Medium Duty Specific EGT's

[ricko]

Originally Posted by RobertWJacobson

Hello again
Are you in OD? I try both over drive and non overdrive, similar results just less power in OD.
How much boost is it producing on the flat?
Around 5psi on the flat.
What is your IAT?
Never payed attention to that.
Have you ever had the IC cleaned?
Nope, truck only has 40,000 miles on it.
I would think that the RPM would be right at 2000.
Are you running a performance tune?
Stock tuning.

.

[RobertWJacobson]

Okay from my experience, the boost is the thing producing the high EGT for you. It is the sustained demand and engine output that is doing it. From what I have learned on mine is that I would recommend a two stage water injection to keep the EGT's in check. First stage coming on at 2 to 2-1/2 psi second stage coming on at 4-1/2 to 5 psi. pushing about 7 gallons each, so you will need to have a rather large tank mounted somewhere on your truck. This will keep your EGT's in check on the flats to slight grades for the steeper grades or longer duration grades you will need the third stage progressive water injection pushing between 10 to 14 gallons per hour. All of these are automatic in their operation and the staging would need to be tailored to your individual truck and towing experience.

Robert

[RobertWJacobson]

Just to make sure. I am not selling anything or recommending any brand of water injection. I am only saying what I have found to control my EGT's, and hoping that it will work for your truck also.

[BIG85JEEP]

I just made a quick trip to Atlanta weighing 25,000 lbs. I ran the whole way with the OD off and never topped 1200 degrees. I pulled Mt. Eagle in TN at 50 MPH. I even got slowed to 40 and was able to accelerate back up to 50. I'm going to get a new intercooler, redo the exhaust and look at the water/methanol system.

I was running about 2800 RPM at 65 MPH.

Can you guys please post up your RPM at 65 & 70 in OD?

Thanks

[RobertWJacobson]

This is with the OD on
I run 63MPH and am turning about 1900 RPM
At 70 it is about 2300 for me.

I have 3.73 gearing

With the OD off I was turning about 2300 RPM maintaining the 55 MPH.

I just brought my trailer home last night and was able to maintain 55 MPH up the grade with the OD off and kept my EGT under 1000. Yes it seemed like everything was passing me but I was happy maintaining the speed limit and the low EGT. I had just installed my 14 gallon nozzle before picking up the trailer. So at this point I am spraying somewhere between 17 to 21 gallons per hour. 7 gallons per hour on the first stage and 10 to 14 on the progressive stage. Thinking of putting a second stage steady ahead of the progressive to take up the difference between them.

Robert

[Jager]

08 Kodiak 4500, 4WD, 5.13 gears, 6 speed, run around 2200 at 73mph

[bamfm7]

I cant help you out with cruising egts....cant remember. I pull a 42' 5th wheel camper (not the one in my avatar) I have the K&N air filter, 4" exhaust from the down pipe back. I am running a EFI tow tune from ATP (idaho Rob). On long wide open up hill pulls my egt gauge gets to 1250. I did the 6th gear upgrade and I cruise at 72mph @ 2300 rpm. IMO if you can get the air in and out of the engine I would look into the tune. The tune may be a little hot for the load your pulling. ***one thing I would look into is the engine tune. When I first got a hold of my EFI LIVE I loaded in a STOCK engine tune from a 1 ton pickup. Wide open it worked ok, But cruising and normal acceleration the EGTs were really HOT. I do not have an explaination for this but I know for a fact that a pick up tune will not work in my truck. Maybe the cams are different????

[Sprj8008]

Try running the stock tune and see what the temps are. I'd bet you can deal with this in tuning. I had problems with the tune being too hot with a heavy trailer. Downshifting helped, but overall it was just too hot. Smoke isn't an indicator. Same amount of fuel with no air will smoke. Add more aid and cylinder pressures and heat increase. Head gaskets don't like the pressure and the pistons don't like the heat. Either way it gets expensive. Methanol might be an option. More timing might give you some relief...
Talk to the guy who's done your tuning...

[BIG85JEEP]

I know there are a few good EFI Live tuners. Do you guys think any of them have the medium duty truck figured out better than the others?

[ronjhall]

My engine EGT's run at 850 with a 60 hp tune. On steep hills they climb to 1200+. But never over 1300. Maybe it is my load. It's usually 23,000 lbs. I am using a VDO analog gauge.