Losing weight for better MPG
05-10-2018, 08:28 AM
#1
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Losing weight for better MPG
I have heard if you lose enough weight off of a 99 Jeep Cherokee XJ you can get better gas mileage? If this is true I am looking at doing a complete fiberglass dog house would this make any difference?
05-10-2018, 08:36 AM
#2
Seasoned Member
I mean... technically yes, but at what cost? Are you building a long distance racer? If youre able to cut 500lbs, you may see .5-1mpg greater. You can better MPG increases from proper tire size and inflation. And what do you mean "dog house"? The only automotive dog houses im aware of are the engine compartment access from inside the cab of older vans, when there was no room under the 12" long hood. If you mean the entire body, why? and its a unibody. The body helps to hold the frame together. If you remove welded body panels, you need to replace with structure supports, like a cage. **haha.... dog house ... cage...**
05-10-2018, 08:42 AM
#3
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Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 L6
Losing weight will have a positive impact on stop-and-go MPG, but won't have much impact on highway (steady-state) MPG. The biggest factor for steady-state MPG would be aerodynamics, especially at speeds over 45 miles per hour.
05-10-2018, 11:50 AM
#4
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I mean... technically yes, but at what cost? Are you building a long distance racer? If youre able to cut 500lbs, you may see .5-1mpg greater. You can better MPG increases from proper tire size and inflation. And what do you mean "dog house"? The only automotive dog houses im aware of are the engine compartment access from inside the cab of older vans, when there was no room under the 12" long hood. If you mean the entire body, why? and its a unibody. The body helps to hold the frame together. If you remove welded body panels, you need to replace with structure supports, like a cage. **haha.... dog house ... cage...**
05-10-2018, 08:30 PM
#7
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Year: 1998
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Honestly for the work and time involved in all of that, you aren't going to see any difference. I put about 60lbs of tools, some lumber chunks, 2 bottle jacks, a chain and my BMX bike in mine after consistently getting 14mpg. Adding roughly 100 pounds of gear to my XJ it made no difference in my fuel economy
Losing enough weight to actually benefit in the fuel economy department is going to be quite a task
Losing enough weight to actually benefit in the fuel economy department is going to be quite a task
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05-10-2018, 08:35 PM
#8
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In town
In town 14 mpg would like to get 3 to 5 mpg more out of the old girl, Freeway I get about 23 mpg and figure can keep that or get 1 to 2 mpg more after a aftermarket cruise control to keep it at 65 or at least enjoy driving longer
05-10-2018, 08:43 PM
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For what it is, the XJs are fairly light. Weigh the hood and fenders, I'd guess no more than 75 lbs for all three pieces. Fiberglass would come in around 20 lbs. That 55 lbs isn't going to make much difference.
Also, you have to look at return on investment. Those glass panels are going to cost at least $300. Assuming you drive 15000 miles a year, at 14 MPG you consume 1071.42 gallons of fuel in a year. 1 MPG increase would save you 71.42 gallons of fuel a year. At $2.50 a gallon, that is $178.55 saved in a year. Not a bad savings, but unfortunately I don't believe the glass front end will net 1 MPG.
I just don't see 500 lbs of dead weight in an XJ to pull. I'm hard pressed to pull 500 lbs out of my 79 Camaro, back when they built cars solid. I put a glass hood on that and shaved damn near 100 lbs.
Also, you have to look at return on investment. Those glass panels are going to cost at least $300. Assuming you drive 15000 miles a year, at 14 MPG you consume 1071.42 gallons of fuel in a year. 1 MPG increase would save you 71.42 gallons of fuel a year. At $2.50 a gallon, that is $178.55 saved in a year. Not a bad savings, but unfortunately I don't believe the glass front end will net 1 MPG.
I just don't see 500 lbs of dead weight in an XJ to pull. I'm hard pressed to pull 500 lbs out of my 79 Camaro, back when they built cars solid. I put a glass hood on that and shaved damn near 100 lbs.
Last edited by bad_idea; 05-10-2018 at 08:50 PM.
05-10-2018, 10:17 PM
#10
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70 lb hood, 50 lb Back seat, 14 lb finder panels X2 and was told to put aluminum rims and factory size tires on. But I'm seeing this its probably not a good Adventure but I'm so glad I joined this post it is helping me find answers to questions that I was having trouble with. But I'm still keeping the 99 Cherokee I'm on disability and it makes it so much easier to get in and out of with my back, Way better than my 2005 Chrysler Sebring. Plus my dad has taken great care of it mechanically
05-10-2018, 10:19 PM
#11
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For what it is, the XJs are fairly light. Weigh the hood and fenders, I'd guess no more than 75 lbs for all three pieces. Fiberglass would come in around 20 lbs. That 55 lbs isn't going to make much difference.
Also, you have to look at return on investment. Those glass panels are going to cost at least $300. Assuming you drive 15000 miles a year, at 14 MPG you consume 1071.42 gallons of fuel in a year. 1 MPG increase would save you 71.42 gallons of fuel a year. At $2.50 a gallon, that is $178.55 saved in a year. Not a bad savings, but unfortunately I don't believe the glass front end will net 1 MPG.
I just don't see 500 lbs of dead weight in an XJ to pull. I'm hard pressed to pull 500 lbs out of my 79 Camaro, back when they built cars solid. I put a glass hood on that and shaved damn near 100 lbs.
Also, you have to look at return on investment. Those glass panels are going to cost at least $300. Assuming you drive 15000 miles a year, at 14 MPG you consume 1071.42 gallons of fuel in a year. 1 MPG increase would save you 71.42 gallons of fuel a year. At $2.50 a gallon, that is $178.55 saved in a year. Not a bad savings, but unfortunately I don't believe the glass front end will net 1 MPG.
I just don't see 500 lbs of dead weight in an XJ to pull. I'm hard pressed to pull 500 lbs out of my 79 Camaro, back when they built cars solid. I put a glass hood on that and shaved damn near 100 lbs.
05-10-2018, 11:18 PM
#12
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Model: Cherokee (XJ)
70 lb hood, 50 lb Back seat, 14 lb finder panels X2 and was told to put aluminum rims and factory size tires on. But I'm seeing this its probably not a good Adventure but I'm so glad I joined this post it is helping me find answers to questions that I was having trouble with. But I'm still keeping the 99 Cherokee I'm on disability and it makes it so much easier to get in and out of with my back, Way better than my 2005 Chrysler Sebring. Plus my dad has taken great care of it mechanically
05-11-2018, 02:53 AM
#14
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05-11-2018, 07:54 AM
#15
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Well how far do you want to go? I retired mine from DD status to toy status. There is no carpet, no back seat, no interior panels, no headliner, cut the dash in half and there are no dash covers, took out the center console, and removed the A/C and airbag systems.
Total weight removed = 275 lbs.
I'm about to remove the doors too which are from 60 - 80 lbs a piece depending on who you ask. If you want to throw all safety, comfort, and driveability out the window sure 1 MPG increase may be possible.
Total weight removed = 275 lbs.
I'm about to remove the doors too which are from 60 - 80 lbs a piece depending on who you ask. If you want to throw all safety, comfort, and driveability out the window sure 1 MPG increase may be possible.