Requesting GEAR FACTS

my first guess would be a lot...

I know 3.73's would be way too much gear for a car like that unless your drag racing it ONLY and you're on slicks... On the street you're not going to want that much gear... I'm going to guess around the neighborhood of 3.27's... someone else will chime in here I'm sure and correct me or add something to this. Hopefully someone with a car that has 500hp...
 
The only fact that I can give you is that when I did the swap from 2.73 to 3.73 w/o changing anything else my RPM moved up about 500 revs in every gear. Cruising down the highway at 75 I turn about 2750 revs. That is all I know
 
How does he plan on launching it at the track with 3.73's? He's going to have to baby it pretty good to keep the tires attached to the pavement. IMO he would get a better launch, and faster times with less gear... and besides, he could bounce that car off the rev limiter in 5th easy. For me I want a car that gets outa the hole well, but isn't going to be hindered by the gear if I ever get a wild hair up my ass and decide to go autoxing... And that cobra would definately run outa gears...
 
The gear ratio multiplies torque, just as the transmission does.

What gear ratio is really only a spec, and should be selected with the transmission gearing, tire size, engine powerband, as well as usage to select properly.

I hate when people say that at a certian power level, as steep gear is too much. That all depends on the vehicle usage. I saw somewhere a equasion where you could figure weather you need more or less gear based on the MPH and ET. I also saw a calculator on a website with something similar. Generally speaking, you want to cross the finish line just past peak HP.
 
grrrrrrr said:
How does he plan on launching it at the track with 3.73's? He's going to have to baby it pretty good to keep the tires attached to the pavement. IMO he would get a better launch, and faster times with less gear... and besides, he could bounce that car off the rev limiter in 5th easy. For me I want a car that gets outa the hole well, but isn't going to be hindered by the gear if I ever get a wild hair up my ass and decide to go autoxing... And that cobra would definately run outa gears...

That is the wrong way to increase traction. That is like swapping to a 4 cylinder, that would solve your traction problem, wouldn't it? In fact with less gear, when you start to spin it spins out a lot faster, so instead of just spinning them a little, you just peal out. How fast are you going on an AutoX track?
 
90mustangGT said:
The gear ratio multiplies torque, just as the transmission does.

What gear ratio is really only a spec, and should be selected with the transmission gearing, tire size, engine powerband, as well as usage to select properly.

I hate when people say that at a certian power level, as steep gear is too much. That all depends on the vehicle usage. I saw somewhere a equasion where you could figure weather you need more or less gear based on the MPH and ET. I also saw a calculator on a website with something similar. Generally speaking, you want to cross the finish line just past peak HP.


I am aware of the other factors involved.

I know if I had a stock engine and bolt ons i would go 3.73's

but with the power Im gunna have, Im wondering if I should just stick with my stock gears and posi and see how it is, unleeesssss, someone on here knows its not a smart idea.


cars an 88gt btw (mm lowers, 26" tire, street car, h&r springs bla bla)
 
I agree with 90mustang... The gear won't be too steep. If you have a good suspension set up than you shouldn't have anything to worry about.

You can make all the power in the world, but without traction it does you no good. Those gears will help more than they will hurt.
 
I know they will help, but I dont have them now and im deep into other projects with the car (gears not being one of them). I guess Im wondering how much im missing out by not having 3.73 gears even with the power level Im going to have.
 
What is your intended purpose with this car? Maybe I should have asked that question first... If you're strictly talking drag car 3.73's will be fine I'm sure... But theres a reason that as people add superchargers and make huge amounts of power on daily driven rides the rear gears decrease numerically...
 
500hp at what rpm, and how is the power being made?
i mean, totally different set of events dependant on if this is a n/a 8000rpm screamer or a 6000rpm turbo motor, or a 6000rpm blown motor.
Each one will want different gearing.

500hp means nothing, unless you know how the hp is being made.
dunno how anyone can make reccomendations based on the info at hand...
 
I guess I am at a loss here. Why does it matter what kind of HP you make as to what type of gears you run? I think you need to decide what your going to use the car for and decide from there. If it's a highway car stay with your higher stock gears. If it's gonna be something that is a track car go lower, and gear it for your HP and RPM range. If it's just a toy and you only drive it now and then and you want the best of both worlds go with the 3.73's. I think the 3.73's are a great gear that works well in both worlds. You have to decide if you want a low geared faster reving car, a taller geared slower reving car, or something in the middle.
 
The best gear is one that lets you launch the best (fastest 60' foot)[of course you got to have the proper suspension,converter/clutch,trans and even motor componets],and one that wont let you hit the rev limiter at the big end.