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even this kit taps out at 96 - so thats the theoretical max. Actual would be lower due to the fuel over here,
again that Hp is of no great interest but the torque is.
I have a DK outlaw 587 with external breathers , v&h twin slash with standard baffles and the DK TTi , tuned with FP3 after a long auto tune session optimised by V&H. I can vouch for the low and mid end - we do group rides almost every week with 3 other 1200s and they cant keep up - they are stock tune with one running an aftermarket set of pipes.
We all know that torque accelerates the bike. But what torque? Is it the engine torque that accelerates the bike? Or is it the rear wheel torque that accelerates the bike? What's the difference between the two? Which is shown on a dyno sheet, engine torque or rear wheel torque?
Let's say I have two equal weight bikes. One is making 100ft-lbs of torque at 5000rpm. The other is making 40ft-lbs of torque at 15000 rpm. Which will accelerate harder, and why?
This is the highest torque you are going to get with a 1250/1275 bore. You will have to go to 88 or 90 cubic inches for more and that a lot of work. It includes boring your cases out as the big jugs wont fit in them stock.
We all know that torque accelerates the bike. But what torque? Is it the engine torque that accelerates the bike? Or is it the rear wheel torque that accelerates the bike? What's the difference between the two? Which is shown on a dyno sheet, engine torque or rear wheel torque?
Let's say I have two equal weight bikes. One is making 100ft-lbs of torque at 5000rpm. The other is making 40ft-lbs of torque at 15000 rpm. Which will accelerate harder, and why?
Can anyone answer these questions?
The one turning 15000 rpm. Horse power wins races.
We all know that torque accelerates the bike. But what torque? Is it the engine torque that accelerates the bike? Or is it the rear wheel torque that accelerates the bike? What's the difference between the two? Which is shown on a dyno sheet, engine torque or rear wheel torque?
Let's say I have two equal weight bikes. One is making 100ft-lbs of torque at 5000rpm. The other is making 40ft-lbs of torque at 15000 rpm. Which will accelerate harder, and why?
Can anyone answer these questions?
15,000rpm bike will accelerate harder.
Because you can gear the 15,000 rpm bike down.
lower gear, more tq to the wheel. The 15x bike then gets more tq to the wheel.
OP could just keep his bike in first gear and pull stumps and wheelies all day 😜
Horsepower = Torque x RPM / 5,252
They arent separate entities
Hopefully my rough guesstimate is close. Im not too savvy in the tech department
We all know that torque accelerates the bike. But what torque? Is it the engine torque that accelerates the bike? Or is it the rear wheel torque that accelerates the bike? What's the difference between the two? Which is shown on a dyno sheet, engine torque or rear wheel torque?
Let's say I have two equal weight bikes. One is making 100ft-lbs of torque at 5000rpm. The other is making 40ft-lbs of torque at 15000 rpm. Which will accelerate harder, and why?
Can anyone answer these questions?
Dynos measure rear wheel torque unless they are attached to the flywheel. Car manufacturer's generally quote flywheel torque, which is...as a rule of thumb...15% greater than rear wheel torque on a car.
Torque numbers drop after 5,252 RPM's. That should be your extreme benchmark number...comparing 5,000 RPM's to 15,000 RPM's is apples and oranges...
Dynos measure rear wheel torque unless they are attached to the flywheel. Car manufacturer's generally quote flywheel torque, which is...as a rule of thumb...15% greater than rear wheel torque on a car.
Torque numbers drop after 5,252 RPM's. That should be your extreme benchmark number...comparing 5,000 RPM's to 15,000 RPM's is apples and oranges...
What tq numbers drop at 5252? What would the point be in comparing 5000 rpms to 5000 rpms?
how can a busa with low rpm tq out 60 foot, 1/8 mile any Harley every produced? Even 150 tq Big twins.....
Assuming you are talking about Sportsters tq dropping at 5252 rpm as extreme. I have 3 Sportsters that peak tq after that. 2 of them after 6000rpm. And they are both quick af. Wonder why? 😜 And I use my transmission like 10 dolla hooker. Up down up down repeat.
A post from aswracing (Aaron from Hammer performance on Another forum.
Gear reduction multiplies torque. The more engine rpm you turn, the more gear reduction you can apply for a given rear wheel speed, and therefore the more torque you get to the rear wheel.
My example about the two identical bikes illustrates this perfectly. Say two identical bikes are running side by side, each at the motor's torque peak. On the first bike, the rider whacks the throttle wide open. On the second bike, the rider downshifts and whacks the throttle wide open.
The second bike is not at it's torque peak. And yet it will walk away from the first bike, even though the first bike is making more torque. Why is that? It's because he has more rpm and more gear reduction. When you downshift, you give the engine more mechanical advantage on the rear wheel. Sure, you lose some motor torque, but you more than make up for it by gearing deeper. You can get away with this because you're now turning more engine rpm. So even though you have less torque at the engine, you have more torque at the rear wheel, where it matters. By allowing you to gear deeper, your higher engine rpm makes every bit as much of a contribution to the acceleration of the bike as engine torque.
This is why torque, by itself without considering rpm, means nothing for performance. Making torque is easy, just gear deeper. I can make a million lb-ft of torque with a handheld drill motor if I gear it deep enough. But it would be moving too slowly to be useful. What matters is not torque, and it's not rpm, it's the combination of the two. That number is called "horsepower".
Bottom line, the engine making the most horsepower will always put more torque to the rear wheel at any given rear wheel speed, always. That's an easily proven fact, not an opinion, it's not something that can even be debated.
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