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Fuel injection would help alot, obviously only if your running a late model or do a conversion. Most people when having lifts that high and big tires like to drop in the chevy 350. I think the Jeep engines, especially the 258, with lower gears would give good efficiency with enough power.
 

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I have been wondering the same thing too. Except I have been wondering what I would get with a late model cj-7 with an inline 6, 2 inch lift, 1 inch body, and running 33x11x15 m/t's
Just been wondering what I would be getting once i build my dream jeep.
 

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The lift really has nothing to do w/ gas mileage, its all about gearing and tire size, mainly. I had stock gears in my Jeep and a Carbed 360 Chevy small block, TH350 Auto tranny and 33" Boggers and would get about 12 mpg on the highway. Which was comparable to my old 258. I cant wait to see what I get with 5.13's and 39.5" Boggers, should be interesting.
 

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Actually lift does effect gas mileage. When your up higher the more wind resistance you have. It does not effect the gas mileage as much as tires and gears but it does effect it. Thats why some guys take the tailgate off or put a net tailgate on cause even that makes a difference.
 

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even on a STOCK truck and tail gate makes a huge difference. i can tell when i am traveling that i get about 20-30 miles per tank more with the tail gate down
 

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I dont know that I agree, maybe a little? See lifting it up higher doesnt really cause more wind resistance....your vehicle is still the same shape its just higher (more air flowing underneath) Removing a tailgate and raising a vehicle are two totally different things. You are changing the shape of the vehicle when removing the tailgate. I think it is very small but I could be wrong, all I am saying is that the real problem comes from the gearing change and more rotating mass, not the fact that your vehicle sits higher.
 

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PS..I am not an engineer, so I really dont know, and I have never lifted a vehicle without putting Bigger meat under it (esp. not 6" with small tires) so I am not saying this is fact I am just giving my unprofessional .02 worth.
 

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the only way the tailgait makes a difference, is when you cruising on the highway or at the highway speeds. i would think the same goes for a lifted truck. the only thing that could possibly be making a larger profile would be the axle being more exposed now, but even that is a stretch.
 

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You are right a lifted vehichle's geometry is similar to that of a stock truck. Now there are two large paths of flow. Top and bottom. Unfortunatley the bottom path is a high resistance one (axles, steering componets, non linear surfaces,etc.) You are going to great the worst kind of resistance--eddy currents. Or non laminar flow. Non laminar = turbulent = bad. The reason that lower vehichles feel less resistance is two fold. One they usually are more aerodynamic. Two the higher you go the higher the wind velocity is. Wind travels faster as it comes away from the ground becuase it experiences the same resistance on the ground as it does on our lifted vehichles. The air flowing below the vehicle has a resistance factor just like the air above it and to the sides. Maybe more? Make sense?? May be not? I am an engineer but maybe not a good one??
 

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Like I said I partially agree, where I dont is that a truck already has a lot of flow underneath it stock. We are not talking about lifting a Corvette or Honda Civic, we are talking about vehicles that are 4WDS and already sit high enough to create undercarriage wind resistance. I think moving the vehicle 1' higher(1 foot is higher than most) will not get into that much faster wind. Im sure there is some effect on gas mileage, but guarantee it is minimal and not worth the worry. If someone is that worried about fuel consumption go buy a Ford Focus.
 

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Lets face it here guys, the simple fact of the matter is that we all (mostly) own trucks (and such). As stated somewhere above, if we wanted really good gas mileage, we would go out and buy a GEO Metro, right?

It takes me about $30+ bucks a week to fill my truck and commute to work and back and cart my 3 boys around and I know many of you out there laugh at my LOW $$$ figures. Knowing this, being a single father I still chose my truck over other, more practical options.

I know to some, the 1 or 2 miles per gallon we may save can be a huge difference in our pocket books, but if it was that much of a concern, the big bad 4x4 would be parked for the work week, right?

Not trying to offend anyone, just my 2 cents worth. That is why we come to this forum isn't it?

Airborne
 

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You are right on. If I gave a hoot about gas I would drive a lawn mower. You gotta make sacrifices. Mine is riding my bike to work every other day.
 
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