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Posted by: Bill Smith Nov 26 2009, 04:14 PM

I recently had a transmission go out on my 914 after 3 years at a DE. My car has a stock 3.2 with a Euro chip and custom Exhaust. I lost 4th gear. Had the usual problem with getting into first. I was also running a Quaiffe Diff. When it happened, I only did one lap due to an unusual noise and then called it a weekend before I tore up the quaiffe. When I got it apart the only two problems were that 3 teeth were missing on one of the 4th gears and the double ball bearing was broken but I may have done this getting the trans apart. IN hind sight, I heel and toe very good but most times dont match rpm versus speed on down shifts which on the tracks we run at is usually 3rd not 4th.

I also have a friend driving the exact set up as I am driving that also has 3 years on his 3.2 with a 901 with no problems.

Several guys at the track said I was wasting my time and money on the 901 and that I should spend the $5000-7000 to go to a 915 or even better a G50.

What do you guys think - Am I wasting my time?

Posted by: SirAndy Nov 26 2009, 04:21 PM

For a DE/track car, i'd go with a 915 or better.

I run a stock 901 behind my 3.6L, but it's driven mostly on the street (with occasional track/AX use). Also, i don't use 1st gear anymore. So far, so good.


A track car sees so much more abuse than a street car, your money will be better spend getting a WEVO 915 with LSD or upgrade to a 930/G50 ...
Andy

Posted by: computers4kids Nov 26 2009, 04:22 PM

Bill, your first 901 lasted 3 years. What kind of hp and torque does a 3.2 put out?

Posted by: ConeDodger Nov 26 2009, 11:34 PM

A stock 3.2 with the original EFI puts out 207hp in US trim. 225hp in euro trim. No idea on the torque. This is without modification. Add headers, a chip, several sneaky things that can be done to a stockish 3.2 EFI engine that replace the airbox with a MAF and you can sneak the hp up. These engines really wake up around 4K rpm with stock gearing. Bottom line, on the street the 3.2 was mated to a 915 and again, this was on the street! Take it on the track and a 901 is not going to last.

Posted by: Dr Evil Nov 27 2009, 12:03 AM

It depends on how well the 901 is built and what tq you are putting out. The rating on the 901 is 300ft/lb. If the box is correctly built, then there should be no problems. The CVs usually break before the gears, even on a V8. However, you can not beat a 915. They are worth the price.

Posted by: J P Stein Nov 27 2009, 07:29 AM

If the needle bearings go, the gear follows quickly.
A good 915 ( much less a G50) will run you around 10K installed.
That's a bunch of 901s + a trans cooler.

Posted by: sean_v8_914 Nov 27 2009, 06:34 PM

trans cooler required on 901 for prolonged track use. most popular opinion about 901 durability is based on teh destruction of old wore out 901s being mated to fresh and strong engine swaps like 3.2, 350 or 3.6. as the good DR states. 901 OK up to 300 if its fresh. when those 35 year old bearings die, they take expensive prisoners.

Posted by: pcar916 Nov 28 2009, 12:29 PM

I've been running a 3.6L motor since 1999 with a 914 transmission both on the street and for AX and DE use. Prior to that it was a 200hp 2.7L motor. The trans finally got a little balky in 2007. But it was only 4th and 5th that seamed to seat twice in the throw. There was a broken detent spring. But the synchro's and spiders still looked good

I have two early 915's (mag case, steel bearing cages) that I'll build up eventually, but the 901 is just too easy and cheap to restore not to do that. And if you have an LSD or TBD in your 914 transmission, it will swap to the early 915 case. Just takes a one-piece bearing retainer and a reinforced side cover to get the case up to full strength. Then you have to shift it of course...

Good luck!

Posted by: siverson Nov 28 2009, 12:34 PM

I went through two 901s and broken CVs/etc before I finally put a 915 in. I think it's definitely the way to go. I used the Vellios kit, but I think the Wevo 915 is a much better option now.

Not only does is suck when the 901s break, it's worse having to worry about it and being careful launching. I didn't build my 3.6 car to be careful.

-Steve

Posted by: Randal Nov 28 2009, 12:58 PM

The big time engine/chassis builders I know say that 250hp is the limit on a 901.

Posted by: naro914 Nov 28 2009, 09:22 PM

I run a 901 on both the race car (200 +/- hp 2.2 engine) and street car (about the same hp 2.7 engine). I stripped 4th gear about a year ago, but it was an aftermarket gear. The rest of the box was good, just the bad gear.

You can buy A LOT of 901 tranny's for the cost of a 915.

I have 4 tranny's - all different gear sets for different tracks. That would cost me a fortune with 915's.

Posted by: marks914 Nov 29 2009, 01:22 PM

Been running well over 400HP through my 914 trans for 7 years now. No problems.
Mark

Posted by: Dave_Darling Nov 29 2009, 04:01 PM

The limit for what is the question. Daily-driver-type reliability? Getting a full race season out of it? Something in between?

I know that Dave Ferguson ran a side-shifter 914 box behind the 2.8 "over 300 HP" motor in his green Six for a long time. He wasn't overly kind to it, either. But he got very good at rebuilding 901-based boxes. He managed to chew up pinion gears at the rate of one every three to five years.

He asked what I thought the grenaded pinon gear was. His reply, with that trademark grin of his, was "that's proof that I have enough torque!"

--DD

Posted by: Bill Smith Nov 29 2009, 06:30 PM

wow - thanks guys - I can go thru several 901's, right now all I am doing is about 6 DE's a year - I do plan on reinstalling my trans cooler and also sticking with Swepco 201 oil. I had the oil cooler in but made the mistake of mounting it to the rear trunk floor - it was really loud when runnning but worked great. The temps were really good with it on but I developed a small leak and took it off - my bad.

By the way - I may have jinzed the buddy of mine - He ran a vintage race at Summit point this weekend and lost 4th gear with 2 laps to go in the Enduro. I bet I'll be talking him into the oil cooler as well