2-1 or 2-2 headers?

[ron850]

What headers would you recommend?
Not looking for ultimate top end power but at the same time not something restrictive at high revs that would give the best torque spread.
Aesthetically I prefer 2-2 systems.
Engine spec std (for the moment) TDMRs, program ign and race cans.

Ron

[SDN]

I have 2 into 1 into 2s seems to work fine and I prefer the look. 2 into 1s will give less weight. Taking a wild stab I think 2 into 1 better for top end and the other give better midrange, Akraprovic did 2 into 1 Over racing two into 1 into two, both featured tapered headers so take your pick BTW where did you get your programmable ignition?

[cobbadiggabuddyblooo]

2 into 1 or 2-2 ,sure there is a weight difference with 1 less can on a 2 into 1 but power wise ,this is all to do with the length of the headers themselves and diameter.
You will notice with an Akrapovic 2 into 1 ,the collection box is around twice the header length up around the front right footpeg compared to you average joe blow 2 into 1 and where a 2-x-2 or 2-2 and std trx headers have their balance pipe situated.
It's all to do with pulse and scavanging effects and the conical shaped headers and internal diameters.
This is one of the factors that give the Akrapovic system is 6hp boost at 45000rpm and 3HP at 7500rpm on a stock motor.
Most large bore systems have a 4mm larger internal diameter header straight out of the head and you will find the collection box or balance pipe in around the same position as the std trx headers but may give you gains of 2 to 5 HP in the top end at the detriment to your low/midrange and may not really start to work until your up around that 4500rpm with the most gains at 75000rpm.