Hi All,

I am working on a tune that will provide stock (reduced from my original 40 HP tune I have been working on ...) boost levels during cruising (highway speeds) but will increase boost beyond stock when additional power is needed.

My assumptions so far:
1) Keep boost stock when rpms are 800 or below regardless of fuel delivery (all mm3values)
2) Keep boost near stock when rpms are below 2200 and fuel delivery is below 75 mm3
3) Ramp up to higher boost levels when rpms are greater than 2200 (10 to 15% over stock)
4) Ramp up to higher boost levels when rpms are greater than 800 rpms and fuel delivery is greater than 75 mm3 (10 to 15% over stock)

I picked 2200 rpms to represent about 72 mph with my tire size. Above that speed I know economy is out the door due to wind resistance ....

I am unsure of what would be a good fuel delivery values to key on since I tow 50% of the time. I want the extra torque/hp when I need it, thus I have also played with fuel timing to increase fuel delivery some. I originally had more boost throughout but saw my fuel economy drop mostly when towing (10.5 to 11.5 mpg versus 12.5 when stock.)

What do most people see as far as fuel delivery (mm3) when towing on flat ground. What are the ranges people see going 55-65 mph?

Is my value of 75mm3 too conservative to begin increasing boost beyond the stock tables?

I have placed my tune in the LLY modified repository if anyone wants to take a look.

Thanks in advance.

1st data log while towing that will tell you were you are fueling on the respective table.


than adjust the areas accordingly


i can cruise empty with less the 25% throttle about 25mm3 cant remebr the mS of the top of my head

So maybe I should use 50mm3 (between 800 and 2200 rpms) as my basis for increasing boost above what the stock tables provide? What I am trying to achieve is a tune that will allow me economical towing cruise but provide some extra power (~40HP) when I need it. That is why I chose 2200 rpms as an upper point before providing 15% additional boost over stock.

im going take a stab in the dark here..... cruising while towing is going to range between 30mm3-65mm3 and between 1600-2500 that includes the range of rpm from when you shift out of one gear and into the next with the tranny in T/H mode and including running about 55-65 which is about 1700-1800rpm depending on the tires

Thanks Malibu795,

That is what I was looking for (just wanted to get a second opinion.)

I hand calculated 18.8 miles/gallon unloaded on this tank using this tune (455 miles, 91.4 liters @ $1.06/liter ....or 24.1 gallons ....;) Driving was unloaded along Prince Edward Island North coast (over several days .... rolling hills, speeds from 30 to 55 mph ... lots of starts and stops.) I am pleased with this so far.

I'll be towing Tuesday so I will be able to verify the 30mm3 to 65mm3 on my truck. I have this tune in the repository.

:)mark

here is two thing that might be useful for you
http://www.dieselplace.com/forum/showpost.php?p=1749936&postcount=10

malibu795,

Thanks very much - got the pid files - I'll use them to log my flow rates, etc. while towing.

:)