After running 38" tires for a few weeks it became apparent that the extra size had a noticeable detrimental effect on the vehicles performance. It was sluggish pulling away, the shift points were incorrect and obviously the speedometer was off.

There are several programmers available for the H2 on the market, but having heard good things about the Superchips Max MicroTuner, I decided to try it.

There are three "standard" programs, "87 Octane", "Performance" and "Performance Towing". The latter two require the use of 91 octane gas, so I went with the 87 Octane program and also set the correct tire diameter. The difference in performance was noticeable immediately.

The shift points were a little high for my liking, so I lowered them slightly and also increased the shift pressure slightly. The H2 now performs much better, pulls away much stronger and doesn't hunt between gears when cruising on the highway. The speedometer, as well as other related instrumentation such as MPG etc, is now also correct. Checked on GPS, the speedometer is now reading less than 0.8% high, which is as close you could wish to get it.

Superchips claim typical power gains of 27 horsepower and 35 lb/ft torque. I have no way of verifying this, but based upon the noticeable performance increase on the 87 Octane program, I am inclined to believe their claim. I'm not sure how much performance benefits can be gained running stock tires, but for vehicles with oversize tires it helps a lot.

The Superchips programmer is easy to use and once programmed is disconnected from the vehicle. Like other programmers it is VIN locked and can only be used on to program one vehicle. However, it can read and reset DTC codes from any H2.

I wasn't sure how much it would help, but was very pleased with the results. Definitely worth the investment, at least for this particular H2.

Club Sponsor

Note: The information on this page is offered for guidance purposes only and is not a recommendation that anyone perform any task described. Consult a qualified technician before performing any work on your vehicle. Any task performed based upon this information is at your own risk. The Hummer X Club, it's members and affiliates, this web site, the creators, owners, contributors to this web site, advertisers or sponsors of events, and any other individual or organization involved with the information provided do not take any responsibility whatsoever for any damage, either directly or indirectly, that may occur based on the information provided. You perform any task described on this web site at your own risk and assume responsibility for your own actions.

© Hummer X Club 2005-2006. All Rights Reserved. All Trademarks Acknowledged.
Hummer, H1, H2 & H3 are registered trademarks of General Motors.