jakub2000

Given that you boost a GT3071R @ 15psi, how much HP realisticly could you expect from a port/polish head with oversized valves on the exhaust side?

Let's guestimate a bit

P.S. Sideways said 50HP, what would be a solid bang for the buck

indebt&lovinit

Only thing i've read is that the S2k has the "king of heads" and that any port and polish will reduce HP somewhere in the rpm range...

jakub2000

Sideways said this on 3rd of March this year:

"Good headwork can add 50 or more horsepower. Just changing the valves won't do it. The heads must be reworked to flow better also."

Sideways

The difference is dependent on the total power output. Low boost applications would see less hp increase than high boost. Using the same theoretical head, boosting 6 psi might yield 20 hp and boosting 30 psi could yield over 100 hp.

It is a major investment but if you want to play you have to pay.

To insure you are not being taken advantage of make sure you have them flow the final product so you can see the difference. Get the flow pressure used in the test. There are several different pressures used and they can be compared using a comparison table.



Intake flows should increase 5% or more and exhausts 10 to 20%. On the S2000 the exhaust is far more important.

honda9krpm

The flowbench test is performed under suction ie the machine draws the air through the head. This is ok for extrapolating improvements with NA engine.

For FI engine will you expect similar change? Is there any physicist in the house?

jakub2000

Now we talk technical, yeah baby!