Optimal Exhaust

[jtodd]

What is the optimal exhaust for a high performance 1.9l for SCCA FP or GTL? I have seen both the standard 4-1 header as well as the tri-Y. What are the advantages of either or some other configuration. I have also read that Stan C has a 'through tunnel exhaust' in his GT - how is this accomplished?

[RallyBob]

Depends on your needs, your driving style, your tracks you run, and your engine's specs. A clubman level engine will need a totally different exhaust than a full-tilt, no-holds-barred/cost is no object National-level engine. And a tight'n'twisty track needs a different exhaust than say, Road Atlanta or another 'dyno with turns' type of track.

FWIW, no one 'serious' in GTL or F Prod. uses a 4-2-1 header, they all use 4-1 custom built designs. 4-2-1 designs tend to be compromise headers, trying to cover a broad rpm range.

What specs are you starting with?

[anastosmotors]

Hey Jeff.
If you want to built headers for your
Opel come to see mine. They are custom
built from a picture that Bob sent
me years ago. I might be able to
scan you the picture too.
It make big improvement.
Pete

[jtodd]

Thanks Pete,
I should be up that way in a couple weeks and I will take a look and some pictures then. Do you have the exhaust running through the driveshaft tunnel? What size tube are you using?

Jeff

[anastosmotors]

Tube 1 5/8"
Length 32" - 34" within 1/2"
Collector 2 3/4" 8" Long
Exhaust Pipe 2 1/2"