interesting exhaust information

[AVE0SAM]

i know i posted this in another thread but i thought it was an important enough topic to have its own thread....hes my post:

theres only one person i know of that has gone 2.25 to 2" and that was brian and he said that you can feel gains from switch from 2.25" to 2"....which makes sense since this is such a small engine.

http://www.k20a.org/forum/showthread.php?t=38783&page=2

a little bit down on this thread a person by the name of Froth uses a formula to help calculate around what size exhaust an n/a engine needs to be effiecent.

area=3.14159265 x 1 x 1 = 3.14159265 in sq

3.14159265"sq x 115cfm = 361.28315475cfm of capable flow

then you divide that by 2.2hp per cfm which equals 164.22 hp, therefore a 2" exhaust will theoretically flow enough to meet the needs of a 164.22hp engine before youstart fighting the exhaust restriction....hard bends also play a factor in this but considering our engine barely makes over 100hp to the crank i think 2" is plently

this should put an end to the whole 2 or 2.5" discussion so i can stop telling people 2" over 2.5" but that whole thread on k20a.org is very informative

[xtreme 2]

very nice

[AVE0SAM]

haha is this a record...33 views and one response. i thought this topic would get more response

[ontarian_frog]

I'm looking at this and it makes no sense. I know I replied something else in the other thread, but I thought about it for some time.

A 1" pipie can flow anything. it depends on how much PSI you're flowing at. Will develop a formula and give you guys a better respond than this.

[aveodude]

A 1 inch pipe cannot flow anything. This is not a PSI thing, it is a CFM thing. Yes you can try to push 300cfm through a 1in pipe but it would create alot of backpressure thus robbing you of alot of power.
Think of it this way. Blow into a straw and then blow into a paper towl holder. Which one is gonna move air faster?

[sappy96]

that formula is crap.

There is a bunch of fluid dynamics involved w/ gas. Scavenging and things like that are not included at in this formula.

[AveoSSSupercharged]

im still going to do a 2.5" exhaust....but i plan on having more hp.

just to let you guys realize also...many of the supercharged cobalts that are pushing 260-280 crank hp are using a 2.5" exhaust still.