I inherited my son's 2000 XJ, 82,000 miles, mostly stock, with Flowmaster Super 40, AEM cold air intake, and Michelin LTX 235/70 tires. I have a 100 mile daily commute, half on 55 mph country roads, half on 70 mph interstates. I get a consistent 20 mpg - actually a little more since the tires are slightly bigger than stock - and I would like to bump it up a little more. I know, I should be grateful for that. It's a 2 door, with 4wd, fog lights on the bumper, and a roof rack. We rarely go off road, only when we hunt, and now we have an ATV for that anyway. So it's 99%+ on the highway, but it comes in handy with our occasional Carolina snowstorms.

My questions: Will it help aerodynamics a little bit if I remove the rails on the roof rack (which I don't use) and buy or make a modest size, flexible front air dam extension? Or would a front belly pan help aero more? Also, does anybody have a roofline extension spoiler on the back? They're the flattop thingies that come straight out from the top of the hatch and stick out 2-3 inches. They're supposed to really help aero on boxy vehicles. My wife's Compass had one. Any more ideas to help aero and gas mileage?

No, I don't want to buy a Honda, I'm an old AMC/Rambler guy who drove Javelins and AMX's, and the sweet sound of the old Rambler straight six in my XJ is like music to my ears. BTW, a Nash-Healey using the grandaddy of the 4.0 six finished 3rd overall at Le Mans in 1953. I know what I have, I like it, I just want to maximize every drop of expensive fuel without getting stupid and lowering a Jeep or disconnecting the 4wd equipment, etc.

I've heard mixed reviews on the bug shield doohickeys you mount above the grill. Some say they improve aero, others say they hurt it. What about you?

Would headers and/or a free flow cat help? Intake spacer? Chip?

I've wanted a Cherokee since '84 and I finally got it. They are still the coolest looking boxes on the road, period. When SUV's dream at night, they dream they are Cherokees, just like all rock n'rollers dream they're Skynyrd and all basketball players dream of being Tar Heels.

Help a newbie brother out...

 

Hey,

You really should be happy with what you have, as it won't get much better than that. Also its a Jeep not a Honda Fit so keep some of those rear spoilers etc off of it.

What you could try is the neon Injectors. I jumped up 3-4 mpg with that.

Thanks

 

I would suggest you try going back to a stock air filter box but remove the little grommit thing that necks the pipe down to like 1.5" just to reduce induction noise.

I too have a Homebrew air intake that I built from 3" PVC pipe and I run a Spectre cone filter. I, too, have a 2.5" exhaust from the "S" pipe back with flowmaster super 40. My 91 Cherokee has 33s, 4.56 gears, lockers f & r, 6" lift, and solid axle shafts both sides in the front and I still get 16-18 MPG on the highway with the 4.0 HO motor and AW-4 auto tranny. I consider myself lucky to get that with my setup. The reason I suggested going back to a stock airbox is that the tables mapped in the ECU for air/fuel ratio are based on the stock setup so, the cold air intake, while giving you awesome throttle response and power, quite possibly could do more harm than good for your MPG at highway speed IMHO. Pretty much nobody wants the XJ stock air boxes so I'm sure you could get one for next to nothing in a junkyard. For the cost it would definitely be worth a try. If it doesn't help you, you can always go back to your cold air intake.

 

Thanks, I still have the stock air box in my garage, I think. I'll look into it. I'm not trying to make my XJ into a rice burner, BTW. I already have a Honda: it has 110 cubes, 106 horses, 120 ft./lb. of torque and two wheels. And both my bike and my Jeep have a nice, deep exhaust tone.

 

Your 20 mpg may be a little high because the 235/70 tire is slightly shorter (diameter) than a stock tire so your odometer is indicating a few more miles (per tank) than with a stock diameter tire.

 

I totally understand you. I have 2.5" flowmaster super 40s on my Jeep and my GMC tow rig with a 454. I wouldn't remove them from either rig for anything!!

 

When you say roof rack are you referrring to an aftermarket rack or the stock cross bars? If it is an aftermarket rack, taking it off will help out your aerodynamics (and mpgs), and since you dont use it I don't think you'd miss it.

 

Just the stock cross bars, but removing those and cleaning up some other aerodynamic issues supposedly nets more MPG, according to ecomodder.com. So does blocking off parts of the grill, but I'm concerned about that because XJ's run warm already. I just wanted to ask some real-world Jeepers here on this forum. Thanks, and any other tidbits of advice?

 

sweet rig

 

?

 

I'll get my son to post pics soon. Stone white, 2 door, ZZTop "glass so dark they don't even know yo' name" tint, black exhaust tip, U-Haul hitch, no chrome anywhere. I think it's a Sport, though, not an SE, Idunno. Automatic, too. It was once a gov't. vehicle, Navy recruiter, I think. Sawblade wheels, I can't decide if I should paint them silver, white, gold, or black, or replace them. Black grille, bumpers and flares.

It goes like stink in the moderate mud use it gets when we hunt. And I used to 4wheel heavily back in the day in everything from CJ's, big Cherokees, Broncos, F-150's, Toyotas with Wolverine 4wd, Scouts, etc., so I've seen a lot.

I love my XJ. I plan to drive it til it drops, then put in a 4.7 stroker.

 

Any of you guys with headers? Chips set up for economy? Aero aids? Tips? There are some awesome rides on this forum! Since mine's a daily driver with a long commute I can't set it up for the off-road stuff I'd do if it were a back-up vehicle.

Thanks!

 

One more question: the hatch is very hard to open, even after I unlock it. I have to pull on it for a while. Can I adjust it, or put graphite on it to fix it, or do I just need to replace the lock? Sorry to ask so many questions, I've just wanted a Cherokee forever and now that I have one I'm a psyched-up 50 year old dude.

 

Welcome to the forum. I can only add check your weight. Remove anything not necessary. Not a fan of those wind deflectors, or covering the grill. I have the stock valance on mine and have 235/70 tires, on my last trip to NC coast I got 16 mpg loaded (we're moving to Newport).

 

That's a common problem on XJs mine does it too. I push a bit just above the handle and it usually opens. The problem is that there's a clip that connects a rod from the hatch handle to the lock mechanism is out of adjustment. FYI if it gets really stuck you can pull the trim from the rear window and reach down to open the hatch. Old guys RULE!!