I am running a set of Cobra Dragster pipes, they are slightly baffled and seem like a good thing, 22,000k's and no problems. I was reading a tech peice on the S&S website and they mentioned that you loose low end power with drag pipes because as the exhust gas back pressure wave goes back up the header pipe it re-enters the combustion chamber through the exhaust valve and during the valve overlap the back pressure wave can exit out the inlet valve so on the next induction stroke you are re=burning these gases. (turbo style??)

Just wondering if anyone can shed some light on this, i love long pipes and have always been under the impression that long pipes help the motor to breathe better.

2008 Softail, 96"B, SE 204 cams, S&S high flow a/c, power commander, Cobra Dragster pipes...

Cheers Patto

I was told many moons ago that no back pressure means burnt out valves, if this is false please tell me so i can go super loud hehe.

 True! Drag pipes are great for top end power if tuned correctly, but suffer at bottom end.

You definately should have at least a little back pressure.

 I used to run drag pipes on my evo, (with the homemade butterfly, washer type baffle), then installed EV27 cam and tacho. 

Cam didn't start to pull until about 3300rpm, then took off like a rocket!

Replaced drag pipes with tapered turbos and then smooth power off cam from low 2000s.

2-1 system would probably have improved even more.

Nice deeper note from turbos as well!

ok on that note then, what pipes are a good option for all round, should i use the stock headers and find some slipons to suit, if so witch ones would suit? or should i find a complete new system?

for good power across the rev range, you cant go past a good 2-1 system, if your not big on the 2-1 sound, tapered turbos or similar are the go.
Considering that you live and ride around Port Hedland, low end power is probably not as big a priority as those, like myself, who ride on windey, mountain roads a lot of the time.
You may be more interested in top end, in which case the drag pipes will be fine.

For tuning drag pipes visit.....http://www.nightrider.com/biketech/exhaust.htm

Ozroder,

No problems at all mate, in regards to the measurement do i measure the complete length fom the flange to the tip, headers included or just the straight sections.

Also the bike has been dynoed by Pattersons in Bunbury and she goes well, i have no complaints at all, would they of picked up or tuned in these pipes during the dyno operation?

any back pressure is no good, you dont want back pressure, ideally the right sized exhaust will create a vaccum NOT pressure, the reason "drag" pipes dont work on the street is given away in their name, they are for wide open drag racing. they are usually to large a diameter for the engine. if you want low/mid with not too bad top end try an rb 2-1. stock headers and S+S mufflers works well. the returning wave your talking about is not pressure it is a sonic wave and the exhaust length and diameter affect when the wave returns to create a pulse that will block the exhaust port, that is why exhausts only work in a certain rpm range. longer pipes will help shift power down lower similar to a smaller diameter change.

the rb racing site if filled with good info and is accurate as hell.