TheDieselPage.com Forums
 
The Diesel Page Forums

2020 - TDP's 24th Anniversary
What's New | Feature Articles | Product Reviews | Member's Area | Free Forum Registration
Duramax 6600 Diesel Page | Advertiser's Section | Classified Ads | The Diesel Page - Publications


Go Back   TheDieselPage.com Forums > 2001 - Current Chevrolet & GMC 2500HD/3500 Light Trucks > Duramax 6600

Duramax 6600 Welcome to the Internet's first Duramax 6600 diesel discussion forum for the LB7, LLY, LBZ, LMM, LML, LGH & L5P RPO code engines. Tips on performance, fuel economy, troubleshooting and more.

Reply
 
Thread Tools Display Modes
  #21  
Old 06-02-2006, 11:27 AM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,763
Default

Just FYI, the changes made should not have had a big impact on DIC readings, in fact, should be none at all...
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
Reply With Quote
  #22  
Old 06-02-2006, 02:15 PM
JoeyD JoeyD is offline
Enthusiast
 
Join Date: Jun 2000
Location: Arlington,MA U.S.
Posts: 1,666
Default

Easy driving is key to higher milage. I have not done any highway only trips in my Express but I average 17.5 all the time. I keep speed under 70 on the highway and take off easy in town.
I would think 20 is possible on the highway is you keep it under 70. With the 6spd ally you guys in the 06's run maybe better
__________________
1998 6.5 2500 4X4 dynatrac pro 60, ARB, 35"BFG's
06 D Max Express 5"MBRP EFI live
Reply With Quote
  #23  
Old 06-12-2006, 11:22 PM
REDTRUCK05 REDTRUCK05 is offline
Enthusiast
 
Join Date: Aug 2005
Location: HUGO, MINNESOTA
Posts: 126
Default new tunes

Quote:
Originally Posted by Kennedy
I can't get 20's at 70 mph, but at 60-ish mph I can run solidly into the 20's. It will be interesting to see what Uncle Wally reports as I just sent him a tune for his dually. The DIC shows encouraging results so far, just need to hand check to verify...
Let us all know how ur new tunes do. Why is your 05 for sale?
__________________
2007 GMC 2500 crew cab LBZ
6.6L duramax
Roof markers and XM radio
Rhino liner
Plat series nurf bars
Putco bed rails
Truxedo bed cover
edge juice W/ monitor temp uninstalled.
Hypertech stage 3
Reply With Quote
  #24  
Old 06-29-2006, 10:12 PM
REDTRUCK05 REDTRUCK05 is offline
Enthusiast
 
Join Date: Aug 2005
Location: HUGO, MINNESOTA
Posts: 126
Default Mpg

Are you happy getting 14-15 under normal driving conditions? U say your best milage is at 50-60 mph? That makes sense, its logic. People just dont drive that slow on the interstate in Mpls. I like to drive the speed limit 70 mph. If I do this I get between 9 and 11 mpg, pulling 5600 lbs. If I treat the pedal " like an egg shell" unloaded I can get 14 - 15 at 70 mph. If i slow it down to 60 mph ( only when I have to ) I can get 16 - 17 mpg. Do you guys really think these numbers are ok? I think not...
__________________
2007 GMC 2500 crew cab LBZ
6.6L duramax
Roof markers and XM radio
Rhino liner
Plat series nurf bars
Putco bed rails
Truxedo bed cover
edge juice W/ monitor temp uninstalled.
Hypertech stage 3
Reply With Quote
  #25  
Old 06-30-2006, 06:05 AM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,763
Default

Quote:
Originally Posted by REDTRUCK05
Let us all know how ur new tunes do. Why is your 05 for sale?
I'm waiting for more feedback from my testers. I started another tester at the Rendezvous.

I'm not really pressing to sell my 2005, but I put it up in anticipation of acquiring a 2006 LBZ.

I expect 19-20+ mpg from a single rear wheel truck driven at approx 60mph. My MPG drops at 70, but seems to drop less with tuning.
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
Reply With Quote
  #26  
Old 07-01-2006, 05:21 AM
ToddMeister's Avatar
ToddMeister ToddMeister is offline
Moderator
 
Join Date: Feb 2000
Location: Michigan
Posts: 361
Thumbs up

I'm the economy tune tester from the Rendezvous John was talking about above. Took a long trip this past week and averaged 20 mpg with expressway 70-75 mph, some highway at 55-60 mph, and a bit of city driving mixed in. Outside temps were 75-80 degrees.

Truck is a 2005 GMC Crew Cab 4x4 Duramax LLY/Allison. Presently 13,000 miles on the truck.

I want to take a trip of primarily 55-60mph highway driving to see what the tune is capable of.

I am also running Michelin LTX M/S 265-75-16 tires, which will lower your mileage a tad bit from the stock 245's.

At 70-75 mph EGT runs 600-650 degrees, and boost is about 3.5 lbs (on flat roads). At 55-60 mph EGT is 550-600 degrees and boost is less than 2 lbs. These readings are taken pre-turbo.

More to come....

Todd
__________________
2016 GMC SLT 2500 CC 4x4 Duramax All Terrain 36K
1995 GMC 2500 EC 4x4 6.5TD,226K,Custom Tuning,HX40W-II turbo,Amsoil Bypass Filter,KD Exhaust,FSD Cooler,KD Headlight booster,Hi-cap Cooling
TDP member #14
Reply With Quote
  #27  
Old 07-05-2006, 04:33 PM
Uncle Wally Uncle Wally is offline
Enthusiast
 
Join Date: Nov 2002
Location: Howard Lake, MN
Posts: 381
Default Mileage Update

John - thanks for the reminder. I'm still out of state so there is more to come.

Initial reports thus far:

I weighed or entire rig at the local feed lot as we were leaving: 20500 lbs.

1st tank w/ DIC (no hand calcs at this time) - 13.6 mpg (the wife drove)
2nd tank w/ DIC - 15.8 mpg (I drove)
3rd tank w/DIC - 14.5 mpg (we both drove) This tank also had some some really steep grade coming through Wheeling, EV and then into PA south of Pittsburgh (all hills).

To come:
Hand calcs to compare against DIC (although I did notice less of a discrepancy with the 'fuel used' portion of the DIC).
Empty tank mileage with only me driving
Complete rundown of performance and mileage when I get back home

Just a quick note. Thanks.

Waldo
__________________
05 K3500 D/A Crew - Sport Red and sexy! JK exhaust and filtration, guages and EFI Live. What a blast!

71 K20 awaiting Cummins 12v swaps

For Sale: Deep Sump Trans Pan for a 4L80E
Reply With Quote
  #28  
Old 08-08-2006, 11:04 PM
Uncle Wally Uncle Wally is offline
Enthusiast
 
Join Date: Nov 2002
Location: Howard Lake, MN
Posts: 381
Default The results are in

OK. Sorry for the wait. Taking 3 weeks off makes for alot of catching up to do.

Hand calcs are as follows:
Tank #1 - 13.55 mpg - DIC showed 13.6
Tank #2 - 13.65 mpg - DIC showed 15.8
Tank #3 - 12.84 mpg - DIC showed 14.5
Tank #4 - 22.36 mpg - DIC showed 23.6
Tank #5 - 16.16 mpg - DIC showed 18.3
Tank #6 - 13.15 mpg - DIC showed 13.9
Tank #7 - 12.29 mog - DIC showed 13.3
Tank #8 - 11.58 mpg - DIC showed 12.2
Tank #9 - 12.04 mpg - DIC showed 13.1

Again - I fill the truck the same way every time: fuel is at the lip and almost ready to spill out with the truck sitting as level as possible - engine not running.

I compared these figures to hand calcs from date of purchase. They are as follows:

Bone Stock - average of 13.91 mpg over ~10k

With JK's exhaust, Uni Filter and Mega filter upgrades - average of 13.72 over ~7k

Add EFI Live to above (only EGR fooled with - no added fuel or timing) - average of 15.9 over ~3k

Add JK's timing tune to above - average of 14.9 over ~5k (this is skewed as a majority of this is towing our horse trailer - only about 1500 miles without the trailer)

The shining star thus far: I hand calced a tank of fuel at 22.36 on a trip from Pittsburgh to Baltimore and back. This was my one chance to use an entire tank without my wife's heavy footed influence (which ever peddle she has her foot on, it goes to the floor). I only stopped once and that was to pull into my buddies driveway. I drove like a grandpa (no offense intended) and treated the throttle like an egg, never going above 55 mph, and coasting to stop signs and lights whenever possible. I know everyone doesn't drive this way normally, but I wanted to know what the truck was capable of. I usually drive this way when I just filled up the tank and am pissed about how much it just cost me. After a few hours, I'm back to my normal style that yields about 18.5-19.5 on the DIC. I usually get impatient with drivers that shouldn't be on the road, so there are a few full throttle runs and the occasional 80+ mph flights. With that said, I'm tickled to death that a 4dr dually can get this kind of mileage and have the power to play around every now and again.

Had I to do it over again, I would have done the same mods within the first 100 miles of ownership, and I still have a couple to go as of yet.

I keep some pretty decent records, so I would expect an update by the end of summer.

Waldo
__________________
05 K3500 D/A Crew - Sport Red and sexy! JK exhaust and filtration, guages and EFI Live. What a blast!

71 K20 awaiting Cummins 12v swaps

For Sale: Deep Sump Trans Pan for a 4L80E
Reply With Quote
  #29  
Old 08-09-2006, 07:37 PM
Albee Albee is offline
Enthusiast
 
Join Date: Apr 2002
Location: Cheyenne, Wy
Posts: 105
Default I wanna play this too

I had a 02 LB7 2500HD W/Allison. Took a trip back to Missouri from Wyoming. From Cheyenne to Lincoln Ne. the truck got 20.7 MPG (hand calculated) running 75 the whole way. On the way back to Wy. the truck got 18.3. Here we go with uphill and downhill and wind. The wind always blows here and alway from West to east. I was very happy. The truck got consistent 15.5 to 16.5 running my day to day routes in town during the summer months. During the winter months it would get right at 14-15 MPG.

The new 06 LLY 3500 Dually, Allison does not do as well. I have not taken the trip back east since had this truck. But running my standard routes here in town the truck gets 13-14 in the summer and in the winter it drops to 12. I now pull a 18K fifth wheel with the truck and pull at 60-65 MPH average. Pull 175 miles to camp over three passes going as high as 9800ft. elevation and the average for the trip is 9.3 there and back. I use much more going than coming home. These were all bone stock truck numbers. I have now added 4" catback exhaust. But do not see much difference, maybe .5 MPG improvement at most. This truck does not do as well as the other one. But as stated before it is heavier and has the extra wheels. But she sure do run good!!

This is a great forum!!!! Keep up the good work guys.
__________________
2006 Chevy 3500 Big Dooley,CC, Duramax/6 Speed Allison, Victory Red. Pulling Jayco Talon ZX F36W Toy Hauler 5;er. 13,400 lbs dry and 18,000 GVWR

Reply With Quote
  #30  
Old 08-10-2006, 06:51 AM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,763
Default

Wow 22+ on a dually! I never figured we'd see a dually cross 20mpg. I've been right around 20 with my single wheel, and recently hit 22mpg. Just need to "back it up" a few times...
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
Reply With Quote
  #31  
Old 08-10-2006, 05:13 PM
Kelly T Kelly T is offline
Motorcyclist
 
Join Date: Jun 2005
Location: Marysville, OH
Posts: 8
Default My 05 LLY

Updated - over 25,000 miles now. 19 MPG seems to be working. Bone stock. 2500 HD CC.

http://home.columbus.rr.com/vfrket/Diesel/Diesel.xls

Note my calculated Miles Per Hour (miles for the tank divided by elapsed time (hours) from the from the DIC) to the far right. BTW, I still like my spreadsheet. There are few rows of data where I had to add a couple tanks together.

Kelly
__________________
Kelly T
Reply With Quote
  #32  
Old 08-12-2006, 12:44 PM
Uncle Wally Uncle Wally is offline
Enthusiast
 
Join Date: Nov 2002
Location: Howard Lake, MN
Posts: 381
Default MPG's

John,

I agree with you. I never thought I would see it either.

Did you have the AC on? I've found that makes a pretty significant difference. Although I will have to admit, it's kind of hard to not run the AC when it's 80+ and humid. Ventshades work pretty good with the windows cracked and the vent on.

I also had the tires inflated to max rating in the rear due to the trailer towing.

I want to try running 235/85's and see if it makes a difference. I have a set off my 94 that's begging to be installed. I just need to use up the ones that are on it now. Just wish I didn't have to machine the Alcoa's to get em to fit.

I'm going to be making a run to Eagle River WI here soon. Hopefully I can back up that 20+ number.

Waldo
__________________
05 K3500 D/A Crew - Sport Red and sexy! JK exhaust and filtration, guages and EFI Live. What a blast!

71 K20 awaiting Cummins 12v swaps

For Sale: Deep Sump Trans Pan for a 4L80E
Reply With Quote
  #33  
Old 08-12-2006, 01:50 PM
rob from bc canada's Avatar
rob from bc canada rob from bc canada is offline
Enthusiast
 
Join Date: Jun 2005
Posts: 135
Default

Kelly T:


I looked at you spreadsheet, and you seem to have a period where your were getting 16-17, and then back up near 19 average. Are these all long trip flatland driving - your average speed per engine hour is about same as mine, or maybe a bit higher.

That is pretty impressive mileage - what did you do different?

Bet I can do with careful driving over a tankful is about 18 US mpg.

However mine is a K3500 = 7000 lbs empty and 4wd, is your perhap 2wd, and less weight, which could make a difference?
__________________
2005 Chev K3500 SRW Dmax Allison Ext Long Box
Reply With Quote
  #34  
Old 08-12-2006, 06:09 PM
Kelly T Kelly T is offline
Motorcyclist
 
Join Date: Jun 2005
Location: Marysville, OH
Posts: 8
Default

Best I can attribute it to is crappy gas in the winter, bad road conditions (some time in 4wd just to commute to work), and maybe some more city driving. My 2500 HD is a 4wd. I live in central Ohio so now and then we get some winter. At the time I was disappointed too.

Behavior-wise - biggest thing is trying not to be hard on the gas in stop/go traffice trying to get out of Columbus when trying to reach the highway. That seems to be the killer on calc and indicated MPG quickest. Sometimes when sitting in traffic (red light, grid-lock) I'll shift to neutral (automatic) so the truck isn't pushing against the brakes. My driving has some hills on it, but not a lot.

I have no bed cover either. I'd like a "Undercover" and an Edge Juice w/Attitude (or maybe a visit to John Kennedy) to see how they play out from an economy viewpoint (and some pep when desired). And then a 4" exhaust (full). I don't do anything wild with air pressure - keep it at the top of the normal limit (50 psi). Not hauling a load too often - when I am it is an morotcycle or 4 wheeler and my milage gets better as it keeps air off the tailgate (or seems too).

2 cents,
Kelly
__________________
Kelly T
Reply With Quote
  #35  
Old 08-14-2006, 11:31 AM
AlbertaDiesel AlbertaDiesel is offline
Newbie
 
Join Date: Jul 2006
Posts: 5
Default Mpg

Hi guys
New here, love the forum so far.
I recently bought an '06 Chev Crew 1 ton SRW LB 4x4 LBZ. My first hand calculation of mileage running empty at average 70mph was 18.32 US MPG. My next was a long trip pulling my 26 foot holiday trailer (which my wife likes to load to the nuts) again at average 70 mph and I hand calculated 10.41 US MPG. Not quite as good as my old '93 Dodge Cummins, but then she couldn't pull that rig at 70 mph all the way, either. I am a mileage buff, too, so I will likely post more results as time passes. With fuel prices skyrocketing lately, good mileage is a big concern. I think a 2 mpg increase would be worth it to justify a "mod".
Reply With Quote
  #36  
Old 08-14-2006, 03:32 PM
rob from bc canada's Avatar
rob from bc canada rob from bc canada is offline
Enthusiast
 
Join Date: Jun 2005
Posts: 135
Default

Quote:
Originally Posted by Kennedy
I'm waiting for more feedback from my testers. I started another tester at the Rendezvous.
...
I expect 19-20+ mpg from a single rear wheel truck driven at approx 60mph. My MPG drops at 70, but seems to drop less with tuning.

This "Economy Tune" for sale yet? What is involved and how much?

Need any Canadian testers???

I've got about 17,000 km on my truck now, and I've kept records for every fillup so far.
__________________
2005 Chev K3500 SRW Dmax Allison Ext Long Box
Reply With Quote
  #37  
Old 08-14-2006, 08:59 PM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,763
Default

The tunes are available any time. There is a review by Todd Smith on this site.
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
Reply With Quote
  #38  
Old 08-17-2006, 10:16 AM
sb359 sb359 is offline
Enthusiast
 
Join Date: Mar 2003
Location: Sechelt, British Columbia
Posts: 49
Default mileage

best i've done is 20.1 mpg empty and 15 mpg pulling a 6800lb travel trailer
__________________
2016 LML 3500 D/A Black CC High Country , Towing a 29ft Big foot trailer
Reply With Quote
  #39  
Old 09-12-2006, 11:14 AM
ToddMeister's Avatar
ToddMeister ToddMeister is offline
Moderator
 
Join Date: Feb 2000
Location: Michigan
Posts: 361
Thumbs up Long trip update

Recently took a long trip to the East Coast over Labor Day holiday about 1500 miles, 90% turnpike/expressway driving 60-70 mph, 10% city driving. Truck had 4 passengers, box full of luggage/cargo. I averaged 19.8 mpg hand calculated, DIC said 19.7 mpg average. I'm am running Kennedy's economy tune from the Rendezvous. And also running LT265 tires, speedo is accurate (verified with GPS). Had lots of driving in the rain and wind!!!!
__________________
2016 GMC SLT 2500 CC 4x4 Duramax All Terrain 36K
1995 GMC 2500 EC 4x4 6.5TD,226K,Custom Tuning,HX40W-II turbo,Amsoil Bypass Filter,KD Exhaust,FSD Cooler,KD Headlight booster,Hi-cap Cooling
TDP member #14
Reply With Quote
  #40  
Old 09-12-2006, 12:18 PM
rob from bc canada's Avatar
rob from bc canada rob from bc canada is offline
Enthusiast
 
Join Date: Jun 2005
Posts: 135
Default

This "economy tune" sounds real good.

I think mine would have done about 17 -17.5 driving as you have described.

If true, at $3.00 per Gallon, you saved about $30 on this trip, and if you keep the truck for 200k you might save about $4000.

From what I saw on Kennedy's site, you need a spare ECM to load his tunes.

What was the procedure for you, and what did the whole thing cost???
__________________
2005 Chev K3500 SRW Dmax Allison Ext Long Box
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 07:28 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Copyright 1996-2020 by TheDieselPage.com - All Rights Reserved