What the hell are you talking about? There is no such thing as a back pressure spec. Its never even refferenced anywhere in the owners manual or the factory shop manual. Back pressure is bad. Over scavenging is bad. Usually people just put giant flow systems on without properly designing them and over scavenge causing problems. Back pressure is a band aid for poorly designed exausts.

 

Oh i agree with you and sorry let me rephrase. When i said "backpressure spec"i was thinking negative pressure. I realize now using those 2 words interchangably might lend itself to exhuast professionals feeling the need to correct... what i asked Coffman was related to negative pressure when the exhaust valve opens - so exit speed and velocity are correct (or remain close to stock). They assured me this was the case (whether thats true or not i dont know as i dont have a dyno in my garage to test the preformance difference between my d&d and the coffman. A good header design or more importantly, the merges, would be the critical points of scavenging and velocity which ultimately help to create more power. The muffler portion of the exhaust is more or less a suppressor of the sound waves.

I was under the impression the baffle is the component that creates the negative pressure in the system and running the bike with just header is hard or bad on exhuast valves. If you could enlighten me on the fundamentals of the baffle in this exhaust pipe it would be much appreciated.

 

LOL someone got their feelings hurt. You obviously have some understanding of the principles and now are upset and feel the need to beat your chest as you think other people don't know how smart you are, otherwise you wouldn't be taking tongue in cheek shoots. Its ok. Next time don't continue the backpressure myth and people like myself won't correct you. Yes, I feel the need to spread correct info when in a technical discussion. People are here to learn, why not teach it right the first time?

 

this isnt the youtube comment section, no need to disrespect anyone. if someone is wrong or misunderstood about something then please be mature about it.

 

+1

Easy guys.

 

Nice username sir.



On an unrelated note, I do NOT plan on doing this however, but out of curiosity if the baffle is taken out of the slip on, that's bad for the valves right?

 

Haha like i said i agreed with you big cat. Sorry i'm still looking for that detailed professional explanation on the baffle/backpressure myth which you really should give after telling me what i dont know. Im all ears. And if you didn't want tongue and cheek shots you probably should'nt reply to a post opening with "What the hell are you talking about"... IMO. But thanks for coming out. After all a guy with over 1500 posts really SHOULD know everything. correct? lol (let me do the big boy thing here and apologize to everyone else on this thread looking for some generic info on this exhuast)

 

On an unrelated note, I do NOT plan on doing this however, but out of curiosity if the baffle is taken out of the slip on, that's bad for the valves right?[/QUOTE]


We should probably patiently wait for boredandstroked to educate us.

(Okay im done.) lol

 

I love how when I say something I'm told to settle down, you continue taking personal shots and yet because you post "lol" its all good. Go ahead and quote where I said you don't know. I specifically asked you what you were talking about, with the word hell thrown in there. You corrected yourself in the next post and at the same time re-affirmed exactly what I had said in my post. I'm sorry the word hell gets you so worked up.

 

Ok wow, well in the meantime I would really like if someone explained the whole negative pressure and proper way to flow exhaust. I have always been interested in it since I have no idea about it and don't know why pure flow isn't good...I'm not completely illiterate about engines just never had it explained to me before.