I just started looking into turbo options for the 6.2L. Can someone confirm that the turbo exhaust/intake manifolds from a 6.5L will bolt onto a 6.2L without modification? If so it seems like you’d be able to do a full turbo swap using used 6.5L parts for under $1k without having to swap heads.
The Pickup, van, and civilian Hummer exhaust manifolds will bolt onto any 6.2/6.5. From there, that's where things go south.
The injectors are different lengths which causes issues for the passenger manifold depending on the injectors installed. More of an issue with CUCV's.
The intake manifold will not work from a HMMWV/Hummer/Van. This is due to the intake manifold bolts being angled vs square. This necessitates the head swap.
Now, let's clear another angle up. The pickup turbo/intake setup. All of this will bolt onto a 6.2 and 6.5. The problem is the HMMWV tub. The passenger wheelwell and heater core would interfere with this setup. Since the turbo mounts to the passenger side of the engine. The HMMWV/Hummer/Van setup mounts the turbo to the rear of the engine in the intake valley.
An enterprising individual could make use of a very rare banks exhaust manifold that mounts the turbo to the front passenger corner of the engine. I know I saw these on ebay a while back. At $400 for the manifold alone. Then build from there. Another path to consider is using the stock 6.2/6.5 "headers" the HMMWV has and hacking up the passenger manifold. One could easily take a plate of steel and bolt down the header. Then cut the manifold down the centerline and extend it out to the front into a 90*. The two cylinder down tubes could be cut down and dumped into the newly formed tube and welded back up into the "jig". From the 90* weld in a turbo flange. The exhaust outlets from the manifolds could then be tied together with a crossover tube. Then snake the exhaust back down along the passenger manifold. Oil supply from the rear of the block, then a oil drain to the fuel pump plate. The intake could just be a simple top hat to adapt.
This is the path I'm going to take with mine honestly. I've got a set of headers and the ability to make all this happen. (Also have a 6.5 turbo) Just not the time currently.
While I can't justify $4-5K for a turbo kit over just doing an engine swap, I can say that a turbo on a 6.2/6.5 makes it feel like a new engine. Yes, it's only 40-50hp at best. But the low end gains are certainly worth it. These trucks are gear bound, so top end isn't a huge factor in this.
Some other useful 6.2/6.5 turbo info. Keep boost under 12psi. I keep mine at 10psi max. Another thing to consider is the pre-cups/heads are different on the 6.2 vs the 6.5TD. Mismatching them will affect CR.
