HOW TO DO AN ADVANCED SEARCH.

Mon Jul 08, 2013 3:56 pm by Admin


For the benefit of 944Hybrids users there are two search functions available for you to use.
The purpose of this sticky is to explain the "Advanced Search" function because it is much more powerful and is the best choice when researching information.

When you log on to the site a list of options is shown in a line at the top of the page. One option is labelled "Search", use this option (NOT the search box lower down on the right).

After you click on the upper search option, a drop down box appears. At the bottom of this box is a radio button marked "Advanced …

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Turbo transmission mods

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Turbo transmission mods

Post  Admin on Wed Jan 20, 2010 7:46 pm

Does anyone have a list of things that could be done to make the turbo transmission the best it can be. And if you know of any shops that can do the improvements would be nice to have that posted as well.
I am looking make the turbo tanny handle 400+hp all day without giving it a second thought. No drag racing, just good hard daily driving.

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Re: Turbo transmission mods

Post  Porch on Wed Jan 20, 2010 7:58 pm

For 400whp, everything i've read says it should be fine as is!

But for the heck of it, if i were to build an all-out transmission: rebuild it, install a 3/8" plate behind the pinion, put a good cooler on it, and then have the whole thing cryo-treated. Solid mount, of course. Should be more than enough to start snapping axles!
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Re: Turbo transmission mods

Post  Admin on Wed Jan 20, 2010 8:12 pm

If you put the 3/8" plate in there what do you do to the case to make it fit?

Is the solid mount necessary for a daily driver?

What could be done to the NA tranny to make it this strong?

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Re: Turbo transmission mods

Post  944-LT1 on Wed Jan 20, 2010 8:12 pm

The transaxles in these 944's have a terribe tendency to twist to the left, putting massive strain and pressure on the drivers side CV and during such events, the left rear wheel is sometimes pushing back. Hence the 944 drivers side CV horror stories.

Ive seen people welding up make-shift panhard bars that attach to the tranny mid case and then to the transmission crossmember and then another from the rear of the tranny to rear upper shock mount using spherical bearings and tubing. That takes care of the torquing and CV problems. But the biggest upgrade for hard driving that I always read about is the solid transmission mount. These mounts in conjunction with the panhard bars should really help in hard driving. Shifting should be more precise, CV's happier, and mo' power translation.

Heres some stolen pics.

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Transaxle cover plate?

Post  87-944S on Sun Jan 31, 2010 5:53 pm

I've heard mention many times of a thicker cover plate modification. Does anyone know where to find such a beast? One of my winter projects is to install the Guards ATB diff I have, replace some bears, install shift kit. I figure before this transaxle goes into the car, Id add the plate if one was available. I already have a solid transaxle mount. Thanks,
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Re: Turbo transmission mods

Post  Porch on Sun Jan 31, 2010 7:16 pm

Well first of all...do NOT do the mod that 944-LT1 posted pictures of! The guy who did it took it off a week later because he said it was rattling no matter what he did to it!

But solid mounts/filled mounts are great! I filled my stock mount with 80 RH polyurethane. It was easy (i just scotch-taped the entire outside of the mount except the top and poured it in) and cheap. Still have half the stuff i used, i'd be happy to sell it to you for $20/shipped. It made a noticeable difference in keeping the transmission still without causing any undesirable NVH... On a launch the transmission doesn't jump around like it used to, which is what causes the CV's to break!

As for the plate mod for the trans, i think there's a picture in the manual? I dunno, i still haven't gotten mine Embarassed Someday soon! It does require you to mill the thickness of the plate off of the piece of the transmission housing that captures it. I don't think anyone has made the plate so far. If someone gets a run of them i'd be willing to buy one at some point....
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Re: Turbo transmission mods

Post  944-LT1 on Sun Jan 31, 2010 7:26 pm

Ones ability to handle the vibrations is different than the topic of the thread. Very Happy Its the same idea of solid motor mount plates.

Regarless, you can beef-up the entire drivetrain but something has to give or act as a "fuse".

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Re: Turbo transmission mods

Post  Porch on Sun Jan 31, 2010 9:24 pm

Okay, fair enough Very Happy
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Re: Turbo transmission mods

Post  Arthropraxis on Sun Jan 31, 2010 10:18 pm

I remember reading that thread on Rennlist. The heim jointed strut brace rattled. The bolted at either end was fine but there was a concern about not allowing for some movement vertically, hence trying the heim joint. I like the urethane mount solution and plan on doing that. I would think running fat sticky tires doesn't help the whole CV breaking issue. I am going to run 245's and make that my "fuse". Tires are easier to replace than axles.
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axles

Post  gamman on Sun Jan 31, 2010 10:57 pm

I would think running fat sticky tires doesn't help the whole CV breaking issue. I am going to run 245's and make that my "fuse". Tires are easier to replace than axles.

I just had this exact conversation with the guy from Raxles. Moving the fuse is what he called it when i was asking about what type of beefed up axles people had been asking for.

Thread drift.
For what its worth, his axles are "rebuilt" sticks, and he uses new cv joints from the "same place" that supplies the porsche factory (?), so they are basically new factory axles. I read somewhere that this place (raxles) was better than stock. He said no, they are the same as stock parts. $200/axle, not bad for new.

However, he said the "upgrade" that people want and should use the 25 splines from the 968 (or whatever the 968 had), which although they have diff splines, they are stronger (due to less joints), and bolt right up). However, that is when he mentioned about moving up the fuse.

I talked to expuppy about this, he keeps an extra when doing one lap.

For what its worth, I would prefer to spend the $1200 (what a used LSD diff costs) on rebuilding a NA to be very stout with all kinds of stuff. Go for it! Of course, you would need to get some kind of LSD. If it came in at ? 1800?? (can that be done?), I would be all over it. 2400 would be a bit too much.


Last edited by gamman on Sun Jan 31, 2010 11:01 pm; edited 2 times in total (Reason for editing : to correct.)
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Re: Turbo transmission mods

Post  Porch on Mon Feb 01, 2010 12:22 pm

The (eventual) weakness of the NA gearbox is that 1st and 2nd gears are not hardened, and neither is the R&P. If you're going to spend the money, just get a good box to start with!

I see low mileage LSD & Cooled Turbo transmissions on ebay all the time for $1000-1200.

I'm a little curious how much worse the stock LSD is than a performance unit, but anything is better than nothing!
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Re: Turbo transmission mods

Post  Luke714 on Sat Mar 13, 2010 4:33 pm

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response

Post  gamman on Sat Mar 13, 2010 11:20 pm

I have been watching TonyG responses to people. His car is as built as any.

His response to people is that he has a spare 5R tranny (R016 I think - basically a non-lsd with cooler).

He does not use the hardened trans, because his LSD is about 2500, and he feels it isn't worth the extra $. His current trans is about 2 years old. He is waiting for the 2yr old rebuilt one to blow, and he will swap the stocker back in. refreshened of course.

He has a completely different cooling setup (IE: a real roadrace cooling package) and he installs or swaps his LSD (massive write up on that - summary: if you really road race, you want a guard (TBD I think its called - 2way), if you autox and RR a bit, a motorsport type lsd will be ok, if you just drive on the street, a stock lsd with refreshened plates should be enough).
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Re: Turbo transmission mods

Post  v8carreragts on Mon Mar 15, 2010 6:19 pm

The things that make the turbo transaxle stronger are (this applies to the turbo, S and S2)

The slightly larger ring gear; larger front pinion bearing; 3rd and 4th gears are splinded to the pinion shaft as opposed to press fit on the non-turbo, S and S2.

These are the big things that increase strength. For the most part, everything else is the same.

The (eventual) weakness of the NA gearbox is that 1st and 2nd gears are not hardened, and neither is the R&P. If you're going to spend the money, just get a good box to start with!

Not true. All gears are hardened otherweise they wouldn't last 50 miles...especially the ring and pinion. The type of hardning can differ however. The only ones with special hardning are the turbo S transaxles. These have shot peened shafts and gears.
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Re: Turbo transmission mods

Post  Vorsche944 on Mon Mar 15, 2010 9:06 pm

So if I am reading all the thoughts on this thread, what I think I am hearing is:

There are basically a couple of solutions to the question Admin asked in the beginning of this thread.

A Turbo Tranny is preferred, LSD is optimal.
Solid or filled mounts will help both Turbo and NA's
The Plate addition will help both Turbo and NA's

The issue of upgrading the tranny only moves the "fuse" to somewhere else. So in designing your solution options, plan for your fuse location and how it will pop. Tires, Axles, Transmission, CV joints ?

If you are building a race car, then the tranny should be a Turbo, LSD optional, with all the mount upgrades and plate added in. Should handle a race fine.

So what do we define a race car as in our V8 conversions. Are we saying that > X HP or > X Torque coupled with this set of x size tires equals this level of mod requirements?

How about a daily driver configuration?

So let me pose another question, for a Daily driver, NA Tranny, if we did the Solid mounts, Plate addition, stock to 9" tires, would this be a usable solution? If not, what could we do to the NA to make is usable? What are the weaknesses and strengths of the NA solution?

Your input is appreciated.

By the way, I like the way Gerry is specifying whether he is talking about a Race or Daily driver setup to keep the content of his comments in perspective.
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Re: Turbo transmission mods

Post  v8carreragts on Mon Mar 15, 2010 10:48 pm

One thing to remember is that when you talk about N/A it means non S or S2 both of which are N/A but have a transaxle of equal strength as the turbo. The difference is the final drive ratio.

Early N/A 9:35 3.888-----smaller ring gear 7.188" with pressed on 3rd and 4th
Turbo 8:27 3.375-----bigger ring gear 7.306" with splined 3rd and 4th
Late N/A 8:31 3.875-----Bigger ring gear 7.306" with splined 3rd and 4th
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