Quote:
Originally Posted by jrw21  . What would you suggest stock valves or upgraded?
So, you wouldn't suggest touching the head in terms of a port/polish job?
Thanks. |
If you know what you are doing port is good but don't touch it unless you know exactly where to grind. Also no polish, a ruff surface is better since we are injecting fuel before the head. We want to have a surface that will induce air tumble. A very smooth polished surface will cause large fuel droplets to form. We want the fuel in small atomized droplets for a good dense charge to be fired by the plug.
If your going with 20psi I would go with the upgraded valves since they are thicker on the seat and will handle the high heat better produced during high boost. Springs are your choice. I run the Busa springs due to the super high lift on intake and high RPM I run. If your not running high lift and rpm the Behive are good. I don't know the price difference. I worry about the M44 crank at 20psi. You know a turbo I-4 at 15psi makes big HP and 20psi it's sick. I think the M44 crank is not forged and the M42 is forged.
Best, John S
Who did you talk to at Metric?