I have heard many times people saying things like "my car/truck is faster because my engine top RPM is higher".
So I decided to check if all this engine RPM hype is based on facts by calculating what is engine RPM of my Savage 21 with .21 engine at top speed (I assumed top speed to be 30MPH).
Below is a diagram of the drive train:
So the final gear ratios are:
1st gear: 13.1 : 1
2nd gear: 9.1 : 1
Meaning that engine needs to turn 13.1 turns (in 1st gear) in order for the wheels to turn once.
Stock wheels are 6 inch in diameter. So their Circumference = 18.85 inch
1 mile = 63360 inch.
So my truck would need to do 30 * 63360 / 18.85 = 100838.2 revolutions to go 30 miles.
In 1 minute it would do 100838.2 / 60 = 1680.63 revolutions.
So 1st gear 1680.63 * 13.1 = 22016.3 RPM
2nd gear 1680.63 * 9.1 = 15293.8 RPM
As you can see engine never reaches its top RPM even if the truck was to go 30MPH in 1st gear.
A logical conclusion would be to say that the .21 engine is to weak to be able to reach top RPM but I have read a thread about a twin engine project Savage truck (which has 2 .26 engines) and it only goes about 33 - 35 MPH despite that it can wheelie at 2nd gear.
[link]http://www.savage-central.com/ftopic1093-0-asc-0.html[/link]
So is the engine RPM talk is just sheer uniformed stupidity?