exhaust manifold upgrade

[micky_blue]

Since im rebuilding my 6.5 i have been hunting for a manifold upgrade for the truck and am not having any luck. I have found a dmax manifold upgrade but don't know if that will fit a 6.5. Anyone have any ideas other than ceramic coating the manifolds?

thanks
micky

[DA BIG ONE]

The exhaust manifolds on the 6.5td are not an issue its the 3" max downpipe limit "space limitation between engine and chassis".

One vendor herein sells different exhaust manifolds and larger turbo for the 6.5 but forget who?

I'm thinking that using 6.2's exhaust manifolds w/turbo on each (twin turbo) into 2.5" or 3.0" downpipes then perhaps into 4"/5" exhaust system is only uprade worthwhile.

[DmaxMaverick]

The Duramax manifold will NOT fit. Different animal. The OEM Duramax RH side manifold is indented, and BD offers a replacement w/o the indent. Not an issue with the 6.5.

What exactly are you trying to upgrade? I'm not aware of manifold issues. Headers can be beneficial for a N/A engine, but the 6.5TD manifolds are about as good as they can be with a turbo. HMMWV manifolds are a bit more free flowing, but they are designed for N/A. Changing manifolds will require significant custom pipe work.

[MJEasly]

I'm not sure of the gains and there are probably other exhaust system bottle necks that are easier and cheaper to address (with better ROI), but extrudehone is an option if you want to modify your stock iron manifolds.

[micky_blue]

I am planning on putting a HY-35 on there so new manifolds for a bigger turbo would be great. if anyone knows who makes those please let me know.

micky

[DennisG01]

About 2 months ago, I searched high and low for new manifolds. Unfortunately I was unsuccessful. The only thing I found was new GM manifolds. They can be bought from various places. As suggested above, extrude honing is about the only option to get something better. I elected to not do the honing and instead just had them ceramic coated. I didn't feel the cost of honing was justifiable for the marginal performance increase. Now, when it comes to mounting a new turbo, there might be adapter plates available or atleast have one custom made - but I've never looked into that as the new turbo I will eventually use will work with stock manifolds. See the "turbochargers" article by More Power in the "Updates" category. I'll be using the turbo Ron Schoolcraft is working on.