I was wondering, I'm probably thinking of getting my IM port matched, but I need to clarify a few things.

1. Do the intake manifold ports match the cylinder head ports evenly?

I ask this because I told my tuner that I wanted to port-match the intake manifold. I told him I had the gasket so that wouldn't be a problem. He clearly explained that there was no point in doing so unless you were porting the cylinder head as well. The reason for this was because you would then have an IM with larger diameter ports matching up with a smaller sized stock cylinder-head ports.

If thats the case, wouldn't air be restricted? For example, an intake manifold port (ported) 1.50" and then matching it up with the cylinder head ports being sized 1.25".

If that again is the case, would gains be reasonable? And/or would this be hitting the low-end, mid or top-end.

Cheers!

 

not entirely

but in the case you do the head later you will already have 50% of the job done...

 

The ports on the head match the gasket (I checked when I did mine) so gasket matching the IM will also match it to the head.

 

mmmm, not sure. I have the head sitting on my back porch, and from what I can tell with a brand new gasket I will be matching the head to the gasket size.

it will create turbulence, which is good because you are right at the injector and the fuel will mix with the air better. it will also create a restriction, which could potentially slow airflow. I will take a real close look when I get home and let you know the difference between the two. I think they are about equal at the mouth, but the throat may need to be widened to match the mouth. thats a whole other can of worms though.

 

RRM suggests their reworked cylinder head has intake ports enlarged 20%. I do not know if they are using a stock gasket at this point or what, I thought they would be, but not sure there. I kind of have to assume they are, as they sell their ported IM separately, and having to re-port your IM to match your new RRM ported head would be....well it would suck. So basically what I'm trying to say in my own confusing way is that I believe that the cylinder head is not gasket matched in stock form.

 

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^ this one is the coolant routing over the egr routing.
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^this one is the egr routing on the intake runner.

pics hosted on my website. this demonstrates both sides of the head, the intake manifold, and the egr routing.

the exhaust side is about an inch smaller than the gasket, which surprised me. It just means you can't gasket match it though.

the intake side is about the same size as the intake manifold.

the egr routing shows you just how much heat is transfered to the head. they should have routed this externally as far as I am concerned. it looks like the number four cylinder will be your weak one, to say the least.

 

Ok, RRM is probably not using the stock gasket then. Any ideas as to what gasket they are using?

Dan, you suggested that the exhaust ports could not be gasket matched. Sorry for the stupid question, but: why? I am clearly missing something here.

 

I always wondered why people would port their IM, and have a restriction. I mean, would this still create gains or restrict?

 

Dan! Migue! Anyone, where is the aftermarket gasket coming from?

 

You're the one who mentioned it! Why ask them?

 

After-market gasket are being specifically custom-made, Migue has the details. Or you can use RPW.

 

Take your stock header off and you will see which is burning leaner...and whick one is cause for concern

my 2nd and 3rd piston heander runners are sparkling metal clean, 1st one is dark as usual, and 4th is like nothing happens at it.... those two pistons scared me though

 

Unless I can't type (which always happens) I was referring to the stock gasket, I'm curious as to where Migue, RRM, and anyone going bigger than stock gasket port sizes is getting them from. I don't believe I've glossed over the answer, but I am a bit clueless

 

^ PM migue.

 

you can gasket match the intake manifold, and you can gasket match the intake side of the head. both have at least an 1/8" you can shave, although I haven't measured it could be as much as 3/16 or a 1/4 overall before the gasket gets in the way.

www.mrgasket.com is a source of gaskets, although you will most likely have to send them a stock gasket. it is a 4g69 after all

I don't think there is enought material to gasket match the exhaust side. there is at least and inch, and likely more, of a difference between the gasket and the head. the gasket is much larger. if you start porting it too much you will run into the coolant or oil journals that run through the head. I haven't looked all that close yet, and don't plan too until I am ready to actually start porting it.

increasing the exhaust ports by that much may be detrimental to the flow anyway, do some research on porting and head construction in general if you want further explanation. RRM ports the exhaust side to what diameter? go with that and rest assured you are doing it rightI won't shave more than a 1/4 total (1/8 all around) off the exhaust ports. the intake side is much more important, the exhaust gases are being forced out by the pistons, which is a physical effect. the intake air is being sucked in(unless you are turbo) by a pressure differential, and therefore requires more assistance.

remember, it's not necessarily the size of the opening that is the main restriction. the throat work is just as important as port size. porting a head or manifold is, or rather can be, much more complex than just opening the hole a little.