Jeep Cherokee Aeromods

[winkosmosis]

BTW it might be worthwhile to try higher octane. Someone posted on NAXJA that his manual said to use higher octane gas at high temperatures, towing, etc. Mine doesn't say that, but I've tried 93 octane and got higher gas mileage... Like 18mpg instead of 16mpg. It wasn't scientific though because I had to fill up at a different gas station.

[pmurcyard]

Im glad this thread is still alive. I have a 98 Grand Cherokee and I first noticed this page last year. Im planning on doing some aero mods. Right now im getting about 22 mpg but I can get up to 26 if i stay at 55mph. I just hate driving slow. I have a scangauge and frequently go on 900 mi trips in the 238,000 mi Grand. maybe Ill make a new thread but for now im thinking about grabbing some sheet metal and starting after I make the 450 mi trip home.

Good job on the cherokee!!! Im looking forward to saving money on gas following your example.

[JeepNmpg2]

Not that I have any room to talk, but have you gotten any further with modding your Cherokee? I still have to say that your WAI is ingenious, I need to figure out a way to make that work with my hacked K&N airbox!

[FastPlastic]

Just pulled one of the highest yet! 19.219MPG's! Most of this was in town driving. I'd say I had maybe 25-40miles of the 339.2miles out on the highway across town. Several of the trips through town I pulled 22MPG's.

JeepNmpg2,
Haven't really had time to work on anything but the nut behind the wheel. Just bought a house, so I've been spending all of my time working on that instead.

winkosmosis,
I've heard many talk about heat soak as a problem. So far I haven't seen any signs of it in my case. Could be the fact that I only do a partial warm air intake. So I pull maybe 1/2 of the air from near the exhaust and the other half from the front of the jeep. Giving me a nice toasty intake, yet not overly hot. My engine temps rarely ever go over 209F and even then for only about 10-15seconds as the electric fan drops it back down. The highest intake temp I've seen was 159F with it typically running between 115F-135F.

I have tried the higher octane. It did push the MPG's up a bit, but after doing the math to figure out the savings I found it to be counter-productive. Instead, I have found in my case a bottle of Iso-Heet(yellow bottle seems to work best for me) boosts my MPG's enough to be worth the $1 I pay per bottle for the 4 packs at Wal-Mart.

[XJguy]

Many years ago, back in the 80's when the XJ was going through police trials, it was deemed the best performer even better than the Crown Vic's in every way, the article was in Motor-Trend I think. At any rate they touched upon the aerodynamics of the XJ, and they said that in spite its boxy appearance it was not as bad in the wind as one might think due to its small overall size. However they said the large side mirrors, huge wheel gaps and relatively enormous fender flares really took a toll on its aero package. You might want to investigate ways to remedy those issues.

[FastPlastic]

So now that it's warmed up and gas is on it's way up again($3.89 today) I hope to look in to a few more mods on the old Jeep. One major modification I made recently is my big move. Got married in Nov and bought a house closer to work. So my 4 mile commute one way is now only 2 miles. An interesting side affect is my MPG's are dropping due to the shorter trips, the engine just doesn't have time to even warm up before I'm there. Good news is from my calculations its a decrease in gas used. I'll keep you posted on what I add.

[Christ]

Might I suggest a house warming self gift of a bicycle? 2 miles is almost walking distance...

[comptiger5000]

^ Agreed. In the warm weather, that would work nicely. Plus, the short trips where the engine doesn't get warmed up well enough aren't exactly good for the Jeep.

[JRMichler]

Two miles.
30 to 35 minutes walking.
7 to 10 minutes bicycling.

[FastPlastic]

Once the weather warms up at night I'm planning on switching to the Ninja. I absolutely love riding the bike, but feel guilty if I don't have a reason too. There are days that I wish I had a block heater for the Jeep to use during winter. But it's a more costly install considering I would also have to install an electrical outlet on the exterior of the house. Seems houses originally built in 1875 didn't have exterior outlets(go figure).