[greenmonster]

Do bigger headers, f e 42 or 45 mm, give any increase in power or torque?
Do they alter the powerband like more power on top?
Anyone has any hard facts (read Dyno)? Both w or w/o crossover interesting.
And I talkin bout engines w at least hicomps and some portwork as I guess
a standard engine won`t benefit from bigger pipes. But I could be wrong...

GreenMonster

 

[brad black]

i have only dynod a st2 with bigger headers and didn't actually ride it on the road, just to the dyno and back. so i didn't get a feel for it so to speak. but, i doubt you'd find any power increase, most likely a bit of a loss if anything thru the midrange and better power from 8,000 or so up.

but the dyno can't measure response, and it may prove to be a bit better there on the road. pretty pricey tho as a general rule for the improvement.

 

[64duc]

Anything that allows the engine to breathe better will increase HP. That said. larger headers alone could reduce HP if they are not tuned to the engine, ie length, size and shape.

 

[greenmonster]

OK, thx. Pretty much what I thought.
Haven`t seen or read anything that bias bigger headers.