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We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.

Poor fuel MPG

Posted

Checked the Mileage when I topped off this afternoon, and  found that I got 13 MPG. Now granted it's winter, and the truck idles more, this is still pretty crappy.

The particulars are as follows: 1998.5 3500 24v, edge EZ box, DAP 100hp VCO sticks, New OE size tires (215 85 r16) 400,000 Miles 5 spd trans. I'm planning on jumping on the quadzilla train this spring, but does anyone have an idea why my mileage sucks so bad?

 

Mark

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  • Owner

Some of the early articles talked about 19 to 20 BTDC at 2k RPM. Which I figured out is wrong. Timing is based off your pop pressure and how far is strays from the 310 bar which is 4,500 PSI. I'm at 320 bar with 4,641 PSI which is about 2 degrees retarded hence why I can reach 26degrees at 2k RPM with timing. Now someone with a low pop pressure say 290 bar could be about 4 to 5 degrees advanced and would have to retard timing. Just seeing his running timing he's retarded to deep yet. Should be some where around 22 to 23 degrees at 1,900 RPMs. 

 

Take some time watch stock timing on level 0. You can add about 2 to 3 degrees more over stock. Only one catch cruise timing has to have 5 PSI of boost or LESS. Don't wanna blow head gaskets.

I bought a tow tune from Mike a year or so ago. He called me last spring and we talked a few "numbers" as I had contacted him regarding a high engine load at cruise. He said it was due to the drag in an auto transmission vs a manual. Since I have the quad and have been driving the same 50 mile round trip commute for 29 yrs now, I want to see if I can get it as fine tuned as possible as I see very different numbers (engine load, boost, egt, timing etc) vs what he has mentioned in some of his threads. He's the guy with the knowledge so I'm hoping he can find me another few mpg! :) Thanks Mike! 

8 minutes ago, Mopar1973Man said:

Some of the early articles talked about 19 to 20 BTDC at 2k RPM. Which I figured out is wrong. Timing is based off your pop pressure and how far is strays from the 310 bar which is 4,500 PSI. I'm at 320 bar with 4,641 PSI which is about 2 degrees retarded hence why I can reach 26degrees at 2k RPM with timing. Now someone with a low pop pressure say 290 bar could be about 4 to 5 degrees advanced and would have to retard timing. Just seeing his running timing he's retarded to deep yet. Should be some where around 22 to 23 degrees at 1,900 RPMs. 

 

Take some time watch stock timing on level 0. You can add about 2 to 3 degrees more over stock. Only one catch cruise timing has to have 5 PSI of boost or LESS. Don't wanna blow head gaskets.

So do the same data collection at Quad level 0 instead of level 3 where I normally operate at? 

4 minutes ago, Mopar1973Man said:

Please look back at my past post fill in the numbers please.

didn't I get you the correct numbers in the post about 6 and 8 posts above? Let me know if I didn't get you the correct info in those two posts. 

 

  • Owner

Timing displayed is what is commanded. So level zero Quadzilla is disabled. Level 2 is stock fuel. Level 3 is CanBus fuel.

 

Timing is more important than fuel. But don't have excessive fuel in your cruise state. This why the 100% stock realm for your cruise state. 

Here you go Mike:

55mph = 1600 rpm, 2 psi, engine load 21, timing 16

65 mph = 1900 rpm, 4 psi, engine load 23, timing 19

65 mph with slight grade = 2000 rpm, 7 psi, engine load 32, timing 14

 

 

light throttle load limit 27%

 

Light throttle timing advance 2%

 

1500 = 13

2000 = 17.5

2500 = 22

3000 = 26.5

 

I'll get Quad 0 data on the way home from work today

Prior tune data/results as posted earlier in this thread: 

55mph = 1600 rpm, 2 psi, engine load 21, timing 16

65 mph = 1900 rpm, 4 psi, engine load 23, timing 19

65 mph with slight grade = 2000 rpm, 7 psi, engine load 32, timing 14

 

Results after our phone conversation today:

 

55mph = 1600 rpm, 1 psi, engine load 24, timing 13

65 mph = 1900 rpm, 4 psi, engine load 20, timing 21

Engine oil temp is about 7 degrees warmer than coolant temps. 

 

 

  • Author

How are you guys going down the road with such low boost numbers? Typically I'm at:

55mph, 1600 rpm, 4-5 psi

65 mph 1950 rpm 9-10 psi

 

This is on flat land to.

 

Mark

  • Owner

Timing is too retarded. More retard in the timing more fire and expanding gases are sent to the turbine to spool.

 

More you advance timing, More the fuel is burnt in the cylinder leaving little expanding gases to spool.

 

Excessive advancement can possibly blow out head gaskets. The trick is to make sure you drop your high timing before boost is made. 5 PSI or less you can run like me 26 degrees. But as soon my load changes it drops to 18 degrees.

 

Poor final ratio. I can tell your on stock tires and too low in the RPM band. I'm running 2k RPM at 66 MPH. Then at 82 MPH I'm twisting 2500 RPM. I'm running 3.69:1 final ratio after tires.

  • Author

Ok, Looks like I'm getting that Quad a little before I planned. Now as far as Poor final ratio, I may be off my 65 mph rpm since I don't have the chance to get going that fast very often, but by my calc it's about 3.70 with a 3.55 gear and 215 85r 16 tires. Am I missing something?

 

Mark

  • Owner

Yeah about right. Didn't know the tires where changed. Then the Edge EZ is not going to make up for the timing retard of the injectors.

  • Author

Ok, ordered the Quad today, and the took a drive around the county.  New intel is:

 

55 mph, 1625 rpm, 4-6 psi

60 mph, 1850 rpm, 7-8 psi

65 mph, 2000 rpm, 9-10 psi

 

Sounds like I need to advance timing a bunch, what about fuel? I'm new to the quad thing so any input would be welcome and  apricated. I know  how to make a 440 run like a raped ape, but diesels are a new thing.  

 

Mark

  • Owner

Fuel table is selectable but I'll warn that if you are attempting for efficiency then you should be 100% or less for fuel table. I typically ride in my defuel table between 0 and 5 PSI. I can climb 7% grades without using any additional fuel above 100% even on higher levels. Hence why temperature are lower. Even while running 200°F thermostat.

 

Thermal dynamics basically states greater differential between temperature will make them attract to each other. So cold is attracted to heat and heat is attracted to cold. The whole idea is reduce the amount of heat dumped in coolant and oil.

  • Author

Ok, I'll wait until the quad shows up and then start playing with that. Until then, I've still got to do a leak down on the road runner, and then work on the kick down linkage on the Ramcharger. Between that and calving there's just way to much stuff needing work, and nowhere near enough time or money.

 

Mark

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Welcome To Mopar1973Man.Com LLC

We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.