4-2-back exhaust? (Dual exhaust)

[Hunter_507]

So i see a lot of people running blast pipes on their 240. I have a stock ka24de,
Headers intake and 3 inch exhaust. I have 4-2-1 headers, and was wondering if anyone ever ran the 2 all the way back with say, 2 inch piping, to blast pipes? Obviously there would be no cat, which is fine cause i dont need one where im at. But would it sound like a 4 inch with blast pipes or would it just sound like a loud 2 inch exhaust (because both side would be 2 inches). I figured
Theoretically on a turbo car, it would give the same release of back-pressure that a 4 inch would, but would allow the car to sit low without scraping on the exhaust? I may be wrong. Just thinking of ideas before i get new exhaust, going ka-t this summer so thats why.

[zurud]

Sounds will be like 2". Backpressure will be like 3". Dual 2" is 1.5 time heavier than single 3"

[Hunter_507]

Okay thank you. Guess ill stick with 3 inch and do blast pipe tips.

[mechanicalmoron]

Unless you're going KA24DETT, I don't see how it wouldn't be considerably harder to fabricate the front end.


From top to bottom, this is 2, 2x2, 3, and 4 inch exhausts, and the open area available for flow in each, in square inches:

2 inch: 3.14
2x2 in: 6.28
3 inch: 7.07
4 inch: 12.57

And, though having 2 cylinders per pipe MIGHT be tunable to flow better per square inch, once again, unless it's twin turbo, since the manifold must bring all cylinders together anyway, you'd have to re-split them, which would detract from any tuning even further - this is a lose-lose proposition. Not to mention, it's a good bet it'd be INSANELY expensive for an exhaust.

If you care that much about flow, and noise is no object, do one of those 4 inch exhausts that exits through the fender, front bumper, or hood.

[Hunter_507]

Eh, i wasn't lookong for something to extreme, my build will stay around 350-400hp so 3inch will be good. I was just looking for something different, thanks explaining!