Cruise timing (How high can you go?)

[Mopar1973Man]

I'm doing some serious research into cruise timing and how far can you go. 

 

Being I'm running 7 x 0.010 injectors popped at 320 bar this makes my injection event a bit later than normal.

 

My current timing is...

 

Now I've got cruise timing set to 6° with a load of 22%. This give me a max cruise timing of 26° at 0% engine load and 24° at 22%. I'm very surprised of how low you can drive the EGT's my 55 MPH EGT hovers in at about 400-450°F and 60 MPH is barely 500°F to 550°F. Boost sits at nearly zero boost at 55 MPH and 60 MPH just barely 2 PSI.

 

I'm well into the 20 MPG bracket now been reaching 320 to 340 miles at a half tank. 

 

Still fighting a lot of bitter cold for startup. Morning travel could be as low as 28°F. Always seem as the IAT breaks over the 100°F realm the MPG jumps up really strong. Like yesterday it maxed out at 81°F outside in Ontario, OR. wonderful weather!

 

As for going any higher, I'm going to use a bit of common sense here. I've already found that 27° to 28° realm is as fair as the engine can go under WOT. Being the cruise timing can max out at 26° at zero engine load but hovers about 24° in a cruise state. For 60 MPH cruising engine load hovers in at 15% to 18%. Idle now at 12 to 13% bouncing. Anything below 17% is gravy the MPG is through the roof in the high 20's and heading for 30 MPG. My safety net is my engine load boundary of 22% keeps me only in the 55 to 65 MPH realm and low engine loads. Once it jumps to 23% it drops to mere 18° of timing and turbo is spooling. I've been trying to build at 60 MPH as a set speed. 

 

I'm doing this strictly for the economy study work and find out what can be had from these engines for maximum efficiency. With the price of diesel now at 2.999 a gallon and still rising time to find out how much can we get out of these ISB Cummins. 

 

I've found now with timing this high for cruise state even the coolant temperatures are down even. Haven't figured that out yet and cooldown of the turbo is even faster now. Idles much less. 

 

DISCLAIMER: I do not suggest following this unless you have the supporting mods and understanding. You've been warned!

 

This was reaching out for 65 MPH and seeing what it would do on semi-flat ground. 

 

Add +1 to speed for actual speed.

Subtract -50*F from the EGT for real number.

Edited April 19, 2019 by Mopar1973Man