tell me about the 160 stat, doesnt the truck run hot for emissions? what about inspections?

 

h2guy8878,
Engine wise it's apples and oranges when you compare your 08 with its prior year. the 08 is a 6.2L 393 HP 10.5:1 compression vs a 6.0L 325 HP 9.4:1 compression engine. The newer engine makes approx 20% more power has larger displacement and runs hotter. Since you have aaddional displacement and higher compression you can't expect not to have to pay somewhere, either with higher octane or more fuel, performance costs money. The new 6 speed transmission tries to helpa littleas the engineers would engineer it to run the engine in a rpm band that whould provide max fuel value (I would assume). Having driven the 08 I can tell you it runs MUCH stronger than its older brothers. Unfortunately running regular fuel in a high compression engine is like shuving your thumb up your *** to keep from farting, it doesn't work well and just plain stinks.

The computers in our GM vehicles include a knock sensor that allows the computer to increase the timing advance just to the maximum point where it does not knock. This provides increased performance. If you run the engine cooler the timing advanced is increased by the computer, gas mileage also increases. Unfortunately the higher the compression the bigger the problem, these engines will knock at a much lower advance setting because they require much higher octane and you have less to work with. My 05 has no problems passing emissions tests or inspections as a result of the lower thermostat. The factory programmed fan temperatures and H2 radiator won't allow the engine to run under approx 185 most of the time, I could make this lower by changing fan (using a aftermarket performance programmer) temperaturespoints butcould begin to create emission issues. This doesn't help you much as you have different situation. I have heard a number of aftermarket tuners are going to be releasing products that will help the 08 allowing you to change transmissions shift points, base timing (depending on the fuel you want to use) and fan temperatures. (search the web for Hypertech, Diablo sport, Jet Performance and Superchips) You can still perform the other items I mentioned and they will help and none of this will affect your warranty. Hope this helps and Good Luck!
Dan

 

HWY at 70mpg.. I get about 13.7

In the city I get about 11.5

 

Jdrew, nice work! I once read a report that the H2 will obtain it's highest mileage ratings at 65MPH, (thats with no appreciable wind) so you might be able to get a bit more. Nice! My 13.4 is an average about 55% city and 45% highway. It tough to get much more from a rolling brick that weights in excess of 6200lbs. PS my neighbor's Excersion gets 6 mpg, uphill, downhill, falling out of an airplane, it just doesn't make a difference, that's it!
Regards,
Dan

 

11.9 here

 

Hummergirl4, What is your ratio (% highway and % city) also what do you cruise at (MPH). Perhaps we can come up with a general stock vs modified gas mileage standard.

I am working on is shortening the step bars on the H2-SUT, I think moving them closer to the body will provide an additional mpg increase as well as giving additional ground clearance and better foot placement for getting into the cab. Gonna give them a chop job this week!
Regards,
Dan

 

Dayum...I had to pay $3.99 a gallon today [:@][]

I'll dump my H2 only if the price goes over $20 per gallon [sm=pimp.gif][sm=pimp.gif]

 

ok guys you are all a great help thank you so much, now anyone know how to reset the mpg guage? call me an *** but im putting a 8" lift and 38's on her this weekend, so my mpg is really gonna suck now, but i guess ididnt buy it for mpg, i bought it because humers rock!!!

terminator, thank you for your time and knowledge. fill me in on the 92 octane thing, and anyone purchased anything from predator motorsports? the trucks on the lift now, just put dynatech ss headers and a b&b exhuast on her, im looking for an intake and a pc upgrade, thanks again guys

 

LOL!!

 

It's in the manual