My stupid cobra is straight through, could roll a golf ball through it. People keep telling me that the valves will tear up if they dont have back pressure? that just dosent sound right to me. Also, how much hp do you lose to having no back pressure?

 

I think it would work, u would lose horsepower but gain some noise. As for the valves i'm really not sure i would just call up mechanics or something.

 

If the pipe is not long enough then u will hurt the valves other than that i think it would be fine.

 

I am pretty sure that the curves in the pipe create some back pressure. They might mean strait pipes, as in like a piece of pipe with no curves will not create enough backpressure. I know On my Yoshimura pipe, I can take the headers off, and look through, and you could also roll a golf ball through it. I don't think you have anything to worry about.

 

through the silencer part?

 

my next door has a DG straight pipe, and he says it loses power. but then again hes a dumbass and doesnt know anything about anything. so i wouldnt listen to him. just my .02

 

Nice job aaron, give advise, but then take it back bc u know nothing. Amazing I tell you, you are Jakals savoir!

-nick

 

its spelled savior nick. lol. but im sure thats just another of the thousand of typos. well, i think that it wouldnt lose power personally.

 

I'm not sure if the same aplies, but with an automobile engine, when running through just the headers, when you shut the engine off, it has a tendancy to draw cold air back up through the tubes. It is the infusion of the Cold air coming into contact with the Hot valves that is an issue. Like I said, not sure if this is an issue with an atv engine.

Back pressure usually effects your low end.
Lack of= decreases low end power, increases top end.
Too Much= good low end no top end.

 

yeah rpm's right you need some pipe to create at least a little backpressure for torque [dont ask me the specifics, it was 25 years ago] and if you're straight pipes are too short, when they cool they'll draw cold air in on yer heads. result: cracked valves or worse, busted valve seats. a quick temp change is not good.
just like messing with expansion chambers on two strokes years ago, four strokes ARE to a certain extent similar. changing the stinger length or diameter on a 2 stroke will change the power output, even installing a silencer will do that. the 4 stroke is not nearly as touchy, but the same rules still apply to a lesser extent. www.toomey.com stuart can explain it better than i can.

and have fun doin it!
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