ISB Fuel Milage while Towing a 4k Jeep

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Well, I and My friends had a Good time In Moab Utah two weeks ago.

As Far as Milage Goes, MY Milage for my 98. 5 ISB while Dolly towing my 4k lb Cherokee was 17. 5mpg @70mph. (see Sig below for aftermarket upgrades)

My Friend (also Flat towing a Jeep) who has a 98. 3 12v Ram with a TST 230hp Plate and the same gears,tires,campershell,lift,limited slip as my 98. 5 ISB and is also a Clubcab was getting about the same milage as me, His Dyno'd out a 200hp. Mine dyno'd out 282hp.

Both truck have 4. 10 gears Sure Grip, Auto, 2500 4x4 Clubcabs.

Just a report for the Early ISB People who are getting told the ISB Doesnt get the MPG that the 12V can get.

I love Moab! Can't wait till the 2001 Easter Jeep Safari in April!
Doug.

BTW Diesel#2 in Moab Utah was $1. 78, While in Beaver Utah,It ran from $1. 80 to $1. 99.

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1998. 5,2500,ISB,Auto,CC,4x4,4. 10's,Suregrip,White Sport,Isspro Boost & Pyro,275hp Injectors,VA,PS Boost Module,DTT Valve Body,BD Pressure Lock,16x8 Eagles,285/75/16 Bridgestone MT's,2. 5" Skyjacker Lift,Stockland Seibring Shell.

[This message has been edited by DieselRam (edited 10-29-2000). ]

 

[Archive]

DieselRam , I'm sure there are about 1,000 guys out there that would trade their 24V for yours. From what I've seen only less than 20% of the 24V get that kind of mileage. About 50% get mileage like me. About 30% get really lousy mileage.

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99 3500 QC, white, 5sp, 3. 55lsd, isspro EGT & boost, 40,000 miles 07-15-00- (EX phord owner) 15-16. 5 MPG hwy ,14-15 city , 10-12 with 4,000lb TT
1500 - 3000 in 4th = 13 sec
VA,1500- 3000 in 4th = 10 sec
275,1500 - 3000 4th = 11. 15 sec
slight mpg increase both ways.
VA+275 ,1500 - 3000 = 9. 0 sec
. 5 or 1. 5 MPG increase over stock. .
PS boost module,100 to 150 lower EGT's, same power.

 

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Towed my 1966 Plymouth Fury (~3800 lbs) 1000 miles to Montana this summer on a dolly. Did 68 MPH all the way because the dolly seemed to wander at 70 or higher. Anyway, I got 19. 9 MPG.

Coming back empty doing 80+, I got in the 17's. That made me think its more related to RPM than load...

Mine is a 99 QC 6spd 2WD. Had about 7000 miles on it then.

Mileage is getting a little better as I get more miles on it.

 

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With my stock 98. 5 24v, auto 4x4 quad cab and 4:10 gaers I get 14 mpg flat towing my CJ7 from SF Bay area to Lake Tahoe area, that is a round trip mileage. I have also towed my jeep on a 1500 lb and a 3000 lb car trailers and still get 14 mpg.

Be carefull flat towing. This is some of the damage to my mod 300. I have locking hubs in the rear and one of them did not unlock. I was in a hurry and forgot to put the case in neutral.
#ad

This is what is left of my spedo gear
#ad

and this is another shot
#ad

And this is the main shaft, the rust is scoring

 

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Originally posted by Bob-TEXAS:
DieselRam , I'm sure there are about 1,000 guys out there that would trade their 24V for yours. From what I've seen only less than 20% of the 24V get that kind of mileage. About 50% get mileage like me. About 30% get really lousy mileage.

Just finished a 3800 mi trip to Bill Kondolay's in BC towing 5th grossing 17500 and averaged 10. 2mpg. I tow at or above the speed limits ( 75 - 85 ) in direct (2800 - 3100 rpm ) or overdrive ( 2000 - 2200 ).
On the flats ( WA coast and OR river to Pendelton, Montecello UT to Gallop NM I averaged 12 to 13.


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2K, 2500,Laramie,Quad,4x4,3:54LSD,auto,reese 15k 5th slider, LAVERNGE BULL BAR,WESTIN NERFS, TA's,9000's, DD1's, VA, boost & elbow, 4", DTT Pac brake controler,VB & TC, Pac Brake, MAG HYTECH onboard.
pullee #1 26' Arctic Fox 5th
#2 22' car hauler w/ 76 Pinto 392cid or 68 Cyclone GT Cobra Jet FB
NRA,VFW,SASS

 

[Archive]

Wow, I only get about 13 MPG towing about 4k LBS. How are you getting such good mileage?



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2001 QuadCab,SWB,Auto, 4X4,4" Flowmaster Exhaust, Bosch 275 Injectors... ... ...
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4-Sale 1994 4X4 cummins, Two tone blue and silver,Auto, all stock 105k very well looked after
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Sky , I think it all depends on the ECM program , the 1st 24V's got great mileage and low end pulling power, then the (EPA ?) made DC put in a diff program, this lowered mileage and lowend pulling power. DC continued to advertise the higher mileage and higher low end torque. even on trucks with the lowered power. A couple newer programs came out to help the low mileage or the low power problem. The changes helped some and hurt others. The 2001 seems to be better than the older 24V's. Maybe DC got a better engineer to write the program.
Just my opinion. about $00. 00015¢ worth

 

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Originally posted by Bob-TEXAS:
Bob, You are right, my truck is an early 98. 5[24v] and when it was new [3k-5k] I got 23-25 MPG and 13-14 towing. After two recalls to reprogram the PCM[ECM?] there was a TSP [Technical Support Bulleten] issued. I had it done[after some arm twisting] and it brought back some of the power and MPG that I had lost after the recalls were performed. I now average 22-23 and 12-13 towing 9000lb 5th wheel from Mass to AZ. Fuel from some dealers messes the figures up.
Truck is: 1998. 5 24V Quad Cab Short Box 5SPD 3. 54 gears. Haulin Son Of A Gun... ... .

 

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On a trip out to Norfolk VA this summer I averaged about 12 mpg towing 7400 of travel trailer and supplies. I was following a fellow camper who had a bow-tie diesel with 4:10 gears, about the same load. Because he was my navigational aide, I stayed behind him, but it was sure difficult. The smalled hills slowed him considerably. We seldom exceeded 55 mph.
On the return trip, I was on my own, so upped the travel speed quite a bit. Mileage dropped to about 10. The engine seems happiest at about 2200-2400 rpm. (3:54 gears) but I believe that it is quite fuel hungry at that speed. Welll, ya don't get sumthin' for nuttn'.

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1999 2500 4wd std cab, Rhino liner, Boss 8' front & custom 7' rear blade for snow removal
1991 W250 4WD 155k mi same as above for plow set up

 

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My trip computer registers 1 mpg high since the dd1's were installed. while towing pullee #1 pulling grades ( grossing 17500 ) in od @ 2100 rpm and 22 psi boost, egt 1000 the mpg is 9, at the same speed in direct @ approx 2750 rpm and 34 psi boost, egt 1250 I get 5mpg. Mileage goes down if VA is hooked up and egt rises well over 1250 so in od I have to back way out of it and in direct I can't even think about any serious grades. Pullee #2 I average 14, some diference is weight but most critical is frontal area.


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2K, 2500,Laramie,Quad,4x4,3:54LSD,auto,reese 15k 5th slider, EISLEY BULL BAR,WESTIN NERFS, TA's,9000's, DD1's, VA(sometimes), boost & elbow, 4", DTT Pac brake controler,VB & TC, Pac Brake, MAG HYTECH, DTT transmission cooler onboard.
pullee #1 26' Arctic Fox 5th
#2 22' car hauler w/ 76 Pinto 392cid or 68 Cyclone GT Cobra Jet FB
NRA,VFW,SASS



[This message has been edited by JNutter (edited 11-03-2000). ]

 

[Archive]

Sky, are you saying that the 4" exhaust and 275's didn't help? I'll put in a separate post about my own terrible mileage but saw your mods and low mileage.

Originally posted by Sky:
Wow, I only get about 13 MPG towing about 4k LBS. How are you getting such good mileage?

 

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This is my first diesel and I can't begin to tell you how disappointed I am. Although I haven't hit 4K yet, my MPG seems to be actually going down rather than getting better.
The only thing I'll most likely be towing is an 1800 LB car hauler w/an approx. 4200 LB Jeep on it. To help break-in, I made sure I left the trailer and Jeep connected and towed it everywhere... even to mail a letter. I kept front tire pressure at 55 and rear at 70. Truck has probably 200 LBS in toolbox... that's it, nothing else.
Around 65 mph, I am taching about 2K. Even the sligtest incline, and I DO mean slight, causes computer readout to show 8 mpg or less. Power is nothing to rave about and my current MPG (mixed, towing & non, highway and city) is less than 12.
Sorry for the long post... I'm just very, very disappointed.

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01 2500 Sport, QC, LWB, Auto, 4. 10, 4x4, Camper Pkg, stock for now