realistic MPG expectations
after some searching, I'm wondering what kind of mileage people are getting when towing. I know the frontal area of the trailer is a big factor, as far as wind resistance, even more so than weight. ...
Forum Discussion
rbpru:
I have done the following:
LT245/75R16 Firestone Destination A/T tires on Jeep MOAB wheels. The track width is increased about 4-5 inches over stock, so the side to side stability is greater. Add to that a 20mm wider tread width, and load-range C sidewalls, and it makes the Liberty much more stable. Tires with installation were about $700, IIRC. The wheels were another $500, bought used.
Powerstop extreme-duty rotors and brake pads. They are low on dust and very grabby. The rotors are solid vented rotors, somewhat thicker overall than stock; slotted or cross-drilled rotors have a tendency to crack under extreme heat. The package ran about $200 delivered.
The entire vehicle is lifted about 2.5 inches using a lift I have built piecemeal. The front uses OME heavy-duty springs with a small spacer on top to even out the ride height, while the rear has full-height coils with AirLift 1000 helper bags inside the coils. This mainly takes the bounce out of the rear when hauling heavy, but it does keep the Jeep more level when towing my boat or flatbed trailer as well. I estimate about $1000 in the setup between the AirLift kit, Rocky Road Outfitters upper control arms up front (they use a Moog 1/2 ton Chevrolet ball joint), stiffer springs and bigger shocks.
I have a Hayden 678 transmission cooler... it was about $70 delivered, plus the cost of a fluid change on the transmission when I installed it. It runs in series with the factory heat exchanger built in to the radiator.
The tune is a bit of a story. I ordered a "MPPS" cable from eBay for $20 delivered; the device allows me to plug in to the OBDII port and connect a computer via USB. From there, I have access to the engine's software and can edit fuel curve, EGR activation (disabled), turbo VGT map, all kinds of parameters. I have limited the torque output of the engine to 330 lb-ft to protect the stock torque converter in the transmission. I estimate the engine to be about 190 hp/330 torque based on the tune and my exhaust (2 1/2 from downpipe back). Exhaust is a Magnaflow muffler that I installed for about $80.
Obviously a proportional brake controller. I use a Tekonsha Voyager 9030, about $80. It is the only type of brake controller I have ever used in the last 15 years. Yes, it is analogue in its adjustments, and it doesn't have all the features of a Prodigy II or III, but I love it.
My next goal is to install a Hayden heavy-duty fan clutch (Hayden 2905). I am still researching the airflow difference between the 3.7L polyurethane fan (11 blades) and the CRD steel unit (5 blades). The buzz is the 3.7 moves more air at low speed, but flow charts show the opposite at higher engine speeds. I will probably stay with the steel fan, because the temperature only rises when screaming along pulling a heavy load.
If you look at the CRD temperature gauge, though, you can peg the gauge and the engine temperature is still only 235*. I feel much more confident towing after learning that, because I can approach the red zone and still not be "overheating," just running hot.
I will post back when I put in the new fan clutch.
Ryan:
The CRDs (mine at least) has an absolute maximum on the axles of almost 5800 lbs. Given the factory curb weight of 4300, that actually leaves about 1400 lbs to play with. My trailer above has a verified tongue weight loaded of just over 600 lbs. I don't usually travel with gear in the vehicle when I haul the camper; there's not much room for it anyways!
Edit to add: My 15.3 was done from the Tri-Cities area of Tennessee most recently to Myrtle Beach via Sam's Gap. Average speed was about 62 mph, which is where the Jeep and trailer felt most comfortable.
I have done the following:
LT245/75R16 Firestone Destination A/T tires on Jeep MOAB wheels. The track width is increased about 4-5 inches over stock, so the side to side stability is greater. Add to that a 20mm wider tread width, and load-range C sidewalls, and it makes the Liberty much more stable. Tires with installation were about $700, IIRC. The wheels were another $500, bought used.
Powerstop extreme-duty rotors and brake pads. They are low on dust and very grabby. The rotors are solid vented rotors, somewhat thicker overall than stock; slotted or cross-drilled rotors have a tendency to crack under extreme heat. The package ran about $200 delivered.
The entire vehicle is lifted about 2.5 inches using a lift I have built piecemeal. The front uses OME heavy-duty springs with a small spacer on top to even out the ride height, while the rear has full-height coils with AirLift 1000 helper bags inside the coils. This mainly takes the bounce out of the rear when hauling heavy, but it does keep the Jeep more level when towing my boat or flatbed trailer as well. I estimate about $1000 in the setup between the AirLift kit, Rocky Road Outfitters upper control arms up front (they use a Moog 1/2 ton Chevrolet ball joint), stiffer springs and bigger shocks.
I have a Hayden 678 transmission cooler... it was about $70 delivered, plus the cost of a fluid change on the transmission when I installed it. It runs in series with the factory heat exchanger built in to the radiator.
The tune is a bit of a story. I ordered a "MPPS" cable from eBay for $20 delivered; the device allows me to plug in to the OBDII port and connect a computer via USB. From there, I have access to the engine's software and can edit fuel curve, EGR activation (disabled), turbo VGT map, all kinds of parameters. I have limited the torque output of the engine to 330 lb-ft to protect the stock torque converter in the transmission. I estimate the engine to be about 190 hp/330 torque based on the tune and my exhaust (2 1/2 from downpipe back). Exhaust is a Magnaflow muffler that I installed for about $80.
Obviously a proportional brake controller. I use a Tekonsha Voyager 9030, about $80. It is the only type of brake controller I have ever used in the last 15 years. Yes, it is analogue in its adjustments, and it doesn't have all the features of a Prodigy II or III, but I love it.
My next goal is to install a Hayden heavy-duty fan clutch (Hayden 2905). I am still researching the airflow difference between the 3.7L polyurethane fan (11 blades) and the CRD steel unit (5 blades). The buzz is the 3.7 moves more air at low speed, but flow charts show the opposite at higher engine speeds. I will probably stay with the steel fan, because the temperature only rises when screaming along pulling a heavy load.
If you look at the CRD temperature gauge, though, you can peg the gauge and the engine temperature is still only 235*. I feel much more confident towing after learning that, because I can approach the red zone and still not be "overheating," just running hot.
I will post back when I put in the new fan clutch.
Ryan:
The CRDs (mine at least) has an absolute maximum on the axles of almost 5800 lbs. Given the factory curb weight of 4300, that actually leaves about 1400 lbs to play with. My trailer above has a verified tongue weight loaded of just over 600 lbs. I don't usually travel with gear in the vehicle when I haul the camper; there's not much room for it anyways!
Edit to add: My 15.3 was done from the Tri-Cities area of Tennessee most recently to Myrtle Beach via Sam's Gap. Average speed was about 62 mph, which is where the Jeep and trailer felt most comfortable.
