I went from 3.31's to 4.10's in my '07 GT and wouldn't have it any other way. No reduction in fuel economy (overdrive!) and the improved accleration and drivability are incredible. Best bang for the buck (next to a supercharger).

 

I got my FRPP 3.73's installed today and I wish I would have done it sooner. Besides a CAI/tune gears are the next best bang for the buck. No more need to turn my OD off in traffic anymore.

 

AC Compressor kick off is at WOT only. That goes back to the Fox Era. If I remember correctly SVO even had it...

 

Keep the 3:55's. JMO~

 

I just took my 4.10's out and reinstalled the 3.55's. The 4.10's were just too strong for the stock tires. Wouldn't take anyone out of the hole on street concrete. Crappy mileage on highway but good in city with 5th gear usable. 3.55's were perfect for 70 mph in North Dakota but 3.73's would be perfect for my highways, 60 mph in Manitoba.

 

Ford Racing=4.10's

 

You do know that OD is just your last gear right? It has NO effect in city driving. It's basically like not shifting into 5th gear on a manual.

 

My vote is for 3.73's. The perfect ratio for a street car. IMO, 4.10's are either for the track, or for people trying cheap-out on improving the performance of their cars.

 

i dont mean to hijack but for those who take their car to a shop to install their gears what kind of price are you paying?

 

I paid $250.00 to a friend to do it. A dealer would be higher.

 

double post.sorry

 

All I know that it doesn't lug around the city now at the same speeds with the shifter left in drive as it did before the 3.73 swap. I have had no need to turn the OD off since the swap and before I spent half my time in the city with it off.

 

Not being a Mustang expert, I'd have to make mention of the possibility that on the automatic, you're more bothered by the lock-up converter than the actual OD gear.

 

Ford Racing gears ONLY.

 

Been over 200 miles with absolutely no noise issues at all. For anyone interested crusing at 60 MPH my RPMS are in the 1900-2000 range which is where I wanted them to be in the first place. I kicked it today at 30 mph to pass a car and I got a nice tire chirp when the trans shifted. Dougs race tune rules! I myself would not go any lower than a 3.90 unless someone spent most of their time at the track but for my personal use 3.73's can't be beat.

 

Interesting debate between 3.73 and 4.10's. I wish someone lived around here with 4.10's i could ride in because I want to feel the difference that everyone is talking about. I just can't see how it increased performance that much.

Here is a question to help answer that...would the same driver in the same car be faster at the track with 4.10's over 3.55's and if so by how much?

 

I would definitely try to find someone who has 4.10's with a manual trans like your car and take a ride in their car first. The RPMs at crusing speed are higher than I want personally with my auto. Thats why I went with 3.73's. It also depends on where you spend most of your time....crusing on the street or racing on the strip. 4.10s with street tires will make bad traction worse and may slow you down even more than 3.55's but from a low speed rollout 4.10s will make the car accelerate faster but rpms at 60 mph crusing may or may not be annoying to you. That is why you need to ride or drive someone elses before you make a decision. I owned a '06 5 speed GT before I sold it and bought my current auto GT and more gear would really improve performance but a jump from 3.55 to 3.73 wouldn't be that big of an improvment with the expense involved. 4.10s maybe overkill for your needs. Maybe a 3.90 set would be a comfortable compromise between street and strip? Good luck on your decision.

 

Ive said it before and Ill say it again, Ive been Running Motive 390s for over a year now without even a HINT of whine.

 

3.90's would be perfect for me but I am concerned about Motive gears. Some say they are great but SOME say they whine.

 

4.10's (vs 3.55's) - all else equal - is good for about a .25 second improvement in the 1/4 mile. Much of the improvement is earlier on in the race (1/8 mile), so it translates into much better acceleration at lower speeds (i.e. on the street, stoplight to stoplight).

Gears are a torque multiplier, by definition. For example, I went from 3.31's to 4.10's in my '07 GT automatic. That's almost a 25% increase in gearing, which makes the car feel like it has 25% more torque. So, a 3.31 car with 400 lb ft torque feels just as quick as a 4.10 car with 320 lb ft of torque. Torque is king at the drag strip, so having the equivelant of more torque (by changing gears) is the reason that ET's improve so much at the drags.

My car is a daily driver and I saw absolutely no fuel economy change in the gear swap. 4.10's seem to be the universally accepted "perfect" gear ratio for our S197's to offset the higher weight of this platform. And with a good overdrive, economy is kept in check. 4.10's are a win-win for racing & economy.