[Stang-kid]

whats the differences between them!
Like torque/ top speed!

[chevy_killer]

Originally Posted by Stang-kid whats the differences between them! Like torque/ top speed!

ok im not going to argue with nobody on this one...i will just leave it up to you who you want to believe....but the 3.55 is more of a high way gear....you wont accelerate very fast but your top speed will be higher than a lower gear like the other gear 3.73.....the 3.73 is a low gear which gives you more rpm's which allow you to accerate much quicker but with the extra rpm's you will lose top speed.....the ONLY way to get a higher top speed in a low gear than a high gear is if you get a taller tire.....but AB will tell you something about friction and crap like that....but im leaving it up to you to decide who is right....but if you want acceleration get the 3.73s but if you want a higher top speed get the 3.55s

[Sa-WaitNoMustang900Turbo]

with the smallest gearing you can fit in your 7.5 rear end your ACTUAL top speed will not be decreased. Your motor wont be powerful enough to make your car 'gear out'

the number refers to the # of times you drive shaft will have to spin to get your wheels to spin once. If you understand the concept of mechanical advantage then you should understand that a gear ratio is essentially a torque multiplier. Say that their are 200'lbs at the ds and the rear end ratio is 4.10, then the torque being transfered to the wheels is essintially 820'lbs. The more being transfered to the wheels the faster the acceleration, but the less time in each gear you can be and the less speed in each gear you will have, so in theory you should be almost about to 'gear out' at the end of the 1/4 mile to have the fastest run your car is capable of. This, however, you will not beable to achieve with a bolt on v6 with 7.5 rear end, all you can do is go as small as possible

4.10 is the smallest gear you can put in the 7.5 rear and the best for speed in that rear. Your first gear will be small if you have a 5spd, and most people say use 3.73's for 5spd because of that drivability 'issue' but i say 4.10 no matter what unless you are above bolt on power.

so,

4.10 if auto

3.73 or 4.10 if 5spd


p.s. dont forget your t-lok when you get the gears!

[Stang-kid]

OK say I am going to race 2 mustangs just like mine!
Manuel trans, BUt one has 4:10s and the other had 3:55 and 3:73! all have t-lok!

Which one would win in a 1/4 mile race!

[chevy_killer]

Originally Posted by Stang-kid OK say I am going to race 2 mustangs just like mine! Manuel trans, BUt one has 4:10s and the other had 3:55 and 3:73! all have t-lok! Which one would win in a 1/4 mile race!

let me put it this way...if your wanting short distances like 1/4 mile...then 4.10s or 3.73 because you eill accelerate faster....however if you want long distances then 3.55 or somthing like that....say your flying down the high way at 60 and you have 3.55s and some ricer flys by you...you still have enough room to accelerate to catch and pass him...but if you get the 4.10s then you couldnt do any thing because you prob would be at 3000...and about the comment above saying something about not hitting the potential top speed because of the set up thats bull crap....lower gears add more rpm's no matter what and it will lower your top speed......except with taller tires

[Sa-WaitNoMustang900Turbo]

I thougt you said not to argue, but if you must I will state the facts.

You cant get low enough in the 7.5 rear to lower the top speed. If you were to get a larger rear and really small gears OR get a REALLY powerful motor on the same gears as you wold have had in the 7.5 rear, THEN your top speed will be lowered/more limited with a lower gear. BUT, with the low power of a bolt on 6er you will not beable to top out your gearing.

This is why:
with the 4.10 in the car and a 75 you should be a like 3k rpm in top gear and lets say you have your revlimiter(what will limit your speed in a gear should you reach a given rpm) set at 6k rpm, so inorder to for the lower gearing to limit your top speed you will have to reach 6k rpm in you top gear, but because you car is at 3k rpm at 75(about what i have witnessed) you would have to reach a speed of 150 to top out, a speed inaproachable for a 200hp 3k lb car.

Then you might say either:
1- but my car CAN reach 150 bolt on. So i'd say: no it cant your speedo is broken, you are skitzophrenic, or you are bsing.

2- the top speed will still be affected by the lower gears because of some ramdom reason. Then i would say: ok that could be beliveable, but only by a miniscule amount, but it could go either way up some or down some.



HERES THE REAL REASONS AGAIST LOW GEARS

1- an engine making the same power at high rpm with less throttle as an identical engine at low rpm with more throttle theoretically sould be making a bit worse gas milage. (but it can easily be made up for by driving style)

2- engine wear, the higher average rpm an engine experiences versus an identical engine with the same maintanence, but a lower average rpm the shorter it life before a rebore and or rebuild

3- everyday driving gearing messed up. If a 5spd your 1 gear could be annoyingly short for DDability if you get 4.10's and no matter what tranny you have or lower gear get your cruising rpm on the freeway will be higher. (higher rpm for the high # gear) That can be bad for the above reasons.

WHAT I THINK

your gas milage shouldnt be that affected a whole lot, and if you dont drive on the interstate a whole lot, then the lowest gear isnt annoying, but if you do, then get a compromise gear like a 3.73 or 3.55. Your top speed should not be affected, but I dont think there is any reason to try to hit it any way. If what I said above you feel does not bug you at all (like most of us) then get 4.10, if it does get a compromise gear like 3.73 or 3.55, but i warn agiants 3.55, it wont be much of a gian a all.

p.s. geat a bigger/stronger entire rear end with about a 3.73 and a real stong t-lok if you plan for power over that of a bolt on engine.

[232stang]

but with a smaller gear you get to your top speed faster.

[Sa-WaitNoMustang900Turbo]

of course you do, you have a faster low speed accel with a lower gear to get you up to your real top speed of 120 or so.

another plus for lower gears

[232stang]

eh its 117, according to speedo and my GPS

[Sa-WaitNoMustang900Turbo]

Originally Posted by Stang-kid OK say I am going to race 2 mustangs just like mine! Manuel trans, BUt one has 4:10s and the other had 3:55 and 3:73! all have t-lok! Which one would win in a 1/4 mile race!

if they are all equal drivers and otherwise equal cars overall, the the one with 4.10's of course!

[Sa-WaitNoMustang900Turbo]

Originally Posted by 232stang eh its 117, according to speedo and my GPS

is that electronically limited or its just that the car has no more pull?

[232stang]

thats the dern governor! it hits it and bounces back, hits it and bounces back.


hmm i wonder how long it would take to blow your engine if you take off the rev limiter and governor. and get to your top speed. and if it just wont go anymore, like lower rpms. drop it in 4th or so. hmmm! too bad i dont have a junker car to do that to.

[Sa-WaitNoMustang900Turbo]

a tuner will take the governor off and it can change your revlimit to a desired more sporty rpm, like 6250.