Finding three tenths of a louzy second.

1fasgsxr said:
Are you running a two step ? I cant imagine launching that high in the revs is needed. What is your boost at launch? Are you running a boost controller?

You don't get any boost without a load, no, not running a two step.
 
AMS 2000...little expensive but I bet it would get you a better launch and boost control. Launching that high in the rpms can't be productive.
 
9.23 @ 153 getting closer.
 

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This might be a dumb question, but have you removed the rev limiter? You can usually get an extra 1000 RPM over where the manufacturer sets the redline (assuming you don't mind rebuilding engines a little more often).
 
Because the torque peak is 8500 rpms, we go slower at a higher rpm, even though the hp is higher. Torque seems to be the pulling factor, hp is a weird factor that doesn't always bear fruit.
 

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Might be worth a try anyway. In my experience, horsepower is the more important factor in determining acceleration.

From a mathematical standpoint, acceleration is just a function of force and mass. Increasing force or lowering mass will raise acceleration. But because the forces we're talking about are measured through the wheels, with gearing being involved, horsepower is the real number. NA engines usually want to be wound out to near redline anyway.
 
Sonreir™ said:
Might be worth a try anyway. In my experience, horsepower is the more important factor in determining acceleration.

From a mathematical standpoint, acceleration is just a function of force and mass. Increasing force or lowering mass will raise acceleration. But because the forces we're talking about are measured through the wheels, with gearing being involved, horsepower is the real number. NA engines usually want to be wound out to near redline anyway.
Nope. Horsepower is torque/time.

Torque is more important for acceleration than horsepower. It's all about the force that wheel contacts the road, and must be greater than resistance to motion. Resistance to motion is the total of all of the friction, rolling resistance, and air resistance that is exerted on the motorcycle, and these values of resistance change as the speed of his motorcycle changes. When force generated at the tire contact point is greater than the total resistance of his motorcycle, the motorcycle will accelerate. The greater difference between tire force and resistance, the greater the acceleration.

When you increase force you increase acceleration. Wheels connect to axle, which connect to final drive, which connect to motor, so force at the contact point (tire to road) is the torque generated by the axle (force x distance = torque). As a result, when you increase the torque at the drive axle, you accelerate more quickly.
 
irk miller said:
Nope. Horsepower is torque/time.

Torque is more important for acceleration than horsepower. It's all about the force that wheel contacts the road, and must be greater than resistance to motion. Resistance to motion is the total of all of the friction, rolling resistance, and air resistance that is exerted on the motorcycle, and these values of resistance change as the speed of his motorcycle changes. When force generated at the tire contact point is greater than the total resistance of his motorcycle, the motorcycle will accelerate. The greater difference between tire force and resistance, the greater the acceleration.

When you increase force you increase acceleration. Wheels connect to axle, which connect to final drive, which connect to motor, so force at the contact point (tire to road) is the torque generated by the axle (force x distance = torque). As a result, when you increase the torque at the drive axle, you accelerate more quickly.

I agree with everything here but would like to add one thing.
Horsepower is unit of power, how much work is being done in a given time. Work is a force times displacement. So hp dictates force*displacement /time. The top speed.

If a vehicle has a cvt transmission, then keeping the engine at max hp would give max wheel torque, but with fixed gearing the engine torque and wheel torque are linearly related.

I know you know this, just thought it would help others perhaps.
 
Here's a dyno of HD's new 107 engine.

Peak torque occurs directly off of idle.

I'd still be inclined to give it some revs if getting from point A to point B were my goal.
 

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Sonreir™ said:
Here's a dyno of HD's new 107 engine.

Peak torque occurs directly off of idle.

I'd still be inclined to give it some revs if getting from point A to point B were my goal.
Where's acceleration over time in your chart? That's a dyno graph. How much time transpired from the beginning to end of their data log. This is about getting something from point A to point B (which is a short distance of 1/4 mile or 1/8 mile) in the shortest amount of time possible. You're missing a most basic theory of physics and drag racing.
 
The dyno chart also doesn't state that the 2017 Street Glide is 830 pounds but the chart is still useful information in determining shift points, no? It may not show the whole picture, but the whole picture is just made up of discrete parts that fit together in a certain way.
 
Here are some numbers based on a 2006 model. I imagine your numbers will vary since you're on an FI setup. You have a dyno of your current build?
 

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I still stand behind my statement that you are launching at too high of an rpm. If it was a bar bike then yeah. When I was going to the track on my Gsxr I was launching at around 5500 rpm and was pulling about the same 60ft times you guys are. Get a 2 step and set it for around 5000 rpms and watch the difference.
That bike should be able to hit high 8's launching it like you just pulled out from a stop light. If it runs slower shifting at redline then that would lead me to believe there is something wrong with the set up. Just my .02
 
Get the stacks plateaued and do ceramic bearings throughout. Won't be cheap but that's a nice reduction of parasitic drag throughout.
 
I posted this on the first page. Between seat time and experimenting at different launch rpms.10,500 launch gets the turbo into work load then in second gear, shift at 8500, which is the torque peak.
 

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Scooter trash said:
I posted this on the first page. Between seat time and experimenting at different launch rpms.10,500 launch gets the turbo into work load then in second gear, shift at 8500, which is the torque peak.

Why shift at torque peak?
Wouldn't you want to shift at the point when the torque at the wheel is the same in both gears?

4593f751d9c61550cb279cb6ce06735a.png


You can see here where the curves for the rear wheel torque intersect, those would be your shift points.
 
farmer92 said:
Why shift at torque peak?
Wouldn't you want to shift at the point when the torque at the wheel is the same in both gears?

That makes sense to me. I should revise my chart.
 
Does he hit the limiter before he can shift into 2nd gear?
How much seat time does your rider have? I have seen guys running 5.60's (1/8th mile ) on extended swingarm bikes with a stock motor and maybe a 50 shot of spray. What brand is the turbo? What size are your injectors?
 
1fasgsxr said:
Does he hit the limiter before he can shift into 2nd gear?
How much seat time does your rider have? I have seen guys running 5.60's (1/8th mile ) on extended swingarm bikes with a stock motor and maybe a 50 shot of spray. What brand is the turbo? What size are your injectors?
He hasn't hit the rev limiter lately, but he did report it seemed early. The turbo is a Turbonetic T3-T4 with a 55mm compressor scroll. The injectors are 620cc, fed with a 225 lph fuel pump at 45 psi.

Here's the kicker in the teether, the plugs came stock gapped at .055" out of the box for the Ford Connect van. I've been just putting them in because the general notion is that you don't have to gap Iridium plugs. The shop manual just says to replace them is dirty or discolored no gap recommendation until you dig into the electrical section and it wants .031-.035" gap. Turbos need to be gapped .001-.005" closer. This might explain the power drop off, I'll find out next race. BLAAAH! Darwin award time. Bought a new set and they were .036", so back to the drawing board.
 
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