The impossible: 04 Yukon XL Denali AWD

[Frank Lee]

Austin to Wichita Falls = 300 miles;
@ 80 mph = 3 hrs 45 min
@ 75 mph = 4 hrs 0 min
@ 65 mph = 4 hrs 37 min
@ 55 mph = 5 hrs 27 min
@ 45 mph = 6 hrs 40 min

See, no drama was needed; the math tells all.

I go 50-55 mph on 55, 60, 65, and 70 mph roads on 350 to 600 mile trips one way with some regularity and have never been so much as honked at, much less felt endangered. You have opted to surround yourself with a couple excess tons of steel and plastic and you are still scared?

What strikes me as funny when I do those trips is I'll see the SAME VEHICLES blow my doors off if not once, perhaps several times during my journey. How? Cuz they are constantly stopping for who knows what (probably GASOLINE ) while I'm not and we keep catching up with each other. See where I'm going with this? They are going 75 mph or more and I am plodding along at 55 mph and from Point A to Point B, they aren't beating me by much if at all due to all that stopping and screwing around. Makes me LOL cuz I've been getting over 40 mpg my last few tanks.

You have chosen a huge unaerodynamic brick; the sheer big size of the frontal area puts it at a disadvantage vs smaller vehicles. The inescapable physics tells us that large vehicles are going to be more affected by aerodynamic loads than small ones practically regardless of Cd. In other words, if you want better economy slowing down in large vehicles is even more effective than slowing down in smaller ones. When I drive my pickup (HAULING, not commuting or unladen) I especially see the need to keep it at 55 mph or less as you can practically watch the gas gauge drop at higher speeds.

But you want aeromods. I'd suggest looking at the mods list at the top of the page and maybe searching the forum for SUV aeromods. It'll probably go, grille block, air dam, rear skirts, wheel disks, mirror and antenna deletes, belly pans, and boat tails, not listed in order of effectiveness. The most effective one of all will be the boat tail and perhaps you can take a cue from the folding tails that are seen on semi trailers these days.

[2000mc]

i think the original post about 80mph was more an attempt to filter responses, looking to improve what the vehicle is capable of on the interstate.

[MTrenk]

SUV = Aero Brick
People still buy them

I think there's plenty that can be done to morph them into somewhat efficient machines! I see on these forums that a lot of focus is put on the frontal area, but I have see mods that reduce frontal area that completely ruin any gains by creating immense drag on the overall car due to the inefficient shape that is left behind. (i.e. the chopped cars with flat roofs and hard angles left over) With an SUV, I feel you are presented with an opportunity for success, rather than starting with a failure, because there are already so many things wrong.

[Flakbadger]

Originally Posted by Frank Lee

What strikes me as funny when I do those trips is I'll see the SAME VEHICLES blow my doors off if not once, perhaps several times during my journey. How? Cuz they are constantly stopping for who knows what (probably GASOLINE ) while I'm not and we keep catching up with each other. See where I'm going with this? They are going 75 mph or more and I am plodding along at 55 mph and from Point A to Point B, they aren't beating me by much if at all due to all that stopping and screwing around. Makes me LOL cuz I've been getting over 40 mpg my last few tanks.

Frank, you just succinctly described my driving experience on vacation this year!

[Frank Lee]

Originally Posted by MTrenk

SUV = Aero Brick
People still buy them

I think there's plenty that can be done to morph them into somewhat efficient machines! I see on these forums that a lot of focus is put on the frontal area, but I have see mods that reduce frontal area that completely ruin any gains by creating immense drag on the overall car due to the inefficient shape that is left behind. (i.e. the chopped cars with flat roofs and hard angles left over) With an SUV, I feel you are presented with an opportunity for success, rather than starting with a failure, because there are already so many things wrong.

I hope that somewhere along the line in your engineering studies you learn to look at the overall system and realize that moving a 200 lb payload down a stretch of smooth pavement with a V8 4x4 6000 lb piece of equipment is an abysmal efficiency FAIL.

[MTrenk]

Lol you're telling me. As a small child I always wondered why there would be one person in an 8 passenger vehicle shaped like box.
The only reason I'm optimistic about trying to develop strategies to make SUV's better is because I live in America, and SUV's aren't going anywhere soon, but maybe I can at least help a bit, and maybe one day I can just sell a bolt on aero kit and make some moolah.

[Frank Lee]

Unless gas prices double I think TruckNutz will sell better.

[MTrenk]

Not if I paint the Confederate flag on ones marketed toward Southerners. Man all my truck buddies from high school would eat that up.

[Cy-Gor]

Originally Posted by 2000mc

i think the original post about 80mph was more an attempt to filter responses, looking to improve what the vehicle is capable of on the interstate.

You are correct.

I will air up the tires and look at new bumpers to see what i can do with the front air dam.

I will see what i can find for materials to make a belly pan.

The truck has auto load leveling so i dont know if i want to mess with lowering it. the miles i put on it would make it hard to justify spending the money to lower it, though i could be wrong.

[mcrews]

actually, the 80mph comment also showed the state of mind of the poster. Along with his 'safty' comments.

Long ago, I learned "if you cant afford to properly repair and maintain it, don't buy the toy to start with"
This rule applies to:
expensive watches......THE CRYSTAL IS HOW MUCH??????????
expensive clothes.......DRY CLEANING IS $%000 for this shirt???????
Big XXX Trucks......IT ONLY GETS X MPG?????????
Expensive Sports Cars.........PLUGS ARE HOW MUCH?????????

anyone one who can buy a big 4x4 is old enough to realize that gas isn't going to get any cheaper....ever.

The majority of mpg inprovemnent is 'Adjusting the nut behind the wheel'.
I can drive the most effecient car on this forum and completly trash the mpg.
I can also drive that 4x4 and get 25% over factory epa.
There is absolutely NOTHING mechanical you can do that would give you a better improvement than slowing down and driving smarter

you come in telling us you 'have to drive 80......' and you've already set the tone of the conversation.