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Old 09-23-2011, 09:09 PM   #56
BSR-1

 
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Drives: 17 ZL1 M6 Black
Join Date: Oct 2009
Location: Capo Beach, Ca
Posts: 1,411
Quote:
Originally Posted by Beauwulf View Post
One of the most important things about a "cleanup" port job is to make them all the same size. Hopefully, you used a template to get them close.... Since the AFR is the average of all the cylinders, a port that is larger than the others (or just flows a lot better) runs the risk of going lean. I think I'd ask Vince to give me a "safe" tune to try it out with and tweak in down via the logs. I'd also keep a good eye on the plugs to gauge the mixture in each cylinder. These are things that can can be mitigated by testing the flow in each port on the flow bench.

Using the gasket to match up the ports from the intake to the head works well... if you do both the intake manifold and the cylinder head. I'm afraid you'll end up with a bit of a ledge on the head side, as is, which will play hell with the flow as the airflow hits the edge of the head.

It's better to make a template from plexiglass of the head ports after you disassemble the intake and then match the intake to the template if your not going to match port the heads...
I've done many port jobs on intakes as well as heads and have never had a problem. I'm going to asses the head ports on my day off and see what will need to be done to make them match.
As for going lean, I have always ended up having to take away fuel after porting.

But my background is in motorcycles and not cars so thanks for the heads up.
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