3406E vs C15

Funny how these threads always get derailed. Lol
The original question was about fuel milage between a E and C15.
Now its a pissing match about turbos and bottom ends. Lmao!!

 

The OP mentioned the Acert in his second post.

Wouldnt the low nox stuff come into play in 2002 or 2004? Seems like the 2ws and 6nz engines that still have their original programming get decent mileage.

 

I had a 3406E (5EK) and now have a c-15 (won't admit the prefix)... I did the Same loads and go to the same places with both . The E did a little better on fuel.......more hp with the C-15 tho.

 

True , he did ask about accert. Lol

As the years went by emissions got tighter and tighter. And you could never go backwards as far as programing ecms go. At least not with the dealers or cat house.
Thats why some the early 5ek 550s pulled so well and did good on fuel. The true low nox tunes were only on the early Es. Hence 40 pin ECM. The newer 70 pin will not accept those early low nox 40 pin file.
This is all factory cat programing I'm talking about here.
Now if we are talkin aftermarket with timing ajustments , that's diffrent.

 

And yes. I have a very early serial 6nz never touched and it runs real good with great mpg. But I think the early 5ek files were even better.

 

The real answer would have to do with you. Are you going to keep this engine for the long haul? Then the C-15, Acert C-15 will get better mileage and durability, with the proper tuning. In short term the file might be better for mileage on the E model, maybe.

 

The hardest part would be actually finding a early 5ek that the ECM has never been re flashed. Good luck. Lol

or just get it flashed with a early low nox file. But we wouldn't have a clue who could do such a thing.

 

The early 6nz files are the best. It's perfect for gliders. I would prefer 6nz on kw. I would like to replace from my t600 into a t660 glider with 6nz 550hp, same color, 13 sp tranny, and studio sleeper.

 

I drive a 1999 KW w900 heavy spec tractor pulling a tridem crude oil tanker trailer in the oil field in Alberta. I have a 3406E engine with an 18 spd trans hauling 90k pounds+ per load. In a 14 hour day shift I burn on average 50 gallons of fuel per day . That's approx 150 miles of driving per day plus around about 5 hours of high idling to run a PTO fluid pump. Plus the truck runs all day long while waiting to offload etc.
My friend doing exactly the same work with exactly the same truck setup except he has a 2005 truck with an ACERT c15 burns 60 gallons of fuel per day.

 

VVA's, VVA low oil sensors, VVA harnesses and VVA housing's have hurt me. I stopped counting after a housing let go and windowed the head ($13,000 for that event) but I am sure it's north of $25,000 just on VVA related problems.

Also have a completely 100% trouble free 6NZ. It;s never been back to the dealer since it left in 2001 so I guess that means it has it's original tune whatever that is. Fuel mileage ain't great I will admit.

Comparing fuel mileage is a fool's game since nothing is ever equal, but if I had to rank them over the years from best to worst it would be:

1998 M11 (10.9 Liter, pre EGR therefore no big surprise)
1986 3406B
1995 N14
2005 C15 Acert
2007 ISX (DPF)
2001 6NZ