Im planning on doing 1mm over sized valves on my head for when I go boost. My question is will i get any gains from this?

 

If you have the head ported and polished by a competent flowtech you should see increases of 10 to 15+ percent in exhaust. Exhaust is the bottleneck.

 

I have heard the same. Leave the intake valves stock size go bigger on the exhaust.

 

What if I go 1mm over on both?

 

It's tight but it can be done.

 

The head is where all the power is built. I always suggest to my customers not to skimp on the head. In a FI situation where air/fuel is being forced in to the motor, everywhere the air/fuel travels should be modified for maximum flow. Oversized valves get more A/F in and out of the motor. Porting allows more CFM's to flow and polishing increases the velocity of A/F passing through and over the metal parts.

We also do a little trick with the way the A/F enters, combusts and flows past the valves to increase the throttle response by 40%. (Area 51 stuff, can't go into detail)

 

Well I just got done ordering a ferea valve train 1mm oversized all around cost an arm and a leg even at cost. Now sending the head out to my friend vinny ten for porting

 

I did 1mm over on both sides... vinny ten! good name! fast supra

 

fast 350z now :0) hows it feel with the valves 1mm on each side how much power are you making?