Has anybody else noticed similar % milage drops per item?
2007 4.7 QC 4X4 now, 2005 QC 4.7 4X2 in the past. 10% less milage on the 4X4 from the get-go. Can't fix that but I figgured I'd post it as a referance.

Current truck is 07 4X4 QC w/ 35/12/.50/17's and a 2 1/2" level. I remember when stock it got about 17 MPG all around (about 10% less then the 2 wheel drive I traded). When I put on the leveling kit it dropped it down about 10% - to 15/15.5 MPG roughly. Stock tires were 245/70/17. Then I installed 315/70/17's and that dropped it down another 10 %. Computer (which has been ext. accurate on both trucks) then showed about 11.5 - 12 MPG. that shows a 20% loss but in reality is only a 10% loss because the computer doesn't know about the 10% tire increase. (truck is putting on 10% more miles then what everything shows.)
My long winded question is has anyone lifted a truck with a "true" all-around lift and not noticed any milage loss? Or would the added hight over take the stock "nose dive" look on airodynamics? It seems that the airodynamics of the truck was better with the front down and I'm wondering if I boosted the rear up a couple of inches and returned the rake I could get the initial 10% back. Re-gear would get back some from the tires but that's not in the works because of not being cost effective and the power is still plenty for me.
I'm not complaining of milage ( or I wouldn't have bought the gtruck and tires to begin with). Just looking for ideas of gaining back somre of the % lost.

 

All of the above will incrementally decrease fuel economy. The level actually does a pretty good number on aerodynamics, there is a reason they spend millions on air tunnels and testing and these trucks ship with the back to front "rake".

Big tires are killers, especially WIDER tires. More surface friction, plain and simple. Not to mention the power it takes just to turn them.

You'll REALLY feel the tire hit if your gearing isn't sufficient to generate the proper power/rpm ratio. 3.55s on 35" tires is just gonna suck ***** (and gas).

I'm at 4" of lift, run 35s and weigh in at a hefty 7000 lbs., but my fuel economy is only about 2 mpg less than stock city and maybe 1 mpg less highway BUT I have a LOT of mods that help with power (and fuel economy is a side benefit on most of them). Running 4.56 gears has helped immensely, as do my e-fan, headers, etc.

There's an old saying goes like "you wanna play, you gotta pay"...

 

I agree. That's why I'm thinking of boosting the rear up a bit. Then I'd put the rake back in the truck and hopefully return what MPG's I lost with the leveling kit. I'm curious if anybody has done it. It seems most actual lift kits always lift the front up higher then the rear so the lifted truck is level.
My real world MPG's is actually 10% better then any calculations or the computer because of the 10% increase in tire size. When it shows 12 I'm actually getting 13.2 - roughly!
I figgure what I lost with the tires is acceptable because I don't intend to do a gear swap. I did it previously with a bronco and the lower gears and 39" tires, even with a 460 swap, gave the truck better MPG's then the stock 351 with stock gears and tires------if I kept off the gas. In reality all I had to do was touch it and it went.
I started paying more attention to this recently as I removed the 315's and drove with the stock tires while cleaning up my rims and waiting for the current 35's. I was reminded on how much 10% can actually amount to. I accepted lower gas milage when I bought this truck and originally leveled it because I'm not to fond of the raked look but if I can return the rake and gain that 10% back I would do it. 10% is 10% If not - oh well. just the price you pay for owning a full sizre 4X4. All I've ever driven and all I intend to. I had a 4 banger YJ that and a 6 cyl trooper for a bit earliear and they weren't much better.

 

Pretty sure trucks are raked for the Payload intended to go in the bed, as HD trucks usually have more rake. Never seen a civic with 3" rake for gas mileage gain. So I doubt u are losing any mpg from a level kit looks better level anyways. U want big gains drop tire size. 35's big for just a level IMO.

 

I'm not complaining of MPG's. If I was I would have bought something better for that purpose. I'm just wondering if there are ways to improve what I've lost if the underlying problem can be fixed (easily and cheaply). Of course tire size is an issue, however, that will not be changed. So I'll acceptably live with that loss. As with the 4X4, Quad cab, full size truck, V8, etc...

I know as a fact leveling the truck by lifting the front up lost 10% right away. Consistant and figured out----not just going by computer. Of course on my truck it is highly accurate, as was my 04.

Just curious if having the truck higher up would overtake the rake on aerodynamics, or is the truck high enough in stock form that it can be lifted a few inches and still keep it's aerodynamics. I know there are many factors involved as well such as tire width and hight as well. However, one factor is that with stock tires on before and after the initial leveling I lost exactly 10% when the nose went up.

BTW, current 35/12.50's as well as the previous 315/70/17's are just right for my truck. No rubbing, look good, and the power is still plenty without doing a gear swap. Thuis truck will never see rocks-- just the road, beach, cornfields for deer retrieval, and dirt/muddy roads to hunting spots.

 

Also has anyone seen any "Real world" improvements with a bed cover? Another practical item which I'd be interested if it actually helped. Does anyone know of any that can go on behind an ovefrrail toolbox or would that be something that would have to be removed?

 

you must have an auto bc I have a 4.7 4x4 quad cab with a 2.5" leveling kit with 35's and I am getting 15.5 interstate and if my dad is driving he can **** off the whole interstate and get 17 outa it. We got a 6spd manual trans, K&N, and flows

 

you can gain back a few mpgs if you add some supporting mods. efan, gears, tuner, cai, exhaust.

 

Unless its a camper shell, bed covers are ugly in my opinion... Anything other than street tires will make your milage go down in most cases. I run 35s with a leveling kit and I get about 11 or 12 mpg and its at least 18 or more on the highway cause of the MDS.

 

Actually I can hit the 15's when highway driving. The numbers I gave are real world "all around" rural. Some stop and go, some short bursts on highway, running late every now and then so perhaps running a little hard at times. It is an automatic. Another thing I've seen is when I bought this truck I was thinking along the lines of the older 302/351 fords in which case the 302 was the better choice unless towing because of economy and power. Since the only towing I'd ever do would be an 18' aluminum boat I went with the 4.7. It seems in the dodge case the bigger hemi would have been the way to go because the milage I see posted isn't any better with the 4.7's---perhaps it is on the manuals though. Again, no regrets as this is perfect for me. Just thinkin of the posibilities.
I could Always get a smaller vehicle to save gas for commuting but knowing me that "smaller" vehicle (think downsized cherokee initially) would turn into a mid-sized grand cherokee or perhaps a bronco/blazer. Then I'd lift it a bit, then bigger tires, then, then----we all know where that leads to. Plus the initial cost of the vehicle and my pick-up would still be my driver. So that idea just wouldn't fly. I know me too well.