Concur. I generally prefer to tow in the higher settings specifically because it takes less throttle input to reach X amount of power.

Unfortunately my towing preferences have little bearing on the OP's issues since I have a handshaker.

 

You really need to slow down and understand the difference between max power and constant power...

My truck dyno's at 516hp on the Dyno tune... Does that mean I am making 500hp all the time? Pulling my trailer at 500hp all the time? No...

Fuel is fuel, be it at 100% TPS or 50%TPS...

Guess what... I was in Colorado working less then 6 months ago, right in Littleton... Denver, Colorado Springs, Penrose... Then before that I was in Santa Fe, New Mexico, before that I was in Boise, ID, before that I was in Phx, AZ, before that I was in SeaTac, WA, before that I was in Prescott, AZ... 16 weeks ago I was in Grants Pass, OR... And 4 weeks ago I was in Henderson, NV... In Bakersfield, CA right now...

FYI... I-80 thru wyoming is no less then 6500' or higher... Pulled that at least a dozen times over the last 8 years.

Please dont even pretend you know the driving experiences I have, I have flat wore out 4 7.3 trucks over the last 15 years, driving from one end of this country to the other, most of that pulling between 5k and 25k... From a 95 (260k), 96 (270k), 97 (250k), 99 (280k) and this current 01 (230k as of tonight)...

Water injection was installed on this truck when I still had a stock turbo and it has been on since. One of the single best mods you can add to a turbo diesel is a quality water injection system, however it is not needed if you have a truck that is operation properly.

If you need a lesson on driving your truck while pulling a trailer feel free to come on down to Bakersfield anytime in the next 3 weeks. I'll hook up to the trailer (10,500 wet weight) and we will take a little drive over the grapevine (from 500' to 5400' in about 4 miles). I will leave the water injection off and we will drive right over that pass, never dropping below 65mph...

The sensible thing to do, is down shift and get the damn RPM's up...

Biggest issue with cruise issues is not having a linear throttle curve. Some tuners like to adjust it to when you are at 50% of TPS travel, you are at 80% or more of fuel... Makes people think they have a sooper fast truck...

Thats all I will say.

Handshaker... AKA rowboat... LOL

 

As for the TPS, I recognized that right away when I first got the tune. I understand the psychology behind it and it makes good sense. Now I know (based on your statement) not all tunes use this same technique - OK, that makes good sense for different reasons.

As for the towing lessons: I appreciate the offer, but I'm not a newb with that aspect so it's not necessary. Does ScaldedDog need to downshift? Absolutely! Is there disagreement there? No. Take one more look at the title of the thread "Why don't my EGTs decrease when downshifting? and I remember one piece of very useful information you conveyed - back off during the downshift. AFTER the downshift is where things are going wrong.

Your throttle is two-dimentional: From less to more. Backing off the throttle alone is not like using a lighter tune. I did some reading last night because I was tired of my not knowing enough about tunes in these discussions. While reading posts here and elsewhere, I see people making statements that would be accurate if the fuel handling was two-dimensional. It's not. These trucks don't have every sensor needed to dial in the tunes to modern standards, but they have enough to make big improvements over stock. Tunes add more fuel in relation to several Xs. There is a complicated series of "if this, then that" taking place when you step on the go pedal and a tuner does it differently than stock. Based on the "more fuel alone" concept, just stomping on the throttle alone would be like running a higher tune and backing off the throttle would be like running a lower tune. Does this really make sense to everyone?

ScaldedDog has thin air, you need to thin the fuel/air mix or you get smoke and heat. Jody had to back something off to reduce smoke during the live tune - that would be the fuel/air ratio. That is precisely what a lower-power high-altitude tow tune does, as well as lower the shift points the way CSIPSD mentioned. The thinner mix robs you of some torque, but the higher RPMs compensate. If you want more go from your truck, try a lower altitude. I see a difference in performance when I drive to Seattle (sea level).

I'm sure CSIPSD's truck is fully capable of what he describes here. I don't have a high enough pass close-by to throw AE on and collect some data with my truck on the issue. My last visit to that elevation was without AE in my arsenal. I will just say "Try the 40t" and I'll stop aggrevating the readers. By all means, try CSIPSD's method because if it works on his, it might work on yours - I never said you shouldn't try it. I am just saying the next time you pull on the pass, have more than "hammer down" in your toolbox.

 

I'm done... People put way too much on all these specialty tunes...

You dont need a 20-30-40-50-60-70-80...90hp tow tune...

 

My CC was overly sensitive, and more so in each higher tune, especially going down a grade. Going uphill there was no problem. During live tuning Jody was able to make the CC less sensitive. How? I don't know, but I beleive it was to the CC strategy and not to each tune.

It is stiil a little sensitive in higher tunes but in stock tune it is, well, like stock.

 

I can live with it the way it is, my HPOP will possibly change the behavior anyway. Thank you for getting back to me on that!

 

Roger that. She doesn't jump up off the line like you slushbox drivers trucks, but she pulls hard. That's good enough for me.

 

Hey I'd like to see how long you'll last draggin my 20k trailer up the Grapevine at 65mph hehehe.....

 

I had a chance to do my typical tow from Denver to Moab and back, and thought I'd update this thread...

Rather than towing in 80t like I always have before, I spent nearly all the time in 60t, and turned it down to 40t on some of the taller passes. My observations:

1) No change to EGT behavior when downshifting, at either the PCM's direction, or mine. EGT's generally go up on downshifts, and certainly don't decrease, unless I back off during the downshift. Of course, then it's the backing off that's lowering EGT's, not the downshifting.

2) I stand by my assertion that the only difference in these tunes is the fuel supplied at a given pedal position. The 40t is easier to modulate EGT's than the 60t, and the 60t is easier than the 80t. I could drive the 60t just like the 40t, but just had to use smaller pedal movements to do it.

3) Even with #2 in mind, I do like having both a 60t and 40t for the kind of towing I do. In the 60t I can use the cruise control to drive the speed limit on the rolling hills between Vail and Moab, without evening having to look at the EGT gauge. The highest I saw on that section was 1250. Flipping to 40t on the passes made them more enjoyable to drive, and safer if there's traffic around that demands more attention than the EGT gauge.

I still don't have a good answer to my original question, but I learned a lot in this thread, anyway. Thanks to all who contributed.

Mark

 

I'm sorry, and this is no knock on you, but if I had to back out of it with stock injectors... I would not only be embarrassed, I would be looking for a new tuner.

I just towed from Bend Or to Great Falls MT yesterday... didnt fill up the water when I left home, so I did not have the benefit of it.

There was not one point on the entire trip where I had to slow down, not once did I have to drop below the posted speed limit... EGT's would spike to 1300, hit the OD button and they drop to 1150 or so and I just keep on trucking up the pass.

I also think I have a boost leak, or the turbo is getting ready to chit, as I never saw over 32psi the entire trip.