What do you consider lugging a ho 6 speed ?

[NIsaacs]

I just read that the standard output has peak torque at 1700 rpm with a 6 speed 68 RFE and 3.23 first rear and the ho has peak torque at 1356 rpm with Aisin 6 speed 3.73 rear axle. Must be true it was on line

Yup, i think so

I know i have to be easy with mine, when I pull out on the main highway loaded and turn left. It is up hill and my left tire will squeal if I gouge on it too much. I have to wait until I am straight, by then it is in 2nd, then go for it. I like it

 

[AH64ID]

I’ve seen references to peak torque being at 1800 and at 1356 on the 1075 HO. Would be nice to know the correct number. 1800 seems more realistic.

 

[Wiredawg]

I’ve seen references to peak torque being at 1800 and at 1356 on the 1075 HO. Would be nice to know the correct number. 1800 seems more realistic.[/Qbeen!

I too believe 1800 is peak, but not terrible at 1350ish either. My 2018 C&C Cummins is 1600 peak tq (750) and 2400 peak HP (325). I assume my new peak TQ and HP is at the same respective RPMs.

 

[AH64ID]

Looking into the stock file it appears 1800 rpms is the peak torque value.

 

[Cummins12V98]

I mostly tow at 60 in 6th with rpm's @ 1,750. Just seems happy and quiet there.

 

[slowmover]

I mostly tow at 60 in 6th with rpm's @ 1,750. Just seems happy and quiet there.

It’s 59-mph/1,725-rpm where I set the cruise on my 555. Guaranteed not to fall below 24-MPG despite major cities, rain, darkness or crosswinds to about 15-mph; truck loaded up to GVWR; across Gulf Coast. (Highs to 27 if conditions favorable).

The NV-5600 & 3.73 on stock tire size.

Being in the right gear at the right moment might take practice, but it pays off.

An auto is easier to live with (they say), but it’s at the margins (transitions) where MPG is found (not stock spec on display, but earned by the operator).

A trans with less than ideal programming has to be worked around. Good as big truck “Autos” have become, one has transitions that — where brakes aren’t an answer re momentum changes — one learns to “wait” for the truck to make up its mind.

More important is that the operator change his habits. FADEC rules, Billy Big Rig drools.

.

 

[AH64ID]

I pulled this from a Stellantis 2022 Product Information Guide

For those that care...

SO: 850 lb-ft @ 1700 is 275 hp and 370 hp @ 2800 is 694 lb-ft
HO: 1075 lb-ft @ 1800 is 368 hp and 420 hp @ 2800 is 787 lb-ft

 

[bcbender]

I didn't know that there was such a difference in the compression ratio.

 

[AH64ID]

I didn't know that there was such a difference in the compression ratio.

That happened in 2019 with the new motor. I think the high compression of the SO is partially responsible for the increased DEF usage, as overall power isn’t up much. It also could have less EGR, like we talked about for the higher DEF usage in the HO the other day.

 

[bcbender]

I have the HO,... so the higher the compression = more DEF or was that the other way around? I am OK with using a little more DEF and not recirculating EXH gas back through the system, maybe my EGR cleaning will not be as bad as some I've heard when the time comes.

 

[AH64ID]

I have the HO,... so the higher the compression = more DEF or was that the other way around? I am OK with using a little more DEF and not recirculating EXH gas back through the system, maybe my EGR cleaning will not be as bad as some I've heard when the time comes.

While there are many variables to NOx production it's fairly generic to state that the higher the pressure/temperature the more NOx we produce. Retarded timing means less pressure and EGR use means lower combustion temps.

Higher compression will yield more cylinder pressure, which means more NOx production. As load increases EGR use decreases. I don't know where EGR goes to 0% on 19+ motors but on my 18 HO the EGR shuts off around 60-70% based on RPM. Above that load DEF is all that's used to reduce NOx, so if the compression is higher the NOx production would be higher.

That's a fairly broad statement, as there are also other things that can be done with tuning. It's just my suspicion the the higher compression is one of the factors with the 19+ SO burning more DEF than the 13-18 SO.

 

[bcbender]

I understand, I was just saying we both have the high output not the standard output but the trend is the same, 19+ uses more DEF... I now have the capability (I think) to look at this so maybe we can compare notes once I get the AlphaOBD up and running.

 

[kthaxton]

I didn't know that there was such a difference in the compression ratio.

Also, and forgive me if you already know this.....the difference in compression ratios is needed because of the increased boost of the HO.

 

[NIsaacs]

Also, and forgive me if you already know this.....the difference in compression ratios is needed because of the increased boost of the HO.

Does anyone know what the boost difference is? In '01, the SO is 16.3 and the HO is 17.1. On the early 5.9, the 6B is 18.5, 6BT is 17.5 and the 6BTA is 16.5.

 

[Wiredawg]

Does anyone know what the boost difference is? In '01, the SO is 16.3 and the HO is 17.1. On the early 5.9, the 6B is 18.5, 6BT is 17.5 and the 6BTA is 16.5.

Nick, I've owned all the gens cept'n the 19+ and I recall max boost in the high 20s to low 30s. All were BOMB'd, so hard to recall differences from stock, but pretty sure I'm not far off. Anyhoo, others may have better recallection.

 

[kthaxton]

I also seem to recall my max boost (2015 SO) being somewhere around low 30's upper 20's. The gauge goes to 35 if that means anything.

 

[gsbrockman]

While there are many variables to NOx production it's fairly generic to state that the higher the pressure/temperature the more NOx we produce. Retarded timing means less pressure and EGR use means lower combustion temps.

Higher compression will yield more cylinder pressure, which means more NOx production. As load increases EGR use decreases. I don't know where EGR goes to 0% on 19+ motors but on my 18 HO the EGR shuts off around 60-70% based on RPM. Above that load DEF is all that's used to reduce NOx, so if the compression is higher the NOx production would be higher.

That's a fairly broad statement, as there are also other things that can be done with tuning. It's just my suspicion the the higher compression is one of the factors with the 19+ SO burning more DEF than the 13-18 SO.

I wonder what the DEF consumption is like on a 2019+ LO (Cab & Chassis) ?

 

[AH64ID]

I wonder what the DEF consumption is like on a 2019+ LO (Cab & Chassis) ?

Haven’t heard yet, but I’m sure one of these days we’ll get a detailed report.

 

[gsbrockman]

Haven’t heard yet, but I’m sure one of these days we’ll get a detailed report.

 

[JLEONARD]

I mostly tow at 60 in 6th with rpm's @ 1,750. Just seems happy and quiet there.

That's about where I tow also, more like 62-63 at 1750. That's NOT using tow/haul mode and mostly in Florida so far.