Dyno numbers for 3:37 and 3.17 which would be higher : V-Twin Forum: Harley Davidson Forums

gofastflhx · 03-29-2008, 11:43 PM

Guys is there a diffrence on the dyno with these two diffrent gears

YankeeBob · 03-30-2008, 06:49 AM

I know there is to the pavement!!

Hillsidecycle.com · 03-30-2008, 08:24 AM

The 3.37 will certainly rev quicker, but the 3.17 ratio, will show a higher hp and torque number on the dyno.

C-Cat · 03-30-2008, 11:28 AM

will the newer bikes (07-08's) with the higher gear ratio dyno more or less hp and tq then the 3.17 gears?

Harleypingman · 03-31-2008, 11:38 PM

The dyno operator should set the ratio as part of the "constants" before calculating tq and hp--the engine isn't doing anything differently regardless of the gear ratio so the numbers should be the same.

Jeffytune · 05-15-2008, 07:37 PM

American Bagger did a test of these, the dyno showed the same curve and output, Torque and Horsepower.

But it gets it to the ground easier.

claydbal · 05-15-2008, 08:01 PM

this is a really good thread actually. what gearing produces the best brag sheet?

when actually it doesnt mater-----------the dyno oerator looks at the curve and knows what he need to do.an old dyno rule is dont pick the gear that shows the best numbers, pick the gear based on tire and drum speed.

think about that one!!!!!!!!!!!!!!!!!!!!!

ceraaa42 · 05-15-2008, 08:28 PM

Quote:

Originally Posted by claydbal

this is a really good thread actually. what gearing produces the best brag sheet?

when actually it doesnt mater-----------the dyno oerator looks at the curve and knows what he need to do.an old dyno rule is dont pick the gear that shows the best numbers, pick the gear based on tire and drum speed.

think about that one!!!!!!!!!!!!!!!!!!!!!

So, my question would be, do the hp/tq curves change with the different gears?

Just the curve not the numbers.

Chris

claydbal · 05-15-2008, 09:01 PM

on dynos i am familiar with, curve will remain the same, numbers will change.

TXCHOP · 05-15-2008, 09:46 PM

Quote:

Originally Posted by claydbal

on dynos i am familiar with, curve will remain the same, numbers will change.

How bout picking a longer gear for a better(longer) sampling rate of AFR?

claydbal · 05-15-2008, 10:31 PM

Quote:

Originally Posted by TXCHOP

How bout picking a longer gear for a better(longer) sampling rate of AFR?

that has been said many times, but in the dyno directions, it says choose a gear that doesnt allow the tire speed to go past its rating, and doesnt overrev the dyno drum.