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Discussion Starter #1 (Edited)
Greetings!
First I'd like to say I'm happy to be a part of this community. The FB groups can get down right nasty and abusive, but I've been observing here and everyone seems to be quite nice so far.
I bought my 2005 Dodge Ram 2500 Cummins last year, and it saved me from spending a whole load of money on a new F250.

I wanted to get a truck before all the emissions complications.

I was in Arizona on business and couldn't believe the condition of the body. Amazing.

Brought it back up north, got it ziebarted.

With 185 K miles on it I knew The trans and the injectors were the issues I'd have to watch. Saving up for a firepunk reinforced trans, I had a sticking-injector-run away incident.

Anyway, injectors have been changed for ones tailored to my specs. 8 holes, hydro ground and matched holes.
More on my injector choice in another thread.

Until I reinforce the trans I'm not doing anything silly in terms of power, so I decided to focus on fuel economy.

I've been remapping the ECU myself using HP Tuners.

First, a little about me, I'm an vehicle and powertrain development engineer. I've been involved in several automotive, light , medium and heavy duty diesels as well as the development of petrol engines also.

It's still an iterative process.

In a nutshell, I upped the rail pressure at the appropriate duty cycle load points, advanced the injection timing (its quite obvious looking at the 05 cummins maps and piston bowl design (a shallow bowl rather thana re-enterant-2-step bowl), a very high priority was given to lowering NOx emissions without using external EGR and/or aftertreatment at the expense of engine efficiency).

I also messed with throttle progression, and closed up the injection pulse widths to compensate for my injectors.

I got 19.95 mpg driving down from Chicagoland to Indiana, some in heavy traffic,
Then 20.67 mpg, heavy traffic and slower highway speeds.

Then up to Minnesota- 19.44 mpg (going pretty fast, not hanging about- really giving it some!)

Worst I got, "not hanging around"- was 18.4 mpg.

I plugged in some of the 3rd Gen particulars into my simulation package. Simulation alone is dangerous, but when done in league with real world- it really allows good understanding of whats going on:

Now, I put my simulation through the Federal Highway Test.

You will see a 48RE ram vs a NV5600. 1st pic is with NV5600, second is 48RE and third shows a 48RE with a hypothetical 3.42 rear end and my bigger tyres (stock diameter is 31.6 inches, my 285/7- R 17s are apparently 32.7 inches diam). The problem I have with the Federal test is that they don't change up to 6th on the NV5600. Nevertheless, the test is more representative of the driving I did in Chicagoland in some traffic and then going down to Indiana.

It also shows that with a 3.42 rear end, the engine operates at higher load, where it runs more efficiently, better 'BSFC' or brake specific fuel consumption.


The pics show where the Ram 'sits' on the engine speed map and therefore the best place to concentrate when re-optimizing the map for best bang for buck. A Ram 2500 probably uses about just under 100 Bhp to maintain 75 mph. Compare that to the 37 bhp or so to push a 2000 model year Jaguar XJR through the air.

This is why slower traffic runs, even with some stop and go traffic are often better in terms of mpg than constant 75 mph runs.
 

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Subscribed. I’m interested in how this turns out
 

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Interested as well
 

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Discussion Starter #5 (Edited)
Can anyone help me post pics? I wanted to show the engine speed-load map of the Ram over road use?

Does the upload feature work? When I drop in there- it doesn't upload
 

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@steve05ram360

Welcome! You'll find Steve and myself as big mileage guys that are both very passionate about tuning for efficiency. I'm glad to see another engineer dipping into this looking for mileage. Steve has a similar pickup to you, but mine is a 6.7. You will find that those piston/injection angle designs aren't quite as efficient as the 03-04 and 6.7, but can still get some really good mileage.
 

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Discussion Starter #8
HI Cpitock, yeah, doing a search I stumbled across a lot of Steves threads and yours and his dialogues!

Very informative. Totally agree regarding the bowl design. I'll cover my conundrum on that on another thread in the powertrain section when I have the time!

How do either of you post pictures? Does that drag and drop thing work for you?

Cheers
 

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Are you posting via phone or computer?

I know on my phone which I use the most to post on here there is a little paperclip icon in the top right that allows me to post pics or whatever within reason! I haven't used my PC in awhile to post on here but I seem to remember a similar icon thing there..
 

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HI Cpitock, yeah, doing a search I stumbled across a lot of Steves threads and yours and his dialogues!

Very informative. Totally agree regarding the bowl design. I'll cover my conundrum on that on another thread in the powertrain section when I have the time!

How do either of you post pictures? Does that drag and drop thing work for you?

Cheers
In the reply boxes there is a paperclip that you hit, if you haven't posted much, you might not have reached min. requirements.
 
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I thought there was minimum number of Posts but it had been a long time I was not sure
 

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I use smugmug... Had photosucket but they wanted a large sum monthly to post pics... Smug mug was $5.

Cody this is the thread you mentioned...? Looking in the wrong forums... Doh!
 

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I use smugmug... Had photosucket but they wanted a large sum monthly to post pics... Smug mug was $5.

Cody this is the thread you mentioned...? Looking in the wrong forums... Doh!
Yes, this is it!

Sent from my SM-G930V using Tapatalk
 
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Discussion Starter #14
OK, I cant post pictures right now then, but I can post some of my simulation results.

The take away from my real world fuel economy results is this- On my other cars, normal cars, like Jaguars XJRs, VW Golfs etc- stop start driving usually brings the average fuel economy down and longer distance Highway driving brings the average up.

For the Ram diesel it seems to be the opposite- I think this is because of the immense frontal area of the truck and the poor drag coefficient- that driving it at speed kills the mpg.

FWIW the simulation shows exactly the same trend. It's best not to focus on the exact numbers of the simulation but to utilize it in terms if trends and then compare it to our real world experiences;

So I have

Stock Quad Cab Dodge Ram 2500 with 48RE , 3.73 rear end and 265/70 -17 tyres

Fed Highway sim avg: 20.94 mpg

Stock QC Ram 2500 with NV5600 ,3.73 RAR and 265/70-17

Fed Highway sim avg: 18.49 mpg
My problem with this result is that the Fed Highway doesn't utlise 6th and revs the engine quite high, more so than any driver seeking fuel economy would- so I would like to modify the shift schedule if possible

QC 2500 with 48RE, 285/70-17 tyres and a 3.42 rear end
Fed Highway: 21.35 mpg- Here you can see the effects of both the larger diameter wheels and the 3.42 rear end. I need to separate out the effects



Stock QC 2500 with 3.73 RAR and 265 tyres
running constant 75mph: 12.23 mpg

QC 2500 with NV5600 with 3.42 RAR
running constant 75mph: 13.51 mpg

QC 2500 with 3.42 RAR and 285/70 tyres
running constant 75 mph: 12.98 mpg

I know I need to separate some of these effects out.

Other notable assumptions- I used a drag coefficient of 0.56 as a guess. The SRT10 was 0.45, the stock 1500 is listed as 0.53 so I guessed at 0.56 due to the higher stance and I increased the frontal area accordingly.

I used 88% as average efficiency for the 48RE- most autos ( like the NAG1 Benz trans are low to mid nineties). Because this is derived from an old torqueflite_ assumed a low figure. This is probably a bit harsh of me but I'd rather be pessimistic.
I assumed the efficiency of the NV5600 at around 98% in direct drive top and 97% in 0.73 over drive ratio.

There's quite a lot of 'stop and go' in the Federal Cycle.

This is the cycle-

https://www.dieselnet.com/standards/cycles/hwfet.php

It doesn't really get up above 60 mph- which is why the figures look quite good.

The other factor is that for the BSFC map (break specific fuel consumption) for the 5.9 Cummins I used some measured data from a Semi Truck dyno data I had and some 8 mode test data I had I extrapolated the rest. Also the spec of he semi truck application of this engine isn't EXACTLY the same as the Ram pick up. In addition, when this BSFC data is derived- its steady state on an engine dyno, what a vehicle achieves when driving can be a bit different.
 

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OK, I cant post pictures right now then, but I can post some of my simulation results.

The take away from my real world fuel economy results is this- On my other cars, normal cars, like Jaguars XJRs, VW Golfs etc- stop start driving usually brings the average fuel economy down and longer distance Highway driving brings the average up.

For the Ram diesel it seems to be the opposite- I think this is because of the immense frontal area of the truck and the poor drag coefficient- that driving it at speed kills the mpg.

FWIW the simulation shows exactly the same trend. It's best not to focus on the exact numbers of the simulation but to utilize it in terms if trends and then compare it to our real world experiences;

So I have

Stock Quad Cab Dodge Ram 2500 with 48RE , 3.73 rear end and 265/70 -17 tyres

Fed Highway sim avg: 20.94 mpg

Stock QC Ram 2500 with NV5600 ,3.73 RAR and 265/70-17

Fed Highway sim avg: 18.49 mpg
My problem with this result is that the Fed Highway doesn't utlise 6th and revs the engine quite high, more so than any driver seeking fuel economy would- so I would like to modify the shift schedule if possible

QC 2500 with 48RE, 285/70-17 tyres and a 3.42 rear end
Fed Highway: 21.35 mpg- Here you can see the effects of both the larger diameter wheels and the 3.42 rear end. I need to separate out the effects



Stock QC 2500 with 3.73 RAR and 265 tyres
running constant 75mph: 12.23 mpg

QC 2500 with NV5600 with 3.42 RAR
running constant 75mph: 13.51 mpg

QC 2500 with 3.42 RAR and 285/70 tyres
running constant 75 mph: 12.98 mpg

I know I need to separate some of these effects out.

Other notable assumptions- I used a drag coefficient of 0.56 as a guess. The SRT10 was 0.45, the stock 1500 is listed as 0.53 so I guessed at 0.56 due to the higher stance and I increased the frontal area accordingly.

I used 88% as average efficiency for the 48RE- most autos ( like the NAG1 Benz trans are low to mid nineties). Because this is derived from an old torqueflite_ assumed a low figure. This is probably a bit harsh of me but I'd rather be pessimistic.
I assumed the efficiency of the NV5600 at around 98% in direct drive top and 97% in 0.73 over drive ratio.

There's quite a lot of 'stop and go' in the Federal Cycle.

This is the cycle-

https://www.dieselnet.com/standards/cycles/hwfet.php

It doesn't really get up above 60 mph- which is why the figures look quite good.

The other factor is that for the BSFC map (break specific fuel consumption) for the 5.9 Cummins I used some measured data from a Semi Truck dyno data I had and some 8 mode test data I had I extrapolated the rest. Also the spec of he semi truck application of this engine isn't EXACTLY the same as the Ram pick up. In addition, when this BSFC data is derived- its steady state on an engine dyno, what a vehicle achieves when driving can be a bit different.
If I have time today, I'll try to get bsfc part load numbers from my truck. I recently put the flow meters on for some testing so this is an ideal time to do it

Sent from my SM-G930V using Tapatalk
 
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Discussion Starter #16
If I have time today, I'll try to get bsfc part load numbers from my truck. I recently put the flow meters on for some testing so this is an ideal time to do it

Sent from my SM-G930V using Tapatalk
Conversely I have a lot of good data for the 6.7, including measured in cylinder pressure data.

All Ram Truck based.

I could have used the BSFC map from the 6.7 for the 5.9 but wanted to do better.

Extracting the BSFC data and inputting into the simulation is a pain!

What kind of flow meters did you use? Coriolis type?
 

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Just a thought, I get the best fuel mileage from my truck when I’m on a long run at an avg speed of 60-65mph. 55 might do better but there’s nowhere that I run this speed at.
 

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Discussion Starter #18
Just a thought, I get the best fuel mileage from my truck when I’m on a long run at an avg speed of 60-65mph. 55 might do better but there’s nowhere that I run this speed at.
I agree that The Ram should get a lot better fuel economy at 60-65 mph (although weirdly, a guy who works for me with a Duramax GM, claims he gets worse at 60 mph than 70- which I find hard to believe).

But much like Steve05 has said in some of his threads, Im doing my tests and driving as I would normally- and quite 'press on'. Im doing this less for the purposes of saving money (Im from Europe originally- our fuel was $8-9 a gallon- its cheap here-trust me!) but more as an exercise for nerdy fun :nerd:.

I will one day try to maintain a constant 65 mph and see what figures I can achieve.
 

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Discussion Starter #19
Thought I would post some other stats for comparison, car data. Often a comparison helps to put things into perspective

This data from the simulation is very well correlated to real world, so I have a lot of faith in it, more so than the Ram Diesel data I put up.

2000 model year Jaguar XJR 4.0 Supercharged- stock

Fed Highway- avg 26.19 mpg. Best I ever got driving highway was 22-23 mpg. I have good faith in the BSFC maps as I was involved in the testing way back and was there at the dyno collecting it! The lie-o-meter on the Jag lies the other way to the Ram and is modest! Must be a British thing!

At 75 mph- it takes 38.9 Bhp to keep it at constant speed


2006 model year Aston Martin V8 Vantage

Fed Highway: 26.58 mpg. Im lucky to get 22 mpg out of mine, but I haven't done a brim to brim real world test.
This data I trust a lot as I was lead on this powertrain/vehicle project way back when, and attained the data myself.

At 75 mph- it takes 33.18 Bhp to keep it at constant speed


2002 BMW M3 (S54)

Fed Highway: 28.49 mpg. I have no idea how accurate this is real world. Ive never owned one, although I have faith in the person who collected the BSFC data for me


At 75 mpg it costs 34 bhp to push the BMW through the air


2012 Dodge CHarger SRT-8

Fed Highway: 22.89 mpg. I have modest faith in this- I used 6.1 BSFC data and extrapolated and cobbled together this data set! Its not far off what some are getting on our Ram Cummins! I have no idea how economical a Charger SRT-8 is real world!


Oh and almost forgot- at 75 mph it costs the Ram 2500 Cummins about 98.6 Bhp to maintain constant speed. Kind of puts things into perspective!
 

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I agree that The Ram should get a lot better fuel economy at 60-65 mph (although weirdly, a guy who works for me with a Duramax GM, claims he gets worse at 60 mph than 70- which I find hard to believe).

But much like Steve05 has said in some of his threads, Im doing my tests and driving as I would normally- and quite 'press on'. Im doing this less for the purposes of saving money (Im from Europe originally- our fuel was $8-9 a gallon- its cheap here-trust me!) but more as an exercise for nerdy fun :nerd:.

I will one day try to maintain a constant 65 mph and see what figures I can achieve.
I can duplicate that in my truck... its the tune doing it. More efficient at the higher rpms @ 70 than at 60. Last summer on a road trip I managed mid 19's doing 85 across Idaho and into Utah spinning at 2500 rpms. Truck was back to stock suspension wise and had 33" tires. Was pretty happy with the 19's and after the trip, truck ran better.
 
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