tomburdge

Generally speaking how much horsepower will a 901 tolerate before reliability becomes an issue?

What can be done to extend this hp tolerance besides perhaps cooling,beefier intermediate plate?

Thanks,
Tom B.

butzip

I've seen everything for Chevy 350s to 3.6s mated up to 901s. I can't speak to the longevity, obviously they were not designed to handle that kind of torque but they seem to hold their own. I say, as long as you're not side stepping the clutch at five grand you can expect decent life from them.

butzip

Here's a mag case 901 on a 3.6

butzip

doh....

tomburdge

Thanks Butzip,

I can see the aeroquip coming out of the box,so you must be circulating through a cooler,right?

What else if anything did you do internal? Beefier intermediate plate?

Thanks,
Tom B.

theiceman

i have heard that you can beef up the 901 with 915 internals ... but maybe I just dreamed it or saw it on a TV show .

theiceman

inew i saw this somewhere

http://www.youtube.com/watch?v=xvkFzqS7UV8

Steve Weiner-Rennsport Systems

901's are torque-limited much more than power limited.

One can install a billet intermediate plate and side plate to improve durability when using an engine larger than 2.5 litres but the limits also must factor vehicle weight, LSD, and tire sizes, too.

915 internals do not fit,....

Pressurized oil cooling systems are strongly recommended for race cars, especially mid-engined ones.

theiceman

Then what was that guy doing on that TV show Steve ? was it not a 901 ?

Steve Weiner-Rennsport Systems

I didn't see any TV show, but those pics above are of a 901.

Granted, there are people who use 901's in high-powered applications but I assure you, there is a lot more than meets the eye.

Having broken my fair share over the years, I know they won't take real abuse from engines making more than 250 lbs-ft for long unless its installed in a very light car.

My objective in engineering any conversions is picking & choosing the most reliable, durable components I can find to ensure the car will not break (very easily). I'd be remiss in my responsibility to a paying customer (or anyone for that matter) if I used or sanctioned the use of such a transmission in situations where the chances of failure are higher than acceptable. That could (rightfully) expose me to accusations of generating business for myself and some breach of ethics.

JMHO, of course.

theiceman

Sorry Steve I should have been more specific .. Check out the youtube link on post number 7.

Steve Weiner-Rennsport Systems

Thats a 915,...

rusnak

The 901 main shaft is cantilevered out from the intermediate plate, which is why they fail in low gear. The main shaft will snap off. That is also why people strengthen the intermediate plate; it takes a lot of twisting force.

I vaguely remember one of the Andial principals (won't say who) casually saying in conversation that the 901 will handle 250 hp reliably, but it would not be fair to quote him on that, since I do not know exactly what setup and application he was thinking about.

The guy who had done a lot with 901s was Vellios, and also Patrick Motorsports has done a lot of stuff.

butzip

Tom,

I took these shots at RSII in Daytona. That is one of Chuck Beck's 904 prototypes. It's running the Tilton pump and yes a small cooler off the back just out of sight. Intermediate plate is a must especially on the mag case 901's.

Hawk2109

Just my .02 cents on this, but I agree with Steve on this. I don't think that I would recommend the 901 for more then about 250 ft/lbs of torque. You could potentially install a new 300M 904 main shaft that would give this gearbox a bit more strength, but even then I don't think I would recommend too much more torque.

Erik Johnson