MPG drop with ARB bumper added?

ciberguenzza · **Posted:** Sun Nov 06, 2005 11:55 pm

Anybody has documented verified data (please no guessing) if adding the ARB bumper drops your mpg?
It seem to be very heavy

uvalax236 · **Posted:** Mon Nov 07, 2005 12:22 am

Yeah my mpg dropped. That is the cost of the added protection for the front end.

RespectMyLibertay · **Posted:** Mon Nov 07, 2005 1:30 am

I'm not trying to be a smart-ass, but adding ANYTHING (weight-wise) to your KJ will decrease mileage. How noticeable will it be? That depends on the weight, obviously. A 75 lb. steel bumper WILL drop it more than say...a hitch receiver. It would be interesting to compare the mileage drop a steel bumper would give with that of a roof rack. Weight does a number, but aerodynamics play a role as well. Adding a roof rack creates wind resistance...something the bumper probably doesn't.
Just thinking...

ciberguenzza · **Posted:** Mon Nov 07, 2005 7:21 am

My roof rack has a built in air deflector and it doesn't appear to drop the mpg or make noise either (another problem of roff racks) I'll post pictures of my rig soon.

However adding off road tires, and a 5 bikes rack did drop my mpg not to mention that my driving habits are different than "conservative" I'm getting 16 mpg in city.

I'm thinking on installing the bumper and was just trying to figure out how much it's going to cost in terms of efficiency.

The other thing is:
There are in the market devices that acording to their advertising they boost your mpg like Tornado, and high flow filters but I haven't tried them yet

JediJeeper · **Posted:** Mon Nov 07, 2005 11:55 am

After extensive studies, here is what I have determined:

Any and all add-ons you put on your Jeep will decrease mileage. There are some scientific reasons for this that I will try to detail.

First of all, everyone is aware and accepts the fact that your mileage will decrease when driving in the city and will be significantly better when on the open highway. The reason that most people give for that is that city driving is "stop and go" and uses more fuel. Well I say that the real reason is the looks. People exert a certain amount of resistance upon your vehicle by looking at it. Case in point: A really really hot car like a Lamborghini gets terrible city mileage... why? because so many people are looking at it.

This is why you get good mileage out on the open road, you have nobody looking at you. How many have said "Boy when I get out on the highway I really can fly!"? That is because there is no "look resistance" working against your vehicle.

There is another form of resistance that can be working on your vehicle as well, "check out resistance" is a real world issue, but the complexities of its properties are too strange to discuss in this short passage. What with its resistance factor being reversed into "get away assistance" if your vehicle reaches a certain degree of visual discomfort and so on.

So, as to your bumper... Yes, you will definitely see decreased mileage, everyone will be checking you out and putting some "look resistance" on your libby. I say, just get used to it, it will be ok.

-Adam

snowsport · **Joined:** Tue Oct 18, 2005 11:52 pm **Posts:** 1211

yeah, if you cover your head with tinfoil, that helps too... :lol:

the1jferg · **Posted:** Mon Nov 07, 2005 2:18 pm

"the real reason is the looks. People exert a certain amount of resistance upon your vehicle by looking at it. Case in point: A really really hot car like a Lamborghini gets terrible city mileage... why? because so many people are looking at it."

This is why my body hurts after walking around the mall or the beach. :lol:

A medical breakthrough!!

RkyMtnKJ · **Posted:** Mon Nov 07, 2005 5:26 pm

haha "look resistance" very nice, very scientific indeed

ciberguenzza · **Posted:** Mon Nov 07, 2005 5:45 pm

Jajajajaja, now I get It, when I was in college I could afford only a small compact, I was spending just a few buck every week on gas...

Now I have a full loaded Limited Liberty I'm spending a lot more in gas, and in fact as soon as I put the off road tires, and the roff rack it start looking nicer and I got more "look resistance"

FreedomKJ · **Posted:** Tue Nov 08, 2005 1:02 am

the1jferg wrote:

"the real reason is the looks. People exert a certain amount of resistance upon your vehicle by looking at it. Case in point: A really really hot car like a Lamborghini gets terrible city mileage... why? because so many people are looking at it."

This is why my body hurts after walking around the mall or the beach. :lol:

A medical breakthrough!!

Yeah, that must be it... :roll:

Wasatch15 · **Joined:** Wed Jul 13, 2005 7:52 am **Posts:** 242

I've had the ARB bumper on since 2002. I haven't upgraded tires yet (still have factory tires), but I do have the Frankenlift. I get 19.4 mpg in city, mostly driving to work (2/3 freeway, 1/3 surface streets). This data is from a Scangauge. Haven't done enough long distance freeway driving to see those results yet.

Guest · **Posted:** Wed Nov 09, 2005 12:32 am

jedi...that doesn't explain my old Isuzu Trooper's horrible gas mileage. of course...it got better mileage in the city than the highway. good ol' 4.78 gears.

nor does it explain my 88 thunderbird's incredible 22 city/31 hwy (and yes, it's a 5.0L), because that's a hot lookin car;)

CraigHart · **Joined:** Sun Feb 19, 2006 6:01 am **Posts:** 1

I have an O4 Cherokee Sport Auto (Middle East specification) with:
ARB front Bumper
Ramsey Winch
OME shock and spring lift kit
4 Light Bar
Renegade/Rubicon roof rack.
BFG 245/75/16 AT's
To answer your questions - yes, there is a distinctive drop in mpg.
I used to achieve, prior to any modifications, a consistent (highway and city mix) 230 miles on 12.7 gallons - 18.1mpg
Now - at best I get 186 to 192 miles on the same volume of fuel, and driving with a light tight foot - equaling 15mpg.

The addition of the bumper has made a distinct difference - more in terms of aerodynamic inefficiency than in weight - there was no real difference in mpg if I travelled alone, or if I travelled with another person in the vehicle, and the bumper + winch combo are equal to the weight of an additional passenger.
What worsened the situation was the fitting of the light bar, and the roof rack.

When I changed from the standard sized tyres to the BFG's, an already dismal mpg rate just deteriorated, partly also due to the change in gearing. The car is now difficult to keep at 70mph, and drops off speed quickly, also due to the bad aerodynamics of the bumper/winch and light bar/roofrack combinaton.

In combination, all the added items have had a drastic effect.

BUT - I would never swop my Jeep for anything.
It goes everywhere, climbs everything and tows anything. Especially LandCruisers.

Eddo · **Joined:** Thu Jul 07, 2005 7:01 pm **Posts:** 1214

Have to agree with Craig. Its more because of the change in aerodynamics than the weight. 75-100 is not really alot of weight. That is usually about half the weight of an extra passenger and I don't see people posting huge mpg drops because they had someone in the passenger seat.

Jeepjeepster · **Posted:** Sun Feb 19, 2006 10:27 am

Eddo wrote:

Have to agree with Craig. Its more because of the change in aerodynamics than the weight. 75-100 is not really alot of weight. That is usually about half the weight of an extra passenger and I don't see people posting huge mpg drops because they had someone in the passenger seat.

Thats what I was thinking eddo. I get the same mpg when I load up with 3-4 people.

Edwin · **Posted:** Sun Feb 19, 2006 11:56 am

the1jferg wrote:

"the real reason is the looks. People exert a certain amount of resistance upon your vehicle by looking at it. Case in point: A really really hot car like a Lamborghini gets terrible city mileage... why? because so many people are looking at it."

This is why my body hurts after walking around the mall or the beach. :lol:

A medical breakthrough!!

AdamIsAdam · **Posted:** Mon Feb 20, 2006 8:25 am

ciberguenzza wrote:

Anybody has documented verified data (please no guessing) if adding the ARB bumper drops your mpg?
It seem to be very heavy

Weight and aero, yup. My Renegade (with roof lights and the 2003 roof basket) always seemed to get lower MPG than anyone on this board!

Mostly city used to average about 12.5. Pure highway with only added weight of skids and gear, was about 17.5 at 75 MPH.

Lift, tires and some more skids, didn't effect my city MPG.

Just added the bumper this winter and my city MPG dropped about 1 MPG.

I just went skiing yesterday and clocked my highway MPG (with skis up top too) at exactly 16.1 at 73 MPH avg. I was happy with that after all the 11-12 MPG tanks I've done locally.

My best ever mileage was obtained by going a steady 40 mph (+- 5mph) without stopping as I drove through the Hamptons (don't want to speed through the Hamptons, trust me!). At this speed, you're easy on the gas, and not getting killed my aerodynamics. I think my light bar REALLY hurst over other KJ's.

Plus, my KJ weighs 4,850 without anyone or anything in it, on 1/2 a tank of gas!

But it LOOKS REALLY COOL, so maybe that's the problem.

Eddo · **Joined:** Thu Jul 07, 2005 7:01 pm **Posts:** 1214

AdamIsAdam wrote:

ciberguenzza wrote:

Anybody has documented verified data (please no guessing) if adding the ARB bumper drops your mpg?
It seem to be very heavy

Weight and aero, yup. My Renegade (with roof lights and the 2003 roof basket) always seemed to get lower MPG than anyone on this board!

Mostly city used to average about 12.5. Pure highway with only added weight of skids and gear, was about 17.5 at 75 MPH.

Lift, tires and some more skids, didn't effect my city MPG.

Just added the bumper this winter and my city MPG dropped about 1 MPG.

I just went skiing yesterday and clocked my highway MPG (with skis up top too) at exactly 16.1 at 73 MPH avg. I was happy with that after all the 11-12 MPG tanks I've done locally.

My best ever mileage was obtained by going a steady 40 mph (+- 5mph) without stopping as I drove through the Hamptons (don't want to speed through the Hamptons, trust me!). At this speed, you're easy on the gas, and not getting killed my aerodynamics. I think my light bar REALLY hurst over other KJ's.

Plus, my KJ weighs 4,850 without anyone or anything in it, on 1/2 a tank of gas!

But it LOOKS REALLY COOL, so maybe that's the problem.

4850 pounds Wow! My KJ only weight in at about 4250 w/ bars skids and tires and I though that was heavy.

AdamIsAdam · **Posted:** Mon Feb 20, 2006 8:59 am

Yup. 4,800 lbs +- 20lbs. I used a truck scale that rounds to the 20 lb mark.

Adding the ARB added 100lbs, again +- 20. Its shipping weight was 130, so I'm guessing it's closer to 120 mounted. This is without winch. I just couldn't justify that additional weight up front!

VTNomad · **Posted:** Mon Feb 20, 2006 9:40 pm

Simple formula: For every additional 200 pounds, subtract 5% gas mileage.

MPG drop with ARB bumper added?

Who is online