85-90 percent of the valve depending on goals is generally used. Turbo smaller areas and NA is usually bigger. In Direct injection it’s a different ball game for sure. Usually a race application only high rpm will use a bigger port but if it’s turbo you can absolutely kill the power.
Porting my NA heads for fun on my new EJ22 im swapping in for my old EJ18. I've done the bowls and the runners. Hoping to pick up 5-10hp. This was a great tutorial. So satisfying to remove casting marks and all that crap. Very easy to get carried away however, and honestly hoping I haven't, lol.
This guy David rocks! On a side note, when were doing this about 23 years ago, A local guy use to tell us about his porting services. LOL I knew that porting can also mess up shit. I would only trust a guy live David. Anyway, we use to hear Hogport. Not sure WTF that shit is, but I knew it was wrong. Needless to say, none of those cars with "Hogport" went fast. Anyway, always enjoy the Headgames videos.
We don't do any motorcycle and only dabble with NA heads. Only time we have done epoxy is to move a port. It's not going to stay in place forever, but it does help. It would be in the runner, but you would have to do a ton of flow testing to get it right. If you don't know where to put it, or have a way of testing I would just leave it alone.
@@headgames Ok great thank you for the reply! I have used epoxy on the bowl section where the lip is under the seat to smooth that area. I didnt flow test it to quantify but the bike did make a decent improvement in HP.
Cubic feet per minute, a measurement of air. 200cfm would be moving 200cubic feet of non compressed air per minute. In this case talking about valves, it is an extra 40 cubic feet worth of uncompressed air per minute into the engine.
I want to say all, but we have not tested all heads. But, around that is really good baseline point. Certain heads we have tested that is a max. Which is where I get the number from.
Be handy if you put some marking out blue on it so we can see it dissapear as you grind. It's hard to know where exactly you are and how much is coming off other wise..
