Tuning 6.0l for efficiency

[wildbillracin]

I am trying to use my v2 to tune a 2002 2500 with a 6.0l in it to get better fuel efficiency. I have done some research and seems to be a near impossible task. I have tuned my duramax with efi live but have not messed around with it on any gas engines yet. Is there any direction anyone could steer me in to help this thing not suck gas AS bad? Thanks in advance for any help

[Taz]

That is a large, heavy truck, and will have a 4L80 transmission. Properly built the 4L80 is nearly indestructible, but causes increased parasitic losses due to the power required to turn it. As you already know, the truck will never be referred to as fuel efficient.

Take a look at the threads regarding Lean Cruise and DFCO (Deceleration Fuel Cut Off) settings. You should be able to squeeze another 1 to 3 MPG in efficiency with some tuning.


Regards,
Taz

[wildbillracin]

thanks for the heads up. I know that this truck is not going to be any economical vehicle of any sort. I am playing with the DFCO lightly. Is there anything I can do with fuel/air, timing or transmission tuning to help out econ?

[ScarabEpic22]

Buy a wideband and then do the Calc.VET to dial the VE tables in, then play with the spark tables.

[The Alchemist]

get the timing right in the light load areas where you are cruising, test drive on the road will identify the important load points . Try to avoid any knock retard in these areas as this will reduce timing past the knock point and take some time to recover back up again costing you economy. Concentrate on the DCFO settings and really nail the on triggers to be aggressive and early as possible upon throttle release AND maximise the on time by setting the "off" rpm very low like 1000rpm to get the best "glide" you can on decel. This has a huge effect on mpg..... Oh and during the DCFO set the throttle cracker (LS1) or Minimum idle airflow (E38 ECU) to minimise the vehicle decelarating to much also maximising the "glide" effect...I usually set this baised towards a slight increase in speed going downhill yet almost speed neutral on the flat but its a feel thing really
Hope this helps,
Mike

[Chevy366]

That is a large, heavy truck, and will have a 4L80 transmission. Properly built the 4L80 is nearly indestructible, but causes increased parasitic losses due to the power required to turn it. As you already know, the truck will never be referred to as fuel efficient.

Take a look at the threads regarding Lean Cruise and DFCO (Deceleration Fuel Cut Off) settings. You should be able to squeeze another 1 to 3 MPG in efficiency with some tuning.


Regards,
Taz

Good advice .
Having a 2005 model and have done lots of tweaking to find that magical sweet spot , you can get so much and that is it . Lean Cruise helps but the weight of the truck just makes LC go in and out to much to be beneficial . DFCO helps as well . The VE table is pretty close if you are stock .

[izcain]

thanks for the heads up. I know that this truck is not going to be any economical vehicle of any sort. I am playing with the DFCO lightly. Is there anything I can do with fuel/air, timing or transmission tuning to help out econ?
Right now I am on a 6.0L 4l65e in a denali so similar in some respects.
I have found that the transmission tuning and torque management decrease really makes things come alive and feel so much better. I figure when it requires less throttle input to feel like I am going the same speed I normally see mpg increase. I have yet to check and see if there is a real world increase from the trans tuning yet since I am onto the fuel and timing right now but I feel it had to have helped!

Look at Joecars input on the top of the trans tuning section and it really helps out (he has helped me a ton with mine!)

[swingtan]

Tips for getting better mileage....

For the engine:

Drive to save fuel, it probably helps the most....
Don't rely on the CL functionality to get the fuelling right. Dial in the MAF / VE and have the fuelling as close as possible without corrections. Then use the short term fuel trims as a safety measure. Personally I usually turn off the LTFT's.
Get the timing right. That's not the most timing the engine will take before knock is detected, it's where you get the most efficiency.
Look at the cold start tables and lean them off a bit, especially if you are in a colder climate. The longer the engine runs the cold start tables, the more fuel it uses.This can help a lot if you do a lot of shorter trips.
You could try advancing the injection pulses, to ensure better vaporisation of the fuel.
Lean cruise may help, if that is an option.
DFCO can be set to come in sooner and stay on for longer as the car slows down. I've had it running fine with a 0.5 second delay and remains on down to 1000 RPM, though I have a manual. DFCO can cause issues with high stall converters though....
With the auto, you could try the following...


For the Auto:

If the TC has a lock-up, ensure it's locking correctly under light loads. Also, release the TCC before the engine goes into PE mode.
Set the shift points to keep the motor out of PE mode. Shift down earlier if need be and ensure the correct gear is selected for slower corners.
Run the minimum amount of fluid pressure needed to make things work. Some tend to just ramp up the pressures for fast hard changes, but the engine must run the pump to keep these pressures high, this reduces economy. Be careful not to go too low though, as slippage can occur.