Well just got results from Flow bench Testing
my ported Head on a gasket matched stock intake manifold.

Firstly we had to do it this way to see were problems are in air flow and where improvements can be made.

The Head alone in normally aspirated config flowed at potential of 281HP.

Bolt a Gasket matched Stock Intake manifold, the HP potential is dropped to 217HP.

I am not going to go into final figures.

But Basically Cylinders 3 & 4 Flow about the same.
Cyliner 2 Flows about 3% More than cylinders 3& 4
Cylinder 1 Flows about 11% less than cylinder 2

So we believe some definate inprovements can be made.

Obvoisly with Forced induction of turbo, the power potential is a lot higher.

yes i do.

like i said before, i wont go into that just yet.

I may release flow numbers after new manifold is constructed.

So you are saying that the head is capable of flowing enough to create a lot of power, but putting the stock intake manifold reduces that potential greatly. Right?

You are looking into producing an intake manifold that is capable of flowing at a much higher rate?

Lets start again.

My Head that has been ported was flow tested on its own.


By Adding on the intake manifold and re-flowtesting the flow was reduced, which is to be expected.
But the reduced flow was considerable.
Also what was found the intake manifold creates un-even flow to each cylinder.

Now we have a base line of what the stock manifold does, we can go forward and make a new modified manifold.

The end result we desire is to even out the flow between cylinders, ie create even volumes of into each cylinder.
The next result we would like to achieve is reduce the flow lost in manifold.

ie in normally aspirated setup, the loss currently is 64HP worth of air flow.
we would like to reduce that to under 30HP loss.
15 would be nice to get, but that maybe wishfull taking into account room in engine bay.

so in even simpler terms, come up with a better flowing intake manifold.

just port and polish or is this a custom piece?

When you say cyl 1 flows 11% less than cyl 2, is that with the intake manifold in place?

Got any theories why that is? I'd guess it's because the TB comes in at an angle not beneficial to cyl #1, but I'm not an airflow expert :)

yes with manifold in place.

yes and problem is due to where tb is located.

First immediate mod is a larger plenum chamber.

apparently euro nDBW have the largest.

yes euro ndbw

Keep us informed on the intake manifold. If ti flows well I would like to get one as well.