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Remove "bridge" in intake runner? GS450

  • Thread starter Thread starter Macmatic
  • Start date Start date
M

Macmatic

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I'm putting together an '87 GS450L from... well lets just say its in kit form right now. Anyway the intake runners in the head have a "bridge" across the bottom, cast in, and I'm wondering if I should remove them. At a guess I'd say they are about 1/2in inside the port and 3/16in high or so. They must be an effort to keep the mixture turbulent so you don't get droplets on the walls? Just guessing here.

Anyway my first instinct is to blend them in with the port wall but on the other hand someone put them there for a reason. Were they right though? I guess that is the question.

/\/\ac
 
Answered this somewhere else recently - I say don't remove.
IMO the inlet port throats are too large as stock and this bridge seems to be there to promote part throttle turbulence & prevent fuel pooling on the port floor.
Ideally you'd fill in the floor and raise the port centerline.
My own 450 has the bridge still there (I'm lazy) and is making about 55HP at the wheel using 35mm Dellortos and .410in cam lift.

Greg T
 
Greg, I think you referred to a reply on my question.
Don't remove that. I almost ruined my head. If it is the same "bridge" we are talking about, it is actually the bottom of the valve spring pocket that is cast in there. If you take it out, you will have oil flowing into the intake port.....and you don't want that:eek:
 
Greg, is this the thread you mean?
http://www.thegsresources.com/_forum/showthread.php?t=160694

That sounds like it is not what I'm talking about. The bridge I mean is at the BOTTOM of the intake runner. Now that I go back out and look at it it's actually about 1/4in from the mouth of the runner, at the outside of the head and not down near the valve.

I'm not sure if Greg and I are talking about the same thing or not. This bridge is about 5mm tall with a small gap in the middle. It runs across the bottom of the port giving it a D shaped profile from head on, with the flat at the bottom.

I'm going to leave it alone unless I get enough feedback telling me otherwise, it just seems add. Heh.. now I half want to scallop the top edge for greater turbulence.

/\/\ac
 
Yes, the bridge at the bottom of the port is what I was referring to - like a fence across with a narrow gap in the middle. I'd leave it.

The bulge in the GS1000 inlets - depends on how thick the head casting is at that point. Obviously some are thicker than others here. Careful measurement is required.
 
I would leave it alone. I believe this is similar to the dam or ledge on the later G models that is actually there to improve the flow through the port. Some hi performance Chevy engines also had this type of shape.
 
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