LBZ: 1200* steady flat ground towing

[rennat_2006]

2006 cclb lbz 5" straight exhaust, magnaflow downpipe, s&b intake, 285 tires, stock tuning.

Pulling my 24ft bumper pull travel trailer (7400lbs) fully loaded but im probably at that weight with the firewood in the bed of the truck and the trailer not just the trailer alone. This isnt one of the high profile trailers either, just a regular old school style.

Going down the freeway at 65-70 in running 1200* pretty much steady, mostly running in 5th gear to try to manage the egts. Any sort of decent sized hill in dropping into 4th and pulling 1300-1400. Seems like im only running 5-10psi of boost at cruise speed.

Like i mentioned above im back to stock tuning trying to fight these egt issues. Aftermarket tuning had the same problems. I dont understand how stock trucks with no gauges are pulling way bigger trailers than what i have and not melting down if their egts are anything like mine.

Ive already checked balance rates and stuff like that and evèrything has been fine. Only thing i can think to have checked next is the intercooler for leaks. Anyone else have any ideas?

 

[04chase]

1200 isnt that high , what are max egt's and for what kind of time? any logs?

 

[rennat_2006]

1200 flat ground running 65ish. Like 1200* the full time im in tow then on hills it goes up from there. On hills i limit myself to 1350 sustained.

I would love to hook a egt gauge to a totally bone stock lbz and see what it does

 

[Turbo Performance]

1200* isn't dangerous high but it does seem on the high side for what you're towing. Boost seems in the range I might expect so I'm not sure you have a boost leak but it definitely won't hurt to double check and cross it off the list. EGT's might just be higher from the low-ish RPM from the tow speed. Might try either towing a bit faster or try 5th gear to bump up the RPM to lose some EGT's if it's borderline lugging with the weight.

 

[Awenta]

That does seem a bit high for flat ground. Whats your rpm at that speed?
And what was the ambient temperature?

Is your air filter clean? Can you verify the vanes aren't sticking. Any smoke?

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[Ridin'GMC]

Since you're running 33" tall tires, it's somewhat moderate for your egt. Bigger tires increases egts a bit during towing. Stock truck are lower to the ground than yours is. But 1200 is a wee bit too high for what you're towing, is the air filter dirty? Boost leak may be possible. I would expect to see at least 7-8 psi towing mostly, 10-15 uphill on a small hill. I pulled 15k and get about 1000-1100* in 4th gear at 2200 rpm on my 37s with stock gearing. Keep the RPM to at least 1900-2200 for towing.

 

[Dozerboy]

How was the wind? It has a huge affect on EGTs. What was you MPG like?

Duramax is rated for 1350* sustained, I think your being overly cautious. Unloaded with a head wind my EGTs are over 1000*.

 

[Digmax]

What is your boost wot?

 

[ALLY Fox]

What are you using to read EGTs? Have they always been high when towing that load? EDGE EGT gauge is notoriously inaccurate. My LLY runs about 900 on flat pulling a ~12K 5th wheel at 63mph (sweet spot) according to my ISSPRO gauge and I seldom see anything over 1200, even pulling big grades. Big tires = big EGTs especially when towing and tire pressure is something to check, I run 75 psi on drive tires and 70 on steer tires

 

[rennat_2006]

2000 rpm running 65ish in 5th gear, closer to 3000 rpm in 4th.
Ambient temps in 40's.
Looking thru window on the s&b airbox the filter didnt look that bad, i will take it apart and clean it for the hell of it when i get home.
No smoke, dont seem to have a problem with the vanes. I was a gm tech so im all to familar with vane problems so i run the truck hard to cycle them everytime it is driven.
Didnt have much for wind on the first half, had some side winds on second half once we got up into the hills.
Havent checked it wot with trailer on but if i remember right im only seeing like 26 or so wot empty.

Heading home tomorrow so i will see how she does this time and will check boost while towing.

 

[rennat_2006]

Running a set of banks mechanical gauges, boost and egt.

55 psi front and rear right now. Usaully run 55 up front and 45/50 in the rears unloaded to get even wear.

 

[THEFERMANATOR]

If it's always been high, then bad egt probe would be my bet. I tow a 32' bumper pull travel trailer, and only run about 800 running 70. I have 3.42 gears, tow in 5th, and I turn about 1900 at 70(pretty much the same as 6th with stock size tires). I have an LB7 though.

 

[NC-smokinlmm]

If it's always been high, then bad egt probe would be my bet. I tow a 32' bumper pull travel trailer, and only run about 800 running 70. I have 3.42 gears, tow in 5th, and I turn about 1900 at 70(pretty much the same as 6th with stock size tires). I have an LB7 though.

This^^^

I chased an egt issuse on my lmm, which turned out to be a bad probe. Swapped it out and all was good, it was a banks probe too...

 

[c20elephant]

If it's always been high, then bad egt probe would be my bet. I tow a 32' bumper pull travel trailer, and only run about 800 running 70. I have 3.42 gears, tow in 5th, and I turn about 1900 at 70(pretty much the same as 6th with stock size tires). I have an LB7 though.

Ferman, keep in mind you tweak the bejesus out of your tune and can change it, some of us have an unlocked tune (Thanks BTW :thumb but we don't have the tuning experience you do...

 

[S Phinney]

If your gauge is right you do have a problem. I pull heavy weights regularly. I do not have those kinda egts. Usually I can maintain 900s and 1100s pulling grades. Of its doing it with stock tuning look into boost leaks or malfunctioning turbo control. If it has stock exhaust look into a restriction.

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[rennat_2006]

Thanks guys. Got to have a cracked intercooler or something

 

[c20elephant]

Boost leak test


https://www.youtube.com/watch?v=x5XoOe3Zjuo

 

[malibu795]

Wind will add egts even 10mph head wind..low tire pressure on trailer, miss alignment of axles etc..

Stock tune truck I wouldn't worry about it.. Sweet spot is above 1900-2000 rpm

Good efi live tune will drop egts..
Comparing my trucks egts to a stock is Apple to oranges

 

[THEFERMANATOR]

The 1st 06 LLY I tuned had a BULLY DOG on it when he brought it to me. On the "TOW TUNE" it would hit 1500 in the blink of an eye, flashed it to a stock LBZ, and EGT's topped out at 1200, and on my performance tune(about a 90-100 HP tune) they topped out at 1300 on his truck. The STOCK LBZ tune was FASTER than the BULLY DOG tow tune setting, and even with a bigger tune than either of them, I still maintained similiar EGT's. These were all unloaded EGT's on flat ground at sea level down here in Florida. Now the economy tune from here I tweaked some, but it will run 600-800 EGT's empty on flat ground with a slight headwind, switch over to the performance tune and they drop back down to 400-500. Tuning is PIVOTAL to EGT's, but so is an accurate gauge EGT gauge. I've seen some that read 400 with the truck off, and would run 1000 idling. Make sure the connections are SPOTLESS where everything hooks up to the EGT probe, and anywhere in between it and the gauge as even the SLIGHTEST bit of corrosion or poor connection will make HUGE changes in EGT readings.

 

[c20elephant]

Ferman, point taken on the EGT probe cleanliness of the connections, I purchased ISSPRO probes and leads with weatherpack connectors several years ago. I installed a probe in both manifolds, that's where my problem began. One side was about 500 degrees higher than other and shit I thought I had a serious problem.

I then remembered when I was reading and did install cat6 network cable throughout the house about kinks in wires. I pulled the gauge out the pod and found I had one wire kinked just a bit too much. I undid the kink and now both sides are within +/- 50 degrees, although the passenger at almost full throttle will rise about 2-300 degrees higher than the drivrers.
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