Horsepower vs. Torque
2nd Gear Member
Joined: Feb 2006
Posts: 165
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RE: Horsepower vs. Torque
ORIGINAL: gspfunk
I'll explain whatever you want if you tell me who's in your avatar!!! j/k...
Stock gears, say 2.73's, mean your drive shaft spins 2.73 times to rotate your rear wheels 1 revolution. Going to 4.10's means it spins 4.1 times to make the same 1 rev. w/ the rear wheels. The lower (numerically higher) gears put less load on the engine and make it rev faster to achieve the same thing, so 4.10's put you in your tq range faster. But, your gears will all also be steeper and you'll won't have as high of a top end.
As for the 2 cars, if they both went to 4.10's and were identical (except for the one w/ more tq), the one w/ the tq would get off the line faster.
ORIGINAL: 72MachOne99GT
Could someone explain to me how going for a lower (numerically higher) differential is explained as taking advantage of "Torque Multiplication"?and would it be true that two cars, with identical stock rear end ratios (3.27 for exampe) would benefit differently if they both upgraded to say a 4.10 the only difference being one had a much greater torque rating?
Could someone explain to me how going for a lower (numerically higher) differential is explained as taking advantage of "Torque Multiplication"?and would it be true that two cars, with identical stock rear end ratios (3.27 for exampe) would benefit differently if they both upgraded to say a 4.10 the only difference being one had a much greater torque rating?
Stock gears, say 2.73's, mean your drive shaft spins 2.73 times to rotate your rear wheels 1 revolution. Going to 4.10's means it spins 4.1 times to make the same 1 rev. w/ the rear wheels. The lower (numerically higher) gears put less load on the engine and make it rev faster to achieve the same thing, so 4.10's put you in your tq range faster. But, your gears will all also be steeper and you'll won't have as high of a top end.
As for the 2 cars, if they both went to 4.10's and were identical (except for the one w/ more tq), the one w/ the tq would get off the line faster.
Imagine you're riding a bicycle up hill. If you have it shifted to the smallest gear on the rear (call this the 2.73) your legs (the engine) have to work really hard just to get the bike moving. So, usually you switch to one of the larger rear gears (or the 4.10), now it takes much less effort to get the bike moving, but you also have to pedal faster. In both cases, your legs are the same strength, and the mass you are moving up the hill has the same dimensions and weight, but with the bigger gear you're applying the force from your legs over a larger diameter gear which gives you more leverage.
You can use the same analogy to explain why a larger gear makes you accelerate faster, but generally lowers your top speed (given you weren't drag-limited).
2nd Gear Member
Joined: Apr 2006
Posts: 235
From:
RE: Horsepower vs. Torque
horsepower is basically the engines ability to carry the torque across the powerband....
that's why deisels are GREAT for towing,they have GOBS of torque at low rpms, to get a heavy load going, but fall on their face after about 3000 rpms....very difficult to keep in the power band...that's why their are so many gears on an 18 wheeler
that's also why rotaries are great racecars...they don't make too much torque, but they carry it across a WIDE powerband...
that's why deisels are GREAT for towing,they have GOBS of torque at low rpms, to get a heavy load going, but fall on their face after about 3000 rpms....very difficult to keep in the power band...that's why their are so many gears on an 18 wheeler
that's also why rotaries are great racecars...they don't make too much torque, but they carry it across a WIDE powerband...
2nd Gear Member
Joined: Feb 2006
Posts: 165
From:
RE: Horsepower vs. Torque
ORIGINAL: gspfunk
gregarious, that's a great explanation!! In fact, that's the next best thing to being able to draw it out in crayon!!
gregarious, that's a great explanation!! In fact, that's the next best thing to being able to draw it out in crayon!!
I'd try an MSPaint diagram, but that could get ugly.
6th Gear Member
Joined: Mar 2006
Posts: 5,373
From: Wichita, Ks
RE: Horsepower vs. Torque
the whole thing with the bike is kinda funny because earlier this year, the teacher in my physics used a bike to explain gears and tq and all kinds of stuff. you guys pretty much got everything explained there. screw school ill just get online!
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