14.0 Detroit mpg

JunkYardDog5958

Well-Known Member
mndriver mndriver what are you getting and what is done?

Anybody else same question.
 

mndriver

curmudgeon extraordinare
Supporter
According to my black book for the month of November I'm about 7.2 mpg.

Long list of what's been done. Longer than I care to type. Suffice to say. A lot of tuning and maintenance. It is not worth my buying a different truck. A truck is the drive line. And my air induction, suspension, trans, differentials have all repaired or replaced.

The last two things I did made the biggest difference of it all. One was free, the other cost me $450. I had the dynamic braking turned off in the ecm and I replaced the fan clutch on the engine. Those two items brought my average up from 6.1-6.2 to over 7.0 mpg.
 
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JunkYardDog5958

Well-Known Member
Ah. Well only time I would if my stock broke and needed replaced otherwise oem is just fine! At $1,600 for manifold (and installing yourself) it would take a lot of miles to pay for it! Think they CLAIM .3 mpg increase. So if went 6.25 to 6.55 would take almost 77,000 miles to get back at $2.30/gallon, cheaper fuel would mean more miles. Copperhead Copperhead what is your experience with ceramic manifold?
 

Southern Fried

Well-Known Member
No offence meant to anyone here.... but I wonder how many of these "burn less fuel" add-ons would you suppose it would take before all the percentages added up to 100% plus and having to siphon off fuel every so often to keep it from overflowing the tanks because you can't use it fast enough??? ;)

I can see the headlines now.....
Truck drivers causing bio-hazards on our roads due to over production of diesel fuels. Govt forms new agency to study the problem. :biglaugh:
 

JunkYardDog5958

Well-Known Member
Most things I'd agree on are snake oil. Being as I've been playing with internal combustion engines and built high hp engines 1 of few things that make sense is ported/ceramic coated manifold. Ported lets exhaust get out faster and coated keeps heat inside the pipes not creeping into the metal. With that said in the turbo world (I've played a lot with with on gas setups, same principle on diesel) keeping heat inside the pipe will spool turbo quicker. If spools quicker you will need less throttle and less acceleration time which creates less fuel usage. I've had gas turbo engines dyno 50 hp more on coated manifold. Peak hp wasn't different but lower range was higher bc quicker spool. Ported manifold would increase peak hp. With that said in big diesel the cost wouldn't justify unless you were replacing broken manifold.

On our gas turbo stuff coating was done to keep under hood temps down but had offset of more power so win win. Diesel motors in class 8 trucks are not squeezed in small engine bay like our gas setups so I under hood engine temp isn't a big deal.
 

mndriver

curmudgeon extraordinare
Supporter
I figure, the guys I'm working with on my tune and my turbo deal with twice the power I run. One guy has an 1100 hp 12.7L Detroit. The turbo guy I asked directly about buying a turbo blanket.

Both of their answers were the same.

"I can sell it to you, but it's not worth it. There's so much air flow through the engine compartment, the temps aren't there to need to protect stuff."

Similar points with the manifold. They have run those engines with and without ceramic coatings on dynos and the numbers don't support the expense.

If they are running that much power compared to me, spending a ton more than me on testing and don't run it, my shade tree experience's are squat.

Mike Mike just had his new Detroit put together with the pp manifold. So it'll be interesting to see his experience.
 

mndriver

curmudgeon extraordinare
Supporter
here's the history of my mileage. My lifetime for this truck is 6.35. My 2015 is now at 6.6 mpg. It will be interesting to see how the rest of this winter turns out. there is no data for Jul / Aug of this year as I was off on medical leave those months.

Mid September is when I finally changed the fan clutch out and turned off the "dynamic braking" setting in the ECM. For those that don't know what that is, it turns your engine fan on anytime the jake is turned on and you are going down hill. it will run for an addition 30 seconds after you come off the jake as well. I seriously believe that was the BIGGEST impact to my mileage.

mileage.jpg
 

JunkYardDog5958

Well-Known Member
mndriver mndriver aw I said I wouldn't waste money on manifold unless I had to replace anyhow. Yeah turbo blankets are great in tight compartments but on big truck we don't fight under hood temps anyhow so wasted money.
 

mndriver

curmudgeon extraordinare
Supporter
mndriver mndriver aw I said I wouldn't waste money on manifold unless I had to replace anyhow. Yeah turbo blankets are great in tight compartments but on big truck we don't fight under hood temps anyhow so wasted money.

I understand that. There are times though I write a response not necessarily for the moment, but for when someone goes necro on the thread in like 3 years.
 

JunkYardDog5958

Well-Known Member
I understand that. There are times though I write a response not necessarily for the moment, but for when someone goes necro on the thread in like 3 years.
This is true lol. I didn't know what dynamic braking was. I can see how that could help quite a bit taking off!
 

mndriver

curmudgeon extraordinare
Supporter
the downside to turning it off is you loose about 25-40 hp of braking hp with the fan not running with the jake. I am in the process of setting up a factory dash switch which needs to be turned on in the ECM and running into wiring / connection/ communication issues. That's what led me to all these "discoveries".
 

Tazz

Infidel
Couldn't they set it to run with your Jake? That is what ours do on the Evolutions. After maybe 20 seconds of braking the fan kicks in (only on high) and as soon as you kill the jake or touch the throttle it dies.
 

mndriver

curmudgeon extraordinare
Supporter
That's dynamic braking.


Convince your fleet manager to turn yours off for 60 days and then compare fuel mileage
 

Tazz

Infidel
Yeah but you said yours ran another 30 seconds or so, ours quit as soon as the brake goes off.
 

mndriver

curmudgeon extraordinare
Supporter
Yeah but you said yours ran another 30 seconds or so, ours quit as soon as the brake goes off.
I don't doubt you, but double check and be sure. I may exaggerate these 30 seconds, but the fan ran longer than the Jakes
 

Tazz

Infidel
I know it does because it is on the Detroits, the Cummins take twice as long to come on and run maybe 15 seconds over.

Maybe on the older trucks it may be different.
 

Mike

Well-Known Member
Staff member
"I can sell it to you, but it's not worth it. There's so much air flow through the engine compartment, the temps aren't there to need to protect stuff."
Also remember, you are cooling down the air going into the engine. The cooler we can get this air, the better.
 
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