Revisiting DX3 power options....

[Rancher Rob]

FWIW, just my own impressions for whomever cares -
I test drove a 2019 DX3 37BH around Portland on a test drive. Sales guy was commenting on the great acceleration. When I stomped on it on flat/minor incline I hardly noticed it accelerating. Could have been many causes as previously listed.

The 2019 XL 37BH is a world apart. It accelerates like my F350 diesel with Bully dog tuner in economy mode. It moves 30k lbs like it's a mildly loaded pickup.
Best decision I've made in a while was to go with the extra XL power for the mountains out here. Still, there are a few passes in Oregon (Or-eh-gun not Or-ee-Gone) that it slows down on. Another 50-100hp would be perfect for out here.

MPG- I don't know, I haven't tracked it yet, but hauling 15 tons up 10% grades at 73mph really sucks the "gogo juice" out of it. I'm guesstimating I average around 3-4 mpg for the day as I usually have my foot in it driving like a mad man to get somewhere before it's dark.

[RKBob]

I’m late to the party but yesterday I just had my 1 year service on the 2019 Dx3 TS I purchased at the Tampa RV Show in January. Freightliner’s documentation listed it as a 2019 model M2106 not a 2018 model. I requested the ECM recalibration to the HB80051.21 or HB80058 as mentioned in the previous posts. My receipt shows reprogram ECM Software HB80378 to HB80337, 1150 LB FT, 350 HP. They had ordered the software package on 12/03!
Living in southwest Florida I have no mountains to test it on but her are my observations. Please note that there was no specific documentation concerning the Allison. From a standing start, max throttle, the 1-2 shift occurred at 2000rpm! The subsequent 2-3 and 3-4 shift occurred between 1700 and 1800 whereupon I had to lift throttle. Previous shifts were occurring at 1400/1500 rpm. On the 25 miles of I75 with it’s normal moderately heavy but fast traffic throttle response from 65 to 75+ was noticeably improved. I consider the $545 (the service center had to purchase the software and tag, $185) well invested. The work was done at the local Freightliner Cummins dealer.

[KRedburn]

RKBob:

Bring it out here to WA. I know of a 9% grade you can put it to the test on.

[RKBob]

We’re planning a trip west this coming fall and should be able to give it a good test then. This past summer we toured the Maritimes up to the tip of Newfoundland and around the Cape Breton Highlands. My index finger wore a blister pushing the shift button trying to keep the rev’s above 1800. I’m hoping this recalibration eases that stress. However being a realist I know gravity is a hard taskmaster!😎

[mookieblaylock]

This is precisely where the new calibration excels; I rarely manually downshift anymore. I think you’ll find that the coach pulls way better in the 1400 - 1800 RPM range now, and you won’t find yourself constantly trying to keep it above 1800.

[RV Randy]

I think the DX3 with the 350/1150 tune is perfect for flat towing a toad or smaller trailer. With the much heavier race car trailer it tows fine on the flats, works harder on the high elevation long/steep grades here in Colorado but still passes the semis. For me, this is a good balance of pulling power, fuel mileage and didn't have to spend 50k more to get the bigger motor.

I drive a lot in the mountains but 90% of my miles driven are on the flats or rolling hills where it does just fine. If I moved up to a double stacker, triple axle trailer then the bigger motor would be nice to have

[JBoyer]

Excuse me if this was covered but did Dynamax concede that upgrading the DX3 to the 1150 torque level was important enough to change for the new model year? I'm asking because while visiting the large Texas RV website, looking at Dynamax rigs, the rear of the new DX3 (I was looking at) has a decal/emblem that shows 350hp, 1150 torque.

[bclemens]

Originally Posted by JBoyer

Excuse me if this was covered but did Dynamax concede that upgrading the DX3 to the 1150 torque level was important enough to change for the new model year? I'm asking because while visiting the large Texas RV website, looking at Dynamax rigs, the rear of the new DX3 (I was looking at) has a decal/emblem that shows 350hp, 1150 torque.

Concede? No. Freightliner stopped making it in the 1000 ft lb. I still think for 90% of the people it was fine...especially when you see SO many of the S2RV's being sold that are still 360/800.

What they wanted to charge us...you could get tuned after the fact for less. Now, we don't get an option.

[JBoyer]

Thank you, BC. Great to know the 1150 torque debate is OBE, at least moving forward.

[StephenLOJ]

I thought this thread would be a fitting first post here since this thread is how I found this forum.

My wife and I recently purchased a 2018 Dynamax DX3 37BH to serve double duty. Enable some fun-filled weekend vacations with the family and to haul my race truck to events across the country about 6-7 times a year. Our home base is in NJ, and most of our trips will remain on this side of the rockies.

The DX3 was the closest square peg I could find that fit in the round hole of what we needed. Space for the whole family, towing capacity, features, and price point. It hits all of them well, but none of them perfectly, which is the whole idea of a compromise I guess. I know that the DX3 is rated to tow 20k, I also know that hitching a trailer that heavy will require using the go pedal like an on off switch and exercising patience in both acceleration and time to climb any grades we might find ourselves up against. I'm ok with this, but I also build and race things, so I know how horsepower and torque work as well as how easy it is to modify stuff.

I'm also learned through the years, that modifying your tow vehicle is one of the worst ideas you can have. Leave that stock and reliable, modify the toys, those are rules I live by now.

However, the L9, ISL9, or whatever you want to call the engine in the DX3 came, from the factory, in higher torque and power configurations that it does in our rig, so going to a higher power factory setup, IMO, does absolutely nothing to decrease reliability. So when I found this thread, I was very happy to know that increasing the power in our DX3 is as easy as a trip to my local Cummins dealer.

Yesterday I did just that, and brought our rig to Cummins in Bristol, PA. I had them perform routing PMs on the engine and genset, and while I was there, flash a new tune onto the ECM. The original tune on our coach was HB80051.12, and we now have HB80058.28. Translation, we went from 350HP/1000TQ to 350HP/1150TQ, much like many others have in this thread.

My thoughts? It is a noticeable change... not mind blowing in any way, nor was I expecting mind blowing. The pull from 1000-1500RPM is noticeably improved, and the pull from 1500+ is much the same. This is exactly as to be expected given the relationship between torque and horsepower. Like many others, part throttle acceleration is where the real improvement is, since there is more grunt available as the Allison hurries through the gears.

I'm excited to see how she does in a couple week as I head to KY for my second race of the season.

However, all of that is the boring part, the exciting stuff is below....


When I was at the dealership the service writer and shop foreman told me a fun story about a similar Freightliner M2 106 RV they had in a few months back. It, too, was a 2018 model year with a L9/3200TRV combo under the hood, but they couldn't remember the exact make and model. That customer basically told them to get the most out of it they could, and gave the green light for hard part changes, not just a calibration change.

The dealer did their homework and this is what they came up with (they printed a copy of his service ticket so I can do the same in the future if desired):

Services:
Rerate to 450HP/1250TQ
Replace Pistons to Option 4955530
Replace Turbo to Option 3798339RX
Change Cal to HB80012.28

Parts:
4955530 Piston Set - $2600
3798339RX Turbo - $5100
3780074D Turbo Housing - $675
Lots of Gaskets, Seals, Fluids, Consumables, Etc. - $760
Labor - $7365


So, Cliff Notes -
350HP/1000TQ to 350HP/1150TQ - $300
350HP/1000TQ to 450HP/1250TQ - $16500


They basically convert the engine to emergency vehicle specs. They even put the coach on the chassis dyno and it tested at over 400HP and over 1160TQ at the tires. Pretty amazing IMO. They also noted that emergency vehicle cals are not really designed for continuous high load WOT use for extended periods of time, like hauling a trailer up a multi-mile long grade in the heat. They're meant to get up to speed quickly and maintain that speed. So with that being said, he warned that the driver needs to watch the engine temp gauge when running heavy and lift when the coolant temps get hot.

With that being said, it might still be worth it. $16,500 is way less than the price difference going to an XL or other M2 112 or larger coach.... we'll see how my rig does through this racing season and revisit next winter.

Anyway, thought I'd share that story, thanks again for the info found here!

[KRedburn]

Originally Posted by StephenLOJ

I thought this thread would be a fitting first post here since this thread is how I found this forum.

My wife and I recently purchased a 2018 Dynamax DX3 37BH to serve double duty. Enable some fun-filled weekend vacations with the family and to haul my race truck to events across the country about 6-7 times a year. Our home base is in NJ, and most of our trips will remain on this side of the rockies.

The DX3 was the closest square peg I could find that fit in the round hole of what we needed. Space for the whole family, towing capacity, features, and price point. It hits all of them well, but none of them perfectly, which is the whole idea of a compromise I guess. I know that the DX3 is rated to tow 20k, I also know that hitching a trailer that heavy will require using the go pedal like an on off switch and exercising patience in both acceleration and time to climb any grades we might find ourselves up against. I'm ok with this, but I also build and race things, so I know how horsepower and torque work as well as how easy it is to modify stuff.

I'm also learned through the years, that modifying your tow vehicle is one of the worst ideas you can have. Leave that stock and reliable, modify the toys, those are rules I live by now.

However, the L9, ISL9, or whatever you want to call the engine in the DX3 came, from the factory, in higher torque and power configurations that it does in our rig, so going to a higher power factory setup, IMO, does absolutely nothing to decrease reliability. So when I found this thread, I was very happy to know that increasing the power in our DX3 is as easy as a trip to my local Cummins dealer.

Yesterday I did just that, and brought our rig to Cummins in Bristol, PA. I had them perform routing PMs on the engine and genset, and while I was there, flash a new tune onto the ECM. The original tune on our coach was HB80051.12, and we now have HB80058.28. Translation, we went from 350HP/1000TQ to 350HP/1150TQ, much like many others have in this thread.

My thoughts? It is a noticeable change... not mind blowing in any way, nor was I expecting mind blowing. The pull from 1000-1500RPM is noticeably improved, and the pull from 1500+ is much the same. This is exactly as to be expected given the relationship between torque and horsepower. Like many others, part throttle acceleration is where the real improvement is, since there is more grunt available as the Allison hurries through the gears.

I'm excited to see how she does in a couple week as I head to KY for my second race of the season.

However, all of that is the boring part, the exciting stuff is below....


When I was at the dealership the service writer and shop foreman told me a fun story about a similar Freightliner M2 106 RV they had in a few months back. It, too, was a 2018 model year with a L9/3200TRV combo under the hood, but they couldn't remember the exact make and model. That customer basically told them to get the most out of it they could, and gave the green light for hard part changes, not just a calibration change.

The dealer did their homework and this is what they came up with (they printed a copy of his service ticket so I can do the same in the future if desired):

Services:
Rerate to 450HP/1250TQ
Replace Pistons to Option 4955530
Replace Turbo to Option 3798339RX
Change Cal to HB80012.28

Parts:
4955530 Piston Set - $2600
3798339RX Turbo - $5100
3780074D Turbo Housing - $675
Lots of Gaskets, Seals, Fluids, Consumables, Etc. - $760
Labor - $7365


So, Cliff Notes -
350HP/1000TQ to 350HP/1150TQ - $300
350HP/1000TQ to 450HP/1250TQ - $16500


They basically convert the engine to emergency vehicle specs. They even put the coach on the chassis dyno and it tested at over 400HP and over 1160TQ at the tires. Pretty amazing IMO. They also noted that emergency vehicle cals are not really designed for continuous high load WOT use for extended periods of time, like hauling a trailer up a multi-mile long grade in the heat. They're meant to get up to speed quickly and maintain that speed. So with that being said, he warned that the driver needs to watch the engine temp gauge when running heavy and lift when the coolant temps get hot.

With that being said, it might still be worth it. $16,500 is way less than the price difference going to an XL or other M2 112 or larger coach.... we'll see how my rig does through this racing season and revisit next winter.

Anyway, thought I'd share that story, thanks again for the info found here!

Additional to the parts used above a larger charged air cooler, and larger radiator should have been added. This part would require a hood change to accomodate the larger cooling system. Then you could run all day with heavy load.

I have a 2018 DX3. I have hauled a fully loaded 35 foot travel trailer behind and hardly knew it was there except on hills. I found that preshifting the trans worked much better than waiting for it to decide to downshift. No semi could keep up with me on some of the steep hills. They were down to about 35mph while I was maintaining 50 mph. My overall length was 78 feet.

I do have the tune that you mentioned for 350/1150 and have found it quite adequate.

[mookieblaylock]

Two things:


1) I thought a damper was part of the CPL difference as well between these two ratings(likely due to the differences in the pistons).


2) I'm shocked that a shop would make these changes without also requiring, at a minimum, a larger radiator. I guess it wouldn't fit, hence the difference between the 106 and 112 hoods, but still...to stand behind their work, it seems like they'd have required something.

[StephenLOJ]

That was exactly the point of what I said.

The 450HP configuration in a M2 106 is designed for emergency use only, and requires the limitations I mentioned above.

The 450HP configuration in a M2 112 is considered a standard configuration since that chassis has a more robust cooling system configuration. That is why the Dynaquest XL is configured that way.

[KRedburn]

Originally Posted by StephenLOJ

That was exactly the point of what I said.

The 450HP configuration in a M2 106 is designed for emergency use only, and requires the limitations I mentioned above.

The 450HP configuration in a M2 112 is considered a standard configuration since that chassis has a more robust cooling system configuration. That is why the Dynaquest XL is configured that way.

Emergency vehicles don't tow heavy loads. I personnaly would not consider towing with the combination that was presented without large cooling system.
Which is in agreement with your second paragraph.

[Orangecrush]

It’s funny, I started this thread because I wanted more power. All this time later, I still have not done the software tune upgrade. The local dealer said they wouldn’t and I haven’t gone to another dealer… one of these days!

Mark

[KRedburn]

Originally Posted by Orangecrush

It’s funny, I started this thread because I wanted more power. All this time later, I still have not done the software tune upgrade. The local dealer said they wouldn’t and I haven’t gone to another dealer… one of these days!

Mark

Hi Mark,
The program change to 350hp/1150lb torque is a standard calibration so any Freightliner dealer should have no issue with putting that in your DX3

[Orangecrush]

Originally Posted by KRedburn

Hi Mark,
The program change to 350hp/1150lb torque is a standard calibration so any Freightliner dealer should have no issue with putting that in your DX3

I agree and that's what I set out to do originally once I knew what I was looking for. The dealer told me they wouldn't do it because the trans was only rated for 1000 ft/lb of torque.

Yeah, yeah.... I just need to find another dealer.

Mark

[Webefine]

The DX3 has a TRV3200 transmission!

[Lubehead]

Just returned from a round trip from MA to the Mid America Truck Show In Lousiville where we had a booth. This time we stayed on the fairgrounds so we didn't bring the 24ft trailer with the Cayenne in it. We very rarely drive without the trailer and haven't had much opportunity to gauge fuel consumption when not towing.


We averaged 9.3 MPG with the cruise set to 65 MPH!