Dyno numbers - 2.5inch Headers vs Stock headers

[sunny]

I would say the data doesn't mean much because there were too many variables. To have real meaning you need to have a run, make the changes and then make the run again in a much shorter period of time.

you mean quartermile?

 

[dougl]

The max torque for the original run was 145. The max torque on the recent run was 160. That’s a significant difference.

 

[stingray]

what I dont understand is throttle response on the bike with open headers is way better than before, huge difference, I move throttle at any gear and it goes which was not the case before.
Second, with open headers my MPG has gone 30% down than before so I need 30% more gas per fill if I want to go same distance as I was going in one tank before open headers.

Less back pressure has improved throttle response. I may have missed the tune part but it sounds too rich now. The most important thing is, how does it sound?

 

[sunny]

Less back pressure has improved throttle response. I may have missed the tune part but it sounds too rich now. The most important thing is, how does it sound?

its very loud

 

[sunny]

The max torque for the original run was 145. The max torque on the recent run was 160. That’s a significant difference.

As Stingray mentioned, could that 160 lb-ft simply be a momentary spike?

 

[dougl]

As Stingray mentioned, could that 160 lb-ft simply be a momentary spike?

Sorry, I didn’t look at the scale on the right. It’s the spike at the end, which isn’t real. The actual max torque is about 140.

 

[Kevin frazier]

The last dyno i had there was a torque spike, a big one, maybe thats why i jammed my torsional damper? Lot of torque, 3 spikes actually, on every pull we were getting crazy torque numbers at the top. This package ate a torsional damper and then at end of summer ate 4th gear. I had a billet one in and trans shaft gears still broke.

 

[stingray]

I see that a lot on dynos. If you watch the engine HP at shutdown will fall off but the torque makes a large spike (after power cut). Was explained to me that the dyno drum is momentarily freewheeling, indicating false torque. Torque doesn't come from an unloaded engine.

 

[sunny]

alright, can some one explain why my gas consumption has increased by 30% with new headers and open exhaust? and my riding riding is same as before, nothing changed.

 

[Kevin frazier]

More air out, more air in, more air in, more fuel. Better cylinder evacuation, before it probably didn’t empty completely, thats why a good tune will dial in the timing and get the fuel right.