I installed a set of Autometer gauges in my truck prior to installing a tune with my Predator programmer. I wanted to put the truck through the mountains in a stock condition so I knew what kind of EGT's were acceptable by GM. I ran some 6-8% grades at all speeds and varying throttle. To my surprise, this truck put out temps in the range of 1000 degrees @ 70 mph all the way to 1250-1300 degrees with the hammer down up the mountains. Now this is a completely stock engine!

My local diesel performance shop has tow tested the LBZ and they tell me that the stock LBZ pulling a 8,000 lb trailer will see temps in the 1500 degree range. They have dyno'd several of these engines and the best torques were produced around the 1400 degree mark. I trust this shop for its knowledge, experience and information since they have been performance tuning the 6.6L Dmax since its conception, with great results BTW.

I was quite surprised to see that the LBZ would produce EGT's like that on a stock motor. That really tells me that GM has "tweaked" this motor to its safe extreme as much as they dare. Anyone who decides to run a programmer on these trucks should definitely have gauges so as not to melt down the turbo or cause serious damage.

My purpose for the tuner is to change tire size so the DIC will read accurately and remove the speed limiter.

they tell me that the stock LBZ pulling a 8,000 lb trailer will see temps in the 1500 degree range.

That does seem pretty excessive. My stock Dodge would hit easily 1400* before modifications while towing in altitude. I read that the new completely stock Fords and Dodge's have high EGT's towing in the mountains too. I think many would be surprised if they installed a pyrometer on thier stock diesel motors and hooked up thier trailer and hit some mountain passes. High EGT's on most stock motors regardless of manufacture is more common than we think.

So what max temp does the shop think is fine for a long grade towing?

I could hit 1400deg with mine when it was stock going up hills floored and empty. 1400deg is OK as long as you don't go for too long that way. People do the 1/4 mile hitting well over this and don't seem to have any problems but that is just for a couple of seconds each time. A larger exhaust and losing the KAT will help.

So what max temp does the shop think is fine for a long grade towing?

They told me I could safely run long grades @ 1400* without any damage. That seems pretty accurate from all I have read in the past 3-4 yrs on the Dmax. He told me he hits almost 2000* racing at the strip. I think I'll pass on that one. :eek:

Are these temps being recorded in the exhaust manifold or after the turbo in the down pipe?

exhaust manifold for me.

Are these temps being recorded in the exhaust manifold or after the turbo in the down pipe?

My diesel shop only installs the pyro thermocouple "pre-turbo". They tell me that there can be as much as 400 degrees difference with a "post turbo" install. The temps I am reporting and stating are all "pre-turbo" numbers and reflect the temperature being sent to the turbo. Personally, these are the only numbers I need to know to run at safe temps.

Just FYI, my LBZ, not sure of altitude here in michigan has to be less than 1000 ft above sea level, runs about 1100 degrees with the hammer down unloaded. Gets there are about 70 mph and hangs there till about 90.. Had to let off at that point. With the predator 65 hp setting loaded, I see them hit about 1200, but that is if I am on it REALLY hard for a long run. Like, on ramp where you are floored for a quarter mile or more. What kind of boost pressures do you make? I am in the 22, 23 psi range..

I have hit 1450 stock going from Den to CHeyenne with an enclosed car hauler with a car in it, about 8000 lbs., bone stock 70 mph head wind gusts, 50 sustained. I actually decided to slow down because it spiked to 1550 a couple of times. Now i can't get over 1350 uphill, hammered with that same trailer and Bully Dog on level 2. Think the turbo helped?

What kind of boost pressures do you make? I am in the 22, 23 psi range..

Mine is about the same, I've seen boost up to 24 psi running stock or with a tune. I dont think the Predator can make boost pressure adjustments.

Mine is about the same, I've seen boost up to 24 psi running stock or with a tune. I dont think the Predator can make boost pressure adjustments.
Predator V2.0 did nothing for boost but I beleive the V2.02 does modify boost tables.