Mpg tune for big tire truck

[Calebrhymes@gmail.com]

Hello guys, im new to the forum. Im looking for a way to increase mpgs on a cummins swapped f250 24v. Stock engine other than 4 inch exhaust and quadzilla v2. Truck is on 37s and has 4:10 gears. Looking for help witg tuning parameters

[Mopar1973Man]

At least final ratio is close enough 3.55 to work with.

 

Working with MPG tuning I suggest you grab an app called Simply Auto. Now you want to start tracking your MPG number. Now only make one change at a time. Don't change too much stuff at once.

 

If you start your cruise timing at 20 degrees at 2,000 RPM it will be close.

[Calebrhymes@gmail.com]

Im new to tuning. Ive been doing alot of research, would would be a good base map to start with

[Me78569]

What load % do you cruise that?  that is going to dictate the tune.

[Calebrhymes@gmail.com]

60 mph if i stand correctly 26-34%

[Mopar1973Man]

16 minutes ago, Me78569 said:

What load % do you cruise that?  that is going to dictate the tune.

 

What we need is to find out RPM, engine load, at lets say 65 MPH. 

[Calebrhymes@gmail.com]

Just going on memory, 65 mph 1850 rpm, 36 % engine load

[Mopar1973Man]

Wow. That is extremely high. I'm typically 19 to 22% engine load at 65 MPH for +75HP injectors. You got to look into you total drag, tires are a factor still rotational weight.

 

 

 

[Calebrhymes@gmail.com]

I have an ecomony based tune loaded and just filled up this morning.....  What woukd you want this tune to look like

[Me78569]

use that one, but increase

Light Throttle Load Limit to 3-5% over what your cruise load is.  

[Mopar1973Man]

You want your cruise timing to float about 20* at 2,000 RPM's. I'm much higher at 22 to 23 degrees of timing at cruise for 2K RPM. My 2,000 RPM happens at 66 MPH which is 3.69:1 final ratio to the ground (245/75 R16 with 3.55 gears). 

 

Set up your cruise timing there and then road test. Then nudge the timing up another degree and check the engine load and pyrometer. As you advance timing EGT and Engine Load will fall.

 

The other factor is quality of the injectors and the pressure they are pop tested for. As injectors slide on pop pressure the timing will naturally advance but the droplets will become larger. Once a injector drop below about 280 bar efficiency falls off fast. I don't see any injectors list ed in the signature so I'm assuming it stock 235 HP injectors. If so I'm going to bet they are worn out.