Kyle,
It does NOT affect top speed, not in a negative way; see the calculation:
80 mph @ 2400 RPM (stock 3.27 gears stock tire dimension)
at a top speed of 137 mph this would be 4110 RPM again with the stock gears. (That's what Ford prooved)
Lets see what the 4.10 gears do:
80 mph @ 3009 RPM (4.10 gears, stock tire dimension)
at the same top speed of 137 mph this would be 5153 RPM
Since we know speeds and RPM's lets have a look at a stock RPM / HP graph of a 4.6 L
At 4110 Rpm's (with 3.27 gears) you see aproximately 195 RWHP that can be used to move the car against air drag. And at 137 mph the car stops acelerating because the force from the air drag equals the force from the motor applied at the wheels.
Now with the 4.10 gears we are looking at roughly 5153 RPMs and a stock Mustang has about 210 RWHP at this RPM.
What does that tell us now? If your car has more HP at a certain speed and with a certain RPM, your car is able to apply more force to the ground.
Thererfore the force of drag can even be higher which would mean at even higher speeds.
WITH 4.10 instead of 3.27 and in 5th gear, with stock tire size (245/45 17) your car WILL go faster! How much? I cant tell. thats a whole different ball game (lots of math, and it requires an acurate dyno chart)
Kyle82484 said:
I have an '03 Mustang GT and I am considering getting some 4.10 gears, I have been reading some other threads regarding gears, but I am wondering what specifically will a set of gears do for the performance of my car, such as a set of 4.10 gears? I saw someone posted that it affects the overall top speed of the car? If so how much? Are 4.10 gears the best ratio for my car?