TheSamba.com :: View topic - 091 bus transmission. What Horsepower is safe? whats the limit?

Wed Mar 28, 2018 4:19 pm

I called a guy that's works on transmissions and he said the 091 transmission can handle 200hp up to about 220hp ok.
He would not put a 250hp or 300hp on a stock 091. He would expect it to start breaking things.

What are your experiences?

He said it would cost me 800 to rebuild transmission.
1,050 to do small things to make it better for off road and rebuild but he would stay under 220hp

He said To build up stuff to handle 300hp I would expect to pay around 3 to 4 thousand.

Wed Mar 28, 2018 8:11 pm

I have an 091 connected to a 2.3 turbo,running 34" swampers, about 250 hp. Only upgrade is a super diff. haven't had any trouble. Just don't drive like an idiot. or learn to fix broken transmissions.
Of course the trans builder will tell you that you need to spend money.

Wed Mar 28, 2018 8:21 pm

I will be attaching it to my ford 2.3l turbo motor. What mods did you do to get to 250?

Thu Mar 29, 2018 5:08 pm

Previous owner Installed a merkur manual boost control. Boost runs about 28 psi. (according to boost gauge)

Thu Mar 29, 2018 6:03 pm

All this talk of how much power the transmission can hold is nice, but rather meaningless. You can wreck a bus box with a stock engine easy if you abuse it...hop the wheels, land with your foot in the gas, etc...It’s all how you drive. Shock loading kills :wink:

Thu Mar 29, 2018 6:06 pm

as stated - depends how you drive it!
if you wanna rev her up and dumped the clutch on any hard pack---- NO
if you wanna hit 200 yards of 3 foot whoops and stay pedal to the floor--NO
if you wanna drive it like a rally car on gravel roads and just roll out a bit/breath the throttle on landings-- mine has done well!
mine setup is a 2.2 with a mostly stock jeff fields 002.. but it has been to him twice when it's nine lives where used up!

Thu Mar 29, 2018 9:21 pm

Hmmm. I like power and I had my heart set on 300hp. To bad I can't find a cheap pair of hardened gears. Rebuild costs the same to install gears during rebuild. The gears are what's expensive.

Fri Mar 30, 2018 5:54 am

database00 wrote: Hmmm. I like power and I had my heart set on 300hp. To bad I can't find a cheap pair of hardened gears. Rebuild costs the same to install gears during rebuild. The gears are what's expensive.
there are some words in that statement that do not belong together in that one statement..
there is a lot to build a reliable 300hp vw trans( main shafts alone are a grand),-- almost money well spent to find a used mendeola nowadays.....
here's a good site if you haven't ran across it- there is nothing "cheap" here though..:)
https://www.google.com/url?sa=t&rct=j&q=&a...DF3etpZYcB

Fri Mar 30, 2018 6:44 am

When I hear 300hp, my mind immediately goes to “is the rest of your ride built for 300hp?”

300hp is a ton of power. In order to use it, you will need more than a built transmission. How about your suspension? Roll cage? Etc... if the rest of the rides isn’t up for it, 300hp is a waste of ponies. Just my opinion.

Fri Mar 30, 2018 8:19 pm

Trying to. I have an a-arm front end with 20 inches if travel and a 5x5 trailing arms with 930 stubs and axels, 930 flanges.

Fri Mar 30, 2018 8:31 pm

database00 wrote: Trying to. I have an a-arm front end with 20 inches if travel and a 5x5 trailing arms with 930 stubs and axels, 930 flanges.
shoot brother your on the right track! screw this vw tranny deal-just buy a used mendola 4d for $5000ish and save your self a boat load of headache! I should have!

Fri Mar 30, 2018 10:02 pm

Where are you finding one of those transmissions for 5k? I might consider.

Sat Mar 31, 2018 8:48 am

I have seen 3 since the first of the year for under $5500 on few web sites and group for sale sites- this one is still up on Racedezert. i wish these were this affordable 5 years ago when i did my eco conversion!

Sat Mar 31, 2018 12:53 pm

I second on going with a Mendeola transaxle.
With the larger diameter of the ring gear (also bigger diameter pinion head) it will take a lot more abuse then a Bus type II trans.

Sat Mar 31, 2018 4:49 pm

Heck with that built up of a set up, I agree with Race-desert, ditch the six rib bus box and move up to something better. That’s out of my league man. I’ll bow out and leave this to the pros. I have never been involved with such a mean ride before. :lol:

Sat Mar 31, 2018 9:36 pm

.u wife would shoot me if I dropped 5k on my buggy right now. I can get 2k right now to out it all together. But if I told her 5 she would give me the speech about priorities and family. Why can't I just win the lottery.

Sun Apr 01, 2018 9:45 am

You may have to rethink how much horsepower and torque you really need with the limited funds you have.
Good luck and have fun with the buggy build.

Mon Apr 02, 2018 11:36 pm

It all comes down to my version of the ancient hot rodder's saying:
"Speed costs money. How fast can you afford to go?"

I'm ALWAYS running across people talking about "more horsepower" But the thing the y NEVER talk about is beefing the trans and the rest of the driveline between the flywheel and the ground. Everybody seems to think that it's just all in the horsepower out of the engine. There are gearboxes used in offroad race buggies that push $30K.

Tue Apr 03, 2018 8:16 am

So it Looks like I am going to bite the bullet.

mendeola md4s-d2
the gears currently in it.

called rc trans it was serviced in 2016
got new mainshaft bearing synchro and seals
along with a new 091 reverse.
Owner says it has 500 miles on it since rebuild. He said he knows mileage because he does races. and has been in 2 races since rebuild.
attached it to his class 12 150hp car.

Guys see any red flags?

Tue Apr 03, 2018 6:58 pm

ahh- you grabbing the one off Race-Desert! good job that is a solid dude and trust worthy...!