First tow in Mountains of CO with my DMAX and I DON'T want my 8.1L BACK!!

[4x4man]

Outside of Steve Cornell, I am not sure who else has traded their 8.1L for the DMAX and have towed the same stretch with both to have a comparison...

I just wanted to post my good fortune with the DMAX after trading my 8.1L on it for towing our 5er. We estimate our 5er weighs in around 10,000lbs. The Juice was set on Level 1, truck had 4,900 miles at the start of trip. The DMAX power and mileage was excellent compared to the 8.1L. On the same stretch of Highway 285 from Denver to Buena Vista the 8.1L got just over 5mpg, the DMAX 9.85 (not adjusted for 265's). At no time was the DMAX run at WOT, yet there were many times, the 8.1L was. From Buena Vista to Gunnison, a few miles of Highway 285, then Highway 50, the 8.1L got just over 6mpg, the DMAX got 11.53mpg (not adjusted for 265's). The biggest difference between the 8.1L and the DMAX was on Monarch pass. This is a 6-7% grade with sharp corners and a summit of 11,312ft. The 8.1L was floored the whole time last year up the pass, only doing 45mph on the East side, and 30-35mph on the West side when we returned home. The DMAX did 50 mph on the East side, a couple of times 55mph when I wanted to pass someone, and the same 50mph on the West side. Both ways the DMAX had power to spare in 4th gear and was probably only half throttle, the only time I slowed down was for the sharp corners. It was nice to know we could make it on one tank of fuel, but we wanted to be sure on the way there. On the trip home we did make it on one tank of fuel, and got 10.4mpg (not adjusted for 265's). The big block could not make it on one tank of fuel and needed to fill up at Buena Vista both coming and going.

I had a huge smile on my face and knew I made the right choice on my purchase. I am very happy with the tow and look forward to many more just like it. Even if the mileage doesn't get any better than this, I am very happy with the double the mileage the DMAX got over the 8.1L.

Bob

[NWDmax]

:D smile.gif ;) :cool:

[David Proske]

Outstanding! :D

[sdaver]

still have my 8.1 but I dont drive it(another employee does).......but I dont miss it at all :D dave

[a64pilot]

One of the reasons the Dmax did so well was the altitude. A wastegate equipped turbo charged engine will maintain sea level horsepower until it reaches critical altitude, "point where the wastegate stays closed all of the time". Being N/A the 8.1 began loosing power every foot above sea level that you climbed. Juice was I'm sure the other big reason :D

[DURAMONSTER]

Damn I wish I could say the same. Mine is a dog at pulling only 7,000K or so. And my milage totally sucks. I have to hit the ODLO button before I evan see a hill just to keep it from going under 50 mph. Damn this thing had better wake up.

[D-max Man]

4X4 man,

I remember going over Monarch Pass (east to west) with the Power Tour rig (for those not fimilar, see it here: http://www.thedieselpage.com/duramax/powrtour.htm ), we were stuck behing a Ford motorhome/van with a Powerstroke that was beltching black smoke all over us. We were finally able to get around them about 2/3 the way up but it was too curvey to open her up. I believe that we ran around 45 mph with a stock engine after we got past them.

The downhill side was fun, I wasn't driving but about 3/4 of the way down, we deceided to pull over and cool the brakes. Even with the grade braking of the Allison, the weight of this rig put a strain on the brakes.

[4x4man]

D-max Man-

Yeah, if it wasn't for the sharp corners you could realy haul butt up that pass. Coming down the west side of Monarch is much tougher on the brakes than the east side as it seems much steeper and has lots of sharp corners. I have heard many say it is steeper than the east side. If I were still driving my big block I would agree as I couldn't get over 35mph on the west side!! But the DMAX didn't break much of a sweat on either side.

The grade braking worked very well, seemed to hold speed just as well as the 8.1/Alli did on both sides so I was very happy with that...but you guys were hauling much more weight than me.

Bob

[4x4man]

Duramonster-

I am now starting to agree with some of the others that maybe there is something wrong with your truck. We made our first test tow with just over 500 miles on the truck for only about 20 miles. While I was unhappy with the "slugishness" on the highway, it never dropped out of 5th on ANY of the rolling hills we encountered. It was also my first tow with a diesel so I had to relearn how things worked as I was used to a gasser... things like waiting for the turbo to spool up for it to accelerate and such.

This was our third tow this year with the 5er and new truck and each time I have had a smile on my face. The first two (around 3,000 miles on truck) were on the plains so there wasn't much towing difference between the 8.1L and the DMAX, except fuel mileage. But the tow in the mountains was when I knew I made the right choice to trade in for the diesel. Power and economy are just incredible!!

While I did have 5th locked out on some of the passes, it was only to make sure it didn't upshift into 5th, lug, then downshift to 4th and back again. I would wait until it would downshift into 4th first, there were many passes that I pulled in 5th, no problem. I just wanted to prevent excessive shifting for the steeper passes. Not because of me, but because other people don't know how to drive a constant speed up hill... It was amazing how many cars I passed up some of these hills, wonder if it was the car, or the driver?? :D

Anyway, you might want to get that truck checked out as I am sure I would have been happy with this pull without the Juice. But being as that I have it........ :D :D :D

Bob

[KevinK]

4x4man,

Isn't all that diesel power nice to play with? As I've discovered, extra power, high alitude, and steep grades are a great combination for extremely high EGT's. If you're going to tow using above stock power, you would be doing yourself a favor by getting an EGT gauge. Granted, I'm driving a Dodge, but when set at about 320rwhp (my COMP box on level 2), I can easily hit 1400* at half throttle and no smoke. EGT's are definitely my limiting factor when towing. Our 5th wheel is also right at 10k pounds. I can drive all the way up I-70 to Floyd hill at 65-70mph, but I have to constantly watch the EGT's.

Kevin

[2DAMAX]

4x4man:Glad to hear of the awesome performance over the 8.1 I sure am glad I did not buy the 8.1.I pull a 16k 5er.
:D :D :D

[Duke]

Duramonster

Take that truck in and tell them your 03' is down on power and that you want it checked out. sounds like you have the same problem I had. Have them check to see if the computer ever seees WOT. The electronic sender is probablly bad as mine was and it never sends the correct Throttle position to the ECM and the truck appears to be a dog! It is worth the time it takes to check it out.

[DURAMONSTER]

Im going down tomarrow to have it chacked out. It seems to be getting slower and slower and the milage is extremely dropping. :confused: