2 1/2 vs 3 inch Exhaust

[vkirkend]

What are the benefits of having 3" exhaust over the 2 1/2 inch exhaust to the rear?

[fastblackmerc]

An engine is like an air pump... more incoming air and more exhausted air is better.

[Zack]

Nothing
/thread

[vkirkend]

I know there was supposedly some benefit to having some back pressure with the smaller exhaust but see some people running with the larger 3" exhaust all the way back. I wondered if there was a hp benefit to the larger exhaust.

[jwibbity]

i thought the general rule was 1" total for every 100 horsepower,

so only if your were planning on making 600+ RWHP would 3" exhaust be necessary

[CWright]

i thought the general rule was 1" total for every 100 horsepower,

so only if your were planning on making 600+ RWHP would 3" exhaust be necessary


+1^^^^^^^^^

[cat in the hat]

i thought the general rule was 1" total for every 100 horsepower,

so only if your were planning on making 600+ RWHP would 3" exhaust be necessary

How do nine-inch tips figure into that ? I mostly see them on cars making about 125 hp, is that one inch of can per 15 hp ? :confused:

[Comin' in Hot]

i thought the general rule was 1" total for every 100 horsepower,

so only if your were planning on making 600+ RWHP would 3" exhaust be necessary

It's a good thing I went full 3"

[71cyclone]

It's a good thing I went full 3"
Yepp ---the old rule of thumb was'' big block' pushing 600 hp can accommodate 3'' exhaust :coolman:

[lji372]

Y'all must be running race cars!!!!

[Loco1234]

fopr most people's MM 2.5" is fine... but if you plan to run big power & Big boost / CFM then the #" exhaust is less restrictice. but if you havent had your headsw redone (port & polished) then the exhaust will not make a difference...

If you cant get the xtra air flow thru the engine....

[JOEMERC]

Not much better for either one if you still running stock manifolds that's where its choking these engines .