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.