How much HP and TRQ does it take to have a 9 Sec. Bike?

[gabbyduffy]

       There is a lot more to getting a 9 sec. slip then Peak power but for arguments sake what do you think is the very least that is needed to get their?

[oldhippie]

According to the Wallace racing calculator ya would need 159hp to get 800lbs down a 1/4 mile in 9.99 seconds...

[strokerjlk]

depends on weight . how good of a clutch set up ya have, 60 ft ability,gearing, and on and on.
i know of a 130 hp 1250 sporty that runs 9's. and a 170 hp 117 bagger that runs 9's. neither got there,without a lot of testing.and tuning.

[Templer]

HP/TRQ OR $$$$$$$$$$

[SixShooter14]

HP/TRQ OR $$$$$$$$$$

No, no....it's HPxTRQ = $$$$$$$$$

[aswracing]

Torque ain't part of the equation. It's already built-in to the horsepower number. Power is torque times rpm. Power made of high torque and low rpm is no stronger than power made of low torque and high rpm.

[Smarty]

Torque ain't part of the equation. It's already built-in to the horsepower number. Power is torque times rpm. Power made of high torque and low rpm is no stronger than power made of low torque and high rpm.

I find that a little contrasting as the motor with the lower torque and higher hp would have to catch the first bike on the big end. Now, could he do it on an 1/8 mile track or a 1/4 mile track. Heck, I used to heckle the young kids that daddy bought the new badass mustangs for with my 4 wheel drive, 4 door, long wheel base dodge diesel. Although I did have it chipped, I would race them red light to red light and kick there ass. It would piss them off too. Much longer than that and they would blow by me.

[1FSTRK]

 
Here we go again   

[Nowhereman]

 

[harlycoop]

TQ = acceleration, HP = speed.

[gabbyduffy]

Here we go again   

......... how big of a difference is their between being in the 9's verses the 10's?

[gabbyduffy]

depends on weight . how good of a clutch set up ya have, 60 ft ability,gearing, and on and on.
i know of a 130 hp 1250 sporty that runs 9's. and a 170 hp 117 bagger that runs 9's. neither got there,without a lot of testing.and tuning.

What kind of numbers were you putting down when you were at 103"? If I'm not mistaken you were in the 120's with horse power or there about?

[aswracing]

TQ = acceleration, HP = speed.

Wrong. RPM = speed.

Power = torque times rpm. It's the combination of force and speed.

[strokerjlk]

depends on weight . how good of a clutch set up ya have, 60 ft ability,gearing, and on and on.
i know of a 130 hp 1250 sporty that runs 9's. and a 170 hp 117 bagger that runs 9's. neither got there,without a lot of testing.and tuning.

What kind of numbers were you putting down when you were at 103"? If I'm not mistaken you were in the 120's with horse power or there about?

I was making 225 hp at 7000 rpm  ,when I ran a 10.0. it can be done with less hp ,if ya got a good MTC 6 finger lockup clutch.
without the blower at 120 ish HP I ran a 11.5

[aswracing]

I find that a little contrasting as the motor with the lower torque and higher hp would have to catch the first bike on the big end.

Take two identical vehicles going side by side, with both motors operating at their torque peak rpm. Doesn't matter what speed they're going, choose a gear and speed that puts them at the torque peak rpm.

On one vehicle, open the throttle wide open, thus producing max torque from the motor.

At the same moment, on the other one, downshift to put to the motor at it's power peak instead, and open the throttle wide open.

Watch what happens. It won't even be close. Even though the downshifted vehicle's motor is making less torque, it will run away and hide. Every single time.

I can explain it to you mathematically if you're interested. But I think that most people can envision the above and realize it's correct.

[Admiral Akbar]

TQ = acceleration, HP = speed.

[Smarty]

Here we go again   

......... how big of a difference is their between being in the 9's verses the 10's?

Oh about a 1' tall trophy  made out of plastic with a wood base.

[Smarty]

I find that a little contrasting as the motor with the lower torque and higher hp would have to catch the first bike on the big end.

Take two identical vehicles going side by side, with both motors operating at their torque peak rpm. Doesn't matter what speed they're going, choose a gear and speed that puts them at the torque peak rpm.

On one vehicle, open the throttle wide open, thus producing max torque from the motor.

At the same moment, on the other one, downshift to put to the motor at it's power peak instead, and open the throttle wide open.

Watch what happens. It won't even be close. Even though the downshifted vehicle's motor is making less torque, it will run away and hide. Every single time.

I can explain it to you mathematically if you're interested. But I think that most people can envision the above and realize it's correct.

Where are they staging this type of racing now? I wasn't aware that was the way it was done now.

[Ohio HD]

HP/TRQ OR $$$$$$$$$$

No, no....it's HPxTRQ = $$$$$$$$$

[aswracing]

Where are they staging this type of racing now? I wasn't aware that was the way it was done now.

OK, well, I can explain it to you in a different way then.

Two bikes are lined up side by side at the tree.

One bike is a ricer. The rider has it wound up to 15,000rpm, where the motor makes 40lb-ft of torque. Total gear reduction through his primary, trans, and final drive is 30:1.

Next to him is an identical weight Harley, with the same traction. The rider has it wound up to 5000rpm, where it's motor makes 100lb-ft of torque. Total gear reduction through his primary, trans, and final drive is 10:1.

Both drop the clutch and whack the throttle wide open. What happens?

The ricer is making 40lb-ft of torque at 15,000 rpm and has 30:1 gear reduction. 15,000rpm divided by 30 means his rear wheel will be turning 500rpm, right? And 40lb-ft of torque times 30 means he has 1200lb-ft of torque at the rear wheel, right?

The Harley is making 100lb-ft of torque at 5000rpm and has 10:1 gear reduction. 5,000rpm divided by 10 means his rear wheel will be turning 500rpm, same as the ricer, right? And 100lb-ft of torque times 10 means he has 1000lb-ft of torque at the rear wheel, right?

So if both of these bikes have the same weight, and the same traction, and both rear wheels are turning the same rpm, and one has 1200lb-ft of torque at the rear wheel and the other has 1000lb-ft of torque at the rear wheel, which one will accelerate quicker?

Bottom line is that the torque that reaches the rear wheel is what accelerates the bike. That's engine torque times gear reduction. The more rpm the motor can make, the more gear reduction you can apply, and the more torque multiplication you get. That's how 40lb-ft can accelerate more quickly than 100lb-ft.

At the end of the day, rpm is every bit as valuable as torque, because the two are interchangeable. Gear something shorter, you trade rpm for torque. Gear something taller, you trade torque for rpm. So torque is no more or less valuable than rpm.

Notice how engine torque numbers did not tell you a thing about which could accelerate better. But the engine horsepower figures did ...

The ricer was making (15,000 x 40) / 5252 = 114hp

The Harley was making (5,000 x 100) / 5252 = 95hp

[Admiral Akbar]

 

[Jonny Cash]

depends on weight . how good of a clutch set up ya have, 60 ft ability,gearing, and on and on.
i know of a 130 hp 1250 sporty that runs 9's. and a 170 hp 117 bagger that runs 9's. neither got there,without a lot of testing.and tuning.

weight!! And how efficiently you can get the bike down the track. My bike a low 11 second bike with me on it, a high 10 second bike with a 200 lb jockey.  I have been TnT this year working on getting my bike down the track efficiently, and have learned quite a bit.  A full vs almost empty gas tank will cost me a mph, but I have a better et cause I can launch harder, a full tank helps keep the front end closer to the track, resulting ina better 60'.

[1FSTRK]

Simply put Horsepower includes tq and time so you want the peak tq at the highest rpm possible to do the most work in the shortest time.

[PoorUB]

Get the weight down 400 pounds and it gets easier. I have video of my Yamaha R1 running in the high 9's.

[Hossamania]

Get the weight down 400 pounds and it gets easier. I have video of my Yamaha R1 running in the high 9's.

So, what you're saying is, I need 612 horsepower to get in the 9's, based on my current not in high school anymore weight?.....