i'm not sure what kind of mods you have done to your car but i cant get anything better than 24mpg on the highway. ive never heard of anyone getting 30mpg in a stang. thats impressive. if the best i can get is 24mpg, then im sure it can drop below 25mpg

 

You'll probably GAIN gas milage with your city driving, and lose a bit on the highway ... reason being is that your smaller gears get you off the line with less effort, so stop and go driving will be easier. But higher RPM's on the highway with yeild a little more gas consumption. I would say it probably all evens out in the end.

To the thread starter - that calculator, is it only for 5spd trannies? Or is my 97 GT auto in there somewhere and I missed it?

 

you have a T-45

 

heres a formula i derived. you can work it out by looking up your gear ratios for your transmission.

RPM=[(MPH)(Trans Gear Ratio)(Rear End Ratio)(336)]/(Tire Height in Inches)

you can use that for automatic transmissions if you just look up your gear ratios on google or something

 

how did you figure 336?

sweat formula though... that comes in handy... that dern website doesn't have a wide selection of trannys

 

its several different constants combine. such as pi. its just used to get the circumference of the wheel and i combined all the constants so all you have to do is put in tire height

 

OK, really, I'm just a little scared of the gears I have bought. I have a 2000 GT, and I bought the 4.10 gears because of the material I have read here. It seemed to me while reading here that these were the gears to get. Now that I have them and am waiting to get them installed, the general concensus is that this will make the car top out too fast. I have noted myself that my car turns @2500 rpms in 4th gear at 60 mph, and 1500 rpms in 5th gear at 60 mph currently. I put borla exhaust on today and while the car was on the rack I rotated the drive shaft to make sure my gears were 3.27s and they are. My question, after all of that rambling, is: Is my car going to top out too fast? I don't race the car at the track, but I do occasionally eat a rice rocket if it is persistent enough to aggravate me. I drive about 30 miles each day to work and my speed is usually about 70 on the open highway on the way. I want to give my car that umph I used to feel when I first drove it, but I don't want to be driving a car that is too wound up. I would appreciate any input here folks. Thanks.

 

you'll only be at 2500 at 70 with 4.10s. thats not bad at all. unless you plan on going 170 on a regular basis then i dont think you'll top out to quick. i say have them installed immediately

 

All I needed was to hear someone else say it. Thanks a lot. They're as good as in.

 

i actually gained speed in the end with the 4.10s because of multiplying action in the higher rpms where as i didnt have all the power i needed to get up to a good speed in OD but it does now

 

There has been too much work and no time for play here lately. We're tooled up and ready to go now, though. The gears will be put in Monday. Hopefully pics are soon to follow. Thanks for the input, by the way.

 

Yo I was looking for a place to get my 3.73's in the san diego area. So far ive only found Pro Gears and they want $790 for parts and labor, but they gaurentee all their work. hmm anyone know anywhere else to go in the area that will be cheaper, but does good work?

 

I was curious, for a daily driver, which gear is best for mpg? I'm contemplating whether i want 3.73, or 4.10. I drive about 40 miles a day.. I almost never go on the highway.

 

For anyone who is wondering (why so much for installing gears). Here's my take: I'm an industrial mechanic, and i have rebuilt plenty of gearboxes for various applications, none for automotive but this should still apply. It aint a simple thing to just throw new gears into anything. Tolerances have to be real close. Too tight of a gear mesh means instant wear. The oil will not get between the teeth as needed. Too loose and the backlash will wear your gears out just as fast. So just take into consideration the ability of yourself or your mechanic to get the optimal space that is needed between the gears, which is normally in the thousands of an inch range. Good mechanics should be paid well for this IMHO..

 

I've got 3.55 gears on mine, and with a car with a lot of power, it's seemed to work well for me..

 

So if I have a 96 v6 stang, would I need a speed cal or could I just buy that little gear, and should I go with 4.10's or 3.73's? The car is automatic btw.

 

i can order just the gears themselves for $160 from here, a kit (fluids, gears, speed calculator) for $330. my question is...is that extra stuff worth it? do i need a tune or calibration after a new gear install? i deff want the gear upgrade, but i'm also on a budget...so nothing unnecessary would be good. haha

 

its reccomended to get the install kit and new bearing if you have high miles. I got it done anyways with only 20,000 miles to be safe. You do not need a tune or recalibrated but if you dont your speedo will be off.

 

I know gears will make me accelerate quicker, but i heard they take off on my top speed? is this true?

 

how often do you drive around a 110+

 

very often i like to take my car to 110+...will the gears make my top speed less or not?

 

i was told that for my 98 v6 auto i should get 4.10's is this right? and what kind of mpg will i lose?

 

All this talk of top speed is retarded. Even with 4.10 gears none of you will ever get your car to its top speed as your cars dont make the power to go past the wind resistance. It will lower your top speed but its still very high more then the 110 someone posted.

 

Ok, this is gonna **** someone off or aggravate them.. But im going built motor and supercharger(in a year or so), i was looking at 4.10's.....but im told 3.90's or 3.73's will be good for forced induction...Which gears would be the best and which gears will i be happy with? i only want to do this once!

 

hell i think anything under 4:10's are for women, but honestly if yer WILL be supercharging 373 might be a better choice, or yer gonna be shifting into 2nd before you can bury the throttle.

 

+1. 3.73's for FI.

 

then 3.73s it will be!

 

I have a manuel 2001 v6 mustang. I bought 3.73 gears but still havent installed them yet. I asked my mechanic about it and he said its really not a good idea since its only a V6 and it will put a lot of stress on my car. He also said i will barely see improvement. Please let me know if this is a bad idea.

Thanks

 

the calculator on the first post is broken. someone is cybersquatting on the page.

 

as i recall someone told me; for a 96 v6 auto, 4.10's with no supercharger, 3.73's with supercharger. what would happen if it was 4.10's and a supercharger?