15,000 mile report..

SargeW · 11-07-2007, 06:45 AM

I just turned 15K on the clock returning from a trip to Pahrump, NV. The rig is running great, and I have noticed a significant increase in power and MPG as of late. I do know that a new diesel has a break in period that can be lengthy compared to gas motors. The average diesel is so tight when new that it takes a while for parts to seat and move a little easier.

On the last trip we traveled a bit over 500 miles. Most of which the cruise was set at 60 MPH and the Jeep was in tow. We traveled some decent grades going up I15 towards Vegas and I let the cruise and the Allison work together to pull us up the grades. When I returned home we had averaged approx. 9.5 MPG for the trip. I am pretty happy with that number, as my Dodge Dually with the 5ver hooked up had a hard time getting over 8 MPG.

I constantly monitor the engine and tranny temps with the VMSpc software, and they are remarkably low. Even going up Cajon pass on the 15 fwy I pulled the grade at 55mph in fourth gear. The Allison never got above 186 degrees, and the coolant held steady at 199 degrees. Remarkable considering that on the flat the coolant was sitting at 195 degrees. That was with an outside temp of 87 degrees.

My fantasy is if I can hit the magic 10 MPG mark while towing the Jeep. Hey, it's good to have dreams

Sarge

SargeW · 11-07-2007, 06:45 AM

I just turned 15K on the clock returning from a trip to Pahrump, NV. The rig is running great, and I have noticed a significant increase in power and MPG as of late. I do know that a new diesel has a break in period that can be lengthy compared to gas motors. The average diesel is so tight when new that it takes a while for parts to seat and move a little easier.

On the last trip we traveled a bit over 500 miles. Most of which the cruise was set at 60 MPH and the Jeep was in tow. We traveled some decent grades going up I15 towards Vegas and I let the cruise and the Allison work together to pull us up the grades. When I returned home we had averaged approx. 9.5 MPG for the trip. I am pretty happy with that number, as my Dodge Dually with the 5ver hooked up had a hard time getting over 8 MPG.

I constantly monitor the engine and tranny temps with the VMSpc software, and they are remarkably low. Even going up Cajon pass on the 15 fwy I pulled the grade at 55mph in fourth gear. The Allison never got above 186 degrees, and the coolant held steady at 199 degrees. Remarkable considering that on the flat the coolant was sitting at 195 degrees. That was with an outside temp of 87 degrees.

My fantasy is if I can hit the magic 10 MPG mark while towing the Jeep. Hey, it's good to have dreams

Sarge

John_Canfield · 11-07-2007, 08:51 AM

Good report, Sarge. I really love my VMSpc, especially the tank-minder and the configurable odometers.

On our way home from our recent trip (and with a new radiator fan motor/pump), we pulled some pretty good grades and the coolant temp never went above 205 even though our engine RPMs were ~1800. The outside air temp was 80, so it will be interesting to see what happens we pull grades in the summer heat.

I think our coach mileage has improved at least 0.5 MPG now that we have about 32,000 miles on it.

Our Jeep Liberty CRD (diesel) only got about 18 MPG (or thereabouts) when new, now we average about 23 MPH (highway.)

Jeeperrmartin · 11-07-2007, 09:38 AM

John you said your mileage increaed .5 to what is the .5 you added it to?

SargeW · 11-07-2007, 12:44 PM

John, I am envious of your diesel Liberty! I wish that Jeep would come out with a diesel Wrangler. In a 4WD magazine that I subscribe to, they are building a project Wrangler in the new 4 door with a Cummins ISB in it. That would be a little excessive for my needs!

John_Canfield · 11-07-2007, 02:05 PM

Jeeperrmartin - this summer we put 8500 miles on the coach and we averaged 7.7 MPG. When the coach was new, the best we could average was around 7.2.

Sarge - the Liberty's engine is okay, not great, but okay. Unfortunately it isn't a Mercedes diesel but an Italian one from a company that was (is) owned by DC. The torque curve isn't very linear - the engine doesn't develop adequate power until it is ~1500 RPM. If I need to make a "hole shot" to zip across traffic, the left foot goes on the brake and the right foot is on the throttle. Darn near killed myself when the Jeep was new and I floored the throttle to shoot across a four-lane highway. Not much happened in the "go" department. I was used to my F-250 diesel pickup - you floor the throttle and you get pushed back in your seat right then and there.

SargeW · 11-08-2007, 05:12 AM

Good info John, thanks. Maybe someone will make a "chip" for the Liberty. They do for everythng else!