More Power & Improved MPG!

**More Power** · 06-09-2006, 10:14

Custom Programming
the Duramax ECM
The recent appearance of custom ECM (Engine Control Module) programming has increased the number of options for nearly every truck owner, whether they're looking for a few more miles per gallon, a safe towing program or a killer track tune. Kennedy Diesel is now offering custom ECM tuning, which provides for a host of additional programming features.

**Bobo** · 06-12-2006, 21:02

That tuning is done via EFI Live. If you want to do your own tuning, EFI Live can be purchased from Kennedy Diesel.

**MillCreekDMAX** · 06-30-2006, 09:13

Just curious, has JK done any programming for 06 lbz engines?

**Kennedy** · 06-30-2006, 19:59

We don't have the tools (EFI Live) to do the 06 yet, but we hope they'll have it for us late this year. I am of the opinion that the best mods are quite q ways off yet for the 06 as the first ones out with product weren't very good with the LLY and pretty much abandoned it...

**ToddMeister** · 07-01-2006, 04:50

I'm running Kennedy's economy tune right now. This past week I took a long trip, and averaged 20 mpg with expressway 70-75mph and some city driving. I am also running 265-75-16 tires. Speedo is correct, too.

On the expressway, at 70 mph EGT is 600-650 degrees (pre-turbo) and boost is about 3.5 to 4 lbs (on flat roads with light head winds). At 55-60 mph EGT is 550-600 and boost is less than 2 lbs.

**Kennedy** · 07-02-2006, 06:40

Sounds good, keep us posted!

**david** · 07-02-2006, 16:24

Thats weird,
My 05 gmc at 70 or so gets 19.8 mpg STOCK .
Why buy a program ????

**ToddMeister** · 07-03-2006, 05:15

My truck will get 19.5 to 20mpg with stock 245 tires. With bigger tires, however, mileage dropped down to about 18 to 18.5 average. With KD's tune, it went back to 20 mpg average.

I may put the 245 tires back on and run a few tanks to see what the tune is capable of.

Originally Posted by david

Thats weird,
My 05 gmc at 70 or so gets 19.8 mpg STOCK .
Why buy a program ????

**Kennedy** · 07-03-2006, 07:09

Some trucks are lucky to see the high side of 16-18mpg, especially at high speeds. I know my 2005 would drop in the toilet running to MO across IA at 75mph. Doesn't drop near as bad now, but I haven't had accurate means of checking MPG on long trips with filling on the fly from my aux tank...

I remember running my 2002 out to SD across I 90 in MN when it was relatively new. I was looking for good mpg and got like 15.5

**mhagie** · 07-05-2006, 08:27

Originally Posted by david

Thats weird,
My 05 gmc at 70 or so gets 19.8 mpg STOCK .
Why buy a program ????

First thing to do is check your speedometer for accuracy, most trucks with 245 tires the speedo reads fast which makes mileage look better than it is.
When I changed to 265 tires my speedo is now dead on by the stop watch method, my mileage dropped just a tad but it is at least accurate now.
middle 18's right now on 60 mile round trips.

Merle

**ToddMeister** · 07-05-2006, 08:41

John adjusted for the 265 tires when he loaded up the tunes. My speedo is accurate, matches my GPS within 0.5 mph.

**More Power** · 07-12-2006, 12:42

Todd's piece is now available as:

Custom Programming
the Duramax ECM
Part II - LLY Duramax

In addition to the 2001-2004 LB7 duramax, Kennedy Diesel (KD) also offers custom ECM tunes for the 2004.5-2005 LLY Duramax Diesel.

**mjammer** · 07-24-2006, 20:45

Todd, is your LLY stock other than JK's custom tune? I would be happy with your original 18.5. That is typically the high side of my interstate mileage if I don't go above 70. A typical mix for me with more city than highway gets me ~15.5.

**ToddMeister** · 07-25-2006, 04:30

Yep, pretty much stock. I've been averaging 19.5 to 20 mpg with JK's economy tune, depends how my foot cooperates with the go pedal. I recently gutted the cat to see if I can gain any more mpg's. I also insulated the stock airbox from the hot under-hood air.

I'll be taking a long trip this coming weekend, pretty much all expressway, and I'll post an update after the trip.

I've found anything over 70mph starts to kill mileage, these trucks aren't very aerodynamic. I also lost a bit of mpg's with the 265 tires, but disliked the looks of the stock 245 tires.

Originally Posted by mjammer

Todd, is your LLY stock other than JK's custom tune? I would be happy with your original 18.5. That is typically the high side of my interstate mileage if I don't go above 70. A typical mix for me with more city than highway gets me ~15.5.

**mjammer** · 07-25-2006, 13:22

Curious to see how the package works on a long haul trip. I just got a new fuel filter and oil change and will be doing a long haul trip soon too pulling a 2500 lb jet ski trailer through the hills of KY. Not a strain by any means but will set a baseline for my truck now that is well broken in (over 18K miles) and has a fresh filter.

**Kennedy** · 08-07-2006, 10:19

I'm sending Todd another revision to test. It worked very well for me and netted best ever MPG running at 60 mph. Hoping that he can back it up for me...

**ToddMeister** · 08-08-2006, 04:12

Looking forward to trying the new tune, John.

I continue to average 20 mpg with the first tune.

**Kennedy** · 08-09-2006, 08:11

Just wanted to cross link this thread to another regarding LLY MPG and results from Uncle Wally's testing:

http://www.thedieselpageforums.com/t...ad.php?t=22979

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Custom Programming the LLY

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