yossarian19
NAXJA Forum User
- Location
- Grass Valley, CA
I'm mostly writing this because I need to decompress a second before I get in the shower. I hope, though, that this helps somebody else to avoid the mistakes I just made.
First off, the XJ: 2100 CFM Electric fan swapped in, set to come on when the ECU tells the AC fan to come on right around 220 degrees. Cold air intake, manifold-back exhaust in 2.5", injector update, automatic, factory tow package. ZJ rear brakes.
The trailer: Uhaul 6x12 (2k empty) 1/2 full of tools & car parts, 1/2 full of usual household crap. No idea how heavy it was when full, though I'd be surprised if it hit 5K.
The route: Out of Berkeley, CA. Through the Central Valley (100 degrees or so outside) & up into the foothills. Long grades up to 10%, some traffic, elevation to 3,000 feet.
My results: Getting out of Berkeley was surprisingly easy. I just put the car in Drive and it would go - it got the freight moving easy. Stopping also fine, steering likewise. So far so good. As soon as I hit the first grade, though, it became clear the 4.0 wasn't up to the task. Temps climbed steadily until 220 or so when, doing 45 mph on the interstate, the fan kicked on & temps as well as speed stabilized & I got over the hill. Things were uneventful until Auburn, CA when the rest of the hills came in. Once in the foothills, I really had to watch throttle opening due to pinging. Temps would hit 220, fans come on, temps keep climbing. Speed was an issue - the Jeep really didn't want to break 40 mph at times but would do so if flogged. Second gear made a few unwelcome appearances. Oil pressure was lower than usual at times due to increased temp (I think). More pinging.
Had to pull over & leave the engine running 2x to let the fans ever-so-slowly bring the temps down. Never over heated but not for lack of trying.
So, what I learned from this and what I'd hope to relate to others is three things.
1. ) 2000 CFM is not enough for an electric fan swap. Not if you are towing in the summer, anyway. I'm now on the fence between putting my mech fan back on, or going to the Taurus fan I've got in the shed. Also, 220 is a bit late for fans to come on under heavy use (though I'd never had a problem in town)
2. ) You should use higher octane gas if you plan on wringing out the XJ. If I'd known it would ping, I would have used mid-grade
3.) A max tow rating of 5,000 doesn't mean you want to tow 5,000 lbs with the XJ. Or even close, really. Running hot isn't the only problem I had. With the 4.0, you'll have your foot buried in the gas & still be limping up hill at 45 mph.
I've now got to consider realistically how much towing / heavy use I'll be asking of the XJ in the future, and whether what I really need is a K2500 Suburban.
First off, the XJ: 2100 CFM Electric fan swapped in, set to come on when the ECU tells the AC fan to come on right around 220 degrees. Cold air intake, manifold-back exhaust in 2.5", injector update, automatic, factory tow package. ZJ rear brakes.
The trailer: Uhaul 6x12 (2k empty) 1/2 full of tools & car parts, 1/2 full of usual household crap. No idea how heavy it was when full, though I'd be surprised if it hit 5K.
The route: Out of Berkeley, CA. Through the Central Valley (100 degrees or so outside) & up into the foothills. Long grades up to 10%, some traffic, elevation to 3,000 feet.
My results: Getting out of Berkeley was surprisingly easy. I just put the car in Drive and it would go - it got the freight moving easy. Stopping also fine, steering likewise. So far so good. As soon as I hit the first grade, though, it became clear the 4.0 wasn't up to the task. Temps climbed steadily until 220 or so when, doing 45 mph on the interstate, the fan kicked on & temps as well as speed stabilized & I got over the hill. Things were uneventful until Auburn, CA when the rest of the hills came in. Once in the foothills, I really had to watch throttle opening due to pinging. Temps would hit 220, fans come on, temps keep climbing. Speed was an issue - the Jeep really didn't want to break 40 mph at times but would do so if flogged. Second gear made a few unwelcome appearances. Oil pressure was lower than usual at times due to increased temp (I think). More pinging.
Had to pull over & leave the engine running 2x to let the fans ever-so-slowly bring the temps down. Never over heated but not for lack of trying.
So, what I learned from this and what I'd hope to relate to others is three things.
1. ) 2000 CFM is not enough for an electric fan swap. Not if you are towing in the summer, anyway. I'm now on the fence between putting my mech fan back on, or going to the Taurus fan I've got in the shed. Also, 220 is a bit late for fans to come on under heavy use (though I'd never had a problem in town)
2. ) You should use higher octane gas if you plan on wringing out the XJ. If I'd known it would ping, I would have used mid-grade
3.) A max tow rating of 5,000 doesn't mean you want to tow 5,000 lbs with the XJ. Or even close, really. Running hot isn't the only problem I had. With the 4.0, you'll have your foot buried in the gas & still be limping up hill at 45 mph.
I've now got to consider realistically how much towing / heavy use I'll be asking of the XJ in the future, and whether what I really need is a K2500 Suburban.