Mission Impossible: Taming the Giants (Excursion/Hummer modding)
 

I must certainly be fun squeezing extra MPG out of a Prius or Insight, but the bigger challenge is getting decent mileage out of the most indecent of all. The Excursion and the Hummer H2.

The (now discontinued) Excursion is nothing more than a Ford Super Duty truck chassis with a station wagon body. Most are diesels. After 2003, all use the 6.0 (IH T366) diesels where the earlier ones use the 7.3 (IH T444) engine. All Excursions come with an automatic transmission. Most are 4x4 but about 25% were 4x2. A 4x2 diesel Ex gets roughly 14 MPG in mixed driving. I could latch onto a 2002 4x2 Ex for about $20,000.

What would be my plan? First a big dose of drivetrain mods. Put the numerically lowest gearing I could find in it. For a 4x4 that means swapping the stock 3.73s for 3.55s. for a 4x2 with the 10.25” Sterling axle I could get 3.08s. Second, I do the “sex change operation” and install a manual transmission. My SD uses a ZF6-650 which has a 0.72:1 overdrive and is built to last forever. In the case of the 4x4 I need more overdrive, so I go to the Tremec T-56 “Viper” transmission. It can take the tremendous torque of the International engines. Then I do some aero mods. If the vehicle is a 4x2 I can slam it 3 inches in front and 6inches in the rear. (No slamming a 4x4, though) This reduces ride height and apparent frontal area. An air dam, side skirts and rear fender skirts and maybe some grille blocking (I’m working on a grille block for my SD). Install a pyrometer to provide EFT guidance for the driver. Maybe I add a digital tach. Maybe altogether I have put an additional $7000 in the vehicle.
MPG Improvements
Regearing: 2.5 MPG for 4x2 1.75 for 4x4
Manual transmission: 2 MPG
Aero mods: 2.5 MPG for the 4x2 1.9 MPG for the 4x4.

Total: 7 MPG (50%) for the 4x2 5.65 MPG (40%)

Not gonna make the Prius engineers lose sleep, but not bad.


The H2 is nothing more than a Chevy Silverado half-ton truck chassis with a tarted-up station wagon body. All use either the 6.0 or 6.2 liter variants of the updated small-block. All H2s come with an automatic transmission. All H2s are 4x4. A H2 gets about 11 MPG in mixed driving. Despite all, the Hummer remains an expensive used car. It is tough to find one under $35,000.

For the H2 my plan starts with losing the gas-pig engine and the frail and inefficient automatic. A Cummins 4BT3.9 four-banger would fit nicely into that deep engine bay and accessory drive parts are available off the shelf. Alternately, a 6.5 Hummer turbo-diesel is a bolt-up. I mate it to a T-56 out of a Camaro. That variant of the T-56 has a huge 0.5:1 overdrive. That big overdrive ratio obviates the need to replace the 3.73 gears in the Hummer. You can’t slam a 4x4 and the Hummer sits so high that beyond maybe some grille blockage and rear fender skirts, you really cannot do much from the aerodynamic standpoint. I include a pyrometer and a digital tach. I have about $8,500 in the mods over and above the cost of acquiring the vehicle.

MPG Improvements

Diesel engine: 4.5 MPG
Manual transmission: 2.5 MPG
Aero mods: 1.0 MPG

Total: 8.0 MPG (73%)

Getting a H2 to 19 MPG would be nothing to sneeze at.

Those vehicles shouldn't even exist. There is nothing to justify their existence except the ego of their owners.

^^^ Im with those guys. Sorry.

I could MAYBE see the excursion as a tow rig that can also haul people/cargo. But thats it. I despise people that daily drive those sorts of vehicles.

It would be a fun pit to toss money at... just to show people up who drive those things, but they are an all around poorly designed vehicle, for hauling people you are almost better off with a small school bus! about the same kind of mileage, and way more space, for hauling cargo... same thing, or small van, hell, the freghtliner vans can do more and get better mileage.

I was going to say that nobody ever lost money betting on the wastefulness of Americans ... but then I realize that GM has set new records doing so. Ford is right behind them. Maybe there is hope.

I think it's an interesting mental exercise. Maybe not for a grocery-getting 19mpg Excursion, but for their close cousin: the Humvee...the evil that started it all...:p

How could Humvees be modified to return better mileage. I bet 90% of the time they are just tooling around the desert, with the rest spent smashing down gates and outrunning terrorist potshots. I believe the military would be heavily interested in fuel efficiency...it lessens the logistics of supply convoys.

I'm thinking high psi tires, overdrive transmission, regeared axles, TDI (if it isn't already implemented), curved body panels (which would probably help deflect bullets/shrapnel), and a severe weight cutting regimen (kevlar instead of steel?)...

Composite HMMWV
http://www.defense-update.com/newsca...e_HMMWV_hr.jpg

- LostCause

what steel panels??? the humvees are made from aluminum with a fiberglass nose, unless your talking about the armor packages, at which point you have steel panels but eh it doesnt really matter to much now, we are looking at new vehicles for the military (yep the humvee is becoming obsolete) as for high pressure tires, they have a inflation system, with the press of a button you can switch the pressure for whatever terrain your on. honestly there isnt much wrong with the humvee other than the people who thought they would make great daily drivers..... they were never intended to be road vehicles....

/rant

just for a note, dont take my rant as attacking anyone, it just annoys me that people wanted to drive around in a "military" vehicle so bad that they became a production vehicles, there are just some things that people should just say hey thats cool, and leave it at that.

just my .02

johnpr is right about the HMMMMV. Even the fuel tank is plastic. As far as reducing their FE, the Army was toying with a hybrid system that could be used in EV mode for stealth.

I'll do research on my own, but does anyone have any idea what the HMMWV is going to be replaced with? I remember seeing potential replacements awhile ago, but they seemed pretty deep in the conceptual realm at that time.

Good point about the fiberglass body-panels, I hadn't thought about that. :) I bet the frame/chassis still weighs several tons on that thing, though.

I realize that the military has more important things to do, but it's mildly annoying to see the total disregard for pollution control/frugality. :( I guess that's one reason to be a pacifist. :p

B-52 Synthetic Fuel Test
http://www.fas.org/nuke/guide/usa/bo...fst8712398.jpg

- LostCause

Silveredwings -

I heard that they were very interested in fuel cells because the water byproduct could be used by the GIs.

CarloSW2

watching TV tonight i can't believe Cadillac is still bragging how big their SUV is. They just don't get it. They are going to come up with the short end of the stick this time.

if i remember correct, the most promising replacement was designed by international but i could be mistaken, i stopped following it a little while ago so i would be verry interested to hear what you find

HMMWV are built light to be air lifted. I believe the non armored versions has a fiberglass body, soft doors and top.

True, but would this really capture the attention of the type of person who already drives or would like to drive an H2 or Excursion? And would they then care enough to do anything similar?

I spend my time with a foot in either camp – eco-modders and pickup/SUV types.

For the pickup types I get a lot of the guff that the Toyota types put on Bondo’s excellent bed cap. I get told my truck looks “gay” and that it cannot tow (I scotched that with a youtube of me pulling a Bobcat trailer up Sandstone Mountain in WV). Even personal attacks. I don’t care. I also stick my nose into political sites so I have a hide as thick as the belt armor on an Iowa-class battleship.

Posts #2,3,4, and 6 exhibit the very same attitude from the other direction.

Excursions and H2 sell for a reason. Somebody has a mission for them. You gotta face facts – not everyone wants any part of a 60 MPG car. Until they build one a 6’10” man can get into without a lot of gymnastics, I don’t want one either.

You make fleet progress by making all the cars more efficient, not just a handful of imports. The US fleet average is 22 MPG. If you could improve it 50% you now have a very efficient 33 MPG and a 33% reduction in fuel usage nationwide.

The HMMV is not a good candidate because of its exotic drive train. It has three Torsen differentials and simply has to have a loose torque converter to dampen all the torsional vibration driving a triple-Torsen vehicle over rough terrain would generate.

The B52 pictures are of B-52s in a edge-of-envelope test. You always do such tests with the engines running very rich so if somethiong goes wrong you can get a quick engine restart. Actually the synthetic jet fuel runs very cleanly compared to dino-JP-5. The picture is a politically motivated cheap shot.

I totally agree. The best way to make the fleet more efficient is to stop making the least efficient vehicles.

I'm not against gas guzzlers. If you need your big truck to haul stuff around all the time then fine. But people sitting in rush hour traffic going to the office in their Excursion are plain stupid.

You are right, but the exhaust trails in normal operation are still pretty significant during takeoff and landing...especially compared to modern-day high-bypass turbofan aircraft. 50's technology still going strong...:(

Short-term replacement (i.e. current HMMWV's replacements):

Force Protection Cougar
http://upload.wikimedia.org/wikipedi...-4393H-041.jpg

International MaxxPro
http://upload.wikimedia.org/wikipedi...ro_Cat1_IL.jpg

Long-term replacement:

About a million candidates still in the running. It looks like the HMMWV isn't getting one replacement, but a whole family of replacements...ranging from golf-cart sized vehicles to 9 passenger trucks.

Apparently two programs exist: the FTTS (future truck transport system) and JLTV (joint light tactical vehicle). The FTTS seems to be all encompassing and focused on overseeing the development of a utility vehicle and a multi-purpose vehicle. The JLTV is a venture between the army and marines to develop a family (5+ vehicles) to replace the HMMWV. It seems to be using input from the FTTS, but is otherwise independent. The JLTV may have stalled (?) and might be going through DoD review at the moment. Anyways, some candidates, out of the million out there. All taken from somewhere on the internet...

Armored Gold-cart
http://www.defense-update.com/images_new1/polaris.jpg

Raytheon's Rock-crawler
http://www.defense-update.com/images_new1/hydra.jpg

Lockheed Martin's Hummer-look-a-like
http://www.defense-update.com/images_new1/lm_jltv.jpg

CTV
http://www.defense-update.com/images_new1/ctv_td1.jpg

Textron's Hybrid Hummer
http://www.defense-update.com/images_new1/agmv_1.jpg

Millenworks LUV
http://www.defense-update.com/images_new1/luv_1.jpg

Closest thing to a jeep I've yet seen
http://www.defense-update.com/images_new/lsv_gd.jpg

I vote for the golf-cart. :) They all look like they'd be elephants on the battlefield...a hummer must be a pain to drive in the streets of LA, imagine driving one of those things in the streets of Iraq. (Armored) Fish in a barrel.

- LostCause

That dude doesn't look any too comfortable in that car. People will do anything for a freebie.

What makes you think the B-52 wasn't fitted with high-bypass turbofans long ago. They no longer have to be fast high-altitude bombers. 400 MPH suffices nicely for the B-52.

I wonder if any of these HMMV replacements can keep up with moble battle formations the way the HMMV did?

It helps with lubrication too.

These things need to be cheap, and that's what steel is. All the great new military tech takes sometimes decades to be available to more than a few units. My university is primarily a military university, and I know many people who served entire tours in Iraq and especially Afghanistan and never had kevlar body armor so we can't expect them to afford it for vehicles.

Besides the steel armor needs to take projectiles much larger than the handgun variety Some JHP bullets out of a high caliber rifle will obliterate kevlar. The bigger threats tend to be rpg's and ied's.

Re-gearing the military vehicles isn't an option usually. They need to haul artillery and things all the time and they usually have a top speed geared to 50 mph, give or take 5 mph.

As a side note my senior project is developing a system to remotely control these things in a convoy in radio denied areas, just so the front one can be destroyed without people in it, by ambushes and ied's. My part is merely the cable tension device for the fiber line so it doesn't hit the ground or become so tight it breaks while the electric motor takes its time to respond.

http://media.buysell.com/userphotos/...1361010136.jpg

Meanwhile, up in the great white north, Canada has replaced its VW TDI powered Bombardier built Iltis with the big Mercedes G-Wagons...

http://www.kingsown.ca/Assorted%20Photos/GWagon1.JPG

Warthog anyone?


http://host.trivialbeing.org/up/smal...rthog-halo.jpg


I don't think we can get rid of Big vehicles, because there will always be big people, and big jobs to be had. But we can improve the mileage of the large ones, and not just introduce new small vehicles. Doing both will benefit everyone.

In the late 50's, early 60's they were fitted with low-bypass turbofans.

Low-bypass Turbofan
http://upload.wikimedia.org/wikipedi..._%28lbp%29.png

Most modern-day commerical airliners and military transports use high-bypass turbofans for increased fuel-efficiency.

High-bypass turbofan
http://upload.wikimedia.org/wikipedi..._operation.png

I suppose they were never upgraded for cost and size issues. The B52 essentially operates like a normal airliner (high-altitude, subsonic, long-range).
Sometimes I wonder why they keep them on. I don't know the last time carpet bombing was used, but there must be a reason. $$$?

Good points about the HMMWV issue. That's cool you get to work on military technology, but why the fiber optic cable? Won't the terrorist know which vehicle is remote control...:p I was thinking infrared, but I guess that won't work in a sandstorm. :o Lastly, won't terrorists get wise to the fact that the front vehicle is a decoy? I wouldn't want to be in humvee #2...:)

- LostCause

They were used in Afghanistan against the Taliban. There highly efficient to bomb the piss out of someone that cant fight back against airpower.

There will always be big people but, I hate it when I see a normal sized soccer mom driving a tank (what I call H2's, Expeditions, Escalade's, Tahoe's, etc) but they aren't even hauling around anyone. The most some ever have is their two kids, so all three including the mother would fit in a family sedan or so. Heck, even the father with the children and mother would fit in a family sedan. Why buy a tank if you aren't super tall (tall just doesn't cut it because I think most tall men could comfortably fit in a sedan) and are just going to be driving around town until it's time to pick up the kids?

/rant sorry. Wowza this thread went off topic. :D

yea. I know. But it also makes me think of myself and then I feel bad :( but at least I don't just randomly drive around. and I get a lot better mpg's than most who drive the same thing around.

i dont want to dispute what you are saying, you are definately right that most people cant claim size as a reason for driving a big vehicle. in fact my wife has a friend who is 5'2" she drove around in a huge pickup truck and it was amusing to see. but as for the tall men in sedans, I am 6'3" which i know is not giant by any means but i have a hard time fitting in compact cars, I have quite a few examples to back this up,
1) when i was still in the service i was looking for a car which was sporty and decent on fuel (20ish is decent to me, low for most on this site but eh whatever) i looked at a prelude and was set on buying it, it was standard transmission and very good condition. i went to test drive and didn't fit comfortably, with the seat all the way back my knees hit the dash and i was unable to shift and my head was against the roof. i was very disappointed and ended up buying the trans am instead which has vastly superior seating adjustment.

2) my mother in laws olds alero with 6 way adjustable seats (i drive this a couple times a month rather uncomfortably) with the seat as low as possible i still hit my head on the roof, and i am either too far from the steering wheel or my knees are to close to the dash, no happy medium.

3) my brothers toyota's and geos he has had many and i never fit in them and long story short i never fit in them just right.

anyhow this is pretty long all for this one point, sometimes fit can kill a car, i dont know why i have issues with fitting in many cars, i would love a good economy car, honestly i would, its just a matter of finding one that i fit into properly :( i think the only reason i actually fit in the trans am is because of the t-tops, i know that if it had a solid roof i wouldnt fit in there either (the top of my head sits where the headliner would be) and with the jeeps they are convertibles (yeah i hit my head in minivans and other suvs too.

/rant

^^john - I guess I'm lucky :p My height (about 6') comes from an abnormally long "neckular" region :D My lower half fits in a miata (older generation - not sure about the new mx5), but my upper half pysically doesn't fit. With a soft top, my head pokes into the canvas :p

Interestingly, I do fit in a Porsche 944 - in the front seats... Yes, they have two back seats. When I sit upright in one of the back seats, my head sticks half way out of the sunroof (very amusing) :p

But that said, I've fit in about every other car (including an old old Lotus Europa) :D And even with that said - 50%tile (American weight and dimensions) crash test dummies fit the cars for IIHS an NHTSA testing :p So the majority of Americans can't claim they don't fit :p

And not very comfortable at that. Again, not everyone wants to do gymnastics or be a contortionist to get into a vehcile.

Dude, 8'5" -- showing the tallest man alive getting into any car is hardly evidence that no one fits into a car....

I know what you mean John... I'm 6'3" also, and a little bigger around the middle than I care to admit... There are cars I just can't get comfortable in. Some mini-trucks too. And even some not-so-mini vehicles. I do not fit well in a Dodge Dakota or first gen Durango. The b-pillar sits where my shoulder should be. I DO fit reasonably in Mini-Cooper. Infact i know a guy taller than me that drives one. I can't afford one at thist point in time. My Neon is a good fit, not great, but I can travel in it cross country no trouble. Or with a second person too. But no way can I fit 4 adults in it.

I've a friend with a Metro. He HATES it, it is cramped for him (he is bigger than me), but loves the mileage. In the year he has owned it, it has saved him almost as much as it cost him to buy.

I once wrote a review, of sorts, after renting a 2002 or 2003 Subaru Outback Wagon. I didn't mind the car in general, but in the couple days I had it, I never found a position that I could even tolerate. Otherwise, i wasn't unhappy with the mileage return, could have used more power, but was a ton of fun offroad to drive.

^^ when i first met my wife she had a neon, i was quite surprised at how tolerable it was but alas that went the way of the buffalo and was replaced with a saturn ion which had a similar fit, my wife crashed that and so ended small cars for us (atleast for now, i plan on building a 3 wheel electric vehicle which will be designed around me driving) i have heard the minis are good for taller people but they are out of my price range also.. i have wondered about the smart cars, they look like they might have a decent fit for us "taller" guys, but not so sure about the bigger guys. hmmmm

I'm 6'2" long-legs and I drive a civic.

New beetle.... A few years ago, there was a segment on NPR about cars for "those that are taller when sitting" (really, it was just for tall/big people). The winner - the New Beetle... It's a wonder why they didn't include that in those arch commercials from way back :p


But all that said... it's really not the outer dimensions of the car (for the most part). It's the interior design. I mean, the Hummer H2 is freaking huge - but the interior is cramped.... I owned a Mazda 626 a few years ago - my top half barely fit, but I had awesome knee room... Take the seats out of a neon - I'll bet just about everyone can say - ya, with a proper seat - I'd fit in here. 2008 Gallardo - "There is headroom enough for a mid-six-footer. It's easier to get into and out of than a Viper or even a Corvette" - and that's a short car :p

I'm 6'3" and I was always able to find a comfortable driving position in every car I ever drove. That includes a 91 metro, a 04 Aveo and a 01 echo. I guess everyone has their own notion of comfortable though.

^^^ thats true, comfort really does vary by each person^^^

comfort for me means I fit and my shirt isn't being sat on my myself.... and my belt is keeping my pants on so that when I sit down my pant's are still on :D" One thing I like... Headroom. That's the only thing that will turn me away.

Mom's Caliber, your knees hit the knee bolster if you do this, but I jack the seat all the way up, and I've STILL got more headroom than my ZJ, and it's seats don't adjust, they are always all the way down. AND it sits shorter than my Jeep too. not too bad for a "compact" I do this cause I like to sit high up off the ground, and see the hood everything over it. You barely see the hood on the Caliber because it's got a higher slope than the ZJ, which is almost parallel with the pavement. A lot better for Aero though.

I don't see why not improve the mileage of any rig. That being said, use it fer what it's built fer, not commuting, not getting groceries from the store, not... Etc.