I have a pile of GMC engine parts (I hauled over 7 tons in two trips!) from a gentleman who spied my truck at a show and came over to talk to me about it. At any rate - among the piles of stuff, I came across these -

I fixtured them up to a 302 exhaust manifold (clamped and bolted as pictured) and the port spacing and size is identical.





The center dump piece is cracked and not worth fixing - but I was thinking that it wouldn't be that hard to fab up a piece to go between these two and use to mount a turbo . . .

Any thoughts?

Ken, that center dump concept is very similar to turbo manifolds being sold now for the 250/292 engines, so it should be just as effective as those that are out there.

I am considering this mostly because I already have it.

I am thinking that I can put these into my milling machine and use an inside out boring bar to clean up the outlets and ensure they are round.

Then get a piece of thick wall DOM that I can bore the ends to match the OD of the cleaned up outlets - and match inner diameter of the outlets and then machine a flange mount and weld it together.

Not sure if I will have problems with the casting / steel interface with temperature swings.

Any concerns?

Ken,
Make a pipe that slips over both ends with a turbo flange welded to the side, but weld only one side and allow the other side to float so it can expand and contract as it wants, similar to what I run on my 37 chevy.

Harry

Nice find! What is the original application for that type of manifold?
Bring the 2 halves out to each side of a divided turbo housing. Put the wastegate at this location. Trying to vent both sides if possible.

I'll draw something up in SolidWorks and see what it looks like.

I don't know what the original application is - I can only guess that it was for a 270 or 302 in a big truck. It has GMC cast into it - and the passages have nice gentle curves to them.

Not sure how to have a common waste gate while trying to run divided passages - I guess I could have an opening that goes into the divider. We will see what it looks like in CAD.

Ok - I messed around a bit with SolidWorks - still not sure how the waste gate will hook up but I have a couple of ideas.





The information I have read on the web says the wastegate should be oriented 45 degrees to the exhaust gas flow - well, with the flow coming from two directions 180 degrees from one another, I don't see how that will work.

Anyone have any dimensions on a wastegate valve?

Ken,

No need to divide, setups making well over 1000 HP with wastegate at 90* to exhaust flow, only makes waste gate more efficent.

As I stated slipfit really helps expansion problems.

Harry

Nice Modeling work, KEN!

It's too bad there isn't a twin port sandwich plate type wastegate around anymore (not that I was able to find, when I was looking ).