EGT temps on 05 LLY

[REDTRUCK05]

I run a 05 LLY. When I pull my trailer at 5600lbs, my EGT temps are between 950 - 1250, run an average of 1000-1150. If I push it 75 they reach 1200-1300. I have Edge with attitude running at level 2 or 3. Does this not seem high? Can I relate this to my S--- mpg?

[MikeC]

Redtruck,

I have an '05 also. I tow a little heavier at 9600# trailer weight. My EGT's when towing on flat areas is easily 1200. Towing on any kind of hill the Attitude alarms at me with EGT's over 1350 and it starts backing off.

I am beginning to wonder if the mods are worth it.

Mike

[Kennedy]

They'll run as high as 1500f stock...

[Roy W]

I pull a 32 foot travel trailer weighing 9200 lbs. On a recent 4500 mile trip I grossed at 17,800 lbs (extra fuel, tires, generator, etc). At 65 mph on the interstate my egt was between 900 and 1100, and it never went over 1300 degrees on grades varying between 6% and 12%. I run my Edge EZ on #1. Switching to a 4" cat back exhaust lowered egt's about 100-150 degrees. I always use tow/haul, and lock out overdrive when speeds are consistently less than 55 mph. Driving ahead when traveling in hilly/mountainous country makes a BIG difference. Nailing the "go pedal" at the bottom of a grade will guarantee high egt's before you get over the top.

[MikeC]

I was used to my 96 Burban 6.5.

With the DMax I thought the max EGT for a long run was 1350 and peaks for short periods also up to 1450. Also, I try to idle until the EGT gets below 300 but It does not go lower than 380, EVER.

I do drive ahead and pull the truck out of overdrive prior to hills. I also use tow haul to get the TC to lock sooner.

I am just surprised how high the EGT's are now that I can watch them.

John, any suggestions on what EGT to have the fuel backed off at, along with what temp to shut down?

Mike

[Albee]

I thought I understood that the computer on a stock Dmax will not let you get EGT's too high. Is this not true with a stock truck? On the newer ones anyway. I very well could be ill advised. Thanks.

[Kennedy]

Mike are you running a cat on your truck yet?

Leave it in OD and let it work on the hills...

[MikeC]

John,

The cat is still there. Seems like my dealership doesn't care about mods but they will not commit to covering the truck with mods in place, or parts gone.

YES, I'm getting doubletalk from them.

It has the Juice with Attitude, Cat back Magna Flow 4", your boost stick with extension.

I ran my 96 Burban in OD but the cruise seems to be less harsh on it. With the DMax, if I don't "drive ahead" and get the truck set for the hill the thing will slow considerably and then work like mad to get back to speed.

It seems to thrash itself less if I prepare it by doing the downshift myself ahaead of time.

Mike

[branstew]

Mods are definitely worth it if you prep the Dmax for the risk of higher EGTs. So, a diesel is fuel throttled. When you modify the injector settings through software you deliver more fuel and for longer periods at the high settings. You have to burn that fuel so yeah your EGTs shoot up. Look into changing the 'Inner Cooler' and the boost tubes to help 'unrestrict' airflow and also produce a larger volume of air being cooled going into the engine. With a cat back exhaust, you shouldn't see excessive EGTs even when towing IMHO.

[Kennedy]

The LB7 had a fully mechanical turbo. It used the increased heat energy from a "chip" to make more boost. The LLY has a computer controlled turbo. It will NOT pick up the slack when you add fuel as it runs on a set of maps with target boost. In fact, the maps are based on the fuel delivery that the ECM commands so if you have extra fuel being added by a chip, the ECM thinks it is delivering less that it normally would on it's own and shifts the boost downward accordingly.

Example: At 2200 RPM say it requires 70mm3 of fuel to do the job. The ECM calls for 187kpa boost. Add a chip that gives the engine an additional 10 mm3 and the ECM now commands 60mm3 of fuel (still getting the 70mm3 actual delivery) and 168kpa...

The Boost Stiock will help with the EGT's of the Edge, OR my custom tuning will help as well.

Opening the exhaust to a full 4" (completely bolt in/out) will help a lot too. Cat back is a waste of time in my opinion.

[Florey]

Don't know that much about the LLY's but I do know that the new tuning available from various venders, (Kenndy being one of the top ones) can really help your EGT problem. The VVT turbo really responds to the custom tunes now available, both towing, and racing as well as economy. I don't think changing out the Innercooler at your HP level would do you much good. Another fix is going to a set of twin turbos. You might want to talk to some of the guys who are running twins on their LLY and get their input. I know my twins really help lower the EGT's on my LB7. My truck never got above 1400 degrees during the pull-off in Montana and I'm running a lot more HP than you are.

[REDTRUCK05]

Can U Email me with the info, Data reports? Thanks JK
The LB7 had a fully mechanical turbo. It used the increased heat energy from a "chip" to make more boost. The LLY has a computer controlled turbo. It will NOT pick up the slack when you add fuel as it runs on a set of maps with target boost. In fact, the maps are based on the fuel delivery that the ECM commands so if you have extra fuel being added by a chip, the ECM thinks it is delivering less that it normally would on it's own and shifts the boost downward accordingly.

Example: At 2200 RPM say it requires 70mm3 of fuel to do the job. The ECM calls for 187kpa boost. Add a chip that gives the engine an additional 10 mm3 and the ECM now commands 60mm3 of fuel (still getting the 70mm3 actual delivery) and 168kpa...

The Boost Stiock will help with the EGT's of the Edge, OR my custom tuning will help as well.

Opening the exhaust to a full 4" (completely bolt in/out) will help a lot too. Cat back is a waste of time in my opinion.

[MikeC]

John and others,

What do I need to do to my '05 if and when I remove the cat?

I found a V-clamp to flange replacement pipe but want to be aware of issues before I create them.

Mike