| Author | Message | ||
     Cataract2 |
Has anyone tried this yet? If so how were the results? | ||
| BadS1  |
Been hashed over and won't work well. | ||
| Cataract2 |
Because? | ||
| Spooky  |
Do a search and you will find!!!! | ||
| Ingemar  |
I think it was because the diameter is bigger so they provide less backpressure, which in turn results in less bottom end power. I don't know if it would help top end though. | ||
| Porker |
I think it boils down to math. You need a certain diameter exhaust manifold for certain hp figures and again for displacement reasons. If a 9 put out 120 + at the rear wheels with stock displacement you would NEED larger headers. In stock config though going bigger is going backwards IMO. | ||
| Static |
"I think it was because the diameter is bigger so they provide less backpressure" sort of. It's basically a matter of exhaust pulse timing and velocity. Behind each high pressure exhaust pulse is a low pressure area that follows. The idea is to have a low pressure area help extract the next exhaust pulse from of the combustion chamber in turn helping pull a greater air/fuel charge into the combustion chamber. This is called scavenging. Pipe diameter directly affects the efficiency of a given engine in a particular RPM range. Larger diameter pipes typically increased higher RPM power at the expense of low end torque. | ||
| Racertroy  |
for what it's worth, i've heard it will work better than stock if you mock up some reversion cones and weld them it...don't know any more than that...but if you can pick some up cheep...may be worth the time and sheetmetal... good luck, --ts | ||
| Ingemar |
Thanks for that explanation Static. Larger diameter pipes typically increased higher RPM power at the expense of low end torque. So what we need to invent is a dynamic pipe diameter that increases when rpms go up  | ||
| Slaughter  |
So what we need to invent is a dynamic pipe diameter that increases when rpms go up Kinda what the factory is selling on the 12? Variable back pressure controlled by the ECM. ...Next question!  | ||
| Ingemar |
Oke. Is a longer pipe the same as a wider diameter header?  | ||
| Static |
"Is a longer pipe the same as a wider diameter header?" Not exactly. in fact a large diameter longer runner length will in some ways act like a smaller diameter shorter runner. (though the details are much more involved) Remember that you are tying to maximize volumetric efficiency within a specific operating range. |
