Basic towing tune on 03-07 Cummins

[GrannySShifting]

Anyone familair with these, know where to start? Just want safe bump up to drag around trailer

[WreckItRalph]

Most of your gains will be in the main timing tables. Without a dyno it's tuning by ear and feel. Low boost fuel table is where you can take the lag out of the pedal, but go easy for a tow tune.

[GrannySShifting]

Most of your gains will be in the main timing tables. Without a dyno it's tuning by ear and feel. Low boost fuel table is where you can take the lag out of the pedal, but go easy for a tow tune.

Ok but what about with a dyno? What are you doing with the main timing tables, how far are you going safe for something dragging 8000#. Have any examples of basic truck with air intake, and exhaust maybe with a mild bump?

[steve05ram360]

Without a dyno, your tuning progress should look like this...

1. Find a route that will allow you to hook the trailer up and give you a good representation of the driving you'd see towing... Hills, high speed, low speed and varying loads.
2. Connect the VCM Scanner and log rpms, speed, throttle position, boost, calculated load, all of the fueling available, all the timing information available, make sure you grab the SCI parameters only for faster scanning
3. With the truck up to op temp, drive the route and log baseline data. Do the baseline data run EVERY day you are adjusting your tune. Start at a fixed spot on the route and end at a fixed spot. Does not need to be a loop, I use a loop near where I stay in WA as it gives hiway, and slower speeds of various loads (hills). You need baseline data everyday you tune because of ambient conditions... they change, they need to be considered when making adjustments otherwise you can start chasing your tail in the tune.
4. Since there is no marker function in the scan tool, I recommend going to 0% throttle at a marker on the route so you know where you were on the route, helps with analysis. If needed make a sticky pad list of the markers.
5. Save the log file in a folder with the date and the actual tune used. Create a notepad file with details on the files tested that day, the weather and results.
6. Analyze the log file against the previous log file for that day to determine what changes you want to make.
7. Monitor EGTs

My recommendations on tuning... (small changes to start so you can familiarize yourself with the effects)

1. Adjust rail pressure to desired settings
2. Adjust duration to desired settings
3. Set timing based on fueling settings with consideration for IATs, Boost, Baro and CTs

It is easy to get timing off from day to day with the changes from the correction tables which can have you chasing your tail. Truck may run awesome one day and not so much the next day (baro, IATs). I started tuning under the worst conditions, IATs up at 110~120*f, got the fueling done then worked on the timing. As the temps drop, you'll want to add timing as the ignition delay increases. I have found less than 1* adjustment from 80*f up to 120*f works for my target, daily driving with mpg being a main focus. Researching I found studies that indicate peak power is in obtained with the peak pressure spike occurring in the 10-16*f range ATDC. Since we dont have a pressure transducer in the cylinder to measure this, the next best indicator for me has been the calculated load. Lower is better... measured at a steady throttle state over the same road locations.

If you have pressure set, duration set and timing set, then change pressure, timing is off as ignition delay changes.

Hope this helps... Using this method has netted me a best mpg of 21.3 mpg over 500+ miles of commute traffic, lots of stop & go, higher speeds and nothing is flat around here. Truck is a 2005 QCSB, G56 MT, 4x4 with 2" lift on 33" tires, 50hp injectors, stock airbox, AFE torque tube, AFE exhaust mani, HTT stage 2.5 HE351 turbo, stock exhaust except for 30" magnaflow muffler.

Experts feel free to make any suggestions, corrections or comments otherwise as I am still a newbie with just over 1 year of HPT experience.