Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-09-2008, 12:52 PM   #1 (permalink)
EcoModding Lurker
 
Join Date: Jul 2008
Location: Missouri
Posts: 28

Boy Blue - '93 Jeep Cherokee Country
90 day: 18.55 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
'93 Jeep Cherokee - Weekend report

This past holiday weekend I did some tweaking to try to improve my fuel economy on the road. Given I drive a '93 Jeep Cherokee with 15 mpg combined, I appreciate any increase in efficiency. Here is what I did and its effects:

- I checked the tire pressures all around, and found my tires to be between 32 to 37 psi. I bumped this up to 40-41 psi (tires max are 44psi)
- I moved the crossbars of the roof rack to the very back of the vehicle, hoping it to act as a spoiler of sorts. Since the Jeep has a vertical backend, I hoped that placing both bars back might help drive air into the vacuum behind the Jeep and create less drag
- I kept rpms < 2000 the whole time
- I used "engine-on neutral coasting"

I'll explain the neutral coasting briefly. I read someone else's post recently about trying to coast on downhills, towards red lights, or off exit ramps by shifting their automatic into neutral. I tried this out a bit and am noticing that the Jeep feels as if there is less rolling drag. My suspicions were that disengaging the drivetrain while coasting creates less rolling friction within the transmission, so you can roll further and with less rapid loss of speed.

I filled up last night after having also done a few days of city driving. Total miles driven was just under 300 on 15.5 gallons. My calculated mpg?

....19 mpg. +4 over combined EPA rating. And I was using the AC.

__________________
Jeep: 25+ mpg or bust
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 07-09-2008, 01:24 PM   #2 (permalink)
Ex-lurker
 
i_am_socket's Avatar
 
Join Date: Apr 2008
Location: Jersey
Posts: 571

Skeeter - '05 Toyota Corolla LE
90 day: 35.55 mpg (US)
Thanks: 2
Thanked 8 Times in 6 Posts
w00t! Good job.

Yes, by coasting in neutral in an automatic you save the resistance of the engine on the transmission. I can coast ~4 x further in N than D.
__________________
  Reply With Quote
Old 07-09-2008, 01:33 PM   #3 (permalink)
Dartmouth 2010
 
SVOboy's Avatar
 
Join Date: Nov 2007
Location: Hanover, NH
Posts: 6,447

Vegan Powa! - '91 Honda CRX DX
Team Honda
90 day: 66.52 mpg (US)
Thanks: 92
Thanked 122 Times in 90 Posts
Send a message via AIM to SVOboy Send a message via MSN to SVOboy Send a message via Yahoo to SVOboy
Nice job,
  Reply With Quote
Old 07-09-2008, 02:15 PM   #4 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,527

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 54.46 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car Mirage - '14 Mitsubishi Mirage ES (base)
90 day: 62.14 mpg (US)
Thanks: 4,078
Thanked 6,976 Times in 3,612 Posts
Nice work. That's a hefty increase.

Re. the roof racks: unfortunately, the only thing you can do with the cross bars to improve aerodynamics is to remove them. Moving them to the rear won't help the overall situation.
__________________
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 07-09-2008, 02:23 PM   #5 (permalink)
Master EcoModder
 
FastPlastic's Avatar
 
Join Date: May 2008
Location: Ames, IA
Posts: 419

98 Cherokee - '98 Jeep Cherokee
90 day: 17.18 mpg (US)

ZX7R Ninja - '99 Kawasaki ZX7R Ninja
90 day: 42.45 mpg (US)
Thanks: 4
Thanked 13 Times in 12 Posts
Great Start What's next a little aero modding?

I did a grill block on mine so far. Been trying to find time to make an under body tray.

Seems like the number of cherokee's on this forum is growing
__________________

Adjusted for my driving habits. 80%city/20%Highway.
20mpg city/30mpg highway or bust! Check out my mods so far
  Reply With Quote
Old 07-09-2008, 02:42 PM   #6 (permalink)
Red
Master EcoModder
 
Red's Avatar
 
Join Date: Mar 2008
Location: SF Bay Area
Posts: 713
Thanks: 1
Thanked 9 Times in 9 Posts
Kewl
  Reply With Quote
Old 07-09-2008, 04:00 PM   #7 (permalink)
Master EcoModder
 
texanidiot25's Avatar
 
Join Date: Jul 2008
Location: Cypress, TX
Posts: 331

Formula - '96 Firebird Formula/Trans-Am
90 day: 19.31 mpg (US)
Thanks: 8
Thanked 31 Times in 18 Posts
I've been doing the Nuetral coasting as well the past 2 days. Certainly does help a good bit it seems.
__________________


Lets see how far it can go

"All I know about music is that not many people ever really hear it. [...] But the man who creates the music is hearing something else, is dealing with the roar rising from the void and imposing order on it as it hits the air. What is evoked in him, then, is of another order, more terrible because it has no words, and triumphant, too, for the same reason. And his triumph, when he triumphs, is ours." -Sonny's Blues
  Reply With Quote
Old 07-09-2008, 08:14 PM   #8 (permalink)
EcoModding Lurker
 
Join Date: Jul 2008
Location: Missouri
Posts: 28

Boy Blue - '93 Jeep Cherokee Country
90 day: 18.55 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by FastPlastic View Post
Great Start What's next a little aero modding?

I did a grill block on mine so far. Been trying to find time to make an under body tray.

Seems like the number of cherokee's on this forum is growing
It may have been posts by you or by DPOV that I found on Google that lead me to ecomodder.com in the first place. I had recently seen the hypermiling article in USA Today, and started doing my own personal research (I'm a medical student, and an uber nerd. I try to validate anything I see in the news with my own researching ).

My next steps are likely to do a partial grill block (your threads are helpful on this!). I want to get my bumper replaced; it's slightly bent, and the right bumper flare is broken off. I'm sure I can improve my aero by fixing that. I am really interested in a front air dam to push air lower and around the Jeep, and I think I've got a great idea for how to do it without it having to be permanent (and can go on/off in under 5 minutes!). I'll share that soon....

Re roofracks: I do want them off. They are tricky just looking at them, though I didn't try too hard to find a tool to fit the star-tip bolts hiding inside the longitudinal rack mounts. I have just looked a little at different kammback aeromods on the forums, and wondered how a plexi partial kammback might be set to mount on those racks. If you built it just right, it might be retractable back over the roof when not deployed on long highway trips. Input on this one highly welcome.
__________________
Jeep: 25+ mpg or bust
  Reply With Quote
Old 07-09-2008, 09:25 PM   #9 (permalink)
Master EcoModder
 
Join Date: Jul 2008
Location: NY state
Posts: 501

XJ Cherokee - '00 Jeep Cherokee Sport
90 day: 12.96 mpg (US)

FoFO - '11 Ford Focus SE
90 day: 36.78 mpg (US)
Thanks: 1
Thanked 51 Times in 38 Posts
Wouldn't that cause excess wear on the auto transmission?
  Reply With Quote
Old 07-09-2008, 10:31 PM   #10 (permalink)
Master EcoModder
 
FastPlastic's Avatar
 
Join Date: May 2008
Location: Ames, IA
Posts: 419

98 Cherokee - '98 Jeep Cherokee
90 day: 17.18 mpg (US)

ZX7R Ninja - '99 Kawasaki ZX7R Ninja
90 day: 42.45 mpg (US)
Thanks: 4
Thanked 13 Times in 12 Posts
Quote:
Originally Posted by DoctorP82 View Post
It may have been posts by you or by DPOV that I found on Google that lead me to ecomodder.com in the first place. I had recently seen the hypermiling article in USA Today, and started doing my own personal research (I'm a medical student, and an uber nerd. I try to validate anything I see in the news with my own researching ).

My next steps are likely to do a partial grill block (your threads are helpful on this!). I want to get my bumper replaced; it's slightly bent, and the right bumper flare is broken off. I'm sure I can improve my aero by fixing that. I am really interested in a front air dam to push air lower and around the Jeep, and I think I've got a great idea for how to do it without it having to be permanent (and can go on/off in under 5 minutes!). I'll share that soon....

Re roofracks: I do want them off. They are tricky just looking at them, though I didn't try too hard to find a tool to fit the star-tip bolts hiding inside the longitudinal rack mounts. I have just looked a little at different kammback aeromods on the forums, and wondered how a plexi partial kammback might be set to mount on those racks. If you built it just right, it might be retractable back over the roof when not deployed on long highway trips. Input on this one highly welcome.
Glad to hear my posts might be helping spread the word out to other Jeep owners.

The grill block is pretty easy to do with the 7 slot jeep grills. Making separate panels for each slot is a little harder but I found over the summer it was getting a little warmer then I wanted, so the setup made it quick and easy to improve the cooling. I figure over the winter I may fill all 7.

I'm very interested in seeing what you have in mind for the front air dam. I had been pondering making one for mine. I was thinking about setting it up to flip down. Make it an L shape so it's always about 1in tall, but for highway trips it could be flipped down making it 3-4in tall.

The roof racks are easy. I had a $20 tool kit from Wal-mart that included the star key for the screw driver. The sets nothin fancy but seems to have a lot of what I need for the Jeep. I went ahead and just took the cross bars off. I kinda like the looks of the side channels, Plus I didn't figure the side channels would really make that big of a difference anyway.

I've also been wondering about a small kammback. I've been noticing on a lot of newer suvs these small kammback looking panels on the back. Just wondering if that would be something that could be set up on the cherokee? I liked the looks of all the ones I've seen. Ford edge/Rav4 etc.

Attached Thumbnails
Click image for larger version

Name:	2008_Ford_Edge_SEL.jpg
Views:	432
Size:	33.0 KB
ID:	1118  
__________________

Adjusted for my driving habits. 80%city/20%Highway.
20mpg city/30mpg highway or bust! Check out my mods so far
  Reply With Quote
Reply  Post New Thread




Similar Threads
Thread Thread Starter Forum Replies Last Post
Report: Improving the Aero Characteristics of a Dodge Ram Pickup Truck MetroMPG Aerodynamics 36 08-06-2013 12:25 AM
Jeep Cherokee Aeromods FastPlastic Aerodynamics 251 07-29-2012 08:52 AM
Glides like a Brick Wall (Jeep Cherokee, GMC Pick-up) DonEaston Aerodynamics 22 10-26-2008 05:17 PM
Off-Road Test: '08 Jeep Grand Cherokee (Rally Race) RH77 The Lounge 4 02-25-2008 04:59 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com