muffler/piping questions

[newaccorddriver]

im in the process of going turbo and ive got a few questions about the exhaust system.
the part that im stuck with is how big of an exhaust system i want to use.
ive got access to 2 nissan altima 3.5se mufflers with pretty good looking tips on them for around $25 each. they both have 2.25" inlets.
i was wondering if its actually a good idea to run 2 of those mufflers on my car while running either a 3" or 2.5" piping all the way to them and use a reducer. im into doing my own custom for the 2 mufflers, but im wondering if its actually a good idea to use that small of an inlet

so you want to go from either 2.5-3" piping into two 2.25" mufflers right? if thats the case i dont think its going to be bad since its dual exhaust

thats kinda what i had in mind. it shouldnt be too bad for back pressure considering its dual exhaust.
its not going to be factory style specs, so one of the mufflers will have more exhaust flow through then the other, but when im driving hard, whatever back pressure is on the first muffler should be relieved by the second muffler right?

If you get a real "high flow" cat (in other words, a resonator that pretends to be a cat), and 2.25" or greater all the way, you'll be all set for turbo.
2.5-3, or whatever largeness possible is best. But 2.25" piping the whole way with one of those mufflers will do you just fine. Unless you're going to try to make retarded amounts of power or high RPM. a20 turbo is fine with 2.25".

ill be trying to make retarded amounts of power when my engine is out by boring the block and getting lower compression pistons if my budget allows them. 2.25" all the way might do, but there are times where 2.25" wont do cause i would probably like to drive around pretty hard in the high rpms

if you want it to be true dual exhuast (as in from the manifold back is two seperate pipes) each pipe will have equal flow. 2.25" would be fine with dual exhaust

it would be nice to have true dual exhaust, but i highly doubt theres enough room to fit all the piping under the car properly, that is why i just wanna split it at the end with a couple reducers. on top of that, i dont think its going to be easy to make a dual exhaust system with my welding skills

[gfrg88]

so you want to go from either 2.5-3" piping into two 2.25" mufflers right? if thats the case i dont think its going to be bad since its dual exhaust

[Versanick]

If you get a real "high flow" cat (in other words, a resonator that pretends to be a cat), and 2.25" or greater all the way, you'll be all set for turbo.

2.5-3, or whatever largeness possible is best. But 2.25" piping the whole way with one of those mufflers will do you just fine. Unless you're going to try to make retarded amounts of power or high RPM. a20 turbo is fine with 2.25".

[2drSE-i]

if you want it to be true dual exhuast (as in from the manifold back is two seperate pipes) each pipe will have equal flow. 2.25" would be fine with dual exhaust

[A20A1]

The restriction is in most cases the muffler itself not the pipe diameter.
So know how much the muffler flows is a good start.
400 cfm is 400 cfm doesn't matter if it's a pipe or a muffler.


Lets say you need a system that can handle 550 cfm / 250 horsepower.

You'll need a single pipe to flow 550 cfm
You'll need to split the exhaust.
You'll need the two smaller pipes after a "Y" to flow 275 CFM each
...and most important each muffler should flow 275 CFM.

1.75" Single Exhaust pipe flows about 275 cfm
2.00" Single Exhaust pipe flows about 361 cfm Good for 164 HP
2.25" Single Exhaust pipe flows about 457 cfm Good for 207 HP
2.50" Single Exhaust pipe flows about 564 cfm Good for 256 HP

2.25” Dual Exhaust pipes flows about 880 cfm
2.25” Dual Exhaust pipes good for 457 HP

how much horse power do you intend to make?

So you're setup for 250 HP

single 2.50" pipe
to "Y"
to dual 2.25" pipes (could even use 2.00" pipes)
to Dual SE Mufflers

But really you could be shooting yourself in the foot if you get poor flowing mufflers.


Also in the case of turbo you want to consider the CFM flow of the trubo itself. as in how much it's putting out.

.

Just so you know the numbers don't mean you can't make more HP with a small pipe diameter but it'll be better to get one size larger because you'll be adding so much extra back pressure once you exceed the CFM rating of the exhaust.