jimw
Just visiting
Member # 88
Posts: 1
From: Benton, Illinois
Registered: 4/7/04
|
posted 4/7/04 2:28:32 PM
I have a 1976 L82 with 4 speed. Mods include double hump heads 2.02, 1.60. alum intake 750 Holley, headers, 465 hydraulic cam. have 3.08 rear somebody changed it. Want to run a 3.70. What rpm will I run at 70mph. I have not decided on tire size yet. Would 3.55 be better? The 3.08 sucks, it is a pig. I want some low end but don't want too much high rpms. any help would be appreciated
|
IA Bump
Just visiting
Member # 93
Posts: 3
From: Michigan
Registered: 4/19/04
|
posted 4/19/04 12:57:15 PM
Figuring out your RPM with different ring gear ratios and tire sizes is pretty easy. Here's a quick calculation for you.
First you have to figure out your tire radius. Alternatively, you could determine your tire circumference by marking a line on the pavement, rotating your tire 10 times, measure the distance traveled, and divide by 10.
You'll also want to know your ring gear ratio, transmission gear ratio, and speed at which you want to know the engine rpm.
Here's two ways to learn your engine rpm:
1) (Speed (mph) * transmission ratio * ring gear ratio * 168) / tire radius (inches)
2) Speed (mph) * transmission ratio * ring gear ratio * 26.75 / tire circumference (inches)
Hope this helps.
|
