Kennedy Custom Tunes MPG Gains for LLY's?

[mjammer]

I am looking at getting the Kennedy Custom Tune ECM for my '05 LLY, especially with the cost of fuel now as I think the return on cost should be pretty easy with the $4+ fuel costs now. I would like to know what some have seen, especially with the '05 LLY's to make sure I am not getting my hopes up too much. The average since I bought my truck is right at 15MPG but through the winter it drops to high 13's. This is a moderate amount of around town, shorter drives as it is my everyday vehicle (~6 miles to work). My longer runs are usually pulling either a 2500LB jetski trailer or a 3500Lb Boy Scout trailer. I also did take a hit of ~1MPG when I switched to the 265 Revo's, even when adjusting for the difference. All this is hand calculated too.

Thanks for any info.

Mark

[More Power]

If you haven't already done it, track you fuel economy over several tanks of fuel, then contact JK about his economy tunes. If given an accurate evaluation, JK will likely provide some assurance for the advertised mileage gains. All vendors are on the hook regarding their product's ability to deliver the gains.

Jim

[mjammer]

I have the whole history of mileage on my truck except for 1 or 2 tanks. I am confident John stands behind his products. I was wanting to hear from others what they have had as far as long term experience and maybe their before/after #'s. If I could get the 19-20 MPG John states on his site, I would be thrilled but he doesn't say what it was before or what cases that was in. I do a lot of around town driving of trips less that 10 miles - lousy scenario for a diesel but that is a lot of my trips when I am not camping, boating, or out with my son's scout troop. Just curious. Maybe I'll just send JK my whole truck history spreadsheet and see what he thinks.

Thanks.

[Philsauto]

I have the whole history of mileage on my truck except for 1 or 2 tanks. I am confident John stands behind his products. I was wanting to hear from others what they have had as far as long term experience and maybe their before/after #'s. If I could get the 19-20 MPG John states on his site, I would be thrilled but he doesn't say what it was before or what cases that was in. I do a lot of around town driving of trips less that 10 miles - lousy scenario for a diesel but that is a lot of my trips when I am not camping, boating, or out with my son's scout troop. Just curious. Maybe I'll just send JK my whole truck history spreadsheet and see what he thinks.

Thanks.

I have bought stuff from John, but I went with stock stuff for my programming. They are not all the same. I have the LB7, so what I have experienced may not apply to the LLY but I hope to find out. I got no fuel economy improvement from Edge, set on levels 1, 2, or 3. I installed the Bully Dog Triple Dog and got no improvement on level 1, but picked up 3 mpg on level 2 on highway driving. But around town, I could not detect any difference. I get 13mpg around town (I'm worse than yours with a 3 mile drive to work). On the road, with the Bully Dog on level 2, I get 21-22. The best I got with the Edge was 18.5.

Do you have a Bully Dog "Tri before you Buy" dealer nearby? The Bully Dog website will direct you to the nearest dealer if you do a search. Bully Dog will allow you to install the program for three days or 10 engine starts for free, at which time the program will expire. The trial program is on level 2, which is the one that gave me highway mileage improvements. The other possibility is if you have a local dealer, ask him if he will let you leave a credit card number and try the programmer for 15 days. In exchange you will provide him with accurate information of fuel economy. If he is like me, he'll jump at the chance to get some solid data that may help him sell programmers.

I really want to chase this economy issue as the price of diesel does not look like it is going to come down. I am about to make a 3000 mile trip hauling a two axle enclosed trailer from Hemet, California to Walla Walla, Wa, and on to Seattle, Wa, and then back home. I mapped out my route and checked fuel prices on the internet. The best price I found was in Pendleton, Oregon, $3.78 a gallon. The average I am going to have to pay is over $4 a gallon. I plan to play with the Bully Dog and Edge programmers on the trip to get some mileage comparisons. I would like to market the Bully Dog product based on mileage improvements, but it is a scary thing to do unless you can back it up with personal research.

[Kennedy]

Have you read the product review here:

http://www.thedieselpage.com/reviews/jkecm2.htm

I'll be right up front on the MPG. I make no promises, but I regularly hear "best ever mpg" reports. My 2005 would run 17-18 at best using everything short of what I list below. It now runs well over 20mpg. I've seen 22+ pretty consistently. Here are a couple of keys to maximizing mpg from any tune:

65mph or less (wind is the biggest killer)

No lifts (wind again)

No wide tires

Good quality fuel and additive

Synthetic lubes

Less trips (warming up takes fuel)



That said, my 2005 LLY despite being a larger truck is my best mpg producer. My tune is responsible for the single largest gain.


As for the Tri-Buy thing, I do not recommend it. This will leave skeletons in your ECM. You can't put code changes into an ECM and expect it to dry up and blow away after a period of time...

[bwoody]

John, what kind of difference do you notice pulling with your tune? I know MPG's are never promised, but have you noticed any MPG towing difference.

[Kennedy]

My towing is so varied it's hard to say. When I go out on a long tow I carry my Aux tank which only allows approximations. Carrying 90 gallons aux and 34 gallons main (never able to use it all of course) I run over 1300 miles. This puts me in the 11+ range towing my 2002 on car trailer which puts me around 20k combined with a LOT of tongue weight. This is running at 5 over posted speed most anywhere that road conditions will allow, and has been done on trips to the DP Pull off, Weekend on the Edge, etc. so we are talking 75mph and up across teh Divide, etc.

I towed this load once in state, and if memory serves it was around 14mpg. I think my tractor on trailer in state runs around 15mpg at 17k-18k combined.

[Philsauto]

John is towing heavier than I did on this trip but I have my fuel mileage for the first leg, Hemet to Walla Walla Wa towing a two axle 12 foot U-haul (low profile) with about 4,000 lbs in it. I estimate my total weight at about 13k. My average mileage with the Bully Dog on level 2 was 16.8mpg, hand calculated, 1100 miles. My best mileage, between Fallon and Winnemuca , Nevada was 18.7 but that is about ideal terrain for economy, perfectly flat, no head wind. I bucked a head wind from Adelanto to Fallon and mileage was 16.3.

I decided to try towing on level 3, and quickly decided that was a bad idea. I made a decision to pass a truck on a pretty steep grade, kicked it in the pants, and roared around the truck. The Allison did not like the treatment, the Edge kicked in and defueled, I lit the check engine light and set a code P0700. I had to pull over to the side and shut down, clear the code, and take off again, which of course gave time for the truck to pass me again. Now that was a waste! I decided towing on level 3 is not a good idea and backed down to level 2.

In general I am extremely pleased with 16.8 avg mpg while towing. I kept the speed around 60-65, as the towing limit in California is 55 and the limit on all of Oregon's back roads is 55. A CHP pulled up next to me on 395 when I had the cruise set on 62. I figured it was a waste to back off, he would either let me go or ticket me for 62, but I guess he decided I was within a reasonable allowable speed.

Cheapest price for diesel was $3.91 a gallon. Ouch!

[mjammer]

Thanks for the replies. I had read the article John as well as everythig else I could track down. The only reports I had seen posted besides the article was Rinkers. It sound slike it might be time to take the plunge.

[Kennedy]

Just sent one down the road last week:


"On the way back from leaving I got 20.5 hand calculated." (unsure the vehicle speed)

Mileage before: Between 15.5 and 16.5 going 70. the best I ever got going 60 and babying it was 18.3

[mjammer]

Sounds like this might be a good use of my tax rebate. Got to keep the economy going, right?

I need to replace my air filter too, would you recommend an OEM or the Uni-Filter Foam? I was checking my Total Power supply and it is low too. Might need a bigger rebate

[Kennedy]

I prefer the Uni as noted in my Tech Tips. You might consider teh air box shrouds from www.coolmyduramax.com as well. I've been hoping Chris would make a set to work with the Mega filter as well. I would definitely suggest waiting to cut the box until you get the shrouds though as my mods are a bit aggressive for his shroud containment.

[mark45678]

I am running JK performance/tow tune , I see 1 mpg better towing and about the same empty. I do think it would be better but its hard to keep your foot out of it . Run really good compared to all other edge products I have had in the past. Low end TQ gains are really noticable when your towing

[mjammer]

Well, I just ordered the custom tune ECM so we'll see how things go. Hopefully I can get it in and installed before a trip I have to Kentucky in a few weeks pulling a trailer for a boy scout trip. Looking forward to it. I also picked up a guage package seeing I was going to be crawilng around the engine and dash anyway.

[mjammer]

I just got the UPS notice that my ECM and Guages are on the truck for delivery. I think I might be coming down with something and need to go home sick from work It might be the ECM Install Flu

[mjammer]

ECM is installed. A pretty straighforward job other than just learning my way around the engine compartment and dash. Note to all, don't install it when it is almost 90 and humid - lots of sweat dripping all over

I'll be filling up the truck tomorrow to start tracking the mileage (after I step on it hard once or twice on my way there just to see how the performance feels before I go back into fuel miser mode).

[mjammer]

Just as an FYI, here is the averages I have seen to date on my truck. I'll keep you all posted as I start getting data on the Kennedy ECM tune. First tank fill-up was this AM and I will be pulling a trailer on a 700 mile round trip next week so we'll see how it does.

Miles Gallons Avg MPG
OEM Avg 20961.7 1360.7 15.405
With 265 Revos & w/o ECM 15128.5 1039.4 14.555
With 265 Revos & w/ECM 0 0 0.000
Lifetime Average 36089.6 2400.1 15.037

[DieselDavy]

Mark,

Any reports for us now that you are back from your first trip?

Dave

[mjammer]

I have done a couple tanks and have seen some improvement. I did two tanks pulling a 3000# boy scout trailer as well as my truck bed full of gear and 6 people in the truck. I got an average of 15.2 MPG on those tanks. The closest similar trip I could find in my log I got 13.9 MPG. My current tank is lookig good too but will need to wait til I fill it up.

One thing on the down side so far is the DIC MPG estimate is way off as is the estimated fule used. Both are running off almost 6% as compared to hand calc and fule pump readings. We'll let it go a tank or two to see if this changes otherwise I'll get John's opinion.

[Kennedy]

Are you running the low tune?

Have you verified speedo with a GPS?

The low tune should leave the DIC just as accurate as it ever was.