[Barry]

I'm looking for information about what rear end gear works well. I have the 3:10 that comes stock. Performance package is 3:55. Has anybody put in a 3:73? I need to drive this car quite regularly, but I do drag race and autocross and am looking for better acceleration. Anybody have any thoughts?

 

[Uncle Meat]

I believe the stock rear end ratio for the Ecoboost is 3.31, not 3.10.

It's up to you man. You have 3 upgrade choices available. 3.55, 3.73, or even a 4.09. You never said what transmission you had which will make a difference because the ratios in the A/T are a bit different than the M/T. Wheel/tire size will also impact final drive ratios. Personally if you are not turning your car into a dedicated 1/4-miler I wouldn't go any lower than the 3.55's. The 3.55's will definitely get you up and going a bit quicker than the 3.31's.

A/T Gear ratios
1 - 4.17:1
2 - 2.34:1
3 - 1.52:1
4 - 1.14:1
5 - 0.87:1
6 - 0.69:1

M/T gear ratios
1 - 4.236:1
2 - 2.538:1
3 - 1.665:1
4 - 1.238:1
5 - 1.00:1
6 - 0.704:1

U.M.

 

[Barry]

whoops.... Manual Transmission and 3:31. Thanks for the info. Was wondering what people who had an actual non-stock gear in the ecoboost mustang thought...

 

[Uncle Meat]

whoops.... Manual Transmission and 3:31. Thanks for the info. Was wondering what people who had an actual non-stock gear in the ecoboost mustang thought...

I'm sure there are a few owners out there who have swapped out the their stock ring & pinion for a lower ratio set, but I'm not aware of anyone on these forums who's done this yet.

U.M.

 

[Barry]

That's what I'm finding out. I'm leaning towards 3:55. Ford spec'd it in the performance pack for a good reason. UNLESS someone out there can convince me otherwise ?