Colorado_Mustang

Gears in the tranny and rear end multiply the torque produced by the engine. Your engine produces a torque curve that changes with RPM. For reference, HP=(RPM*torque)/5252. If your engine produces 100 lb-ft of torque at 1000 rpm, and your run that through a 10:1 gear set, you'll have 1000 lb-ft of torque at 100 rpm (assuming no losses, of course). Notice how the horsepower is the same. However, you will accelerate much quicker with that 10:1 gear set than you will with the 1:1.

Now, if you change gear ratios, your end speed will be constant and your engine speed will change, moving you along the torque curve. If you're at 100 lb-ft of torque at 1000 engine rpm through a 10:1 gear and change to a 5:1 gear, your output will still be 100 rpm, but your engine is now at 500 rpm, where it produces, say, 50 lb-ft of torque. Through the gear multiplication, you're now putting 250 lb-ft of torque to the ground with your 5:1 gear ratio, making acceleration more difficult.

That help?



Much faster than any legal speed limit you'll find in the US.

Hotwad02GT

try using this calculator. It's from the 4.6 tech thread sticky.
http://www.tchracing.com/tech/gearca...selectedgear=4


stock tires + 3.27 in 4th = 5703.2 rpm @ 120 mph
so pretty much any time you want or need to