Formula for R.P.M
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Re: Formula for R.P.M (Perfomer)
You need to know your tire height, rear end gear ratio and your gear ratios in your transmission. There is a calculator located at http://www.smokemup.com . If you don't mind me asking....why the 4.88 gears, do you run strictly 1/8 mile with your car or is it a high winding motor?
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
Re: Formula for R.P.M (Perfomer)
I am putting 4.88 gears , currently running 3.73 , Does anyone know the formula to show what rpm the motor will turn in the 1/8 mile? any help would be apprecated Thanks Dwight
If you are simply comparing 3.73 to 4.88 I think you just take the ratio of the 2 ratios, ie 4.88 divided by 3.73 = 1.308, so at any point, at any speed your engine will be turning 1.308 times faster for a given speed.
So, if with the 3.73 you are turning 5000 rpm, at that same speed (in the same gear) you will be turning 6541 rpm with 4.88 gears.
[Modified by MNJack, 11:38 PM 4/14/2004]
Burning Brakes
Joined: Apr 2004
Posts: 997
Likes: 0
From: Click Avatar for Contact Info
Re: Formula for R.P.M (Perfomer)
If you're running an automatic transmission, you may want to contact TCI or B&M about a torque converter recommendation with your new gearing.
In racing, the only thing better than cubic inches is cubic dollars.
:auto:
Lowcountry Corvette
www.LowVette.com
In racing, the only thing better than cubic inches is cubic dollars.
:auto:
Lowcountry Corvette
www.LowVette.com
Thread Starter
Instructor
Joined: Nov 2002
Posts: 228
Likes: 0
Re: Formula for R.P.M (bence13_33)
Thanks for the info , I am running 1/8 mile only with the 3.73s Igo thru the lights at 4800 rpm 6.78 et at 101 mph. I think that with 4.88 will put me at 6100 thru the lights and pick up the et by a couple tenths. I am running a 327 with a 501 lift crane cam 9.5 compression and a 175 shot nitrous , 60ft times are 1.45 . I found a formula at richmond gears
