15hp? you didn't specify whether this was a DS or a V-8.....were they talkin' a DS?

Drag Pipe! I've tried it all ways in all configurations, sometimes with brand x headpipe, brand y mid, and whatever end.... you just can't beat a drag pipe....yet?

Everyone likes to talk back pressure, and maybe it's easier to think in those terms, but it's all about velocity and harmonic waves.

222

 

No not a DS or a V8. Beleive it or not my bud has a Raptor(Dont tell anyone)LOL. The sad thing is alot of guys will beleive that crap. Oh well Ill still be looking back at them at the finish line. Good stuff Thanks guys

 

You can get almost 10 HP just by changing out the exhaust and opening up the airbox on a stock Raptor. If you leave the stock exhaust on a built big bore Raptor, switching to a set of tuned dual reverse megaphones will easily add 15 HP on the top end if everything else is ready to breathe. My first reverse megaphone drag pipes gained 8 HP over a good Rossier exhaust but lost torque in the midrange, same motor on the same dyno the same day. It's all relative, no pipe is best for every application.

 

As far as the big #'s are concerned.

When Dynojet developed their kit using my DS they told me that my CT exhaust made an xtra 10 HP.

ALL ON THE LOW END. IT LOST 1 PONY ON THE TOP.

222, the exhaust I run on my son's 450R is called a Pulse Charger.

It was developed using harmonic/sound waves theory.

 

15 hp out of a pipe is totally possible. Hell, my stickers alone gave me 15. It all in how you line them up. A fraction off and you will lose power.

 

I've begged those guys at pulse charger to send me a prototype- doesn't even have to fit right- they've got bigger things to do than chase a DS650 exhaust though.

222

 

Ask for dyno sheets from the pipe builders - most will say they don't have any. Why? Because they want to sell you a pipe, not let you compare. There aren't many companies where you can get an actual dyno sheet showing you how the pipe does. 10 hp, 15 hp, 200 hp, if they can prove it with a non-doctored dyno sheet then that would be a good tool to look at. I only know of one or two shops that sell DS pipes that actually have a variety of dyno sheets available. Don't ask for a dyno sheet from White Brothers - you'll get put on hold for like an hour, not so fun. (Personal experience.)

 

Back pressure is kind of a generic term that alot of people use. We should redifine it as "exhaust speed".
Why do you think a billet end cap makes more bottom end than a CT with disc system installed? The back pressure of the disc system should make big bottom end according to most people.
Now why does the CT make way more top end and over rev than a billet end cap? After all the end cap is wide open and the CT has discs stopping up the end which should hinder high rpm flow.

The answer is exhaust speed. The end cap allows for fast exhaust speed at low rpm but when the rpm gets up past 7500 vacuum becumes too great at the exhaust valve and cylinder pressure is pulled out of the combustion chamber.

So how would you cure this high rpm problem? Slow down the exhaust speed. Thats what the CT does with its disc system. Or you could run a smaller exhaust cam! Thats right a SMALLER exhaust cam for more high rpm power!! [img]i/expressions/face-icon-small-shocked.gif[/img]

 

I love this forum

 

Misterhp,

Is there anything you can do to keep from losing cylinder pressure at higher rpm's that does not inhibit exhaust speed at low rpm's?

Ron