01GTvertible

i want to definately put different gears in my car. i have an automatic, and i also plan to put a supercharger on it in the near future. what gear ratio do you guys think i should run? and i know that the gears will effect your speedometer, but will it affect my odometer as well? thanks for any info and opinions.

04mustang

wont effect your odometer will effect your speedo meter you will need a speed cal or a chip to fix that. if you are going S/C i say go with 3:73 or 3:90 since you have an auto.

99_gtx

I was told that 4.10's was best for the auto to make up for the loss in the low end? Just what someone told me, i dont realy know. Im going with 3.90's to replace my 373's. I love the 373's but i want alittle more without reving too high.

01GTvertible

i remember someone posting that 3:73's would shave like 4-5 tenths off quarter mile time. does this also apply to automatics?

99_gtx

yah, but it wont shave as much cause of the shift points. Thats why i was told to go with 4.10's

04mustang

if you are staying N/A than go with 4:10 or 4:30 but if yo are going with an S/C than go with the 3:73 or 3:90 cause you will have to much power for that high of a gear .

Monch

i stay with the stock gearing if you add a SC. you'll see a big increase in power at the low end with the typical 8 lbs of boost, i think you'd have some traction problems with anything higher than 3.55's, might be a real problem when its wet.

mdvaldosta

it depends on what kind of supercharger you go with. if using a centrifugal like a vortech or procharger then run the same gears you would run if NA (ESPECIALLY if your using the stock stall converter). If using a roots or twin screw type blower then I'd go 1 step down, since they make their power down low you wont need as much gear to get going.

cammedlx

i have to agree with 04 mustang 3.73 would be the way to go with the s/c

IntruderLS1

You should just save your money mate. Unless you're getting them for dirt cheap, and can put them in yourself, it'd be a wast to go from 3.73 to 3.90. If you feel it at all (which you might, or might not), I'm sure it wouldn't be as much as if you took that money and did something else to your car. Just my oppinion, it's worth exactly what you payed for it. But you should deffinetly ask around.
To the poster I would have to agree w/ what they're telling you. With a supercharger, stick to the lower gears. They're less likely to break on you, the traction won't be as big an issue, the car will feel more stable in day to day driving, and your gas miliage will improve dramatically (obviously unless you're driving like an animal all the time). A guy on LS1tech has a Vortec on his car w/ nothing else (2.73's I believe, which is what we get stock), and driving the speed limit the whole way on a long trip he got over 40 miles per gallon. Just food for thought.