cool_as_crap

Alright, so I was looking at getting a racing beat header/presilencer setup again, and I noticed this:

http://www.racingbeat.com/resultset....rtNumber=16408

I was thinking of using this with a true dual exhaust setup. With 2 presilencers, it should be a bit quieter than the single presilencer/collected header I had before.

But now the important question, would this setup yield more hp? I've heard good things about true duals on an n/a.

Thanks for any help.

Latin270

I dont think the gains are significant. I'd say RB collected header to Bonez high flow cat and you'll be set.

Roen

iTrader: (2)

There's a whole thread on exhaust theory somewhere in the 2nd gen section. Lotsa good info.

j9fd3s

iTrader: (3)

yeah, i think roen and i both posted in it...

the basics are that we're looking for 2 things.

1. low backpressure, backpressure in the exhaust is always bad....

2. tuning. with a good collector, the right header length will put a vacuum on the exhaust port and make more power at a given rpm

#1 helps everywhere, #2 helps only in a tuned range, but is powerful, and if you get these both to work together, you're making big power.

so you want low backpressure system with a "tuning" to maximise the engines powerband. for example a PP engine makes peak torque @8000ish rpm, so you want a header that maximises torque @8000rpm, and continues to flow into the power peak over 9,000

peejay

And the part that a lot of people don't fully grok is that excessively large pipes *create* backpressure because the gases lose too much speed, and thus inertia. When that happens they need extra help getting pushed out... resulting in *backpressure*.

And that backpressure magically goes away when engine speed goes up, increasing exhaust velocity and inertia.

And that's basically the point behind pipe tuning. Reflected waves are only useful at discrete points, but being able to capitalize on the gases' inertia pays dividends almost everywhere.