For H1 owners. - Fuel mileage questions. (Full Version)

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For H1 owners. - Fuel mileage questions.

H1Intercept -> For H1 owners. - Fuel mileage questions. (9/15/2007 9:26:28 AM)
Hello. I'm a new H1 owner. I'm working on getting it set up for long distance (mostly on-road) traveling and would like to save the trial and error headaches by getting info and opinions from fellow H1 owners on the following: (my current setup is in red) What year is your H1? - 1999 What model do you have? - The Wagon Is it gas or Diesel? - Diesel How many mpg do you get? - 10 to 12mpg. What size tires do you run? - 38x15.5x16.5 Dirt Grip What air pressure do you run on road? - 40lb Do you know of anything I can do to approve fuel mileage? - Not a clue If you could please copy and paste the above questions in a message and reply with your answers, I would really, really, appreciate it. Thanks a million in advance.

Injunfarian -> RE: For H1 owners. - Fuel mileage questions. (9/15/2007 10:10:47 AM)
Although those Tires are a great tire if you are mainly focused with on road fuel milage I would suggest getting some GSA's should improve your milage a bit. Also be sure to use your cruise control that also helps with milage. Next dont SPEED you speed in these things it not only overheats them but reduces your fuel milage alot.

axleman -> RE: For H1 owners. - Fuel mileage questions. (9/15/2007 10:14:36 AM)
What year is your H1? - 1994 What model do you have? - 4 Door HT Is it gas or Diesel? - Diesel How many mpg do you get? - 12-13 mpg. What size tires do you run? - 37x12.5x16.5 Unicure MT What air pressure do you run on road? - 40lb Do you know of anything I can do to approve fuel mileage? - You already have the best gear ratios for mileage, so nothing to do there. The #1 thing you can do IMO is to watch your speeds. Mileage seems to drop off pretty fast above 60mph or so. Also keep your weight down. All of the accessories are cool and most are very useful, but it is surprising how much weight it all adds. Big brushguards, roofracks, tire carriers & spares, winches, rock tubes, etc. adds up faster than you might think.

H1Intercept -> RE: For H1 owners. - Fuel mileage questions. (9/15/2007 2:21:13 PM)
Injunfarian and axleman, thanks for the quick reply guys. So it's a good idea to try and stay under 60mph at all times? Injunfarian, what would you recommend I do to lower the risk of overheating? Duel engine cooling fans. Are they a good idea? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=76 How about this Intercooler system? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=68 What kind of engine life (mileage wise) should I be able to get out of my stock 99' Turbo Diesel, (while treating it right of course)? Is 40lbs a good number to run in my 38 inch tires, or can I go higher? (and if I can, do you think it's even worth it?) The stage 4 predator kit. Does anybody have this? Does it increase fuel mileage? Does it cut or lengthen the engine life? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=417 When I have to replace the engine, (hopefully not before 300,000 miles?) would it be a good idea to put another 6.5 engine in or go with the 6.6 Alpha? Can the above, engine fans, intercooler system, and stage 4 kit be used on the 6.6 Alpha engine? I know I just asked a s*** load of questions here so I apologize, but I really appreciate anyone taking the time to answer. Thanks. ;-)

Injunfarian -> RE: For H1 owners. - Fuel mileage questions. (9/15/2007 2:41:59 PM)
quote: ORIGINAL: H1Intercept Injunfarian and axleman, thanks for the quick reply guys. So it's a good idea to try and stay under 60mph at all times? Injunfarian, what would you recommend I do to lower the risk of overheating? Duel engine cooling fans. Are they a good idea? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=76 How about this Intercooler system? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=68 What kind of engine life (mileage wise) should I be able to get out of my stock 99' Turbo Diesel, (while treating it right of course)? Is 40lbs a good number to run in my 38 inch tires, or can I go higher? (and if I can, do you think it's even worth it?) The stage 4 predator kit. Does anybody have this? Does it increase fuel mileage? Does it cut or lengthen the engine life? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=417 When I have to replace the engine, (hopefully not before 300,000 miles?) would it be a good idea to put another 6.5 engine in or go with the 6.6 Alpha? Can the above, engine fans, intercooler system, and stage 4 kit be used on the 6.6 Alpha engine? I know I just asked a s*** load of questions here so I apologize, but I really appreciate anyone taking the time to answer. Thanks. ;-) Dont have to stay under 60mph all the times but with a Stock 6.5TD i wouldnt suggest going much over 65mph but yea best cruising speed for these is around 60mph As for overheating Id suggest just keeping an eye on your temp on the highway should be 190-205 i think is a good range if it goes above 205 maybe let off the gas. As for cooling fans that be great idea if you have the money so would a intercooler system(the intercooler system should be able to give you more milage as well) Also with the intercooler system if you have the chip you could add more boost and get alot more HP and milage As for 40lbs that is a good number if you go over that number you could expect extensive wear in the center of the tread shortening the life of your tires and might be a bit more expensive than the fuel you would save and a bit more rougher ride. As for replacement of engine I'd truely suggest the Dmax conversion if you have the cash to do so, you will get a rock solid engine that is very reliable and has GREAT fuel milage 20+mpg also will be able to do 70mph+ on the highway no problem. As for using the fans and intercooler I believe you should be fine reusing those on the 6.6(BUT DONT quote me on that id suggest checking into it a bit more yourself) as for the chip etc you definately would have to get one that works on the Dmax. But if you cannot afford the 25-50k pricetag of the conversion then yea I'd suggest getting another 6.5TD and using performance/marine parts to make it more solid, run smoother, more power, and a bit more milage. As for the lifetime of an engine its hard to say. I have heard these things lasting from 25k (due to cracked cylinder) to 400k+ without a overhaul it all depends on how well you treat and maintain them. Mine is currently going onto 100k miles and I have abused it and by the looks of the interior etc when i purchased it I believe the previous owner(s) abused it as well. Sometimes I guess you can luck out as well.

H1Intercept -> RE: For H1 owners. - Fuel mileage questions. (9/16/2007 1:36:43 PM)
Injunfarian, thanks a million for the answers. You rock! I'll post how everything goes. Have a great weekend. Thanks again. ;-)

axleman -> RE: For H1 owners. - Fuel mileage questions. (9/18/2007 9:22:38 AM)
quote: ORIGINAL: H1Intercept Injunfarian and axleman, thanks for the quick reply guys. So it's a good idea to try and stay under 60mph at all times? Injunfarian, what would you recommend I do to lower the risk of overheating? Duel engine cooling fans. Are they a good idea? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=76 How about this Intercooler system? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=68 What kind of engine life (mileage wise) should I be able to get out of my stock 99' Turbo Diesel, (while treating it right of course)? Is 40lbs a good number to run in my 38 inch tires, or can I go higher? (and if I can, do you think it's even worth it?) The stage 4 predator kit. Does anybody have this? Does it increase fuel mileage? Does it cut or lengthen the engine life? http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=417 When I have to replace the engine, (hopefully not before 300,000 miles?) would it be a good idea to put another 6.5 engine in or go with the 6.6 Alpha? Can the above, engine fans, intercooler system, and stage 4 kit be used on the 6.6 Alpha engine? I know I just asked a s*** load of questions here so I apologize, but I really appreciate anyone taking the time to answer. Thanks. ;-) No, you don't have to stay under 60 at all times. I have driven mine on the highway at 65-75 for hours. The engine can take it fine assuming the cooling system is ok. In the context of trying to save fuel though 60 is a good highway speed. As far as the cooling fans go, based on my own observations and those of others, you won't necessarily get much benefit from them. When all is well, the stock setup actually cools pretty well. Keep it in good shape and it should be fine. Engine life is a total crapshoot on these trucks. Some only last 20k or so while others go hundreds of thousands of miles. It's hard to say what a good average is, but I suspect somewhere in the 100k-120k before needing something major. I would not be counting on 300k. SHould you have to replace it and can afford it, the Duramax conversion is the way to go. If not, drop a modified (but with reliability in mind) 6.5 back in and keep on trucking.

H1Intercept -> RE: For H1 owners. - Fuel mileage questions. (9/18/2007 1:34:41 PM)
Axleman, Apparciate the post and feedback on the cooling fans. Do you have any experience with Predator's Stage 4 kit or Intercooler system? Why I ask is I'm wondering what kind of fuel mileage increasement I would be looking at after dumping $10,200 into my Hummer.... Any idea? Stage 4 kit: $4,499.95 http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=417 Intercooler system: $4,495.00 http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=68 Cooling fans: $186.95 http://predatormotorsports.com/index.asp?PageAction=VIEWPROD&ProdID=76 I asked Predator but they wouldn't give me an answer, they just said it would "improve it a good deal" whatever that means. Yeah the extra power would be really nice but if the above is only likely to bring me up to 13mpg then my current figuring of; 30,000 mile yearly trip, at $3.00 a gallon, at 12mpg is $7,500, and so the 13mpg would only drop it $500 bucks to $6,922. However, if it will get me 18mpg (probably dreaming right?) that would drop my 30,000 mile trip to $5,001 saving me $2,500 a year making the mods pay for themself in four years. Also, are these mods likely to shorten, lengthen (or do anything) to the engine life? That probably seens like a stupid question, but I use to professionally race quads (ATV's) and squeezing the most power out of them wasn't always the healthiest thing you could do. Thanks, Caleb PS: My H1 currently has 19,000 miles on it. Hopefully mine isn't one that will only last till 20k. ;-)

axleman -> RE: For H1 owners. - Fuel mileage questions. (9/18/2007 9:07:40 PM)
Ok, now we are getting to the meat of things. You are gonna be driving a ton of miles every year and you want it to be reliable and get better mileage (no offense, but you picked the wrong vehicle for that! [;)] ) With that in mind, if it were me, I would not do those kinds of power mods. First, I think that you would lose some longevity. Like it or not, our engines are pretty much the dogs of the diesel world. Compared to more modern diesels, they are wimpy, inefficient and much less reliable. Adding 185hp, which is not far from doubling the stock power, has got to have an effect on its lifespan without doing some serious internal mods to beef things up. Second, and I could be wrong, but I seriously doubt you will be seeing 50+% of mileage improvements from them or any other mod short of an engine conversion. At best, I wouldn't expect more than 2 mpg, if that. You will get just as much improvement (for far less money!) from driving a decent speed, putting your truck on a diet, and maintaining your truck religiously at the appropriate intervals. Now that's not to say that any of those are bad products. A 185hp boost has got to be a lot of fun [:)]. I just don't think that they are going to accomplish your goal.

hmcoleap -> RE: For H1 owners. - Fuel mileage questions. (9/20/2007 11:44:32 AM)
Axleman wrote: "You are gonna be driving a ton of miles every year and you want it to be reliable and get better mileage (no offense, but you picked the wrong vehicle for that! ) " I agree 100%. The H1 is a great vehicle for a lot of things, but lots of long trips on the highway is not one of them. I would compare it to trying to modify a Ferrari to better handle driving on dirt roads year round at slow speeds.

H1Intercept -> RE: For H1 owners. - Fuel mileage questions. (9/20/2007 4:56:11 PM)
No worries. I knew what I was getting into before I bought the H1. ;-) Read all the changes through out the years and decided on 1999 or above. (wanted the 2006 but couldn't afford it). I storm chase in tornado alley a little over two months out of the year in peak tornado season, (April thru June). I got sick of the utility box vans getting stuck on any dirt road that turned muddy, having to turn around when I hit any debris, or flooded out roads. 90% of the time it's just boring on road driving, hence the above questions to get the most mpg and longest engine life. But, the other 10% I need a real vehicle. ;-) I'll post some pictures in a few weeks. Got it pretty torn apart right now installing the Doppler radar and stuff. alexman, thanks for your insight on the engine work. Religious maintenance it is. ;-)

Injunfarian -> RE: For H1 owners. - Fuel mileage questions. (9/20/2007 7:58:13 PM)
quote: ORIGINAL: H1Intercept No worries. I knew what I was getting into before I bought the H1. ;-) Read all the changes through out the years and decided on 1999 or above. (wanted the 2006 but couldn't afford it). I storm chase in tornado alley a little over two months out of the year in peak tornado season, (April thru June). I got sick of the utility box vans getting stuck on any dirt road that turned muddy, having to turn around when I hit any debris, or flooded out roads. 90% of the time it's just boring on road driving, hence the above questions to get the most mpg and longest engine life. But, the other 10% I need a real vehicle. ;-) I'll post some pictures in a few weeks. Got it pretty torn apart right now installing the Doppler radar and stuff. alexman, thanks for your insight on the engine work. Religious maintenance it is. ;-) Wow! that sounds like a blast! I always wanted to storm chase... Actually try to everytime there is a tornado warning around here(pretty well never) but we did get 2 last year! Although the wife doesnt agree she did come with me in the first chase.

3hummers -> RE: For H1 owners. - Fuel mileage questions. (9/23/2007 8:45:28 AM)
The GSAs will be a lot quieter and get a little better mileage. I have found that I get 11.5 mpg at 65 mph in my 97 wagon. I have another H1 with MTRs and they are great offroad tires but noisy on the road.

H1Intercept -> RE: For H1 owners. - Fuel mileage questions. (9/24/2007 4:11:37 PM)
Injunfarian, Cool to meet a fellow storm chaser. ;-) You'll have to fly down and chase with us next year. Check out our website for more info if you want. www.H1-Intercept.com You'll have to excuse the out-of-date picture of the Hummer. I'll be uploading current photos here shortly.

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