New Kennedy Diesel custom ECM on the way!

[Mark Rinker]

Ordered a tow/economy tune ECM for my 2006 K3500 hauler today.

Hoping to save $$$ towing boats this summer, as fuel prices continue to spiral. Will keep the stock ECM handy in case I need to go back to the dealership for warranty work.

More info soon from a(nother) 7,000 mile cross-country jaunt with a 31' boat and triple axle trailer in tow...

[Mark Rinker]

New ECM arrived Friday. Looking forward to installing it. There is a performance shop near here with a chassis dyno - may call them Monday to see if I can get a before/after measurement without spending an arm and a leg.

Newer ECM sure are alot smaller than the LB7 2001/2002 I have seen in the past - are they still located under the fusebox on the driver side wheel well area?

[Mark Rinker]

Installed today no issues. Startup normal with no codes. Took a short test drive, but flatbed is loaded with items for delivery so no heavy acceleration. A little more diesel rattle at cold startup, but had nearly subsided once temps were up slightly and I was back in the driveway.

Interested to see results of first tankful, with light flatbed load.

[MikeC]

Mark,

Just wondering what you have seen so far.

Mike

[Mark Rinker]

The trucks just returned empty last night from the Vancouver delivery. Have to crunch data for final numbers, but it appears that towing average numbers were slightly better, even under the windy/hot conditions that were encountered. Performing a controlled test was our challenge - with slightly different loads over different terrain, and different drivers/habits. As an example of variances from expected results to actual - my recent FL to MN average (with OEM tune installed) was right at 9mpg with a ~900# motorcycle on the flatbed. Previous trip with same boat, no motorcycle was 8.5mpg, calculated on loaded miles only, but a different driver. I can only attribute the difference to wind and/or driving styles. (Funny it appears that my help has a heavier foot than I do...suprise suprise...)

Another consideration - a seemingly miniscule .25/mpg improvement when in the 8.5mpg loaded towing range is still a healthy 3% savings. On a 3,500 mile loaded segment at $4.90 fuel - that is $57.60 in fuel savings. It all adds up more quickly as fuel prices get higher.

Another interesting stat yet to be calculated will be the unloaded miles home - this is where we can save significant $$$ when running empty with no load. Stock average for the K3500 dually has been an unimpressive 16.5mpgh at 1900rpm cruise, 6th gear or about 68-70mph. (Obviously, we could slow down and improve this number more...). The duals and hauler body that extend above and wider than cab, plus towing mirrors don't help with aerodynamics of this rig.

Power improvement, reduced downshifting, and 'OEM-plus' manners and driveability is the same quality as we have come to expect from Kennedy tunes. Driver reported from mountainous, hot Montana segment that the tune might even be 'a bit too much' as it wants to 'run uphill at speed (loaded) when on cruise control and in 5th' and he had to kick it off (cruise control) and drive more moderately to stay behind car traffic since overdimensional loads must occupy only the rightmost (slow) lane unless passing - and that should only be done with great caution. Truck was holding 5th/6th gears well, with only a few overrev (5th to 4th) downshifts encountered in the hills - which was characteristic with the OEM tune in place as well. "You can't expect to drive on cruise control, in the hills towing 10,000# and listen to the CDs", is what I told the driver..."Get off cruise control, shut off the radio, and stay in your peak torque range of 1600-1800 and accept the ground speed it gives you."

Certainly not a bad problem to have if you subscribe to the theory of MORE POWER is good... We will be switching this rig over to the gooseneck trailer for a few weeks of city/regional hauling. I have months of aggregated results from this truck/trailer combination on a spreadsheet with the same driver, same routes, similar loads that will give an even better picture of towing averages.

Summary - and more detailed results to follow...

[Mark Rinker]

Results from first full week of regional hotshot gooseneck hauling is in:

• 11.1mpg average mixed city/regional deliveries pulling 25' gooseneck
• 600 mile roundtrip with a light 3K load, and empty trailer home yielded 13.6mpg

More miles, more loads, more data will help us zero in on a meaningful average number. So far, our overall reaction is very positive. If we can find a solid 5% improvement in fuel economy with this tune, it will save MRE ~$1500 in fuel in the first year.

[BigLar368]

I have been to John's web site and if I remember the tow tune is 40 hp. Do you think the higher tune would get just as good mileage if you drove it under the same conditions you have posted on this thread? I have recently installed the BD exh manifold and 4" magnaflo and I am interested in the higher tune but want the same mileage I get now (19 to 20 highway). 95% of my driving is to and from work. I have about an 8500lb fifth wheel that we plan to use on vacation this year. Will probably pull it at least 5k to 6k round trip. After the ECM upgrade I dont have much more planned for it performance wise. Thanks in advance.

[Mark Rinker]

Not sure about your 2007...from what I know of the 2006 (LBZ) tunes, there is an appreciable increase in mileage over stock. It hard to say, from application to application. Talk with JK - see what he recommends, I have found him to be realistic and conservative when it comes to both performance and mileage expectations.

[BigLar368]

Sorry. I ommited the fact that mine is an LBZ same as yours. Was just curious what HP level you got.

[Mark Rinker]

The 70hp version. I am exchanging it for the 40hp version, should have some numbers on this tune, soon. Hoping for even better mileage numbers with lower fuel rates.

[BigLar368]

Did you feel the 70 HP was too much? Reason I ask is not very many others that have JK's tune with their LBZ's. Just trying to get a little real world feedback before I take the plunge. Thanks

[Mark Rinker]

Yes, the 70hp tune was more than needed for our application which is constant, heavy towing. For a daily driver with only light recreational towing, it should be fine and many RV'rs are running it, according to John. Again, consult him on this as I don't tow RVs, as you plan to do. You might get some references with similar rigs?

[Kennedy]

About all of my LBZ tunes running out there are the 70HP variety. Both the 40HP and the 70HP share similar power curves, it's just that if you "go deep" with the go pedal, the 70HP has more. In my experience, the 70HP tune has done well, and I haven't heard of issues, but I do suspect that if this level of performance were put into the hands of someone who is rough on things, they probably could wreck things. This really hasn't been the case, but Mark has hired drivers in his trucks looking to rack up more miles in less time for best pay.

I forget the handle , but Mr Moss had a post a while back about problems towing/high egt's etc and ended up running my tune with success.

[Kennedy]

http://www.thedieselpageforums.com/t...ad.php?t=32233

7. Custom tuning by John Kennedy. The tuning offers a lot more pull and the truck just does not have that feel anymore that is working a little to hard and that you might ought to ease up a tad. The EGT’s non towing are definitely lower about 75 to 100 degrees. Towing EGT’s are lower too as long as load is not too extreme. What
I observed during the only chance I have had to tow since the tune was installed, is that when loads approach
the 95% range the EGT’s will still become excessive. The highest that I ever saw before the tune and the other
modifications to cool things down was 1380 degrees and I immediately backed out of it. This time with the
additional cooling I went ahead and pushed things on a long steep grade out of Santa Rosa, N Mex. and the
EGT’s got to 1460 degrees before we crested the top. One instrument that I was lacking on that trip was a boost
gauge so I do not know what kind of pressure I was getting from the turbo; I have a good one now and will be able
to see how that looks on a trip in two or three weeks over some even demanding climbs. I will not let the EGT’s
get that high again but will be able to see what boost is at high load percentages and be able to talk to John to
see if any futher improvement is possible. It may very well be that this is as good as it gets and anything better
is beyond the realm of reason. The Kennedy tune is an exceptional value and far exceeds any generic that I have
had in the past. I am very pleased with this modification.

[Mark Rinker]

...Mark has hired drivers in his trucks looking to rack up more miles in less time for best pay...

Actually the majority of test miles were rolled on by a known, careful operator, who was paid by the hour. (The other was even longer term, even more careful, and not paid at all...me!)

Agreed that if you turn just anyone loose with a chipped truck for towing, they could do damage with a reckless right foot!

[BigLar368]

JK if its ok I would to call you by phone to ask some more indepth questions about your tune. I am definitly interested. I only plan on pulling a fairly light 5th wheel but want to get the best performance and MPG as possible. The most important part of the tune is the abilitly to disable the EGR without the blocker plate and finger stick. I still have plenty of warranty left and if something arrises I don't want any Sherlock Holmes/GM techs digging for reason to void me. As far as the 70 HP thats just an added bonus....)

[Kennedy]

Absoluetly please do call or email whichever is best for you. I can be hard to reach, but once you have me it is VERY rare for me to initiate the ending of a conversation. I try to stick with the present call until the caller is finished and let others go to voice mail, then I return calls between incoming calls. I don't hold a phone to my ear these days, I have a wired earpiece in as I am on the phone a lot...