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For those of you who are new... bought my truck with 13.3k miles on the clock back in 2006. Truck has already seen a lot of change over the years with light performance mods, tuners, lift and tire changes. Its been off road on the White Rim trail (avatar pic), trudged thru the Sierra Nevadas and in various spots in the Cascade mountains. Its been airborne on 1 occasion, beat many times and has still keeps going. It has let me down a few times, transmission mostly and a couple of electrical issues, one of which was my fault (loose ground wire). To say the least its been around the block a few times.

Currently, to my surprise it does not use oil from oil change to oil change. I have had it use oil however under certain circumstances, high rpms under zero load on steep grades. Not sure why but seems like the oil level drops when these conditions present itself.

Anyways on to the fun stuff... Taking my truck back to stock front end... tired of working on it. So, steering is swapped back to 08.5 steering, replaced the ball joints (carlis worn and need to be looked at), possibly swapping back in stock springs and removing spacers in rear to bring it back to stock height or slightly lower.

H2's are coming off in favor of a 20# OEM wheel, 1st gen spyntec's are coming off for 2nd gens to better be aligned with the OEM wheels specs.

Fan clutch is having an issue, already worked on the fan shroud I build a couple of years back and have cut it down some in an effort to get it to fit with the OEM radiator (did not fit with the BTR radiator that used to be in there. Dragging this down to Cali with me over the holidays with the intent to attempt to get it in there. I already know how it performs and have no worries once its in there that it will keep things in check.

What I wanted to know was how much each change contributes to any mpg change. Before the fan clutch issue, I could count on 20~20.3 mpg all day everyday too & from work. Did not matter if it was rush hour, hiway speeds, mpg was always in that range.

With all that said, first up is the fan swap. It is very clear when the fan clutch is locked up vs unlocked. Throttle response takes a big hit, which affects mpg, lately low 19's are what I'm seeing. Part of this is because of the cooler intake temps but not much. I have the current tune dialed in with IATs down into the low 70's which I see fairly often day to day, usually climbs up into the low 80's. OATs are in the upper 30's low 40's.

So for anyone looking to know potential mpg changes with:


  • E-fans (2 volvo fans, each pulling 3700 cfm on high)
  • light weight wheels, current wheel is 30#, next wheel will be 20#
  • stock height vs 2" leveling kit
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"Baseline mpg" quirky fan clutch for ~410 miles, no fan for ~85 miles, e-fans installed, one interferes with fluidampr and has been removed. No power to the fans as of yet, CTs are more consistent around 200*f, lower temp swings.

495.5 miles, 25.087 gallons, 19.751 mpg Fan clutch, air dam in place, ~85 mi no fan.

52x miles, 70+ at times, 20.348 mpg, No fan power, rush hour traffic often and timing rattle. IATs mostly in the 60's and barely into the 70's for most of the tank, last 120 miles had IATs in the upper 70's low 80's with ambient temps being higher all day

518.3 miles, 26.338 gallons, 19.678 mpg No fan power, IATs mostly in the 60 & 70's, high winds & heavy rains for several trips on this tank.

497.5 miles, 25.586 gallons, 19.444 mpg no reason for poor mpg... road conditions were OK, one trip had heavy rain for a short distance. tweeked timing, IATs upper 60's to upper 70's.

404.8 miles, 20.717 gallons, 19.539 mpg, no reason for poor mpg, road conditions were OK, stuck in accident traffic for 45 minutes. Updated tune installed after this fillup. restored CT/IAT table to equal KGT file

29x.x miles, <unknown gallons>, 20.586 mpg, good weather, 70+ mph at times, 1000-2300 rpms used. fixed the tune, reverted the CT/IAT warmup table, took it back to the last KGT file table and left the IAT compensation table as it was. I can hear certain areas of the tune needing to have timing backed off a bit, most likely cause of the advance on the IAT table. Will fix this later as its a minor issue.

42x miles, <unknown gallons>, 19.527 mpg, great weather, Canada track trip, intermittent mis-fire/vibration started after 200 miles, cause unknown. MPG was looking great before that. First inspection points to a bad output TC bearing. does not seem like it would be related to a mis-fire, it could just be bad vibration being interpreted as a mis-fire. Will get the bearing fixed and go from there.


@350 miles on this tank, had to go back to a base file. Existing file did not want to run with ambient temps @30~32*. Found this out the hard way after coming back from Cali (flight) and no time to fix it. Base file is the one created by HPT when I vin locked my truck.
19.140 mpg 487.9 mi, 25.491 gal HPT base file installed, odo approx 0.5 mph off on low side

Current tank notes on 2/23... 33 mi in 4wd, ambient temps in the upper 20's, IATs in the 40-60 range, wheel install done. 70~75 mph @ times, minimal stop & go... @80 miles. Installed V2_0 air dam, then ran test runs to check it out, multiple runs testing air dams and IAT data collection. All still on base tune, new wheels installed.
551.1 miles, 27.847 gallons, 19.790 mpg

492.2 miles, 24.346 gallons, 20.202 mpg... speeds kept in check, hit 67 a few times but most of the tank was as expected. Winds and heavy rain on 1 45 mi trip but for only about half of that distance. Updated ECM with speedo & gear correction.

3/11/2018
Miles = 572.7, gallons = 27.232, mpg = 21.030. TQ LOM = 22.7mpg speedo corrected, IATs climbing higher with a few trips into the 70's & 80's 21.3 mpg tune going in today 3/11

552.5 miles, 25.757 gal, 21.4 mpg. TQLOM = 22.2 mpg. ~23+ drive events from 3/11 thru 3/17, ~10-11 cold starts, couple of days with IATs up in the 80's, 1 into the 90's, mostly 60-70 range. A new personal best in the colder months, especially over a 6 day period. Speeds mostly 60-65, 67~70 a few times.

569.2 miles, 26.623 gal, 21.380 mpg. TOLOM = 21.2

Fan power connected 3/24
3/26
525.5 miles, 25.451 gal, 20.647 mpg TQLOM = 21.2

Lift removed, guilty of 70+ on several occasions...
581.0 miles, 26.913 gal, 21.588 mpg TQLOM = 21.3

4/5/2018
533.1 miles, 24.003 gal, 22.207 mpg. Lift gone, speeds 68 or less, fan disabled, coasting where it makes sense, IATs in the mid 60's, lower 70's. 04/05/18, 20 trips on this tank over 3 day period

<unknown miles>,<unknown gal>, 20.6x mpg (SIL drove & drove it hard...)

570.7 miles, 26.334 gal, 21.671 mpg, TQLOM = 21.3 mpg, nasty weather on the front and back end of this trip, Col River trip, 2 summits. HSS installed on this fill up.

4/20/2018
493.7 miles, 22.449 gal, 21.992 mpg. TQLOM = 21.6 mpg. HSS tank, warmer weather

04/21/2018 - truck retuned

4/23/2018
491.3 miles, 22.980 gal, 21.379 mpg. Truck retuned, not so kind to throttle at times during the tuning. IATs up into the 70-90 range, adjusted the pedal map.

4/27/2018 - way more 70+ mph speeds than recent tanks, stuck on the wrong side of the morning accident today and crept along for 20~25 minutes. Intake temps up there in the 80-95*f range. Both fans hooked up on low and are doing a good job of keeping temps in check. High connection not yet made, fan switch in hand & needs install.
4/29/2018
547.1 miles, 25.321 gal, 21.606 mpg.

5/4/2018
457.4 miles, 20.512 gal, 22.299 mpg

5/8/18
573.6 miles, 26.875 gal, 21.343 mpg, lots of 70+ mph, high iats, trailhead climb (wta day), passing on 2L rds.

5/12/18 Aero updates installed prior to fillup, front grill block, wheel well vents, rear spats
636.6 miles, 29.658 gal, 21.464 mpg, no attempt at for driving for mpg, lots of 70+mph, high IATs, steel toed boots on, and are not good for mpg driving! (foot injury)

5/13/18 Columbia Gorge trip, IATs on way back 105-108*f
349.5 miles, 16.012 gal, 21.827 mpg, speeds 68 or less. 359k miles

5/18/18 typical work week traffic, IATs up in the mid 70-95 range...
576.4 miles 25.974 gal 22.191 mpg, speeds 95% good, couple of higher speed drives on commute home.

05/22/18 Rain, heavy foot, 70+ IATs 70-95 range typical traffic
485.0 miles, 23.288 gal, 20.826 mpg,

05/25/18 bumper mod IATs good
275.4 miles, 12.643 gal, 21.782 mpg,

06/17/18, 464.9 mi, 24.395 gal, 19.057 mpg. Cali trip, 80+ mph

06/16/18, 435.7 mi, 24.093 gal, 18.084 mpg. Cali trip, 75+ mph

Retuned in higher rpms, set higher altitude maps = to sea level and reduced FP 2 mpa on ea table vs the lower alt table.
06/23/18, 536.6 mi, 25.535 gal, 21.014 mpg. Normal commute minimal eco driving, 70+ mph at times


For reference, hpt mpg thread, best comparison for current tune, intake temps were higher & had fan clutch installed
https://www.cumminsforum.com/forum/3rd-gen-powertrain/2075258-hpt-mpg-thread.html

<MPG data>
Date_________Miles____Gal______MPG
07/08/2016___551.8___ 28.016___19.696 UDC programming/190*F stat
07/15/2016___554.4___ 28.596___19.387 Stock programming
07/19/2016___574.0___ 29.532___19.332 Stock programming, higher speeds & warm IATs
08/06/2016___490.3___ 26.355___18.618 3rd event delete, stock file, fan activation temp change from 24*f to 29*f
08/18/2016___549.2___ 26.929___20.394 3rd event delete, rail pressure, duration & some timing... key was the pedal table.

04/18/2017___515.1___26.xxx____19.49x lots done, finally getting consistent numbers
07/08/2019 531.5 miles, 24.896 gal, 21.348 mpg zero eco driving speeds 70+ at times.

Fan install images & first impressions

https://www.cumminsforum.com/forum/3rd-gen-non-powertrain/2376698-11-years-345k-clock-time-makeover-4.html#post27718146



Current truck config... 2" thuren springs, full leaf pack in rear + 1 spacer, H2 wheels (thought I weighed them @ 30# ea)






H2 Wheels, 30.8#








4th gen wheels




Wheels installed...


Front air dam installed... brown piece in front of the axle


Stock Height...






pulley install
https://www.cumminsforum.com/forum/3rd-gen-non-powertrain/2376698-11-years-345k-clock-time-makeover-17.html#post29054337
https://www.cumminsforum.com/forum/3rd-gen-powertrain/2508749-lightweight-pulleys.html

aluminum driveshaft
https://www.cumminsforum.com/forum/3rd-gen-powertrain/2468821-aluminum-driveshafts.html

Electric water pump install
https://www.cumminsforum.com/forum/3rd-gen-powertrain/2512127-electric-water-pump-swap.html
 

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Subscribing as I always learn from you.
 

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Subscribing as well for the same reasons. I have a long list of "going back to stock" items that i'll be incorporating over the years. There's a strong correlation between age and truck mods; as I start getting older, my truck starts going back to OEM specs. Following along on your journey.
 

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I have electric fans, not the Volvo type but the Flex Fan kit installed due to bad bearings and replaced busted radiator and two fan clutches...

1. I did see a pretty significant change in mpg while running empty and just cruising, +.9 / 1.0 mpg (cruising is just like 72mph on hwy in no hurry and no load)
No stock shroud made water pump replacement a 10 minute job and easier to see the front of motor to watch for issues
I saw a significant drop in voltage by stock alternator when everything was running, look at having your stock alternator rebuilt to higher specs by a local shop
or invest in a aftermarket higher amp version
2. Stop and go traffic even with fan on high I did have cool AC but stretched the ability of the fans when it was 120F on the asphalt in July stuck in Atlanta on I75
and hauling a medium heavy load
3. I am going back to the manual Hayden clutch and adapter with stock fan, I will lose the mpg and the ability to change my water pump in 10 minutes but I think it
be worth it (holding onto electric setup just in case)
 
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TECH SPECIALIST
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Discussion Starter #5
I have electric fans, not the Volvo type but the Flex Fan kit installed due to bad bearings and replaced busted radiator and two fan clutches...

1. I did see a pretty significant change in mpg while running empty and just cruising, +.9 / 1.0 mpg (cruising is just like 72mph on hwy in no hurry and no load)
No stock shroud made water pump replacement a 10 minute job and easier to see the front of motor to watch for issues
I saw a significant drop in voltage by stock alternator when everything was running, look at having your stock alternator rebuilt to higher specs by a local shop
or invest in a aftermarket higher amp version
2. Stop and go traffic even with fan on high I did have cool AC but stretched the ability of the fans when it was 120F on the asphalt in July stuck in Atlanta on I75
and hauling a medium heavy load
3. I am going back to the manual Hayden clutch and adapter with stock fan, I will lose the mpg and the ability to change my water pump in 10 minutes but I think it
be worth it (holding onto electric setup just in case)
Before you go back to an OEM fan setup (fixed clutch or otherwise), pull your flex kit and insert a divider between the fans. Both fans on high will not pull its max amount of air as they will be working against each other. I found this out a couple of years back, results are in this post...

http://www.cumminsforum.com/forum/general-diesel-discussion/1706266-diy-fan-test-chamber.html#post19521922

One Volvo fan test @ 12.3v drew ~3350 cfm whereas the dual fan setup test @ 12.1v drew ~4550 cfm. That right there says the dual fans are fighting each other for flow. Divide the shroud and the fighting ends which allows each fan to pull its max that it can. At 12.3v dual Volvos should be able to draw ~6600 cfm on hi. When I jumped the Vfan to the trucks batteries & bumped the voltage up to 13.6v, flow increased to ~3600 cfm for 1 fan. That's still not at the voltage the truck runs at, I would expect that 3600 cfm to go up further while the motor is at a higher rpm. With that said, I expect to be running just one fan most of the time when they do turn on.

As for the alternator, yeah I'd agree it can use a bump in output. I thought I read that there was a 180A drop in that came with some package offered from dodge... ???? There are other ways around the drop in alternator current draw, one of which is to use a PWM (pulse width modulated) signal thru a FET (field effect transistor, aka an electronic switch) and alternate which fan is being driven. That would take some design work as it couldn't be done thru the Volvo relays. It might also be possible to use the ECM's fan clutch control output to control them... also would need some design work done.

Back to your existing setup... another thing to consider is the temp of the AT trans cooler, if after dividing the shroud temps are still not quite what your comfortable with, consider a +4qt trans pan, bypassing the heat exchanger on the block and an aux cooler mounted under the cab with a fan mounted on it. I say that because if you think about what the fans have to keep cool, condenser, CAC, trans cooler AND the radiator, its a lot to ask for of any fan setup. Any help you can give them the better.

For reference, this thread has the truck seeing a 30+ *f drop in temps when going from the flex kit to the Vfans... worth reading.

http://www.cumminsforum.com/forum/3rd-gen-performance-parts-discussion/1857074-electric-fans-flex-lite-kit-doesnt-cut-need-ideas.html
 

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Discussion Starter #6
Subscribing as well for the same reasons. I have a long list of "going back to stock" items that i'll be incorporating over the years. There's a strong correlation between age and truck mods; as I start getting older, my truck starts going back to OEM specs. Following along on your journey.
Yeah fixing it is getting old, I'm at that point where I'd rather have a shop bust the knuckle :grin2: I'll save my wrenching for the fun stuff.

I will say this though... the stock steering sucks. There is no comparison in the steering feel from the thuren kit I pulled and the stock setup. I will be selling it along with the steering knuckles and the pitman arm at some point.
 

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I'm at that point where I'd rather have a shop bust the knuckle
Amen to that, especially when I look outside and the mercury is in the single digits.

I will say as far as steering goes, nothing was like the Thuren steering I had on my 04. I currently have the synergy linkage, creative fab brace, and the bushings in the column; it's about as good as this truck will get. I'm admittedly a perfectionist but i'm satisfied.

The upper control arm brackets are gone from having the lift put on, in about a year or so i'm going to take a road trip to have the synergy arms put on and the drop from my 3" coils to the 2" "leveling" coils. Of course at that time i'll have to re-gear for stock rubber...it's just money right:grin2:
 

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Im with you guys on "keeping it real" I like to call it. If it requires more PM than factory I want nothing to do with it. Similar example is I have a drag link with heims and I'm not a fan. My power steering is leaking, My input shaft is leaking, Tcase output leaking. I'm fixing all this crap and just wanna drive the damn thing. With no clunks or leaks. And with 1100hp...

And for the first time in my life I think I'm putting smaller tires on a vehicle. Just tired of wearing parts out and pushing them past their designed limits.
 

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Discussion Starter #9
Upper CAB brackets on the axle removed for a different setup?

My original frame side tracbar bracket was swapped out for one that would fit the ballistic joint on the bar I have. After 5 years of service, every tech still says it is tight with no movement on either end.
 

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Yeah fixing it is getting old, I'm at that point where I'd rather have a shop bust the knuckle :grin2: I'll save my wrenching for the fun stuff.

I will say this though... the stock steering sucks. There is no comparison in the steering feel from the thuren kit I pulled and the stock setup. I will be selling it along with the steering knuckles and the pitman arm at some point.
Steve, what’s wrong with your steering that you want to swap it back to stock, Is it problematic? Also the 6.7 alternator is of higher amps and it looks like it bolts into our trucks. All you need to change is the field wire connector which I’m pretty sure is available from the dealer.
 

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Discussion Starter #11
Steve, what’s wrong with your steering that you want to swap it back to stock, Is it problematic? Also the 6.7 alternator is of higher amps and it looks like it bolts into our trucks. All you need to change is the field wire connector which I’m pretty sure is available from the dealer.
No, the steering was awesome, no problems with it. My reason to swap it back is to be able to take it to any shop and say fix it. OEM parts are readily available and whatever the issue is can be resolved pretty quick. With the heim joint setup, parts have to be in hand AND have to find a shop willing to do the work, otherwise its up to me. I got to a point where I did not have to do an alignment after heim joint swaps, made a test fixture that sets the distance for the toe and the drag link. Works awesome.

the Hemi trucks have a 160A alternator that was used with the plow package, going to have a look at those to see if they are a drop in without any plug changes. Also fwiw, I still have the original alt from the factory. If when the fan kit is in there and there is an issue that concerns me, I'll figure out a solution. If that 160A alt drops in, then that would be the first step.
 
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Discussion Starter #12
I should add that the thuren steering had been on there since 2007 or so...
 
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These are all the reasons you see me reverse leveling and using the lightest OEM wheels available. Unless you drop huge money on a nice lift kit, these things wear out quick and then they are a pain to fix.

I use all the preventative items, steering box brace, always use good grease, use high quality tires, and I keep all 4s on the ground.

I love the people that buy 1200 dollar 6 inch lift kits then ask why their truck wanders around the road like a drunk

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Discussion Starter #14
did you reverse level your truck?

I found a set of wheels, the 6 spokes like whats on your truck, hoping they are still available when I roll thru the guys town on Saturday.
 

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did you reverse level your truck?

I found a set of wheels, the 6 spokes like whats on your truck, hoping they are still available when I roll thru the guys town on Saturday.
Yes reverse leveled. I left the overload spring in and glad I did on the few occasions over the summer when moving pavers.

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Can you post a picture of the divider?
? tell us what to use to make the divider? I have the the flex o lite fans an would like to do this . I pull a 36 ft 5th wheel in so cal. on a good grade it runs around 205max. darren
 

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Discussion Starter #18
About the fan situation... I saw last night a kit that utilizes a power stroke fan clutch to eliminate the electronics in our stock clutch. Just thought its interesting and don't know if it applies to you but cool to know its out there. https://www.strictlydiesel.com/p-2754-cummins-fan-hub-adapter.aspx
There was a thread on it a month or so back, I forget who has it in place (2 of them IIRC) and both say the setup works well.

http://www.cumminsforum.com/forum/3rd-gen-powertrain/2334673-fan-clutch-conversion-parts.html



Can you post a picture of the divider?
? tell us what to use to make the divider? I have the the flex o lite fans an would like to do this . I pull a 36 ft 5th wheel in so cal. on a good grade it runs around 205max. darren
ON my setup it is heavy gauge sheet metal tack welded in. If your shroud is aluminum, you may be able to use something like heater duct banding... the stuff used in attics to support heater ducts. Its easy to bend into place and would be good to just bolt it down with a few L brackets. It needs to be as tall as the outer edge of the shroud.

http://www.cumminsforum.com/forum/3rd-gen-performance-parts-discussion/1857074-electric-fans-flex-lite-kit-doesnt-cut-need-ideas.html#post21390418

205*f... I run my truck all day long @ 203~205*f... the bigger problem is keeping it there. For me its part of the reason for the good mpg.
 

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Home depot even sells flat stock aluminum that could be TIGed in place. Or you could buy some aluminum angle and lath screw it into place or even use nuts and bolts for that extra bit of excessive..

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Discussion Starter #20
Yeah that is also true... forgot about that option. It would be good to hear from a Flex fan user who can give before and after results. I would still like to test a Flex fan on the test chamber I built. Wife keeps trying to get me to toss it... nope, no way, aint gonna happen dear... lol Actually, the response should be, go get me a flex fan off the dodge ram kit, let me test it then we can toss it hahaha
 
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