Hi everyone,
While cleaning up my lmi I noticed how rough the passages are, in the old days people would to great lengths to gasket match and polish their intake ports.

Is this worth the effort on a stock 13B? How much horsepower would it add, if any?

Here are a few pictures of what I have:





Your replies are very appreciated, thanks!

 

I would not polish them. The rough surface creates turbulence that helps atomized fuel mix with the rapid air flow. It mixes more of the fuel just above the metal surface so it doesn't stick to the intake runners as much. More consistent fuel mix.

If you need more airflow, you need a bigger intake and throttle body setup.

 

if there is any huge casting flash, you might knock it down, but otherwise i wouldn't touch it either

 

I agree with the rough port walls. How do you feel about gasket matching. Is it worth the effort?


It would not take much grinding to do. Why does the gasket have such large openings for the Aux. ports?

 

I wouldn't bother grinding either. You'd have to port match both the manifold and the engine ports, and it kinda goes outside the scope of a stock manifold setup. I'd do it more for a aftermarket manifold for racing stuff, but if it's a daily driver, you'd never notice the difference from stock

 

Thanks, so port matching on a stock daily driver is a waste of time!

Exactly what I needed to know.