View Full Version : Final Drive Modification

10-18-2010, 07:04 PM
As some of you know, the final drive of an RC gearbox is 3.933, while the standard E150F has a 4.285.

So by swapping the 4.285 final drive into the RC box, you lower the gear ratio, increasing acceleration.

Worth it?

If I wanted to do this I could simply swap the output shaft, ring gear and oil pump gear from my old transmission to the RC? Is it hard to do?

What would be better for daily driving, 3.933 or 4.285?

Here's a good link about the topic.


10-18-2010, 11:21 PM
After going through the BGB it looks like the whole transmission has to come apart.. Quite the hassle.

I may attempt to rebuild my old transmission one day but for now I think I'll just leave them.

Though now I'm wondering.. The RC gearbox has a shorter 1st and 2nd, longer 5th, which is great.. But why a higher final drive?

10-20-2010, 10:54 PM
So you could actually drive it to the race. :)

I too have this transmission in my autocross car, and it is great for autocross, but a pain for day-to-day driving. I'm sure that is why the final gear is the way it is.

10-20-2010, 11:37 PM
but a pain for day-to-day driving.

How so?

10-21-2010, 02:49 PM
The gears are REALLY short.

They are great for autocross or rally where you need to be in the boost quickly, but on the street you are shifting ALL THE TIME, hence "a pain for day-to-day driving".

(There is also a large spread between 4th & 5th)

10-21-2010, 08:15 PM
Thanks for the info.

I haven't had a chance to talk to many people who've had experience with both the E150F and the E151F. Its nice to have an idea of what to expect.

Does the longer 5th gear hinder daily driving? I assume it would be great for long highway trips.

10-21-2010, 08:26 PM
I think it does because it is really too tall for in town......unless you have long distances between lights.

It is good for highways however....which I feel sure was its intent since the spread between 4th & 5th is so large.

10-22-2010, 01:15 AM
5th is the same for the RC and regular trans. I've had multiple of both apart.
1st and 2nd are shorter though, because of the taller final drive. I personally like the RC better than the regular, the only thing that was a pain was cruising in 5th at about 55 mph. In traffic I had to do a lot of 5/4 up/downshifting. It is really nice once you're up to about 65 though, little better gas mileage.
Pair it with the RC ECU/AFM and it feels even better.

I've also made a hybrid trans with the regular final and 1/2 from the RC. 1st is too short IMO. No need, It goes by so fast you can't really do anything.

10-22-2010, 10:18 AM
Is the RC transmission in demand? I have a couple standard transmissions and an RC transmission. I may sell my RC trans if the right offer came along. I have yet to use the RC transmission, but if the engine is any indication of how well the origional owner took care of this car, I am VERY impressed. The oil was clear, the engine had irridium plugs, the compression was perfect within 2psi of each other, and no boost modifications.