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Silly Question about OEM Roof rack crossbars

Drewlee77

NAXJA Forum User
Location
Abilene, TX
Do the factory crossbars cause much drag? I'm about to drive 1000 miles towing a trailer... so my gas mileage will be bad enough. I intend to remove them sooner or later, but I don't have a little torx head driver to get rid of it.

So my question is, would it be worth it to get rid of them before the trip or just wait until I can borrow something to get them off?

I can't imagine it making much of a difference, but even .5 mpg would more than pay for the price of a screwdriver to get rid of them.

Don't flame me too bad, I'm just being hopeful. I am dreading the gas bill from this trip. It's probably gonna cost $150-200 just in gas.
 
If I thought I could get .5 mpg better by removing my rack it would be the first thing to go. I don't think you'll notice much difference, but hey the less weight the better...
 
you may want to remove the antennae... lmao
but if you want to get technical...
yes it does create a very minimal drag, but probably less than the mirrors, flares, panel under the bumper, windsheild wipers...
while your at it you could duct tape the cracks between the fenders, hood...
also you may want to watch the gas pedal, it is the biggest fuel drinker.
my wife gets 24 mpg in her altima , but when i drive it i get 32+
the less you push on the pedals the cheaper the operating cost...

and be sure you have a smooth cover over the trailer...unless it is a box trailer, then your ok...
 
Well, I know when people put a spare tire up there, they lose 1-2mpg. Even if it was only .3mpg, I would think over 1000 it would be worth it to take them off. I was going to take mine off when I was only getting 11mpg, but thank god I fixed that problem. :)
 
Hmm... I like the duct tape idea....

I found someone to borrow the torx screwdriver from, so as soon as its light outside I'll remove them. I didn't imagine it would do anything, but sometimes little things can have a big impact - I was really just being hopeful.

It's a 5x8 uhaul trailer. I have the whole back loaded down and will have maybe 200 - 300 lbs in the trailer. What kind of mileage can I expect? I usaully get 18-19 on this trip (not many hills, Texas to Georgia) do you think I can get 14 or even 15 mpg or is that too optimistic? I've never towed anything with this truck. (4.0 Auto)
 
The roof rack is a minimal contributor to your overal drag coefficient. To minimize the cross bar drag, move them towards the rear. The impact to the air flow is seen closer to the front of the roof.

BTW, you really don't have much choice in what your MPG will be, with the exception of your right foot.

You might be able to get gains with new plugs, and if you create an adjustable MAP, if you have one to modify. I didn't look up what year you have.
 
ZmOz said:
Well, I know when people put a spare tire up there, they lose 1-2mpg. Even if it was only .3mpg, I would think over 1000 it would be worth it to take them off. I was going to take mine off when I was only getting 11mpg, but thank god I fixed that problem. :)

What was causing you to get only 11 mpg? I ask because that's about all i'm getting , and I haven't figured out why yet.
 
cougar101 said:
What was causing you to get only 11 mpg? I ask because that's about all i'm getting , and I haven't figured out why yet.

It needed a tune up. The entire ignition system had over 195,000 miles on it. :shocked:
 
The best thing you can do for an older XJ is to run a can of BG44K through the fuel. It cleans the injectors and carbon from the cylinders. I run a can every 10K miles. Most of the injector cleaners are a waste.
 
i wouldn't recommend running injector cleaner through an older engine 100,000+miles unless it has been used in a regular maint. program for a while... when you get this many miles on anything,that hasn't been cleaned before, the carbon and varnish buildup is so great that when the cleaner starts breaking it up, it can clog the tip of the injector.
the best bet is to pull the injectors and find a shop that will clean them, alot of heavy diesel shops can perform this...or try some of the injector cleaner that is in a pressurized can that hooks into the schrader valve on the rail...

injector cleaner is worth it but not if its too late...
 
xjhm, what do you mean by "unless it's been used on a reg. maint. program for a while"?

My car has just over 90000 miles & I have no way of knowing if it's ever had injectors cleaned in any way. I just put a 5 oz bottle of Lucas UCL in w/the last fill-up. Was that dangerous? Should I have the (just replaced) filter checked again or is the Lucas too mild to worry about?

How can one tell if his injectors need the kind of professional cleaning you suggest? How much does it cost?
 
There's no reason you can't use injector cleaner on an old engine. In fact the older it is the more you should do it. It's the oil you don't want to be messing with in high mileage, and not be using any of those oil flush solvents...
 
I can't believe you own a jeep and don't have a selection of torx bits, how do you replace a headlight ??? Screwdrive with hollow handle and torx, phillips, straight bit about $3 at most stores. Buy the bit, pull the cross bars and see what happens.
 
i believe the factory roof rack does affect mileage a little, you dont have to remove it, just move the front crossbar behind the b pillar, you should see you mileage go up a little, also try putting in some fuel injector cleaner in your tank, how old is your o2 sensor if its over 30-50k you should replace it.
i actaully did all this to my xj in about a months period, i decieded to see how far i could really go, i ended up going 350 miles till i ran out of gas(interesting thing though is i ran out at 347 and it still had 3 miles left in it, dont know if that was good for the engine having it run out of gas and stalling a little till it gets some more gas to the engine), most of that was city driving and about 200 miles were on a dead o2 sensor.I can't tell you what exactly worked best for my milage but the combination of these three things made one huge differnce.
o2 sensors may be a little expensive like 80 bucks or more, but if you know someone whos a mechnic they can probably get you one for whole sale, its like 20-25 bucks cheaper. (cant we buy everything at whole sale?? lol)
 
I have one torx bit... I haven't replaced the headlights yet... but I am about to. I don't have many tools... I've only had the Jeep for a couple years now (36k-65k miles) so nothing has really broken yet. All that to say, I have only needed one other Torx bit.

Anyway... I have completed my journey. 14-15 was a little optimistic. I got 12-14 depending on the terrain. But it seemed to get better as the trip went on. Can the computer compensate a little for the extra load or was it just an illusion?

EDIT: btw - I have 65k miles, so I checked my O2 sensors, but they both checked out fine.
 
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