So I posted back in December that I was having trouble with mileage in my 01 3500, and 6 months later I still am. Engine load at 65-70 usually hangs out at around 32-35 if the ground is flat, and the way my tune is set up (just like what is recommended and also based off tunes you guys have made) I'll cruise at about 15* of timing. I've checked everything for drag and still have found not brakes dragging or anything. Bout the only thing maybe out of line, would be at idle after it's warm it'll stumble a bit, but it still maintains the 6-9% load, I even saw it at 12% with the AC on.

 

So anyways, would I do any damage by setting my load limit higher to maintain the desired 19-20* at 2k? I've gone through multiple tunes and like I said before, I can feel the changes in the way it drives but man it does not change economy at all, period, and I'm getting fed up and I'm about to go back to my smarty....

15 degrees at cruise @2,000 rpms is pretty low. Even pulling my travel trailer on flat ground My light load timing runs about 23- 24 degrees of timing but I’m running studs. My light load limit is set at 32%. My base scale at 1,500 rpm starts at 16 degrees but my injectors are set at 320 bar. You should be fine running 20 degrees of cruise timing at 2,000 rpms. What does your base timing scale look like? 

17 minutes ago, Threadzy said:

15 degrees at cruise @2,000 rpms is pretty low. Even pulling my travel trailer on flat ground My light load timing runs about 23- 24 degrees of timing but I’m running studs. My light load limit is set at 32%. My base scale at 1,500 rpm starts at 16 degrees but my injectors are set at 320 bar. You should be fine running 20 degrees of cruise timing at 2,000 rpms. What does your base timing scale look like? 

The tune in currently running starts at 15*, then 2k is 19*.

What is Your light load percentage set at?

21 minutes ago, Threadzy said:

What is Your light load percentage set at?

Light throttle load limit is set at 25%. It's been a bit since I've messed with tuning and such since I just started driving a lot again since Rona hit, so I gotta relearn what everything does 

Start at 30% I wouldn’t go much higher than 32. I’m running at 32% because of my larger than stock tires. 

6 minutes ago, Threadzy said:

Start at 30% I wouldn’t go much higher than 32. I’m running at 32% because of my larger than stock tires. 

I'm running 235/85/16s, which correct me if I'm wrong, are bigger than what came stock on the dually's? So that may be my problem, cause Mike did mention tire size but I've always heard you want bigger tires to drop the rear end ration down for better mileage so I never thought anything of it or to change anything to compensate for that.

 

Edit: just checked the door sticker, 235/85 is stock tire size. Makes even less sense to me!

Edited June 27, 20204 yr by TheGreatWhite

My truck on flat ground floats around 25-30% engine load. Try raising yours to 30 and test on a flat road. I set my cruise control so the throttle stays pretty even to maintain cruise mode.  

5 minutes ago, Threadzy said:

My truck on flat ground floats around 25-30% engine load. Try raising yours to 30 and test on a flat road. I set my cruise control so the throttle stays pretty even to maintain cruise mode.  

Will do! My plug for my rear diff speed sensor is broke on the pigtail, a long with a bad abs module, so I need to find a new pigtail or plug if you know where to snag one!

Unfortunately no. I’d check eBay though. 

14 minutes ago, Threadzy said:

Unfortunately no. I’d check eBay though. 

I've tried just simply googling it and it'll just pop up pigtails but of course like every manufacturer they have to have their own proprietary clip for every sensor, and my local salvage yard hasn't gotten a 2G in for awhile (which is good, but bad in this case )

I've ran as high as 23 to 24 degrees of cruise timing at 2k RPM.

2 minutes ago, Mopar1973Man said:

I've ran as high as 23 to 24 degrees of cruise timing at 2k RPM.

Your head must have been loving every minute of that.

No issues, coolant ran 195 to 197, EGTs were normal 600*F at 66 MPH at 2,000 RPM. Even engine oil temp hover at 175*F. Remember my pop pressure is higher and later injection event.

6 minutes ago, Mopar1973Man said:

No issues, coolant ran 195 to 197, EGTs were normal 600*F at 66 MPH at 2,000 RPM. Even engine oil temp hover at 175*F. Remember my pop pressure is higher and later injection event.

See I've just got stock pop pressure, and now that I have a new job, should I maybe bump up to 150s and a higher pop? I've still got stock head bolts and all, haven't done much to the motor but I definitely want a bigger turbo.

 

As well as my oil temp is ~4* cooler than coolant temp it seems.

Only got a 60/60/12 turbo. But still can reach 47 PSI for boost. Im already got ARP 425 studs. Stock is 54/60/12 for HX35W.

10 minutes ago, Mopar1973Man said:

Only got a 60/60/12 turbo. But still can reach 47 PSI for boost. Im already got ARP 425 studs. Stock is 54/60/12 for HX35W.

If I went up in injectors would it be wise to do so with a turbo as well?

With the Quad you could put 7x.10’s ,150 hp, injectors in and tune it down. Then later put a bigger turbo in. Another pro having a Quad. 

set your cruise load limit %5 above what your typical highway cruise load is. 

35 minutes ago, Me78569 said:

set your cruise load limit %5 above what your typical highway cruise load is. 

Even if it's at like 34% load for an example?

yep,  you can run a lot of timing without issues.