Combustion Contraption

No. Don falls on the conservative side. I think everyone over 75 or so does. *cheap shot*

Phil M

I should have known Don was old enough to see the fall of the Roman Empire.

BTW, Tim Radley, are you a professional head porter or did you just port your ITR head?

Tim Radley

Yes and no. Work on my head at the moment. Hard to find the time as i'm doing a lot to it and coming to the busiest time of year for me.

drift4jesus

I wonder if I should feel like I'm 'cool' since I've met Vizard and have read a lot of his work. Although that mainly pertains to wedge motors (23degree are his forte.)

I typically stay as conservative as possible for my valve to throat ratio's if it is going on a street car. My customers seem happier with a fatter power band and more throttle response than having higher peak #s. Then again nearly all of my honda work ends up on street cars.

The O.P.'s bowl looked ok and should clean up with a simple valve job. In performance applications the seat is usually moved further toward the edge of the valve face and you'll run a narrower seat than what a p72/pr3 casting comes with. (excluding itr) Moving the seat out will hopefully bring back the lower angles of your valve job.

I think I've got a couple untouched castings in the shop still that I can measure what the stock valve to port ratios are to add to the mix. I use the same tools as CC.

You can't attribute all the weight shaved on a ITR intake valve just to the undercut stem... if you inspect them side by side with a gsr/b16 valve you'll notice that the face also gets machined down making the head even lighter/(weaker?) but this is also done because it helps flow too.

b20vtech

ok,

paulITR

Can you elaborate?

87% of the valve diameter or of the 45 seat angle outer diameter?

b20vtech

87% inlet throat

28.95mm throat / 32.98mm valve gives me 87.7%