Yea, you need an air powered 1/4" die grinder with a couple of large football shaped burr bits for roughing. Then a couple of smaller diameter burr bits for finishing. Ball shaped. If you want to go deep into the manifold. Then you need burr bits with a 6" shaft on them. You'll burn up the Dremel on the first port you try to do. I get my die grinders from Sears. I burn them up, and they give me a new one. :D Local Sears store has them on stock to boot. :D

Just wanted to thank rusty for the heads up on the die grinder, so far its working great. After further measuring the gtm exhaust manifolds the hole is 1/4 smaller then the flange where it connects to the turbo slowing the air flow down. Will take some pics tomorrow and show my progress. I will wait and send these to vsr because if they can fabricate these I want you guys to have the openings the same size to allow more exhaust flow going to the turbos. Stay tuned!!:tup:

burrs leave a shitty finish tho i recommend using some spiral rolls on an arbor for clean up, and they are cheap at harbor freight, spiral rolls are the way to go on aluminum too if you plan to port anything else. if you for some crasy reason decide to use a burr on anything aluminum make sure to use copious amounts of wd40 or a lube like LPS

What you can do to is. Get a piece of 1/4" diameter metal rod. Cut a slot in one end of it about one inch long with a hack saw. Now get a piece of emery paper about one inch wide and about six inches long. Fold it up twice, and stick it in the slot in the end of the rod. Now you can use that for polishing up the rough areas. You can use different grits of emery paper for different finishes. ;)

Aluminum takes a different type of burr bit. One used for hard metals will clog up. It has to be a courser bit.

You're welcome. :tiphat:

Cosmo I'm waitin to see how everything works out for you! Let's gooooooooo

I'm taking off all day tomorrow to work on those manifolds before I send them down to vsr. Them thangs are going to flow like mo-jo!!! More than likely I will smooth out the intake runners as well. Pics tomorrow!!!

Before and after. I may have loaded the after first. lol
Went ahead and grinded one tonight. Notice how the gasket doesn't cover any of the exhaust flow now.?

Hey gtm this is the way it should have been done!!!!!!!:rofl2::rofl2:

That looks nice!! ^ Damn I never noticed that. Great call

Thanks, I'm working on the other one right now and will post pics later..

How sharp is the edge on the inside of the flange? Did you round that off? Pics of these kind of things are always kinda hard to see.

Sharp but I took my time and grinded it down for a smooth transition... Will take better pics later..

Cool.

Very nicely done Cosmo.


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Here is a pic of the driver side gtm exhaust manifold before and after the grinder. Who wants to bet it's going to flow a lot better now!!!