Motorcycle back pressure without baffle?

Question

Following a previous question I wanted to get some input on what alternatives there may be. I've been considering drag pipes with two 90 degree angles to hopefully build a little back pressure. I would think this would do as much as baffles right? Another thing I saw was someone put a metal strainer from home depot in the pipe. The ones like you put in the kitchen sink with all the holes in it, and then they drilled out the middle leaving only about a half inch around. This seemed like a decent idea also as it would appear to work similarly to a baffle. Any thoughts on how to get beck pressure without baffles or mufflers?

Answer 1

Very good, BUgz. I liked that.

Answer 2

Who told you back pressure is a good thing?  It's not.  Actually, backpressure will build bottom end torque but it will kill your top end, that exhaust needs to get out in a hurry.  We struggle everyday to build better exhaust systems with less back pressure yet remain quiet enough to elude the keepers of the peace.  That is the whole battle, less backpressure means more power but it also means more noise so there is always the struggle to have the cake and eat it too.

Answer 3

Back pressure is not bad, I am not an internet hero...but back pressure is not bad. Yamaha spents TONS of money developing their EXUP system that creates back pressure at low RPMS and increases low end torque.

V-Twins are all about low end torque due to their lower rev abilities. A bike that can run at 12,000 RPMS obviously needs to get rid of exhaust gases very fast, but V-Twins dont push 12,000 rpms.

To the other poster, if you dont think a little back pressure increases low end torque, then explain to me why Yamaha developed the EXUP system????

Explain to me why top fuel dragsters have pipes with a sharp bend in them instead of short straight pipes directly out of the cyclinders?

Zero back pressure KILLS your low end torque...you have to find that fine line between low end, and top end...find the pressure that optimizes both. Yamaha did it with an EXUP system that operates off of a TPS sensor..the more throttle you give the bike..the more free flow the exhaust has.

Now, to answer the posters question... yes creating sharp bends in the exhaust will create back pressure and increase low end torque... but the pipes will have to have equal amounts of back pressure or the bike will pulse from cylinder to cylinder. You would probably be better off trying to find a nice set of tuned drag pipes for you bike.

Answer 4

Why do you want to introduce backpressure?

Backpressure is bad.

A lot of internet heroes will tell you otherwise, but they are wrong.