I’m new to the forum but thought i would share where I’m at with this conversion for my 1984 S3 HE sedan. Box is assembled on the bench and all other parts acquired awaiting a time slot availability with my genius mechanic and for me to get a week off work so I can climb under and do the heavy stuff. We’re not planning on making driveshaft mods. The standard diff is a 2.88 (its a NZ car). Ratios are as follows: 3.76, 2.19, 1.41 and 0.86. 0.72 was also considered for 5th. Wheel/tyres are standard 215-70s on the lovely 15in Pepperpots (rolling diameter 26.85in). However, because decent tyres are so hard to get for 15in rims these days I’ve been offered a set of very nice XJR 16in rims with Pirelli P6000 tyres and I believe these may be the way forward. Just on that topic of rims- I don’t know why some foundry doesn’t produce a limited run of 16in Kent rims as I think the Kents are simply the greatest for 70s/80s jag sedans and I’m sure they would sell like hot cakes. Anyone agree?
Yes indeed, it would be the best of both worlds, depending the cost of course.
Aristides
Should be fun
A T5 and Kents are the way to go!
I always thought the T5 to use is one of the “World Class” versions with the 2.95 first gear that were original on Mustang GT 5.0 V8, because there is a real strength difference vs. the 3.76 first gear T5.
Your choice of ratios for the 2.88 is absolutely the best set I’ve seen yet for the 2.88. It is what is required to continue to use the 2.88.
I recognize the fragility of the 1st gear relative to the 2.95 or so another lister has suggested, but, I have driven a 3.27 first against the 2.88 and its too tall. The 3.76 oughta be JUST RIGHT. That, and the spread is exceptionally well chosen. Really inspired- can’t say enough!
I would not go 2.95 first unless you have at least a 3.54 in the diff.
Well done! I will be looking forward to your driving experiences.
-M
The T5 needs SERIOUS aftermarket help. The “World Class” T5s are weak, the non-World Class T5s are outright pathetic.
A heavy car, “highway” rear-end gearing, and sticky tires make things even worse. Very mild driving makes things a bit better. (i.e., not using much throttle, and very gentle with the clutch) What fun is that?
Guys want to put T5s behind tuned ~5-liter V-8s. My advice is to install them using wing-nuts, so when they shatter they’re easy to replace. GM and Ford put WC T5s behind 305s and 302s, and had heaps of warranty issues despite stock tuning.
As always, there are some aftermarket “solutions” to the OEM problems; but they get expensive.
IIRC, the ones in Mustangs were better than the ones in Camaros. It might
have been that the 1st gear ratio wasn’t so low, so it had less tendency to
tear up, I dunno.
I used a NWC T5 in my '83. I never had any trouble with it, but then again I
didn’t really abuse it much.
– Kirbert
The 3.76 first gear T5 was used in low powered 4 cyl and V6 applications that are much lighter than your S3. Your car is ~ 4,400lbs not including fuel and passengers. I’m sorry, but it is unlikely to last under spirited driving - and nobody does a manual transmission conversion for gentle cruising.
I understand your dilemma with the 2.88 differential ratio and wanting it to be quicker off the line. At 6,000 rpm a 3.76 first gear gets you to 45mph vs a 2.95 first gear which gets you to 54mph.
Here is one of the stronger 2.95 T5’s available rated for 400hp and 330 torque:
https://www.astroperformance.com/product/new-tremec-t-5-5-speed-transmission/
There are some billet components and stiffeners that will work in lightweight (3,000lbs and lighter) drag cars that run into the 9 second zone and increase the transmission torque capacity. The T5 was never intended for heavier cars, its case design and gearset are too lightweight.