Advice on mileage/safe tuning for towing?

[MikeOD]

I'm looking for advice on where to go with a tune to try to get some better mileage than stock out of an LBZ truck when commuting, and to make it as safe as possible when towing.

What changes have you guys found with the timing calculators, more timing below a certain threshold to make the MPG, and less above that threshold? How do you determine that?

What have you done with boost and fuel? I think he wants at least a little more power than stock, but probably not like the current tune we have in the truck.

[mecanicman]

Click here for a set of instructions on setting up a tune, just ignore the dpf stuff for your application. You could also do a search for Mcrat 20/20 tune which is pretty much the same thing. Click here for a timing calculator and posts describing best settings and why. Stay out of idle areas for fuel and boost, manually limit timing tables to a maximum of 30 degrees. You will still need to advise your customer to not tow in 5 or 6 gear under load(up hill, into the wind) as the trans will not last. A pyro would be a good plan also depending on size of pulling load.

[Johns98TA]

Dont add much power if you are towing heavy. I tried running a hot tune (with stock fuel system) and my torque converter was slipping badly when trying to climb hills in 5th and 6th. I had to reload my stock fuel and timing tables to keep from frying the converter. I would say that stock power levels are pretty close to the limit of the stock converter when towing something heavy. And by heavy I mean 6 ton (or more) trailer weight.

[mecanicman]

You sure it was the convertor? I have not seen a stock convertor slip, but definatly seen 5 and 6 gear slip. Convertors usually just brake the mounting pads off when you put to much torque to them.

[autoparts]

Is it true that on a duramax you can make it 30mpg?

[mecanicman]

I have not achieved it....im thinking not achievable in us gallons. There are hand held programmers that have an effect on the dic displayed fuel economy that show over 30mpg, hand calculating shows otherwise. I have a friend with a LB7 2wd that has achieved 28 imperial mpg(about 24 us mpg if I have my conversion right) on flat prairie with no load. Best I have seen.

[autoparts]

can you give some advise to help improv my 2006 duramax mpg.

[mecanicman]

Roger gave you some pointers, I would suggest trying it without increasing boost in cruising range, but the advice is sound. What are you getting now, what are you using truck for, and what do you hope to accomplish?

[autoparts]

I cant open the timing folder

[mecanicman]

do you have microsoft excel?

[autoparts]

Im getting over 16-18mpg hwy no load down the hill and I tow some heavy load over 10,000pounds and it gets over 10-12mpg hwy. And how do you do %s on the timeing.

[Johns98TA]

You sure it was the convertor?

I dont know for sure since I wasnt logging anything when it happened. May well have been 5th and 6th clutches slipping. It felt just like a clutch slipping on a manual-trans vehicle. I just figured it was the converter since it was only doing it in 5th and 6th.
Regardless, If you turn up the power much more than stock while towing the trans can not handle it. I got lucky I didn't hurt anything or limp it. Towing the same load with stock LBZ power level and all is fine.
For mileage, I have found that the stock tune is pretty much as good as I could get. Driving habits affect MPG more than anything