hey parkland....how about jotting down some of the liters and kilometers you use to get your mileage.....cant help think you are miss calculating.
I think all 450's are dual rear wheel...figured anyone in the know would know that...plus his rear end gearing if its ultra low like 4:88 would def not give him mileage to brag about.

 

He did a gear swap.
I really don't have the chance to run enough highway miles to get a good picture. Most of my highway trips are under a tank.
Most of the time I average under 20 mpg for sure, because there is idling, short trips, stop n go kind of stuff.

God winter is coming, she's got to idle, I don't like getting into a cold truck

 

lots of low idle is a no-no on these trucks...if you have upfitter switches [or you can put in a switch] you can go to high idle [1200 rpm] the wire being found hanging loose up by the obdII port...in a bundle...I forget color.

 

It high idles on its own after running for 30 seconds if its cold.

 

Apparently this is not a good idea i spliced tge white wire ran a switch to the dash drilled the holenfornit and everything after reading online. Well after all that i found outbthat bbc.co that wire controls a coolant pump for the fuel. My switch now controls a set of led light bars and the wires have been soldered back to stock

 

Well,

The truck is still giving up some wicked MPG for me like this!
I did install a lift kit and larger tires this winter, and noticed in town mileage get a touch worse.
Highway took a small dip, but nothing major, about 1.5 mpg.
Turbo actuator still moves freely, so that's still not an issue.
Over all this time, one thing is apparent, that is there is no reason for the 6.4 to run such high boost levels other than emissions.
Why aftermarket tunes leave the boost so high, I'll never know.
I do wish there was a real way to fix the problem, as the truck stinks warming up when it's cold out without the vvt to help warm up.
I think the crummy boost control is the primary reason why even some tuned 6.4's can have such junk mileage.
Not only does all that boost stress parts more than required, but air transfers heat to metal better the higher the pressure, so it stands to reason that higher than required boost helps waste heat into the pistons and cylinder bore and head.

I do wish I could have the vvt turbo pickup and spooling like before, but I much enjoy cruising at 5-10 psi down the highway instead of the insane pressures like before.
I've found that the tow tune is excellent for running with the vvt disconnected, smoke is minimal. It really works pretty good. Very laggy, but if you mash the pedal, things do happen as soon as the RPM's hit about 2000.

I'm just going to keep running like this, until I can find a way to properly fix the issue, or what I call an issue. Even towing, it just didn't seem to be a problem, EGT's stayed safe. Certainly there are tunes that would melt the pistons out of the block, but the tow tune seems to facilitate running without the vvt hooked up just fine. Towing the camper was lower boost than the truck used to run empty lol.

I've thought of modifying the connecting rod from the vvt actuator to the turbo vvt actuator arm, but the computer would just try to adjust to get what it wants anyways, so that won't work.

I've thought of hijacking EBP, MAP, boost signals, and emulating them with changes, but that won't work either, because the computer doesn't always call for the same boost, so it's not a linear adjustment.

I've talked to some tuning guys, but they don't seem to be interested. Doesn't sound like they want to really change much, maybe it's hard, or impossible. They pretty much say that it needs that much boost because it's the engine design, but that is totally not true.

So it will keep getting driven as it is, and maybe one day a new idea will come along. Till then, I'll keep enjoying my laggy but normal boosted truck haha. I don't doubt it might last a long time running 1/3rd of the boost it used to lol.

 

Parkland

Boost and throttle.
Did a little watching this morning on my boost and throttle opening on the way to work. First a little truck description, H&S tuned, running 300HP tune.
Going to work this AM, cruise set at 65, throttle % varied between 4 and 13 % with the flow of the landscape. Boost ran from 3 to 8 LBS(as best as I could tell).
I have my defuel set at 32 LB's of boost on the H&S and I've never defueled. I don't understand why your pushing so much boost!

 

I don't know, I heard the exhaust pressure sensor can get plugged, but I've seen a few 6.4's fairly low mileage and they all seem to act the same.
I think it's the tuning, the boost does not correlate with the air needed like say a 7.3.

It boost normal off the get go, but once it's rolling good, boost takes off way to high. I've seen this over and over on every 6.4 I've been in, so I don't think it's a personal problem on my truck.
Maybe the H&S tuning is different?

The way it seems the tuning works in the 6.4 computer, theres a spot in the fuel acceleration, where if you accelerate mildly, the boost climbs slowly and goes high, but if you punch it, it goes more normal.

With the vvt plugged in, If I drive on a flat road, and accelerate mildly, it can hit about 25 psi boost, and if I punch it, you can hear the vanes open up, and it might only hit 29 - 30 psi and already making insane power. Boost climbs from there, but it's like it just makes huge boost for no reason while under mild throttle. I assume that is the tuning for the EGR, which is active during casual driving. It seems like the culprit is that they leave the EGR boost control in the tunes even when the EGR is disabled in the tune.

With the VVT active, 10-20 psi would not really make any power, unless you accelerate quickly, but too mild, and the boost would creep up to crazy levels.
With the VVT off, 10 psi is a generous acceleration, 20 psi is quite a bit of power, like really aggressive speed to be driving with in town. The only time it will hit 30-40 psi is floored. IMHO, the way it should be.

I just think the EGR tuning was never fully erased out of the aftermarket tunes, at least the spartan ones.
Anyone I've talked too about this, is like well it runs such high boost because it's got so much power. That is just the dumbest thing, even if it was 2000 hp, it doesn't use any more power to roll down the highway.
It needs enough boost to burn the fuel, and keep the EGT's good, more than that, and all it's doing is putting extra strain on parts.

That's my opinion, and I'm sticking to it.

 

Personally i don't think the milage increase is the decrease in the boost alone. As a result of insufficient boost when the VGT is unplugged the PCM is running in different areas of the map affecting PW, Timing ect, which as a whole could be the result of better milage. Running a scan and logging would indicate whats going on.

If you like this why not just have a custom hybrid tune written. The same concept was done on the 6.0. Matt Gouge wrote several of these back in the day for the 6.oh's. It was a hybrid economy tune that ran lower boost and lower PW, better timing etc, tell you got 3/4 throttle, then you either ran the normal map or a slightly higher performance map. So of the line you could have full power and good response you just have to hit 3/4 or more throttle to get it. Just a thought.

 

I would consider it if I could find someone who could write a tune for the 6.4 that does that.
I've asked several people, and they say ya I'll write whatever you want if you pay for it, and when I mention the boost flare issue, they say well thats sometimes hard to control because the computer can change parameters on the fly, and not every parameter is currently tunable, or so they explained.

 

You have two options maybe three.

Jared at river city diesel or Matt Gouge at Spartan Diesel are the only two that have written custom files user specific that i know of.

At this point in time river city diesel is your best bet. Spartan Diesel really does not write custom tunes anymore unless you can talk Matt into it and currently he is all wrapped up with the 6.7. Talking him into it would be bring the truck to him and working it out.

Call river city and see what they have to say. There set-up to do it but its like pulling teeth to get the files, they seem to cater more to customers doing complete builds.

Last but not least you could purchase a used H&S tuner and then get the MCC file to write your own calibration files. The MCC would allow you calibrate the VGT% vs RPM or back pressure desired which would allow you to accomplish your goals. People currently do it now just to get the extra sound at idle.

A sct tuner might do the same thing with the MCC, anyways heres a forum you could ask more question about the MCC and DIY running http://powerstrokearmy.com/forums/fo...play.php?f=162

FTE is a great site for factual info the 6.4 in a stock platform , but i honestly haven't found the aftermarket info on the 6.4 in high performance detail any where near the detail you will find at powerstokearmy.com. Id say there forum is the most knowledgeable when it comes to high performance aftermarket upgrades, and aftermarket tuning information for the 6.4.