exhaust for 4age....

[rodimus]

hey guys

im after a exhaust system for my 4age in my AE85. ill probably go for a 2.25 inch. But dont know about the lengths and fatness's of the kobes/resonantors, to uses, what r u guys using?

The person whose doing my transplant will probably weld it up for me, but
how much better is a mandrel bent exhaust? Cost is very important.

[RedMist]

It totally depends on the cam profile you have. I've never speced one for standard cams however there are two things you want to look for in a modern exhaust. Because of modern interferance collectors 4-2-1 are now more efficient THROUGHOUT the rpm range. You get much greater mid range and a slight increase over a 4-1 exhaust. Secondly you want long primaries and short secondaries. The longer primary allows you to exhaust pulse tune through a longer rev range.
I run 304 degree 415 thou lift cams (yes very wild), and a Lynn Rodgers speced exhaust. 27inch primaries running into 10 inch secondaries. Your length and diameter will need to be modified for the cams you run. However I don't have the equations to hand. You should be able to find something in this regard on the web.

Daniel

[Disco]

Hahaha Daniel, you always impress with your wild cam specs...

I think the answer to the question is:

If the engine is a stock 4AGE bluetop, 2.25 sounds about right,

mandrel bent exhausts are far superior because they have the same diameter all the way through (with a press bent pipe, at the bends, the metal on the inside of the corner squishes up and the pipe is not 2.25" in the bends, it's usually a bit less.)

When you say cost is important you are really saying that you don't wanna spend lots...

if you don't wanna spend lots, unless your mate is a really good welder, mandrel will probably be out of the question...