How r u guys getting these good mileage? I only get 8.5 driving to lake tahoe on the 5 freeway

 

I take the old two lane highways whenever I can because I enjoy the scenery and find the driving relaxing. This also means I'm usually going 55. Other than that, my H2 is all stock.

 

(This is not to endorse any of the following engine additives/components). Since maintaining a log of my highway driving habits. I stay on-top of my engine tune with scheduled maintenance services/tire pressure. Also I run the mobil 0 w30 synthetic in the winter and 5w 30 in the summer with Z-max oil additive/ also Z Max in the fuel.Try to replace most of your lubricants with synthetics. Also I run a light alloy custom wheel(Mazzi). I run 87 octane,unless I'm trailering one of my classic cars and then I run 91/93.I have an K&N air intake system with an after market exhaust(less restricted). These modifications were NOT intended to save fuel but for increase performance . The increase gas mileage was an unexpected surprize,avg 16-18 mpg is ONLY on the highway. I have not tried tracking my mileage when in the city.
(One last note) I do recall some literature stating that a supercharged engine is a "more efficient air pump".

 

I put afe intake and corsa exhaust on mine and mpg went down 1.5 mpg for some reason. If any reason you can think it would help.

 

I just got the magnacharger on mine. I am running 37's on it. I was averaging 10.5 before the s/c, now it is down to 8-9. What am I doing wrong. I would love to get 15mpg on freeway.

 

The following is my response to a friend who had a question about "Performance Chips" and "Performance Software"
Hell 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)

 

i would think if Hummer replaced a lot of steel with aluminum and fiberglass and took a 2000 lbs off the final weight, the truck wouldnt be as good for off roading but could possibly be sold as a MPG alternative.

 

Indeed! If it were as simple as upgrading the software, I suspect GM would have done it years ago.