Head Porting

[GSR-4]

Hi Guys,

I have rebuild my 1G engine with a new FP 3052 turbo and all other lovely things, my Q is that: is my top rpm power will be effected due to OVER porting the head and the intake manifold.

I had my head and intake manifold ported to the extreme, the opening are really big to a point that the mechanic is asking me to get another head and do all the job again!

please advise.

MODS
1G with FP 3052 and 850cc injectors. HalTech ECU
forged pistons and rods. 1mm oversize valves and webcam shafts
and all other things you would put on a 1G

Thanks A lot

 

[sophat34]

there is alot more to porting a head, especialy on the intake side, than just the size of the opening. basicly when your ports are enlarged they will flow more air, if done correctly it will still maintain an acceptiable amount of velocity, thats what gives u tq from what I understand anyway. there is more to it such as the air swirling and such but its beyond me. if its too big then who ever ported it needs to step up and offer a solution to the problem. I dont think that just enlarging the openings or gasket matching should have that drastic of an effect though. I didnt notice any thing diffrent when I did it.

 

[4pistons]

Why did your mechanic tell you to get a new one? Was it ported so large that it broke through to the water passages? Or does he just THINK it is too big? I would think as long as it didn't break through you're fine. Got any pics?

As sophat34 said making a port big does not mean more power, you have to increase flow along with velocity. Fortunately on a forced air car you really can't get too big as boost maintains your velocity. Unfortunately it will feel soggy when not in boost.

Rick - '91 GSX

 

[Larry L]

I ported my head only to match the gasket, And it is my understanding that opening them up any further does very little unless you have a flow bench and can test the cfm's. However, unless you broke through the water passages it should be O.K...

I have a friend in Miami that did what you did and he states that it gave his mad torque under boost. Good luck!