I'm a complete noob with this Mustang but I've been listening to you folks talk about gears being the "best bang for the buck" in terms of speed/accel. So I told a guy at work about this and he claims it would be stupid to change the gear ratios because I would lose my top end speed/acceleration.

He went on a long tirade and explained how gears worked in a nutshell.

So, before I get my hopes all up and high for "GEARS", mabey I should get the scoop.

What and how much would I be giving up with 4.10 gears?
I have a manual GT.

 

Well here's my short tirade on why that guy doesn't know what he's talking about. 4.10 gears in a basically stock Mustang will actually increase your top end. WHAT??? You say? Here's why. And I'm really tired of explaining it so all you others that like to give this advice "4.10's are WAY too much gear for your car on the street" take note.

Mustangs do not have enough horsepower to overcome the drag at high speeds. Let's say for instance that your top end is around 155 drag limited. With the 4.10 gear, your engine doesn't have to work as hard to turn the rear tires. So not only will you get there faster, but since you're now actually using the horsepower more efficiently, you may actually get a 165 mph top speed.

Again, there is a point to where the gears will slow you down. But you'll need to be making way more power over stock. Get the idea?

 

"4.10's are WAY too much gear for your car on the street" What do you mean by this?

 

Had you read that completely, I was saying that people that don't know what they're talking about will say that a 4.10 is too much gear. I'm saying it's not.

 

Your "friend" is not all there!

Technically, yes, gears trade RPM for Torque or vice-versa. In a perfect world where there was ZERO air resistance, then yes, changing to lower rear end gears, such as 4.10s, would lower your top speed. But, in the real world it is much more complicated than that.

Like Sidewayz said, due to air resistance switching to 4.10s will not noticeably affect the top end of your car. It could even increase it.


In my opinion there are two basic facts to be concerned about:

First, a car with lower gears (4.10s) will ALWAYS out-accelerate the same car with the higher gears (stock 3.55). It doesn't matter if you're in first at a standing stop or if you're in 5th on the highway. If you switch to 4.10s you will have better acceleration EVERYWHERE.

Second, who cares about top-end speed. I mean, how often do you actually drive at 150+?

 

wow, thanks for the info. I was under the same impression about loosing top end.

Can anyone post mpg changes after getting 4.10's in a 5 speed? I generally run about 80mpg to and from work and i'm curious what that rpm change with 4.10's will do.

 

I will mirror the prior comments. I have had 4:10's in my manual for a month and they are OUTSTANDING! I use to cruise at 80 @ 2500 rpm's and now at 2800. A whopping 300 rpm variance. The car pulls out of the hole like it could pull a house of it's foundation and 5th is much more reactive to throttle. I have no regrets at all. Mile fuel mileage went down by a whole 2/10ths of a mile and part of that is my loving the extra torque! Just do it!!!!

 

It should actually get a little better milage around town. The stop and go crap is easier on the motor with the higher gears.

Wow...Maybe I was wrong about the '05 section. You guys ask for info, I give it to you, and you say thanks. The 99-04 section, I've had this discussion about gears 1000X's, and the know it all's that have never turned a wrench on their cars argue with me.

 

I know sht about mechanical issues in cars... I'll say that right off the bat.

What are the "negatives", if any, of having 4:10s? In an automatic? Manual?

 

There really aren't any negatives. Other than on average your car is going to run about 300 rpms higher, and you honestly will lose a little MPG in the long run...But not enough to make a difference. You're talking less than a dollars worth of gas in-between tanks.

Other than that, you're actually putting less strain on the engine and drive train itself. Well, in theory you are putting less strain, but it's going to accelerate so much better, you'll be hammering on it all the time!