Big5.0.13.7sec.

SO why do people actually change tio 3.73 gears???

I have 3.73 gears but they were on when I got the car.
I mean just for .40 of a sec? I mean these gears seem to tear up my gas milege... not to mention the rmp's it runs at on the highway... i mean a constant 2.5 grand cant be good for engine life can it????

Let me know!!! Thanks!!!!

SilverStallion

Well since most people with 3.73s either dont drive on the highway too much, or dont care about gas mileage...that doesnt seem to be a problem. And what other mod can u do that will give you 4 tenths for 180 bucks?

luckythirteen13

2.5k RPMS that doesnt seem too high. then again i drive 120 on the freeway. my main concern is my top end, i dont want to me limited to much on my top end. i know i will loose some, but the question is how much?

roundman

check out this thread for all my mods

https://mustangforums.com/m_205780/mpage_3/tm.htm

roundman

give me the speed now at 2000 rpms and what gear you're running and I can figure this out for you. or just tell me how tall the rear tires are and I show you how to figure it out too.

roundman

I went to 3.73 when my Stang was still street driven so I could get the hell out of the way of everybody else because the stock 2.73 gears in an auto Stang don't let it accelerate worth a damn. yeah, it got as much as 27 mpg with them cruising the interstate at 70 mph but who wants to drive a 5.0 slug! a constant speed of 2,500 rpm is not going to make any appreciable difference in engine life, especially in a V-8, that's still loafing along. If I remember right, my crusing speed at 70 mph only went up from 2000 to 2200 rpm after I installed the 3.73 gear. you must be running a shorter tire than stock. that is another way you can run the 3.73 and not run the engine as fast, just put taller tires on the rear wheels and this will slow down the engine for the same highway speed that's giving you the 2,500 rpm now. BTW, my '88 with chip has to use 92 or 93 octane gas too, but I didn't lose hardly any mileage when I changed the rear gear and I didn't buy the car as a gas miser either!
The single biggest reason people get bad mileage is their heavy right foot! You can have the performance and fun of a V-8 with low gears and still get decent mileage as long as you don't drive it all the time like you're going down the drag strip!

Big5.0.13.7sec.

Yeah thats a good point there really isnt another that has that bang for the buck!!!!

Big5.0.13.7sec.

Yeah I agree once you pointed that out 2500 is not to high seeing it's a V-8. Im not really saying I am trying to get a gas efficent car, obviously thats not going to happen. But i commute to school, just trying to get the best I can. I dont drive like im at drag strip everyday!LOL.

The tires I have are 275 40 17. In the rear and 245 40 17 in the front. im not sure i understand what you mean by shorter than stock tires.

Thanks!!!!!

SilverStallion

Well the bigger the radius on a tire, the farther it will go in one turn. to find your speed with any gears u take the RPMs, multiply it by sixty to get it per hour. Then divide it by ur gear ratio to find how many times per hour your tire is spinning. Then multiply that by the distance it goes in one turn, which is the circumfrence (dont know how to spell that), or pi x diameter. That will give you it in inches, then just convert it over to miles(divide by 63360), to get your miles per hour. Hope i explained that correctly.

luckythirteen13

roundman, i have stock sized tires. id go check for sure but im school and my car parked about a half mile from where i am.

will i still be able to do 100mph without blowing the motor apart?