Go Back  Jeep Cherokee Forum > Technical Discussion > Jeep Builds
Ecomodding! Making my XJ overland rig drive on-highway just as well as off-road >

Ecomodding! Making my XJ overland rig drive on-highway just as well as off-road

Jeep Builds Make your own jeep build thread here, discuss and view jeeps here. All Jeep models are welcome here.

Ecomodding! Making my XJ overland rig drive on-highway just as well as off-road

Old 01-05-2018, 03:53 PM
  #16  
CF Veteran
 
Join Date: Oct 2015
Posts: 3,157
Likes: 0
Received 7 Likes on 6 Posts
Default

'00 with CA Emissions. 161K. Pretty new cat back exhaust (Walker parts), all four O2 sensors (also newer), cleaned the IAC and throttle body awhile back, fresher plugs (Cheapo Champions), Valvoline Synthetic in both diffs, 195 degree thermostat, brand new 4 hole injectors (also newer), 225 75 15 Cooper Discovery HT's (also newer), no lift, roof rack still on, all three skids, rear factory mud flaps, factory running boards, bug deflector up front, rain guards on windows, have cruise control, newer pads and rotors, newer complete back break job, put in a leather removable headrest interior with a power driver's seat (mention this because I figure it adds a little weight), 3.55 gearing, run 35 lbs in the tires (nitrogen), and probably a couple other things that I am forgetting.

I mention all this because while I did not really care what my Jeep gets for MPG ( it is what it is) I did want it to get the best it could and wanted you guys to know the specifics.

The 2 longer trips I have taken. Little over 20 MPG on one and almost 21 MPG on the other. I am OK with that. Frankly it is a little more then I thought it would be with a CA Emissions '00.

Last edited by Ralph77; 01-05-2018 at 03:59 PM.
Ralph77 is online now  
Old 01-06-2018, 09:22 AM
  #17  
Senior Member
 
Join Date: Feb 2011
Location: orrville ohio
Posts: 822
Likes: 0
Received 0 Likes on 0 Posts
Year: 1994
Model: Cherokee
Engine: 4.0
Default

Originally Posted by Bugout4x4 View Post
How are you getting 20 with an F150 pulling a trailer??? lol
i have the 2013 supercrew with a 5.0 it has canadian emissions and it will get 20+ mpg towing on the highway if i don't run the heck out of it
tinytrax78 is offline  
Old 01-06-2018, 09:41 AM
  #18  
CF Veteran
 
Bugout4x4's Avatar
 
Join Date: May 2015
Location: Arizona
Posts: 4,475
Likes: 0
Received 0 Likes on 0 Posts
Year: 97
Model: Cherokee
Engine: 4.0
Default

Originally Posted by tinytrax78 View Post
i have the 2013 supercrew with a 5.0 it has canadian emissions and it will get 20+ mpg towing on the highway if i don't run the heck out of it
Man, that is fantastic for a gas 5.0. The best I got out of my Dodge diesel pulling a trailer and being easy on it was 18. But I'm getting 22 with a 1 ton dually when unloaded.
Bugout4x4 is offline  
Old 01-07-2018, 11:25 AM
  #19  
CF Veteran
 
Join Date: Oct 2017
Posts: 1,382
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

I certainly did not buy a Diesel thinking I would get good MPG!! LOL.....I'm lucky if I can get 18 MPG unloaded with my 2005 F350 Diesel DRW.
XJIrish4x4 is offline  
Old 01-07-2018, 11:34 AM
  #20  
CF Veteran
 
Bugout4x4's Avatar
 
Join Date: May 2015
Location: Arizona
Posts: 4,475
Likes: 0
Received 0 Likes on 0 Posts
Year: 97
Model: Cherokee
Engine: 4.0
Default

Originally Posted by XJIrish4x4 View Post
I certainly did not buy a Diesel thinking I would get good MPG!! LOL.....I'm lucky if I can get 18 MPG unloaded with my 2005 F350 Diesel DRW.
Lol... I was really surprised when I got it. I think the difference would be mine is the turbo Cummins 12 valve and it's only 6 cylinders. They actually do pretty good on fuel until you start building them up.
Bugout4x4 is offline  
Old 01-07-2018, 12:19 PM
  #21  
Seasoned Member
Thread Starter
 
mannydantyla's Avatar
 
Join Date: Dec 2016
Location: Lawrence ****ing Kansas
Posts: 388
Likes: 0
Received 0 Likes on 0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0
Default

I assumed it was the diesel too. Well I'll be damned!

---------------

I bought a welder! I just ordered it from amazon, it's an inverter DC stick welder and it was only $170! This is the one I got: http://amzn.to/2CA4wNH Since it's DC it can even weld aluminum (with aluminum welding rods) and be converted to a TIG welder with a kit.

So... get ready to see some fabrications!

First up: aerodynamically friendly roof rack. Like an Xterra's. Ok, so no roof rack is more aerodynamic than any roof rack at all but this is a Jeep god dammit and it's my adventuremobile and I may need to strap something to the roof one day.

Similar to this but without the side-to-side tubes



After that I want to build a front skid plate and possibly a rear bumper.

The problem with the rear bumper, aerodynamically speaking, is these bumper end caps sticking out and scooping air:



With those out of the way I can cut and fold the rear lower fenders and recude the amount of the sheet metal that is blocking airflow behind the rear wheels.

So if I could build something like this, that would be ideal:



I'm looking for anything that is advantageous to both off-road performance and on-road performance! Skid plates and a smaller rear bumper fit this bill perfectly.

hmmm looky what I found https://www.dirtboundoffroad.com/diy...erokee-xj.html

Last edited by mannydantyla; 01-09-2018 at 03:40 PM.
mannydantyla is offline  
Old 01-09-2018, 04:43 PM
  #22  
CF Veteran
 
Tbone289's Avatar
 
Join Date: Oct 2011
Location: SEMO
Posts: 1,394
Likes: 0
Received 0 Likes on 0 Posts
Year: 2000
Model: Cherokee(XJ)
Engine: 4.0 L6
Default

Originally Posted by mannydantyla View Post
First up: aerodynamically friendly roof rack. Like an Xterra's. Ok, so no roof rack is more aerodynamic than any roof rack at all but this is a Jeep god dammit and it's my adventuremobile and I may need to strap something to the roof one day
If you're doing it for just for possibly using it one day, why not do something removable? I use a Yakima with gutter mounts on mine to put canoes and kayaks on (lots of beautiful rivers around here), and it probably takes me 3 minutes to remove or install. I very rarely drive around with it unloaded--I just take it off when not loaded and store it ready to go in the rafters of the garage.
Tbone289 is offline  
Old 01-10-2018, 11:01 AM
  #23  
Seasoned Member
Thread Starter
 
mannydantyla's Avatar
 
Join Date: Dec 2016
Location: Lawrence ****ing Kansas
Posts: 388
Likes: 0
Received 0 Likes on 0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0
Default

I'm skeptical of my assumption that removing the bodywork behind the rear wheel (cut and fold) will help reduce the drag, it might even make it worse. More research is needed, but so far my understanding is that you want "fairings" in front and behind the wheel openings to reduce the "flow detachment" (negative pressure zone that causes turbulence) that occurs behind an obstruction like a mirror, etc.

Maybe I should look into something called a diffuser. It could go under the gas tank (gas tank skid plate diffuser!!) and link to the rear bumper. Might resemble the geometry of a fastback mustang or something.



I'm trying to do some research but I'm pretty much in the dark when it comes to lifted offroad vehicles because all the wind tunnel data is made with sports cars and economy vehicles.

And the general wisdom to making these cars more aerodynamic: the lower they are to the ground the better. Well that's not going to fly with a jeep rock crawler. By lifting it, the main problem is that it's exposing more of the tires to frontal pressure by lifting the wheel well over them.

Imagine this being the tires:



Originally Posted by Tbone289 View Post
If you're doing it for just for possibly using it one day, why not do something removable? I use a Yakima with gutter mounts on mine to put canoes and kayaks on (lots of beautiful rivers around here), and it probably takes me 3 minutes to remove or install. I very rarely drive around with it unloaded--I just take it off when not loaded and store it ready to go in the rafters of the garage.
So I'm actually going to do something similar, you'll see. Some will say it's pointless, because it kinda is, but it will look cooler than stock. Basically, I'm going to build the rails that go the length of the roof, and the rails that go across the roof will be removable and will not be attached normally. I say it's kinda pointless because this is just like the stock roof rails lol but I already bought the metal and made all the cuts. Just need to weld it together and paint it.

Last edited by mannydantyla; 01-10-2018 at 11:20 AM.
mannydantyla is offline  
Old 01-10-2018, 11:16 AM
  #24  
Seasoned Member
 
Joshua White's Avatar
 
Join Date: Oct 2015
Location: Clearwater FL
Posts: 381
Likes: 0
Received 0 Likes on 0 Posts
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

I would imagine it's not tires that are your biggest factor, it's all of the exposed components hanging down. Axles, steering, springs, arms, tires...then all of the other things that contribute to hangups hanging down like they normally would (tcase, cross-members, driveshafts, mounts, sliders)

My understanding from the Ecomodding I've researched is you want to start with as flat a bottom as you can get and then start from there (when it comes to the underside of the rig)
Joshua White is offline  
Old 01-10-2018, 12:29 PM
  #25  
CF Veteran
 
Bugout4x4's Avatar
 
Join Date: May 2015
Location: Arizona
Posts: 4,475
Likes: 0
Received 0 Likes on 0 Posts
Year: 97
Model: Cherokee
Engine: 4.0
Default

Originally Posted by mannydantyla View Post
I'm skeptical of my assumption that removing the bodywork behind the rear wheel (cut and fold) will help reduce the drag, it might even make it worse. More research is needed, but so far my understanding is that you want "fairings" in front and behind the wheel openings to reduce the "flow detachment" (negative pressure zone that causes turbulence) that occurs behind an obstruction like a mirror, etc.
Yep... Like someone else said around here, it has the aerodynamics of a brick. And like I mentioned earlier, all you can really do to help is scoop and deflect air back into the rear vacuum area to reduce the drag of this brick.
Bugout4x4 is offline  
Old 01-10-2018, 02:47 PM
  #26  
Seasoned Member
Thread Starter
 
mannydantyla's Avatar
 
Join Date: Dec 2016
Location: Lawrence ****ing Kansas
Posts: 388
Likes: 0
Received 0 Likes on 0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0
Default

Originally Posted by Joshua White View Post
My understanding from the Ecomodding I've researched is you want to start with as flat a bottom as you can get and then start from there (when it comes to the underside of the rig)
Yup, that's what I'm doing! Hell, that might be all I can really do as I'm certainly not going to sacrifice off-road durability or anything

Originally Posted by Bugout4x4 View Post
Yep... Like someone else said around here, it has the aerodynamics of a brick. And like I mentioned earlier, all you can really do to help is scoop and deflect air back into the rear vacuum area to reduce the drag of this brick.
good idea
mannydantyla is offline  
Old 01-10-2018, 03:26 PM
  #27  
Seasoned Member
 
Joshua White's Avatar
 
Join Date: Oct 2015
Location: Clearwater FL
Posts: 381
Likes: 0
Received 0 Likes on 0 Posts
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by mannydantyla View Post
Yup, that's what I'm doing! Hell, that might be all I can really do as I'm certainly not going to sacrifice off-road durability or anything
The benefit of doing that is you could just kill two birds with one stone. Belly skid = flat bottom
Joshua White is offline  
Old 01-10-2018, 05:57 PM
  #28  
Seasoned Member
Thread Starter
 
mannydantyla's Avatar
 
Join Date: Dec 2016
Location: Lawrence ****ing Kansas
Posts: 388
Likes: 0
Received 0 Likes on 0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0
Default

I got my first city MPG reading, but it's only half a tank of data:

12.7 MPG

Together with highay (16.7) make it a combined 14.4 mpg.

Not very good. Worse than I expected, tbh. Maybe I should just get a TDI motor and auto tranny... Actually, maybe I shouldn't be surprised. It's almost the EPA's city mpg of 13 for these jeeps

Originally Posted by Joshua White View Post
The benefit of doing that is you could just kill two birds with one stone. Belly skid = flat bottom
That's my goal - find things that are helpful to both offroading and aerodynamics. You'd be surprised how many others like it I've found: fender flare delete, hood vents, rear lower fender cut and fold (I'm still figuring this one out), side mirrors delete, a gas tank skid plate that doubles as a "diffuser", etc.

Things that stick up/out/down and hit trees and branches and rocks on the trail will also hit air/wind on the highway!

Last edited by mannydantyla; 01-11-2018 at 09:44 AM.
mannydantyla is offline  
Old 01-17-2018, 03:06 PM
  #29  
Seasoned Member
Thread Starter
 
mannydantyla's Avatar
 
Join Date: Dec 2016
Location: Lawrence ****ing Kansas
Posts: 388
Likes: 0
Received 0 Likes on 0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0
Default

The roof rack is off and I'm in the middle of fabricating a new one (with my new welder! turns out that welding galvanized pipe is a terrible beginner's project, lol) that will feature removable cross bars.

...

New idea: indentation of the fender right behind the front wheel, and air curtains (not to be confused with skirts!) for the front wheels! The indentation is easy; the air skirts will have to be fabricated along with a new front bumper (maybe one day far into the future). Ecomodding is an amazon thing. So many activities! So many enhancements to be made! Can you tell I'm excited!



(source: http://ecomodder.com/forum/showthrea...s10-35043.html )

An extreme version of the fender indentation:


And here's how air skirts work to reduce turbolant air around the front tires: http://ecomodder.com/forum/showthrea...tml#post496612

I feel like a BIG improvement that can be made with my jeep, with the huge openings for the tires, is at the front wheels. BMW agrees, they say on their official blog that 30% of the drag is at the wheels. http://www.bmwblog.com/2014/02/26/bm...n-engineering/ (the article is really really good btw)



Also, notice the articulation of both front and rear wheels, I need every inch of the wheel well when offroading:




Lastly, here's a nice visualization of my jeep's aero:



Note the blue pressure zone under the rudder.

(lol ok ok I stoll that joke from here: https://robrobinette.com/S2000Aerodynamics.htm )
mannydantyla is offline  
Old 01-17-2018, 05:20 PM
  #30  
Seasoned Member
 
Joshua White's Avatar
 
Join Date: Oct 2015
Location: Clearwater FL
Posts: 381
Likes: 0
Received 0 Likes on 0 Posts
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

Please don't weld galvanized pipe...you could die
Joshua White is offline  

Thread Tools
Search this Thread
Quick Reply: Ecomodding! Making my XJ overland rig drive on-highway just as well as off-road


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: