cruiser787904

I have just started porting a set of 243 heads for a stock cube LS1 with a TVS1900. I have been reading about porting and watching youtube videos and since I have a set of 243 heads laying around I figured why not learn.

From what I have grasped is that on the intake side you don't want drastically increase volume but streamline things to increase flow. This makes sense to me in a NA set up since the air is being drawn in by the intake stroke but wouldn't this be different in a boosted application?

My theory is based on boost being a measure of air that does not make it into the combustion cycle. In this case it seems that you would want to increase volume behind the intake valve. The more boost pressure behind the intake valve will allow the greatest volume of air to enter the combustion cycle with the only limit being the valve size, valve job and cam.

This makes sense to me but I wanted some opinions on it to verify my thoughts. One drawback might be drive ability and tune ability when not in boost.

I have also realized that when porting you need to show a lot of restraint and patience and should be focused on less is more. I am guilty of being a bit aggressive with the die grinder but I am going to let the results speak for themselves. Needless to say I will post a thread with pics for feedback so I can learn from the feedback

Thoughts?

ringram

Do lots of searching, there is loads of info out there.

You are too far from your destination for a single reply to help IMO.

cruiser787904

Thanks. I have done a lot of searching and I keep searching and looking at pics but I cannot find any information in regards to porting differences between NA and boosted applications.

It stands to reason there is a difference between the 2 since in a NA application air is getting drawn through the cylinder head and in a boosted application it is getting force fed.

So I am looking for theory which has no bearing on where I am at as far as porting. Maybe there is no difference between porting a head for NA vs boost but I would like to find information to support that if its available.

96capricemgr

iTrader: (1)

There is no "suction" with NA it is just atmospheric pressure as opposed to extra pressure from boost. Particularly with a blower it is pretty much just extra atmospheric pressure. Now with a turbo you have exhaust back pressure that enters the equation.

Sounds to me like you believe blindly bigger is better and are begging for someone to agree.

ringram

No difference NA to FI except incoming air density.

(ie) Whats the difference between NA at sea level and FI 1bar boost at 18,000 feet as far as intake pressure is concerned!?

Answer is nothing!

Tony @ Mamo Motorsports

Bingo....a much misunderstood topic right there.

Port for efficiency and max flow across the curve while keeping an eye on the proper cross sectional area for the displacement targeted, RPM, and general application in question.

That's the abridged version.....LOL

-Tony