Hey, I am really wanting to buy a Used H2 within the next year, and I'm wanting to hear from some H2 owners what their best mileage has been. I know there's so many products out on the market that can help increase your gas mileage, such as K&N cold air intake, a power programmer, a computer programming chip, exhaust modifications, etc. I really want to get me an H2! I just want to see what the best gas mileage some guys are getting with some of these modifications. I would mainly be driving it around town and back and forth to college everyday.

 

ive gotten as high as 16mpg doing about 62 to 65 mph on the hwy with no winds.

ive got an intake and gibson exhaust.

 

I get 12 to 12.5 avg with my 06 sut. I would say if gas mileage is a hold up dont buy one you wont be happy. You dont buy a hummer for gas mileage you buy one because you love them.

 

I drove the back roads from Vegas to Palm Springs and averaged 15 mpg down and back with my H2.

 

As others have mentioned, don't buy the H2 if mpg is a concern, especially when city driving. All the modifications you have listed is about how I upgraded mine along with the Magna Supercharger. Also run the lightest synthetics your mfg call for, 0 w 30 is ok for colder climates and 5 W or even 10 w 30 in warmer areas.Change your fluids at scheduled intervals and replace with synthetics (Gears,joints ect), and run the lightest wheels you can afford(decreases rolling resistance).Although I DO NOT endorse any particular product and it MAY NOT help you but I also use ZMax engine and fuel additives.
I did these upgrades to enhance my engine performance. The increase mpg was a side affect.(avg 17 mpg HIGHWAY ONLY).

 

The following is my response to a friend who had a question about "Performance Chips" and "Performance Software"
Hello Friend,
Can't say for sure about those performance chips....but I recently saw a posting about someone who attached a software upgrade device to the OBD port and downloaded some performance software into the OBD computer for better performance.
And literaly messed up the whole operation of the vehicle.
Shifting was all off sequence and erratic and the vehicle's performance overall was totally ruined!
I wish I could remember the exact posting and redirect you there...so you can read it for yourself.
I believe this process is called: ECU REMAPPING & CHIP TUNING OBD CAR DIAGNOSTIC SOFTWARE.
Please be careful with these products...you can't transform the performance of a HUMMER into that of a Volkswagon.
We must be realistic....It's just not possible as far as Vehicle weight, engine size and capacity is concerned. Just by the physical nature of the size and weight of the vehicle and engine, this efficient performance cannot be achieved.
Perhaps the OBD computer can be reprogrammed for better performance but the software is not compatible with the physical mechanics and design of the vehicle.
Keep me posted on your progress.
Safari Hummer H2
UPDATE: Found the posting!
Titled: "Hummer Crazy Issue"
By: gfng
Date: 1/20/09
Reference to: DIABLO PREDATOR (software)