BFG KO2 37s on Ecodiesel very suprising initial results with driving characteristics and fuel mileage

[jywolfe]

Changes from previous trip were approximately 375 pounds with passengers, luggage, gear and cooler. Trip was driving on interstate, state highways and rural backroads with little change in elevation with undulating terrain. Average fuel economy on the way down with 125 miles driving an average of 56 MPH, sustained speed of 70+ on interstate roughy 85 miles with very light traffic, and 45-60 MPH on state highways and backroads the remainder. Trip included 7 stoplights that I stopped or slowed down for and 5 stop signs. I had a regen 21 miles in and no significant wind. Average on computer was 24.6.

On the way home today we had significant headwinds. Cold front coming in. I didn’t reset the computer but the average fuel economy dropped to 23.6 by the time we got home. Hand calculated for entire trip was 22.9.

I captured some data from JScan along the way. At 70 MPH on flat stretch, RPMs were 1680 in 8th gear. Torque was plentiful and pleasant at this speed and the engine just purred along. In 7th gear it was 2109 at same speed. Rarely did it downshift to 7th at speeds above 65. It now shifts to 8th gear at 62 MPH on flat roads and once in 8th gear it would hold down to 55 MPH and re-accelerate without going to 7 with normal acceleration. Below 55 it would normally downshift to 7th.

I also monitored engine torque with the option on JScan under transmission module. My plan next time out is to attempt to log torque data at highway speed in 7th and 8th gear. I noticed today that when in 7th gear (versus 8th) at 70 MPH, torque decreased and turbo percentage went down as well. Initial impression is at lower RPM in 8th the turbo may be spooling more. Gonna try to find the torque sweet spot within my preferred cruising speed range next trip.

Sponsored

 

[Swegian]

Tazer FT on both till speedo/GPS on Waze same:

21 jlu 3.0d '35" 11.5 at4s Falken', w/stock rubicon wheels 7.5×17, round town 21-23, hwy up to 27 (max 70mph, 90% 60-65).

21 JT 3.0d (same tires & wheels), round town 18-22ish, hwy up to 24ish

Lost the 2-3mpg from (stock 33" Falken M/T01) expected on both from many on this forum. More so in the JT, I expect due to weight.

High end on JLU new was 29hwy 2/3 hours consistently. Was down to averaging 27 hwy same trip when I changed the tires at 65k miles with 50+% of tread left. They were getting pretty noisy!

 

[NC_Overland]

KO2s are light and run small. I’m not surprised. Glad it’s working out well for you.

 

[mtudb24]

While not a diesel, I'm seeing just over 17 on a 3.6 with 37's and 4:10's with Mopar lift. I was just over 18mpg on average combined on 35's and dropped about 1 mpg when switching to 37's. This mileage was over a 1100+ mile combined city / highway / light wheeling period of driving with 24 hours of engine run time.
This was on a trip to the UP which included about 20 hours of highway, 2 hours of light logging trail wheeling, and 2 hours of city stop / start driving.

I'm not complaining at all. Truck has tazer calibration for the smaller then advertised 37" BFG KO2's which are just about 36" overall height when mounted.

 

[jywolfe]

Update with some torque data and highway cruising speed with just the driver and small bag luggage. I settled on the range of 66-67 MPH on the interstate after logging a trip today of approximately 221 miles. At 66 MPH the engine was turning at ~1575 RPM and on flat sections of the road the ECU was targeting 250 N*M (184 ft lbs torque)of crankshaft torque and would hold steady at 25 MPG under these conditions. Slower speeds between 60-63 had better fuel economy in 8th gear, but I had to compromise with a higher speed in order to stay with traffic in the right two lanes. Overall fuel economy on this trip was 24.5 MPG, with 39 degree F ambient temps. I drove this trip in reverse last week at higher speeds, ranging between 73-75 MPH on the interstate portion (~120 miles) and only averaged 23.6 MPG.

What I found is target crankshaft torque in the range of 245-260 N*M provided the best fuel economy at highway speeds without going too slow for 65 MPH posted speed limit traffic. I typically drive faster, but I was experimenting and actually enjoyed the reduced road noise and low rpm hum of the Ecodiesel under 1600 rpm.

I also took the vehicle to Discount tire this week and had all of the BFG KO2s tires road force balanced. I am thoroughly impressed with the difference. These tires continue to impress and I am happy with how the Jeep drives. My tire pressure when warm is 31 psi.

I think when No2 diesel comes back around in the Spring it's possible I may see 25-26 MPH again if I stay in the optimal range for speed and torque above. .

 

[Jocww]

Welcome to the club of the super secret awesome mpgs.

 

[JTdiRtyD]

I think when No2 diesel comes back around in the Spring it's possible I may see 25-26 MPH again if I stay in the optimal range for speed and torque above. .

Yeah I see about 2mpg drop with winter blend No2, but I see around 5mpg drop on average in the winter from remote start idling.

Sponsored