Dyno questions? - Page 2

Cutty72 · 12-14-2008, 06:34 PM

Quote:

Originally Posted by ebbs15

same here... they're always sitting cause they have to shift... and it takes too much coordination apparently to do with out sitting

Most dyno runs (that I've seen) are a single gear pull. usually one gear down from top (ie 5th for sportbikes, 4th for most HD's) as that is the closest to a 1:1 ratio.

marko138 · 12-14-2008, 06:47 PM

Quote:

Originally Posted by Dnyce

never seen it done like that honestly

Me either. Dood was sitting on mine when it was done.

HRCNICK11 · 12-14-2008, 11:01 PM

I have always used 4th on sport bikes. When not doing a all gear pull.

Cutty72 · 12-15-2008, 08:49 PM

Quote:

Originally Posted by HRCNICK11

I have always used 4th on sport bikes. When not doing a all gear pull.

From what I've seen doing that will probably give you a slightly higher torque number, and a lower hp number.
At least that's what I saw on the dyno down in IA.

5th is the closest to a 1:1 gear ratio

HRCNICK11 · 12-16-2008, 09:45 PM

Quote:

From what I've seen doing that will probably give you a slightly higher torque number, and a lower hp number.
At least that's what I saw on the dyno down in IA.

That can't happen....... (Torque x Engine speed) / 5,252 = horsepower ...... Its mathematically impossible.

Cutty72 · 12-17-2008, 05:55 PM

Quote:

Originally Posted by HRCNICK11

That can't happen....... (Torque x Engine speed) / 5,252 = horsepower ...... Its mathematically impossible.

Riddle me this then. Why are the peaks from 4th 5th and 6th not all identical? (run started in 2nd)
All gears were run to redline

HRCNICK11 · 12-17-2008, 08:40 PM

I did not say that it would not increase. I said they must remain proportional.

Horse power is just another way to measure torque that also considers RPM. You can take a given torque and RPM and use math to get horse power. This is the reason that torque and Horse power are always equal at 5252 RPM if they are not then the correction factor is really messing up your measurement.

I would suspect that your HP increases in higher gears are either from the correction factor. Or because the weighted drum has higher energy(harder to stop) at higher speeds. It might even be a flaw in the machines sensors.

Thats reason all gear runs are only used to look for lean or rich float or main jet conditions and the actual numbers should not be considered for actual measurement.

HRCNICK11 · 12-17-2008, 08:51 PM

Here I'll show you say you have 40 Ft/pounds of torque at 4000 rpms

40 X 4000 / 5252 = 30.4645849200304645849200304...... HP

Every time, the math never changes its always that HP for that torque at that RPM. If the torque goes up for a given RPM the horse power has to follow they cannot go in different directions. They are always proportional they can not be inversely proportional.

Cutty72 · 12-17-2008, 08:52 PM

Gotcha. I misunderstood your first post. Now it makes sense.

HRCNICK11 · 12-17-2008, 09:03 PM

I kinda key in on this point

Quote:

higher torque number, and a lower hp

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12-14-2008, 11:01 PM	#13
HRCNICK11 Canyon Carver Join Date: Nov 2008 Posts: 429	I have always used 4th on sport bikes. When not doing a all gear pull.

12-17-2008, 08:40 PM	#17
HRCNICK11 Canyon Carver Join Date: Nov 2008 Posts: 429	I did not say that it would not increase. I said they must remain proportional. Horse power is just another way to measure torque that also considers RPM. You can take a given torque and RPM and use math to get horse power. This is the reason that torque and Horse power are always equal at 5252 RPM if they are not then the correction factor is really messing up your measurement. I would suspect that your HP increases in higher gears are either from the correction factor. Or because the weighted drum has higher energy(harder to stop) at higher speeds. It might even be a flaw in the machines sensors. Thats reason all gear runs are only used to look for lean or rich float or main jet conditions and the actual numbers should not be considered for actual measurement.

12-17-2008, 08:51 PM	#18
HRCNICK11 Canyon Carver Join Date: Nov 2008 Posts: 429	Here I'll show you say you have 40 Ft/pounds of torque at 4000 rpms 40 X 4000 / 5252 = 30.4645849200304645849200304...... HP Every time, the math never changes its always that HP for that torque at that RPM. If the torque goes up for a given RPM the horse power has to follow they cannot go in different directions. They are always proportional they can not be inversely proportional.