A V-Twin matching a 'Busa in hp/ tq.Are you on crack.Let me guess your the probably the same guy that didnt know how to put air in your tires on one of the previous threads.Geez Laweez

 

yeah thanks for that, the question was about torque the bussa part was just the first bike that came to mind, i should of said YZf 450 this is my dirt bike.

or perhaps CB 125 might of stood up better.

 

It's not that simple. For example a V-Rod accelerates much harder than a TC96 despite having less torque. Same with a 600cc sportbike, it pulls way harder than a TC96 Harley. Sure the sportbike weighs less, but even if you factor in the weight the Harley still has better torque-to-weight ratio, yet less pull.

In reality, what matters is actual rear-wheel torque, which is not measured by a dyno. To get actual rear-wheel torque you have to multiply the engine torque with the total gearing. This way you can make shift-point graph which shows the actual rear-wheel torque for each gear and speed. It looks like this:

http://www.sportrider.com/tech/146_0.../photo_02.html

So you can see that the R6 makes close to 800lb-ft in 1st gear.

Now if you make a shift-point graph for a TC96 Harley (which I may do if I find the time) you will see that the R6 puts out more torque at the rear-wheel at almost any speed compared to the Harley. The only place the Harley may pull harder is at very low speed, because of its low gearing (if you look at the graph you see that the R6 reaches about 70mph in 1st).

 

Some more thoughts:

It all comes down to two things: torque and RPM. The Harley doesn't have enough torque to overcome the R6s RPM advantage. The high RPMs of the R6 give a significant gearing advantage over the Harley, which means it can run much shorter gearing while still maintaining the same speed as the Harley.

It takes a specific amount of work to accelerate a bike from 0-60mph (or any other interval). Horsepower tells us how much work an engine can do and it is calculated from both RPM and torque. So, it doesn't matter if a Harley makes 120 lb-ft of torque. If it only makes 120hp it is not going to run with a 170hp, 85 lb-ft GSX-R 1000, since 170hp does a certain amount of work quicker than 120hp.

That's really all you need to know: More power means a specific amount of work is done quicker = quicker acceleration, regardless of torque. Which also explains why a V-Rod is quicker than a TC96 Harley despite producing less torque: It produces more power = It does work quicker.

The link below does an excellent job of explaining torque and horsepower, and the importance of high rpm for performance. It's a must read for Lefthandedss:

http://www.nrhsperformance.com/tech_power.shtml

 

Torque is defined as "twisting force".

Torque x RPM ='s HORSEPOWER

 

[quote=beaureed445;4268311]
im not sure i'll ask the mechaniC

 

Thanks Fred00 that was a really good read, and if my calc's are correct 118ft lb x 6200 RPM devided by 5252 = 139.29931 hp that said please rate my writen exam on what i just read, and be brutel if i totally missed the mark.

The way to make more torque is to get the air flowing faster through the cylinder heads, and have that crank spinning as fast as possible, emptying the chambers quickers gets it reving harder and brings up the torque, but because the V-TWINNS Dont rev as hard we need to put bigger pistons in them to raise the torque not relying on huge RPM to cover our bases when calculating our rear wheel Hp.

torque and RPM equal Horse power