BC

So I went to my Garage desk to start port matching my S4 heads before thier rebuild to the intake manifold. I already have the seals and all that, first I lay the seal down on the head. Well, not much difference here. The seal is even angled with the flow of the intake port and manifold.

But whats with these little half moon shaped protruding from the already half moon shape for the injector area? Its as if the rubber justs out a bit more then normal to hold the injector head in place? Wierd.

I alsmost feel like these should be removed. What if you put the injectors in and it pushes them to just the wrong angle and you lose 10 or 15horses?

Does anyone have any pics of the ports or intake manfold matcing that was supposedly hand done on the 89GT? It doesn't seem as straight forward as it was on the 2V heads. There doesn't even seem to be very much to do here. Maybe some on the intake manfold - it seems smaller then the gasket and head holes.

Anyone?

BC

Bumping for the morning afternoon crowd.

drnick

i remember looking at the manifold and heads on my GTS lump and thinking there werent obvious areas to make 'easy' gains. i quickly figured it would take someone with experience to improve the stock items, and would probably cost disproportionately to any gain! IMO

BC

Your right Nice. I was just trying to do some port cleanup so there were no steps between the manifold and head. That area of the rubber I am describing is weird.

BC

Okay, I have finally gotten some pics of out my camera that are acceptable for this thread and clear.

This extension from the half moon on the gasket is what I am talking about:



I understand that I should just see this as a reason to not do any port matching, but I can't. There has got to be a reason, good or bad, for this design. Either it makes the mold release easier, or Porsche did it this way to really make the injector tip go into a certain direction.



Now, the other issue is that there seems some very abrupt changes to surface and direction in the port area between the head and manifold. Really not clean looking at all - and that damn gasket is jutting into the air again. - Try and notice that the injector path cast into the head actually goes to the front valve.

Bill Ball

Well, it looks like a stop for the injector, although the injectors are held in position by the rail clips. It shouldn't effect the injector tip as it would protrude beyond the crescent. One thing Andy mentioned that you can't do anything about is that the injectors are positioned on the outside wall, spraying a lot on the wall. Andy moved them in a half inch or so on each side in his Supermodel manifold. The whole S4 manifold design with all the convoluted air tubing is a mystery to me. Andy's plain pizza box design, off-boost, works at least as well.

BC

There are people have build engines here - the S4 kind - and nobody will chime in (Other then the ever-conversational Bill Ball - thanks Bill)?

Bill Ball

Your pictures do make the question clear enough. Where are the engine builders?

BC

<crickets>

namasgt

Interesting old thread, so is it worth it to match the intake ports to the intake runners?, what about the gasket deal?
I,ve seen it done on Cheby engines but does it make a big difference?

blau928

The rubber bit is a stop for the injector pintle cap.. There are some tricks that can be done to resolve the groove, and one of them is weld it up if you are not going to use it.. However, I will not be welding up mine.. Another trick I have seen done, is placing vortex inducing divots at certain places in the groove to create turbulence for the fuel to better atomize.

The long answer is it depends what you are using to inject fuel into the motor, and if it will use the same injector pointn to intorduce fuel into the runner..

I guess the groove could be epoxied, but i do not know anyone with a 928 that has done it. many chebby fellas do it on their heads to fill voids, shape runners, and ports etc... they also weld ports and reshape them. I am not sure of the material composition of the 928 head, so not sure of the welding..

Bope that helps Brendan...

Hey, where are your injectors going anyway..?

BC

In the stock location at this point. Pointed nearly straight down into the port, but those gaskets will not be used in this intake design (Todd's picture shows his, mine will be nearly the same) I don't think. Things have changed alot since I posted this.

blau928

Hi Brendan,

I hear ya loud and clear on things have changed..

I also didn't like the way the stock injectors are angled, so my design has the injector on the other side pointing at the back of the valve instead of spraying onto the wall of the runner like the stock ones do..

We shall see if it stops the puddling, especially under SC load, as I had to compromise due to space...

I'll post a pic of the injector block later..

I did not weld or epoxy the groove for the old injector to port match the intake and head.. If it gets bad, I will do it on the spare motor though..

toofast928

Brendan,
Are the gaskets from Porsche? If not try your local dealer for few gaskets just to see if they differ.

BC

The gaskets I took pics of were from Porsche. I no longer will be using the gaskets, I believe, at this point as the intake is now different.