6.5L TD Hummer H1 Engine Modifications

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paulmillerplu

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Sep 9, 2009
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Hey there,

I am just starting to modify my truck (2000 H1) and was looking for some advice on engine modifications.

Have a stage 4 predator motorports package currently in it (PCU, HO Injectors, HO fuel lifter pump, HP wastegate controller, exhaust, pmd isolator, etc).

Was wondering about possible propane or water or water/methanol injection to go with it?

Maybe a dual turbo setup (although I the space under my hood in running very low)?

Does anyone know of if this is worth it and what the best option/kit would be?

Does it have to go in the bed if it is propane or can it be mounted under the rails like the fuel tanks on the other side?

Any other options for getting around 25/30 MPG (other big diesel trucks get this mileage or better, currently getting 12/16)

thanks for your help and hope to get alot of thoughts...
 
paulmillerplu said:
Any other options for getting around 25/30 MPG (other big diesel trucks get this mileage or better, currently getting 12/16)
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Not many! I averaged 17mpg city/hwy before I changed gear ratio's now I'm about 15.5-16 or so (hand calc'd)... I drive 12 miles into town every day at 60mph and about 2 miles across town to work at 25-45mph. And back...

Usually when someone tells you they are getting 30mpg they are full of crap... There are a few out there but not many...


Sorry can't help much on the power adders... that's one motor I've never owned...
 
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Your best option for getting 25 mpg on diesel in an H1 would be to cut a hole in the floorboards and go "Flintstones"....;)

Do you have EGT and Boost gauges? I am not familiar with the package you are running, but you are probably at the 6.5s limits without getting into it and spending a bunch. If you are running any more boost and fuel than stock, you definitely want gauges on that thing.

I guess a propane kit would work on a 6.5 and give better diesel "mileage." If your propane is cheap enough, it probably could pay for the system with enough miles driven.
 
I have pyrometer and boost gauges.

it is pushing 315hp right now and the MPG has increased with the stage 4 kit.

Was seeing if anyone had experience with other options and how they worked? Hummers are notorious for bad mileage and size so trying to figure out any other options.
 
Nobody gets 25/30. When I hear people claim they do...I say HOGWASH!! I have a 92 Dodge 250 2WD regular cab long bed with a stock 160HP/400TQ Cummins 5.9...and 4spd auto. I might get 21 empty on the highway with no wind...and going the speed limit. But there is no way these guys with 4x4 Crew Cab 3500 duallies get 25/30. I have plenty of friends with newer modern diesels including mods etc. They all wish they got 20 and frequently complain because how they were duped into thinking they could get much better.
 
That makes sense.

not really caring about the MPG, although it is always nice to get a few extra.

more concerned with the other questions...turbo's or injection setups?

any feedback on if/how these work and if they are work it?
 
well i havnt worked on the hummer's at all but my day of driving a diesel started in a 93 6.5 TD 4x4. Before i done some work on it i could get 20 to 22 mpg on the highway. If your wanting to get more power out of it call Heath Diesel that the only thing they work on. If it was the mechanical pump you can turn timing up and turn a screw or two for fuel and for trubo get one off of a 12v add a intercooler. Injectors put the marine one in and good lift pump. Make sure the cooling system is up to par that the worst enemy of the 6.5 TD there know for cracking the heads. They make a high flow water pump for them and a sec.coolant cross over for better coolant flow. Also with the older 6.5 TD if started getting up to 17 to 20 psi of boost the head bolts would stretch. Lower compression piston's is a plus in the 6.5 TD or find a set of heads off of a 6.2 and it will also lower compression in help with heating issues.
 
jordanjames81 said:
well i havnt worked on the hummer's at all but my day of driving a diesel started in a 93 6.5 TD 4x4. Before i done some work on it i could get 20 to 22 mpg on the highway. If your wanting to get more power out of it call Heath Diesel that the only thing they work on. If it was the mechanical pump you can turn timing up and turn a screw or two for fuel and for trubo get one off of a 12v add a intercooler. Injectors put the marine one in and good lift pump. Make sure the cooling system is up to par that the worst enemy of the 6.5 TD there know for cracking the heads. They make a high flow water pump for them and a sec.coolant cross over for better coolant flow. Also with the older 6.5 TD if started getting up to 17 to 20 psi of boost the head bolts would stretch. Lower compression piston's is a plus in the 6.5 TD or find a set of heads off of a 6.2 and it will also lower compression in help with heating issues.
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cant replace the turbo with a regular pickup one, they are mounted in the valley pan at the rear of the engine and bolt to an oil passage at the back of the block, completely different from the trucks......It is also impossible to add a intercooler, 1: the way the turbo is designed it is impossible to do, and 2: there is no room in the front of a Hummer to put it, the radiator, trans-cooler, and power steering cooler are in the way, the all lay at about a 45 degree angle and have a big "sealed" fan shroud mounted to the bottom of it.....

I got full military TM's on the tear down and rebuild of the military HMMWV, so if you need anything let me know......I know all about these beasts, I used to fix them daily over here in Iraq......I'ver got an injection pump swap down to 2 hours and 45 minutes with 2 experienced guys......
 
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