3inch or 4inch Exhaust?
07-11-09, 06:53 PM
#17
Why do you need a 4inch exhaust in the first place? The only reason is if you were running upwards of 800-900hp. I'm just a little upwards of 750hp right now and it feels like my 3.5" is holding me back a little bit, but just barely and not by much. I'm going to upgrade my turbo setup soon to make more power and I'll upgrade to 4" at that point. If you're not turbo'd, you will lose significant power by putting a big exhaust in.
Right now I run a single 3.5" back splitting to two 2.75".
The cross sectional area of a 3.5" pipe is approx 9.6sq-in. A 2.75" pipe has 5.9sq-in so multiply that by two for the twin exhaust and you will get around 11.8sqin. Therefore the rear section is not causing any further restriction.
For the single 4" to twin 3". The 4" pipe has 12.56sqin, 3" pipe has 7.06sqin. The twin 3" pipes gives you 14.13sqin of cross sectional area. So the single 4" to twin 3" will work fine as well.
Right now I run a single 3.5" back splitting to two 2.75".
The cross sectional area of a 3.5" pipe is approx 9.6sq-in. A 2.75" pipe has 5.9sq-in so multiply that by two for the twin exhaust and you will get around 11.8sqin. Therefore the rear section is not causing any further restriction.
For the single 4" to twin 3". The 4" pipe has 12.56sqin, 3" pipe has 7.06sqin. The twin 3" pipes gives you 14.13sqin of cross sectional area. So the single 4" to twin 3" will work fine as well.
08-21-09, 04:24 PM
#19
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nobody makes one. You'll have to get it custom made at an exhaust shop, which likely would be cheaper anyways. Don't bother with a 4inch exhaust by the way unless you're stroked to 3.4L and running like 30psi of boost. I wouldn't even bother with a 3" unless you're over 10psi.
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