the axle to allow for axle plunge. The problem is that the spline joint will lock up under load, thus locking the axle length, this will then break something. Older race cars use a a ball-spline joint to try and eliminate the locking up under load. The Corvette uses a completely different system where the axle is a fixed length and is actually used as the upper suspension link (same as Jaguar
E-type) You can't run solid cv joints as the suspension moves in an arc (as stated previously) and therefore the axle length has to change. It's not possible to run a solids rear suspension as you would loose traction. even Top-Fuel dragsters have some sort of rear suspension movement.

Turning the 944 into a dragster is going to be a long and expensive process as the weight transfer under load (because if the poor weight balance for drag racing) only stresses the trans and related components above their design limits. I would suggest you read some technical books about drag race car dynamics. Your basic lack of knowledge of suspension theory is going to be a drawback in your quest.

rage2

Wouldn't you want less stiffness in the rear to get the weight to transfer to the rear for better traction?

I know when I went with a stiffer rear suspension setup, I lost a lot of traction. My stock soggy suspension was wicked for the dragstrip. No wheelspin in 2nd gear and up, even when powershifting.

Matt H

What you really want is very stiff fronts, longer than normal shocks in the rear (say 6" of travel) and a very stiff shock with a medium spring. The softer the shock the more traction off the line BUT you run a very real risk of bottoming the shock out. Drag racing works as a system just like road racing, if you want to be good at it there are a lot of trade offs from every day use.

GMS - is right, the transfer of weight and where it sits is also a problem.

HOWEVER, I dont think he is talking about ANY of this. What he wants to know is if he can take his DD there and have some fun without breaking CVs. In that case I suggest as did someone about an inch down that you have custom CVs made.
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