Topping your topic with titanic text.


If this thread grows long (like the last one), it's going to be a bugger to locate specific information. I came up with a master plan - you post your graph/data here with questions, then I'll (eventually) be along to...

1. Try to come up with a colorful name for the issue (I can't promise success here).
2. Give it a "headline" look, making it easier to skim among many posts per page.

 

High EGTs While Towing

So the title says it all but here are the details. Last year while pulling the boat, about 6k, I noticed high egts. I doesn't matter weather I am pulling a long hill or if it is just an overpass. While IN overdrive my EGTs would easily reach 1200*. When I take it out of overdrive it did drop a little but not much. I have to back way out of the throttle to get temps to come down. I have read about other people pulling the same load and barely hitting 1100* on a long hard pull. I have talked to Gearhead about it and he sent me a different tune to try but it didn't change anything. I think it could also be the cause of low MPGs. The graph below is pulling my 6k dump trailer on I40 in Oklahoma city. There are not any big hills just overpasses. This is going over an overpass in OD. Egts were between 1100-1200.

 

Great job on the headline there... anybody would find that at a glance.

Downshift. Really. 1600 RPM is not where the torque band is... it's closer 2000 to 2600 RPM. When you are asking the truck to grunt, you want it at it's optimum RPM for the maximum torque... and the higher RPMs spool up your turbo to inject more cool air into the engine. You're trying to get the job done with just more fuel - but you need more air with it.

What HP tune are you pulling with? When it comes to towing, the lower HP tunes do better - like about 40HP.

 

I understand where the power band is and that downshifting SHOULD lower the Egts but shouldn't I be able to go over a small overpass without downshifting and not hit 1200*.
I. know I read somewhere the other day that someone was pulling a 5er up a hill in OD and barely hit 1100.

 

I hope they chime in. I don't know what their speed/RPM was, which sticks, what tunes, rear end, turbo, where their probe is, etc....

Maybe I read your data wrong, that looked like 1600 RPM at 60 MPH, but upon reflection - that doesn't sound right. What was your RPM when things got warm?

 

I've driven my rig across the upper half of the US, nowhere in CO recently though, and with my DP60hp tow flash pcm I have to try to get it to 1200. With the new F6 and some a 80hp tow it will get to 1300.

My rig is a 24' GN LQ horse trailer, and the combined weight runs from 18k to 22k depending on the amount of horses and dogs I have on board.

 

That is what it is showing. I am right at 2000 rpm at 70 so that would be close. I just don't feel like I should have to baby it while pulling that small of a load no matter the hill. The overpasses here are really small usually no more than 20 ft rise.

 

That's what I was thinking. If I was pulling that heavy I would expect it but not with 6k on relatively flat highway with Matts tunes.

 

Where is your EGT probe located? What is your gearing?

I'm right at 1850 RPM at 65 MPH and 2000 RPM at 70 MPH, so you must have 3.73 gearing. The other person climbing hills might have 4.10 gearing, or their probe is further from the manifold... hard to say.

Are you blowin' coal in your tune?

I have one "hill" nearby that gives me 1000-1100 empty (65 MPH in OD with big tune) - but that is one aggressive hill. It's the kind of hill where you need a decel tune, or to ride the brakes (empty) to go down it without a runaway condition. Downshifting drops the EGTs right quick. BWST tried that hill while towing in a big tune and he couldn't go slow enough to back the EGTs down. He had to grab a lower tune to get things under control. If it's a short hill, you can run hot (over 1250 degrees) for under a couple of minutes before the metal absorbs the heat. Saying that... I try to avoid 1250 degrees at all times.

Looking at one of your data files, I see you have a boost fooler... so your data doesn't show your true boost. I might need a full spread to suss this out (like the one you took on Oct 19, 2012).

 

Last year when I was pulling the boat the probe was in the up pipe. When I installed the new uppies a month ago I moved it to the manifold.

I first noticed the problem last year when pulling the boat. Leaking up pipes and probably other boost leaks even though I could build over 20 psi. It did not matter what tune I was in , I had to slow to around 40 to keep the temps at or below 1200 when pulling a decent hill going to Greers Fairy in Arkansas. The boat is 5500 lbs. I thought the new spider boots, up pipes, HFO, and 6/6 wheel would more that fix the problem.

However I don't notice much if any lower temps. Maybe 50*. I do get a good puff of smoke at start or when I hit the throttle on the highway to pass but it clears up when boost builds. I don't roll coal but I do think it is more than Matt thinks it should have. Although I don't have any frame of reference for that.

 

Gearing is 3.73

 

My EGT probe is in the rightside exhaust manifold....3.73 gears.

 

Hmmm.... When my injectors and turbo were stock, Stinky could blow about 22 PSI boost in stock tune (air, exhaust, fuel, and red line mods). I was getting wonky readings on my boost gauge after a number of WOT runs in 80E and I discovered a leak in my intake plenums. I'm not saying this is the issue with yours, but I threw that in there for reference.

 

More thoughts: I was distracted by air on this... but there is another element that drives the EGTs way up - oil. I define a "hot tune" as one that asks more from the engine than it can deliver without heating something up. Low ICP can raise EGTs, but there are a lot of root causes for this condition. I'll look more carefully at your data again.

 

After careful review of your data, something looks a little "hinky" with your IPR. The number at idle looks a little low for 30% nozzles, but it looks normal at WOT. I also have to ask if you ever solved your high Perdel problems. I see so much going on in your old data I have, and with the experience I've gained since this data was taken... there is a plethora of issues I see.

I'll need some fresh WOT runs with:

• Fuel Injector Pulse Width (0-5 ms)
• RPM (0-3500)
• Injector Control Pressure PSI (0-3500)
• MPH (0-100)
• Injector Control Pressure Duty Cycle %
• Mass Fuel Desired %

Are you getting any banging, clicking, or excessive cackle on one side more than the other? Smoke or haze (any color)? Is it pretty stinky by the tail pipe at idle?