4age Exhaust Manifold

[306rwd]

Has anyone any recommendations for pipe sizes and lengths for a 4-2-1 exhaust manifold?

The engine is a small port 4age, standard valves, ported head, 45 DHLA carbs and approximate power - 185bhp. Cam lift is 8.3mm, don't know duration off hand but it is not too cammy. It is a rally car so torque is more important than max bhp.

It is expensive to get a one off manifold made so I only get one chance at it so any help will be appreciated.

Thanks

[oldeskewltoy]

I tried to get a similar thread going in a different forum.....
http://www.hachiroku.net/forums/showthread.php?t=8327
You can at least see the KBD.... unfortunately the KBD is likely too small for your app since the primaries are only 38mm

[Chrisso]

With regards to length, have a read of this to start. There is a table which allows you to roughly calculate the length based on your expected power band. Roughly, I would expect you would want the primaries and secondaries to be long so as to keep the usable power as low down in the range as possible.

http://www.billzilla.org/engexhaust.htm