Big suburban or small jeep
 

Hello all,

I've been thinking a lot for the past while since I've had my suburban on how to Eco-mod it. I bought it to use off-road, but I really want to take it to places that are hundreds of miles away without breaking the bank. Ha!

It seems to get pretty good MPG in town and on the shorter trips I take, but I haven't done any mpg tests with it unloaded. I think it does get at least 13 in town, and off-road mixed in.

It has a 40-Gallon tank and I am imagining how amazing it would be to get 20 mpg (straight pure freeway) and to be able to travel so far on a tank.

I often drive between Idaho, Utah, Nevada and California on the I-15 which is mostly flat with some mountains but it's overall net isn't much.

I know the mirrors are just humongous, I can fab up some much smaller ones. and the grill opening is huge. I have trouble keeping it up to temp, so maybe a grill block would help?

Also, there is a Huge mechanical fan that I'll be changing to electric with a thermostat.

I'm to the point where I have to make some changes to the vehicle to get it to go where I want off-road.

One thing, is that I need larger tires 35" and a lift to clear them, and probably a larger heavier rear axle. I know that will murder my MPG. But I was thinking of a way to use a winch strung under the vehicle with some snatch blocks to lower the vehicle for long drives. Do you think that lowering a truck would help mpg on the freeway?


Another option is just converting to a much lighter single cab truck body. Which is very easy and cheap, I have a ton of parts available for that. But I don't have a truck bed, so I would make a flat bed, But that's probably worse aero than a Burban unless I made the roll cage sort of kamm-back shaped and had a vinyl top made for the back. This is doable but I'm not sure if it's worth the work compared to a suburban body in the end.

The last option, and this might be the way I go either way, is to convert to a postal jeep. The oldest really small ones.I can swap everything over to one and be at about 3000 lbs roughly. Much better than 5000 I'm at. I could also keep the smaller 31" tires. I could still put smaller mirrors, and grill block, and do the lowering trick on the tiny jeep.

Do you think venting the fenders on a jeep would help?

I know that's long, but in short:

Much smaller, though slightly worse CD and smaller tires. Or larger and heavier but with better CD, though with bigger heavier tires

20mpg is the goal

A postal jeep. I would definitely utilize doors

http://ecomodder.com/forum/attachmen...9&d=1448136184

At least with a body-on-frame layout you have more flexibility to perform extreme aeromods, but the Suburban being longer allows you to enhance the aerodynamic a little further.

I think diesel is going to be your best shot at hitting 20MPG with an offroad-ready rig. A guy I work with has an lifted old Land Cruiser with a Cummins 4BT swap and went from 10MPG on a good day with the gas engine to 20MPG. A Cummins B3.3, 4BT, or VW TDI would work in a Jeep. In the Suburban you could maybe do the 4BT, but you'd be best off with a pickup truck diesel.

An uncle of mine used to get 42MPG out of a 4-door Suzuki Vitara with a 50hp 1.6IDI Volkswagen EA827 Diesel.

If you want to raise it and lower it, have you thought about airbag suspension?

I was under the truck a few weeks ago, and I noticed the transfer case hangs down pretty low, and the hitch was looking like it was in a horrible place for wind. Already took that off! Towing isn't efficient.

I'll probably design an aero-ish skid plate for that.

I think the truck will definitely benefit from tire air deflectors, and smaller mirrors. Both really cheap changes.

I'm going to make some new bumpers and probably get a winch regardless. If it can't be arranged to lower the vehicle some way,

I may just get air bags to provide clearance for the larger tires instead of a traditional fixed height lift. That's actually a great idea!
The truck will have on board air anyways so filling the bags won't be a problem.


My main goal is to extend the range of the truck in pure highway driving between far trails like Vegas, Moab, Colorado and California where it is hundreds of miles of highway between recreational areas.

I don't want to upgrade the engine, though a tune and headers-exhaust have given some people up to 2 mpg

On another note;
The 4BT would definitely be awesome for mileage! But my truck has a brand new engine right now lol.

And, I figured out that even the smallest jeeps are so bad on gas with a 4 cylinder that I totally threw out the jeep idea.

From everything I've heard regarding GM trucks (based on the 4.3 anyway, which is what my vans had), swapping your belt driven fan for an electric fan will probably be your best bang for the buck.

Actually, swapping out the Suburban with an AWD Astro or Safari might not be a bad idea. You'd have tons of interior room, with a more compact package. They aren't all that frugal, but I was routinely getting 23-24mpg out of a 200,000 mile, 2wd Safari well before I knew of hypermiling. The AWD vans can hold their own out in the wild too.

Haha! Dually noted :D

That would be good, I do have an electric fan just haven't installed it yet. I usually collect everything then do it at once cause I hate dragging projects out!

The safari with the v6 would definitely be better on gas, but I am going to need all the off-road capability I can get! The whoops at Barstow and the hot tubs in Moab are insane lol.

If I can get mine to be able to be about like this pic, (it's on bigger tires than I will be) but 2" lower on the highway and 1" higher in the dirt. I think that would be sufficient. I certainly don't want to be a redneck riding high on 44's and a 12 inch lift.

Is that a 6 by 6 in the picture?

It might murder you, if the chassis is under tension from the winch and it fails in transit. :eek:

Suburban, van or Jeep—do this:

http://ecomodder.com/forum/member-fr...pe-ii-boat.jpg

It could be good for a maybe 10% gas mileage increase.

Frank Lee -- That's pretty much perfect.

Is yours an automatic transmission or a manual? I had a 1991 K2500LD (6 lug) and I saw a 3+ MPG increase just from swapping from a 4L60 (similar to 700R4) to a NV4500. It is actually posted on here somewhere if you search. I had that truck up to 18MPG with no real serious mods, just the transmission swap and air dam replacement.

Keep the Suburban versus swapping to a truck body or a jeep, having the four real doors is nice. I would probably still be driving my aforementioned K2500 if it had four real doors.

On to off-road ability, you mention you need 35s and a lift. My biggest beef with 35s isn’t the 35” diameter; it is that you are usually only able to find them in fairly wide widths. In addition to additional aerodynamic drag, this also increases the weight of the tire. I would suggest looking at 34” tires, such as the BFG KO2 in 34x10.5R17 or the almost 34 255/85R16 tire size, such as the Cooper ST Maxx. (I have 255/85r16 on my Tacoma) These tires offer lots of ground clearance without excessive width or weight. To make up the difference between the 34’s and the 35’s shave your differentials. Shaving the differentials 1” while on 34s would be like having 36s. Look at military vehicles, their tires are tall and skinny, and some vehicles (HMMWW) are sitting on portal axles to give extra clearance at the differentials.

Also don’t go full on mud terrain on your tires, try to stick to ATs as they handle so much better on the roads and in fact some of their features (sipes) help you offroad more than you might think. Match your air pressures in your tires to the conditions.

Put air deflectors in front of your tires. Make them out of conveyor belt. Also make a conveyor belt air dam. You can drag it offroad and you won’t tear it up, but it will improve your fuel economy and improve your onroad handling. It doesn’t matter how great your truck would have been offroad if it ends up in a ditch on the way there.

I would suggest not putting a lift kit on your truck. All this does is raise your COG without offering you any real ground clearance at the axles. Instead, make skid plates to protect your underbody if you do drag it. These could also have aerodynamic benefits if you make them like a belly pan. Trim or roll your fenders if you have to to fit the tires. Remember lift kits alone don’t keep you from rubbing they just change how often you rub because unless you limit your up travel your tires can still cycle all the way up, and in fact on solid axles with one side in full droop and the other side in full compression taller springs can actually make you rub worse.

If you want lift, put air bags under the truck with valves you can access from the cab, but don’t inflate them when offroad (as this often limits your flexibility and would raise your COG) until you actually encounter a situation you really need the belly clearance (e.g. high centered on your belly or about to go through deep water).

Use close to stock height flexible springs to make sure the truck can flex and keep the tires in contact with the ground. Also get selectable lockers, electric or air operated. This would be a better offroading improvement than anything else listed.

You mentioned an axle swap. If you wanted more strength without going all the way to tons, I would look for a 14 Bolt semi-float 6 lug rear axle from early 90s heavy duty 1500s or light duty 2500s. This would be a definite improvement over a normal 10 or 12 bolt, let you keep your six lug wheels.

Run stock alloy wheels (to reduce weight) with the appropriate offset so you don’t stress your wheel bearings. Respect the hub or lug centric nature of your axle, have a machine shop turn the wheel hub seat if you want to run newer factory alloys with the smaller hub diameter. Have a matching full size spare, used is ok but a dry rotted 30" street tire is not.

Have enough tools to reasonably be able to fix an issue or get yourself unstuck, but don’t bring the kitchen sink. A powerful come along, jack with cribbing, straps, shackes, shovel, etcetera matter a lot more when you are stuck than a lift or bigger tires. Try to watch how much weight you add and where you add it. Wheel easy, don’t just slam and power through obstacles, drive carefully and with purpose. Go slow and enjoy the fact you are outside enjoying a technical challenge of driving through the terrain. Why rush through everything so you can go back home? Engage your brain at all times, as offroading is inherently dangerous, but focus on your surroundings is required. Wheel with another vehicle if at all possible, making sure they have the same goals for the trip as you.

If you haven’t already look at the expedition portal site. They have lots of examples of purpose built vehicles that have the modifications that matter to get them places, however the mall crawlers have started to infiltrate the site so you have to wade through that now to find the meat.

That was a good read.

Not only for off-road, but also for highway speeds, cinch that air dam down really tight.

http://ecomodder.com/forum/member-fr...6-bedammed.jpg

This example is inflexible, for a different environment; but look at the dozen screws (under pan washers) holding that on. Granted they are at higher speeds, but (seriously) it's a Beetle—how fast could it go? :)

They said they had to take it off to get the car on a trailer.

If the conveyor belting is held with L-brackets, make each one a little quarter-elliptic spring, stiff enough to resist the air at speed, but flexible to take abuse off-road.

Like others have said Diesel in the Suburban or get something smaller.

You can get a rust free Geo/Chevy Tracker (good on gas) for under $3,000 in Arizona.

Maybe shoot in between real big and real small and get a clean Isuzu VehiCross for about $6,000.

Both the Tracker and the VehiCross have been known to better Jeeps off road and have that rareness factor.

http://40.media.tumblr.com/521960dd5...t9po1_1280.jpg

Go with the Geo Tracker. Did you know both it and the Geo Metro were based on a car called Cultus? How cool is that?

Put a boat tail on it built to the spec that Redneck used on his Metro. :thumbup: Plus you get that laundelette body style. The only thing cooler than a Subaru Brat with the T-top. It would accept a pickup truck style aerolid.

How fast did it go?

how fast
 

I'm not sure about the Bugs,but a Karmann Ghia ran 150-mph.A first!

I think I was getting 24 mpg when mine was new back in 1990. I did mostly city driving and it was just under 20 mpg. After 20 years of ownership rust finally took her down,

Zebra Tracker by George Kachadoorian | Photobucket
http://i184.photobucket.com/albums/x...acker/ZT-3.jpg

I converted to an electric fan on my 4.3L in the S10 just over a month ago. I had it powered up to the big fuse for the ABS (which I don't use). This allowed the fan to run after the ignition was off, and when it got cold killed the battery. It is now wired to the A/C fuse (A/C non-working as well), others have it wired to the back-up lights or the wipers are also good junction points in the engine bay fuse box.

With electric fan, a little bit more get up and go, and the feeling I'm getting better mpg, but cannot confirm as the odometer stopped working last year. Trips which used to use close to a half tank, are now 1/3 of a tank trips. I think my old fan clutch was original on a close to 200,000 mile truck. I read they last 50,000 to a max of 100,000 miles, 75K on average.

FYI: Just as good, perhaps greater improvement by switching to Shell gas. I swear this nitrogen enriched V-Power thing is not hype, not marketing, it works. Better gas mileage, better acceleration, smoother running............I do not lie.

Both my S-10 and vintage Porsche 911 run on it now, I try not to use anything else.

Are you sure the Tracker was based on the Cultus?

Probably because it has zero ethanol content. I've never been able to see a difference on V-Power vs E0. Why would nitrogen, an inert gas, be a good thing to add to fuel anyway?

They share engine architecture and that's about it. Both were available with the same 1.6.

I never heard/read the zero ethanol claim before, will research it - good news for vintage vehicles if true.

The nitrogen or "Nitro" as Shell likes to brand it is said to lower the friction, hence the alleged HP and MPG gains.

These claims have been verified by labs, but since Shell was paying for the bills I have to hold out a small bit of skepticism myself despite my own personal experiences.

The reason I have minor reservations allocated for doubt is that my two vehicles for the past three years were running on Costco gas. As I understand it, they were exempt until last summer from adding detergents to the gas like oil companies are required to do, because they were technically a grocery store. The exemption has now run out, I made my transition to Shell at about the same time.

Three years of no detergents, then sudden cleaning may explain a few things. However, about every six weeks I try gas from somewhere other than Shell and immediately notice a performance drop, mostly on how smooth my S10 truck idles and how perky the Porsche is.

Below are some posts on the topic in another forum from earlier in the year, plus a video:

Gas Quality question - Pelican Parts Technical BBS
<iframe width="560" height="315" src="https://www.youtube.com/embed/4WPfLnVuQyM" frameborder="0" allowfullscreen></iframe>

Link to video, forgot embedding doesn't work here:
https://www.youtube.com/watch?v=4WPfLnVuQyM

Yep, the Tracker has a truck frame, not a uni-body.

Here is the frame crack in the rear well to prove it.

http://i184.photobucket.com/albums/x...r/IMGP7647.jpg
http://i184.photobucket.com/albums/x...r/IMGP7506.jpg

Not sure what was holding the front of the truck up either.

http://i184.photobucket.com/albums/x...r/IMGP7487.jpg
http://i184.photobucket.com/albums/x...r/IMGP7492.jpg
http://i184.photobucket.com/albums/x...r/IMGP7493.jpg

The road salt killed the electrical system though this engine bay hole:
http://i184.photobucket.com/albums/x...r/IMGP7498.jpg

Go to Arizona if you want one, they no longer exist in Michigan.

I suppose it may not apply to America, our fuels are different. Most of our fuels are E0, in fact it's hard to get E10 or E85.

I often hear reports about V-Power preforming better on US/Euro sites, and yet I've never really noticed anything at all really switching from E0 95 RON to V-Power 98 RON, even on cars where others swear there's a night and day difference.

I know if I go from E10 to V-Power yes, there's a difference.

The US test market was California starting about a year ago. It came to Michigan (the mid-west) only about late May, early June of this year.

At one time I posted a Detroit News or Detroit Free Press on-line article about it.

Shell has been using the Nitro and V-Power labels longer than that, these recent changes are game changers in my opinion.

https://en.wikipedia.org/wiki/Chevrolet_Tracker_%28Americas%29

I mis-remembered. I thought it said on the same assembly line as the Metro, not 'alongside' the Sidekick.

I am so sorry.

My 1990 tracker was purchased mid-June and made in Canada/CAMI factory.

Closest vehicle on the road to it today is the Juke, I say that for it's odd quirky but cute looks which some people reject. In 1989 the Tracker was considered radical looking when it came out, some people loved to hate it. Same with the Juke today.

In western Canada, Shell Nitro+ is the best. Costco fuel in Canada is garbage. I've tried Costco fuel in Washington and Montana and it was decent. Number 2 I would say is Esso 91 where they don't sell 94. Esso's 94 is ethanol boosted and they just blend at the pump with 87. I have yet to try the Chevron 94 ethanol free in British Columbia... maybe in February

I also have logs on gasbuddy by gas station to prove what I've found.

That needs an aero cover that turns it into an RV (with the motorcycle out of the way).