Hummer H2 - How Can I Get Better MPG & Reduce Emissions?

[savoF3]

This thread is fun. I'm really interested to see how this turns out. 50% gain in a couple days is great. And you must have an awesome wife to pick it up second hand. Just browse some of the gaslogs and notice how many notes that say something like "Was doing great, but the wife had to use the car."

Also I wanted to revisit this:

Originally Posted by Coyote X

Assuming it is an Auto trans. The first thing you should do that will help is to try and keep the torque converter locked up as much as possible. The converter probably locks up at 45mph when in OD/4th gear. So if you have a choice in going 40 or 45 I would say go 45. Any time the converter is unlocked you are using a lot more gas than you should. If you are driving in traffic between 35 and 45mph pull it down to 3rd gear. 3rd will lock up at 35mph. But if you go over 45 for more than a few seconds go ahead and go back up into 4th. Also any time you hit the brakes it unlocks so avoid using them as much as possible.

This I did not know and is potentially huge for me. I drive a lot of segments cruising at 35mph. Are you saying all I need to do is move the lever from 'D' to '3' and keep my foot off the brake to get the converter to lock up at this speed? Not that I expect you know exactly how my particular tranny (Grand Caravan) will behave, but should I just put it in '3' when I start out in town and leave it if I'm not going to get to fourth gear range (either 42 or 45 for me)? Or will it cause side effects I don't want (like raising shift points for 1-2 and 2-3)?

[GasSavers_Red]

Originally Posted by zpiloto

Yea i don't get it. You drive what you drive. The guys wife just improved the H2 mileage by 50% and he has not even been here a week. Here's some one with one car, carpools to work and is teaching his wife how to hypermile, and she doing a heck of a job. Proves you can hypermile anything with applied effort. He probably burns less gas than most of the people here even though it's 15 and climbing. I think you need to loosen those Halo's up a bit. I'm impressed with the the effort from the whole family. Keep up the good work.

I agree. They are doing an excellent job with the H2.

[Telco]

Need to check into the details on your trans with the dealer. Ask them about the lockup points and what gears. Not all transmissions will have a 3rd gear lockup.

[HummerH2]

MPG went down to 12.7 in city. My wife is still trying to get used to the new driving behavior. I am sure it will take her a couple of weeks to get a handle of it.

I have asked her to use the car only if needed.

As for the question of where I live, I am in Northwest Arkansas.

I am seeing good solutions on making changes to the car but I am not as savy on cars as most of you. It may have to be explained to me in a more simple and detailed manner.

I appologize for my lack of knowledge on the car convertion (mechanical changes) area.

Thanks for the support!

[savoF3]

Hmmm, this is what I found on my tranny on allpar.com.

In the A604 and 41TE, lockup can occur in both third and fourth gears (and second under special conditions) between 27 and 50 mph, depending on engine load and throttle position.

27mph was lower than I thought. And according to the manual putting the lever in '3' just disables O/D. There's no 'trick' in putting it in '3' to enable lockup below 4th gear.

[CoyoteX]

On a GM 4l60e/65e car I know that between 35 and 44mph the converter won't lock up in OD but if you pull it down to 3rd it will lock up above 35mph. In OD it locks up at 45mph. It unlocks any time when you give it more than about 1/4 throttle.

My Camaro had those settings in the factory tune. A Monte Carlo and GMC Sierra I drive pretty regular also seem to be programmed pretty similar in how they handle the lockup functions. None of them will stay locked up in OD below 40mph. But will stay locked up in 3rd down to 30mph. The GMC has the tow mode button and it modifies the shift points and lockup but I am not sure how the tow mode is configured.

I still think the easiest thing would be to have a light that comes on when the converter is locked so you can always adjust your driving style to keep the light on as much as possible. I wonder if there is a setting in the scangauge that can show when the converter is locked up?

[HummerH2]

Originally Posted by Coyote X

On a GM 4l60e/65e car I know that between 35 and 44mph the converter won't lock up in OD but if you pull it down to 3rd it will lock up above 35mph. In OD it locks up at 45mph. It unlocks any time when you give it more than about 1/4 throttle.

My Camaro had those settings in the factory tune. A Monte Carlo and GMC Sierra I drive pretty regular also seem to be programmed pretty similar in how they handle the lockup functions. None of them will stay locked up in OD below 40mph. But will stay locked up in 3rd down to 30mph. The GMC has the tow mode button and it modifies the shift points and lockup but I am not sure how the tow mode is configured.

I still think the easiest thing would be to have a light that comes on when the converter is locked so you can always adjust your driving style to keep the light on as much as possible. I wonder if there is a setting in the scangauge that can show when the converter is locked up?

This is a great idea about the light. It will help my wife quite some! How could I do this?

[HummerH2]

I have found somenthing very interesting. Using Shell vs. any other gasoline makes me improve MPG.

Does this make sense at all?

[GasSavers_Red]

Could simply be that the Shell gas has more detergents then an other station. So you engine gets a better "cleaning" using Shell then someone else. How many miles are on your H2? Might want to give SeaFoam a shot or try some acetone treatment.

[Hockey4mnhs]

i agree 100% with ryland i prolly do use more gas in a day then they do and thats all that matters.