blown 944

Finally broke a transaxle.I added up my runs and I made over 180 passes with this one.

Tried some shorter goodyear drag radials and the thing hooked like never before. Got off it and back on it right off the line. Still ran 11.8 and the mph was .... 125 mph!!! That run definately did some damage to the pinion gear. The next run it let go going into third gear. I could hear a little bit of a different noise when cruising through the pits. I probably should have called it a day.

Although it was a break day, I still ended up happy. That MPH puts me at close to 500 rwhp at low boost.
This thing likes a little lower gear at this boost level.

Put the spare transaxle in this morning and pulled both the recently broken one and one that had a second gear issue from a few years ago. I think I can use one of the gears out of my recent transaxle in the really old one to have another spare.

pic of the carnage. Kind of strange that the pinion took so much damage and the ring gear isn't even close to being as bad.

Xaerran

rutrow!! It sounds like you still had a fun and productive night! Congrats

V2Rocket

perhaps you should send your case off for machining...i forget who it is but someone offers a service where they machine part of the trans case and install a billet reinforcement plate that keeps the pinion in place better (apparently they find the issue to be flexible casting)...maybe the V8 guys do it?

blown 944

I think I saw something about that on renegade hybrids.I'll look into that further.

333pg333

Do you mean a billet side plate? I got California Motorsport to make one up for the 968 gearbox. Considering it was the first one they did the price was very reasonable I thought....just can't quite remember how much. But I'm sure they could do something similar.
That's an amazing ET Sid on such low boost. The mind boggles!!

Will Feather

Sid, I think you showed some interest perviously in running a G31? Ever consider it? Not sure if it would best suited in a drag race environment.

V2Rocket

heres a picture of it...
http://stweb.peelschools.org/sssweb/...upgrade20.html


http://944hybrids.forumotion.com/t87...ates-we-got-em

admiralkhole

Are you talking about this?

http://stweb.peelschools.org/sssweb/...tep/index.html

TPC sells the reinforcement plate. You get the end cover on the trans milled down 1/4".

I've heard of guys being able to beat on the trans more and launch harder with this done, I don't have any first hand experience with the mod yet though so you might want to do a little research first. I have an extra end cap that I've been saving to get milled down, I just keep forgetting about it.

EDIT: looks like we found it at the same time lol

blown 944

From what I have read, the gears are quite a bit beefier. I was going to do the swap before I dropped the valve in my last engine but had to spend the $$ and time on engine. It requires swapping the trans, TT, and shift rod IIRC. I had a line on a local car, but didn't want the whole car and then the engine broke too. I may really get into this again soon if another option doesn't present itself. I'm also going to talk to the guys over at gbox and see what they may recommend as a best starting point.

Thanks for the links Spenscer, I'l read again on how it strengthens the trans overall, but doesn't look like it does anything for the R&P to me


Also thanks for the link. If nothing else I'll keep the a spare end cap to do this.

blown 944

Did they tell you how it improves the trans? I'm guessing that it stabilizes the ring gear under load.

Not so proud of that ET since I've ran 11.6, but the MPH..... Now that is impressive to me.I tuned it just a little leaner than I had it and swapped tires. Obviously it liked it.

I'm thinking that it'll run 130 at well under 20 psi. If I get the other spare trans fixed this weekend I'll turn it up a little on weds.

V2Rocket

maybe a later-model audi trans is stronger in the R/P department...?

Dave W.

The pinion shaft pushes away from the ring gear under load. When the case flexes the pinion moves farther away from the ring gear. You want the load pushing against the base of the teeth where the teeth are thickest. When the case flexes under high power the load moves up toward the tip of the teeth. The billet side cover can also help stabilize the diff/ring gear. Another way to partially compensate for case flex is to shim the bearings a little tighter, just a few thou can make a difference.

blown 944

I'm still trying to figure out what the plate does? You still have the main case mating to basically the same surface area with a shim between. I didn't really have a chance to take a real look at it today.

333pg333

Sid it's been some time since I was in discussion with CMS but I know this is not an uncommon mod for GT3/2's, Cups etc as the cast part is prone to cracking. I would think that for you this wouldn't hurt but might be worth contacting them to discuss. I dealt with Roger who was very helpful.

Dave W.

It's hard to see in this pic, but maybe the plate sits against the flat spot where the bearing rides? In this pic the pinion shaft is low/center. It looks like there's a machined flat that might be on the same plane as the case end. I can also see a slot at 2 o'clock that lets oil flow into the bearing, but it might be a weak spot too.