How much do 4.10 gears affect mileage and top end?

[Schlitz-420]

Does anybody know how much the affects are of going to 4.10 gears from what i believe the stock ratio of 3.55 in regard to both fuel economy and top speed? Does having a manual trans have any relevance to decision? About how much are the 4.10 gears from FRPP? Thanks a lot.

 

[Spdfreak]

Hmm, I thought the MT had 3.73s, and the AT had 3.55?

 

[Schlitz-420]

Hmm, I thought the MT had 3.73s, and the AT had 3.55?

Thats what i was told as well but the only print i have seen says 3.55 but that makes more sense. Thanks.

 

[OsirisGT]

AT is 3.31 and the MT is 3.55

 

[AJC-05GT]

Not much at all - I put in 4.10. In my opinion the car is more drivable around the city. when you get into the 75+ range on the highway the mileage is more impacted.

http://www.corral.net/tech/gearcalc.html

stock tires 235/55 r17:
5th gear Engine RPM: 1791
Vehicle Speed: 60
Read End Gear: 3.55

5th gear Engine RPM: 2068
Vehicle Speed: 60
Read End Gear: 4.10

5th gear Engine RPM: 2586
Vehicle Speed: 75
Read End Gear: 4.10

5th gear Engine RPM: 2239
Vehicle Speed: 75
Read End Gear: 3.55

 

[anthony05gt]

4.10's will have you at around 2700 rpm's @ 80mph.
Manual GT's have 3.55's
Auto Mustangs and V-6 manual cars have 3.31's.

The added performance from 4.10's is well worth the slight impact on gas mileage.

 

[Schlitz-420]

Not much at all - I put in 4.10. In my opinion the car is more drivable around the city. when you get into the 75+ range on the highway the mileage is more impacted.

http://www.corral.net/tech/gearcalc.html

stock tires 235/55 r17:
5th gear Engine RPM: 1791
Vehicle Speed: 60
Read End Gear: 3.55

5th gear Engine RPM: 2068
Vehicle Speed: 60
Read End Gear: 4.10

5th gear Engine RPM: 2586
Vehicle Speed: 75
Read End Gear: 4.10

5th gear Engine RPM: 2239
Vehicle Speed: 75
Read End Gear: 3.55

Thanks a lot guys, i was thinking it was the most logical next mod for me (CAI and programmer on the way). Not to mention it is a pretty cheap mod ($225 parts). Do any of you guys think it is worth it to replace the differential as well? and if so what would you recommend (Traction-Lok, Auburn...)? Thanks again guys.

 

[mpentico]

I found the 4.10 gears to be the best bang for the buck right after the CAI/tuner.

Be sure to have a professional install your gears for you, as a poor install will lead to gear whine, or maybe even worse.

I have horrable gear whine but can not afford to have the job re-done. And by now the gears are worn improperly, so the gear whine may not go away even if they are re-set correctly.

On another note, I've lost about 3MPG since the gear install.
I now average 18MPG with a 30 mile per day commute on both highway and city. (20 miles highway, 10 miles city)

Still worth the increase in accelleration.

 

[firemanken]

i've lost about 2 mpg with the 4.10 gears. i have an auto tranny but it's fun to hear the car chirp when it hits and 2nd and 3rd gear when you stomp on it