Will you lose HP with 28t pulley? [Archive] - 1130cc.com: The #1 Harley Davidson V-Rod Forum

: Will you lose HP with 28t pulley?


Vinny
11-04-2003, 08:25 PM
While at the dealer today to pick up the v-rod,I wanted to see their demo v-rod,w/the supertrapp.Talking to the service guy,and he said that they only got 107hp.That's with the race tuner.I got 113 with the pcIIIr.

But he thinks it's because of the 28t pulley they put on.
Then he said I could be that it doesn't have many miles on it.I had 1200miles when I had mine dynoed.

what gives?

Max
11-04-2003, 08:44 PM
Usually an engine that is broken in or seated will produce more hp. The 28tooth pulley should not effect hp at all.

Vinny
11-04-2003, 08:54 PM
That's what I thought.

mjw930
11-04-2003, 09:46 PM
Unless they didn't correctly calibrate the dyno for the new ratio. HP is nothing more than torque * rpm / 5252. If the is calculating a lower RPM through a miscalculation on the final drive ratio the dyno will report lower numbers. Let's see, 117 * .93 = 108 :)

CW-VRod
11-04-2003, 10:05 PM
Got me wondering! I have a 28T on my bike and when was dyno'd i never told them that was the case! Would that have mattered?????

Max
11-04-2003, 10:07 PM
No, A dyno does not need to be set for your gearing. The dyno could care less what your gearing is, it measures speed of the drum and rpm of the engine. At least all the dynos that I have run do it in this manner.

CW-VRod
11-04-2003, 10:11 PM
Man,
What took you so long to reply!! LOL:notworthy :D

mjw930
11-04-2003, 10:22 PM
Max,

I remember seeing in the setup guide for one of the dynos and it included a correction factor for the gearing. I think it was for testing a bike that didn't have a tach pickup. With our coil over plug ignition how do they get an ignition pulse to fire a tach signal on a dyno?

Max
11-04-2003, 10:30 PM
They can use a paperclip to attach to this but I have a lead off of mine for them to hook upto.

http://www.v-rodforums.com/pics/000323.jpg

mjw930
11-04-2003, 10:43 PM
Ok, now I'm feeling really stupid. I didn't think that one through. The calibration was so the computer could show MPH.. :whack:

Max
11-04-2003, 10:49 PM
Mark the first dyno run I made the people did not have any idea how to hook up so It took a lot of looking to come up with that connection. The dyno we have for cars is nice, I have an inductive pickup that will measure even sitting on the windshield, all I have to input is the number of cylinders.

Max