1st Tow with NEW Truck - Diesel Forum

07HEMI4ME · 04-15-2006, 09:48 AM

Question? This was my 1st tow with my new truck (see Sig)My last truck had the 7.3l in it. When pulling at 55-60 mph truck would be running at ~2000 rpm in Tow/Haul and ~1600 rpm out of Tow/Haul, is 1600 rpms lugging the engine? should I keep it in Tow/Haul?

My 02 with the 7.3l never had a problem towing at this speed/rpm and if I came to a small incline the turbo would just spool up and carry us over it without down shifting, on this truck truck downshifts, I take it this is normal. Different Beast I guess.

I must say the Integrated brake controller is great, you do not feel the trailer braking as with the old truck/brake controller.

william_04_X · 04-15-2006, 10:45 AM

i keep my truck in T/H whenever i'm towing my trailer...when i had my pyro on the truck while towing my trailer, i noticed that i could really get the egt's up when the rpm's were low and i wanted to accelerate or maintain speed going up a moderate grade without downshifting...1600 rpm's is fine for steady, flat cruising..

throttle response has been a good indication for me ...if i give it a little go pedal with a load, and the rpm's don't move, i know i'm just making heat in the motor and goose it to get it to downshift...you'll get used to a motor that spins faster..

ChiefGReid · 04-15-2006, 02:12 PM

On flat ground, it is my experience, RPMs should be around 1700. When towing over mountains or hills, I get the best performance when the RPMs over 2,000. I keep an eye on EGT and Boost. I try to keep my boost under 25 lbs.

Experiment a bit and you will soon see where you get your best performance.

I find that the tow/haul and general towing performance is way better then my old 7.3 01 PSD.

07HEMI4ME · 04-15-2006, 03:08 PM

[ QUOTE ]
i keep my truck in T/H whenever i'm towing my trailer...when i had my pyro on the truck while towing my trailer, i noticed that i could really get the egt's up when the rpm's were low and i wanted to accelerate or maintain speed going up a moderate grade without downshifting...1600 rpm's is fine for steady, flat cruising..

throttle response has been a good indication for me ...if i give it a little go pedal with a load, and the rpm's don't move, i know i'm just making heat in the motor and goose it to get it to downshift...you'll get used to a motor that spins faster..

[/ QUOTE ]

I guess I will have to, the old 7.3l if it downshifted and went to 2600-2800 you really knew it this one (6.0l) it seems to like it.

Also this was flat land (Florida)

What about fuel mileage? the 7.3L like to be kept under 2000 rpm, what is compareible in the 6.0L? 2200-2400 rpms?

**Kanman** · 04-15-2006, 04:03 PM

Lugging a diesel certainly is the death of these engines. Watch your gages and experiment with what speed vs rpm vs your gages for your best bet. I don't own a 6.0 so I really am unsure about the 1600 RPM. It certainly is less cubic engines than the 7.3, so I would "assume" they require a few more RPM's to stay in their working range.

You sure wont hurt a thing running more RPM's

**SmokeyWren** · 04-15-2006, 04:34 PM

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... is 1600 rpms lugging the engine?

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No.

Since your tranny is automagic and controlled by the computer program in the PCM, you're not smart enough to lug the PSD engine. The PCM is smarter than you are, and knows when it should downshift to prevent lugging the engine.

Hand shakers are different. The driver has to know when to downshift to prevent lugging the engine. But not with your TorqueShift tranny. [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]

954doorf350 · 04-15-2006, 07:05 PM

are 20" wheels stock on this truck? maybe that is why rpm is so low. with the same 3.73 gears matt

ljack10270 · 04-15-2006, 09:41 PM

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I get the best performance when the RPMs over 2,000.

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I thought you are susposed to get your best gas mileage by trying to keep the 6.0 under 2000 rpms while towing? [img]/ubbthreads/images/graemlins/shrug.gif[/img]

barrelhorses · 04-15-2006, 10:07 PM

I just finished a 1600+ pulling trip with my trailer and two horses. I averaged 11.13 mpg running 65 to 75 mph (rougly 1900 to 2100 rpms). The tranny downshifted on pretty much every hill, boosting RMPs up to about 2400 or so.

07HEMI4ME · 04-17-2006, 05:45 AM

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are 20" wheels stock on this truck? maybe that is why rpm is so low. with the same 3.73 gears matt

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Yes they are

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I just finished a 1600+ pulling trip with my trailer and two horses. I averaged 11.13 mpg running 65 to 75 mph (rougly 1900 to 2100 rpms). The tranny downshifted on pretty much every hill, boosting RMPs up to about 2400 or so.

[/ QUOTE ]

I'll take 11 MPG, I was getting in the low 10s pulling at 70 MPH (2,000 rpm) on th e7.3L

The last leg of our return trip was interstate ~16 miles, I set the cruise on 70 and the darn thing kept wanting to downshift for every little overpass and even on the flat sections, bringing RMPs to 2200-2400 range, the 7.3L never did this.

I guess IM going to have to re-adjust to towing all over again. We are going to East TN the 1st weeek of June, it is going to be a long trip if the truck will not hold 70 on flat land with wanting staying in shift all the time, it might just drive me crazy.

barrelhorses · 04-17-2006, 06:10 AM

[ QUOTE ]
[ QUOTE ]
are 20" wheels stock on this truck? maybe that is why rpm is so low. with the same 3.73 gears matt

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Yes they are

I guess IM going to have to re-adjust to towing all over again. We are going to East TN the 1st weeek of June, it is going to be a long trip if the truck will not hold 70 on flat land with wanting staying in shift all the time, it might just drive me crazy.

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Remember that overall tire diameter is more important than wheel size. It is completely possible for the 20" tire/wheel combo to be the same diameter as say a 17" tire/wheel combo. I haven't done any actual comparisons myself, but I wonder what the diameter of the stock 17" tire/wheel combo is? I also wonder what the diameter of the "stock" 20" tire/wheel combo is? I believe my 18" tire/wheel combo is about 33" but will measure again to make sure. Overall, I doubt that marginal differences between tire/wheel sizes will make that much difference in RPMs.

My truck never offered to downshift on flatground, unless I decided I needed to pass somebody [img]/ubbthreads/images/graemlins/smokin.gif[/img].

07HEMI4ME · 04-17-2006, 09:45 AM

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
are 20" wheels stock on this truck? maybe that is why rpm is so low. with the same 3.73 gears matt

[/ QUOTE ]

Yes they are

I guess IM going to have to re-adjust to towing all over again. We are going to East TN the 1st weeek of June, it is going to be a long trip if the truck will not hold 70 on flat land with wanting staying in shift all the time, it might just drive me crazy.

[/ QUOTE ]

Remember that overall tire diameter is more important than wheel size. It is completely possible for the 20" tire/wheel combo to be the same diameter as say a 17" tire/wheel combo. I haven't done any actual comparisons myself, but I wonder what the diameter of the stock 17" tire/wheel combo is? I also wonder what the diameter of the "stock" 20" tire/wheel combo is? I believe my 18" tire/wheel combo is about 33" but will measure again to make sure. Overall, I doubt that marginal differences between tire/wheel sizes will make that much difference in RPMs.

My truck never offered to downshift on flatground, unless I decided I needed to pass somebody [img]/ubbthreads/images/graemlins/smokin.gif[/img].

[/ QUOTE ]

Just messured them and the 20" wheels and tires are 33"

rubystargoats · 04-17-2006, 04:04 PM

Different beast indead, I traded from 7.3 manual (1800 to 2400 RPM when pulling) to 6.0 auto and after 22,000 miles it still dosn't feel right to turn a diesel the 2800 to 3200 [img]/ubbthreads/images/graemlins/blush.gif[/img] RPM the 6.0 likes to run with the auto when pulling hard. With 4 tons of hay and over a ton for the trailer, or the slide in camper and boat it will pull any grade at speed and gets 10.5 MPG or more while doing it, so it can't be all bad, I just can not get used to it [img]/ubbthreads/images/graemlins/tongue.gif[/img].
When the warranty is up Maybe exhaust and custom SCT will make it all better [img]/ubbthreads/images/graemlins/smile.gif[/img] , at least I will get TC lock in 3/4 not just OD.

Mike_Costello · 04-18-2006, 08:17 PM

I'm in the middle of a short vacation to So. Cal. from Nor. Cal. Pulling my 5th wheel I averaged 12.2 until I got to the grapevine which dropped to 11.5 because of the grade. The 5th wheel is running at about 10,500 loaded. Tow/haul up the grade remained steady at 27-2800 rpm with actual speed 55-60mph. Truck did a grat job--no complaints! This wasn't my first tow, but the longest one with the truck broken in. Mike.

Painted Horse · 04-18-2006, 09:42 PM

The 20" are 60 series and the 18" are 70 series. Which means the sidewalls are smaller. So the overall tire diameter is the same for both tires even though the rim is bigger. 33 inches. If you mount a 65 series tire on the 20" rim, then you will get a taller tire.

The tow/haul mode tries to keep the engine in the powerband. You'll notice coming down a slight grade in tow/haul at maybe 30mph, it'll keep the engine in a lower gear in the 2000 rpm range, vs the older 7.3L trucks would upshift to a higher gear and you'd loff along at 1200-1400rpm. If you needed to accelerate, the 6.0L is already in the power band, The 7.3L would have to downshift to 3rd or 2nd and then give you power.

If you are worried about seeing your tach at 2800rpm when climbing a hill, wait until you see it at 4000rpm coming down hill!