I just had a dpf delete kit installed from what appears to be the cat back (egr back) with a bully dogg triple gauge tuner installed and my mileage hasn't improved any at all. Is the elimination of the regen the claimed increase in mpg? Mind you the tune is set to no power as i told the shop i dont goof around or race or none of that stuff in my truck. I just wanted longevity and better mileage out of it.

I am still glad i did it, truck sounds good and doesnt regen anymore and smells like a diesel should lol. The throttle response is now immediate and with the almost elimination of back pressure she coasts a lot farther when i'm off the go pedal lol

I was just hoping for a bit better fuel economy i guess. What other 2 thousand dollar mod do ihave to do to my rig to get better mileage? lol

And i dont race kids on teh street or want to "roll coal". Just want to have a truck that lasts a long time and does what a diesel should!! I really do love this truck, i'd like to make 'er last!!

 

Hi PinkyRingz, I'm gonna move this to the 6.4L forum.

From my understanding, stock power level tunes don't provide much, if any fuel economy improvement. Inefficient tuning is the reason for the lousy fuel economy, not so muchbackpressure from the DPF.

 

I thought I had it in the 6.4 but apparently not lol thanks man

 

Good luck on any appreciable mileage increase--over 150000 miles with a MiniMaxx and maybe .5 better. However, if I run on the hot tune--not rodding it, just driving--it will creep up to 18-19 on the computer. Grin goes away when putting a pencil to it--back to 14.
Joe

 

Fuel economy improvements? Internet will either tell you 3-4 mpg improvement or .5 mpg improvement. Based on your experience, which do you think is closer to the truth? My personal belief is that you delete the DPF and EGR for longevity and any fuel economy improvement is negligible if not unmeasurable. BTW ... you can buy a lot of diesel for $2k so I think most folks are simply after a more reliable truck.

 

We have seen everything from a loss to a huge gain... Every truck is different and fuel will vary greatly here in the US.

Unfortunately there is no magic answer. I can tell you that the higher hp tunes (200hp+) WILL net you better fuel economy. However... If you aren't hand calculating you will never get an answer. The pcm takes inputs from the frp sensor to calculate fuel economy, this means higher hp tunes will push larger amounts of fuel. In most cases this will cause the readout on the dash to become skewed.

There are a lot of other factors involved as well. A 6.4 will never get great millage... It is just the nature of the heavy/powerful beast. But if you have 3.73 gears and are running a 215 or 275 tune you should be averaging between 15-17 depending on driving habits. If you are lower than that its time to start looking at your brakes. Our trucks tend to have calipers that seize and will drag. It is pretty obvious what the impact on fuel economy is with this. I actually have a bad right rear caliper on my truck atm and my fuel economy went from 17mpg to 13mpg... My dash readout went from 17.1mpg down to 16.8..............


With stock power and no drive line issues you should average roughly 13-14mpg... That is completely normal for a 6.4 that is deleted with no power added. It is also good to remember that you are driving a truck that weighs 8500lbs empty... In my case I am at 9300lbs atm. These trucks DO NOT get good fuel economy, most people actually only average about 11-12 mpg in stock form with 3.73 gears... And getting rid of the regen cycles you will only gain about 1-2 mpg.

 

Agree with CrazySob, if it wasn't for the regen issues and maybe an EGR issue here or there it wouldn't be worth deleting. I get 15 hand calculated 50/50 city and freeway driving and mine is 2WD. On a trip empty at 70 I get 20MPG, but at least I don't have to drain my extra oil out anymore, I'm sure my rocker arms love that the little oil they get is undiluted now.

 

The real reason our trucks get such pi$$ poor fuel economy is quite simple... The 6.4 has pitiful low end power compared to a 6.7 or any of the cummins variants. All of the power on a 6.4 comes on right at or around 2k rpm... That means if you want useable power around town you end up farther into the throttle before you really get moving.

It is also why these trucks have a "light switch" effect when accelerating. Once the turbos catch the fuel and you hit 2k rpm they just take off.

Long story short the 6.4 was and never will be designed for fuel economy. It is a motor built for power and it excels at what it does lol.

 

I don't agree with that. These things are turning right about the same RPMs on the highway that the 6.7L trucks are. My 6.4L truck rarely downshifted on the highway, and I some fond memories charging up grades on the interstate with 10,000 lbs behind me in top gear. That pig was still hard-pressed to see more than 15 MPG on the highway.

I think it's all about tuning and what was necessary to get the engine in compliance with emissions regulations. I'm guessing that stock DPF-off tuning retains the same inefficient programming.

 

No offense Tom but line a deleted and tuned 6.4 up with a deleted and tuned 6.7 and you will have a perfect understanding. The 6.7 will pull on the 6.4 right about to mid 3rd and then the 6.4 will just take off. Our trucks are known for amazing top end power and lack luster low end. Pretty much all powerstrokes up till the 6.7 lacked power down low. And you are right, they will hold right at the same rpm but that doesn't mean the truck is in its power band. If you accelerate from 55 and then from 70 you will see exactly what I am talking about.

At 70 a 6.4 with 3.73 gears is holding right at 1950-2000rpm with 10lbs of boost... From there its literally a rocketship if you stand on it. From 55 you won't have crap worth of pulling power till you either down shift or the turbo lights off completely and helps pull you up into the power band.

But you can really feel the difference if you have ever driven any of the cummins variants. Right from a stand still they put torque to use and it shows in 2 ways... First and most important is towing ability... Second is fuel economy. They don't rev hardly at all when accelerating around town compared to a 6.4 unless you stand on it. They just don't need to...

 

I'm not talking about power Matthew, the power band is definitely lower in the other engines you mention. I went from a bone stock 2008 6.4L truck to a 2011 6.7L truck after my wife wrecked my '08. Peak torque on the 6.7L is at 1,600 RPM, as it is on the ISB they put in the Ram, and you can definitely feel it while driving.

I was talking about fuel economy, and both trucks are geared similarly.

 

But my point is its how and when the truck applies that power... The 6.4 doesn't make use if any real power until about 2k rpm. A 6.7 psd or cummins both have more usable power between 1500-1800 meaning they burn less fuel cruising around AND while at 65 on the freeway.

That is also why low boost fueling will increase your fuel economy in a 6.4 greatly... But now we start running into reliability issues... Heat and cylinder pressure are the enemy of the 6.4... At low rpm the motor can't push out enough heat for the pistons to survive that much fuel. But that is a whole separate subject.

Fuel economy is directly impacted by power, but its more important when that power is applied.

 

Pinkyringz; don't be afraid to turn it up.... It's not a 'race-thing' - it's a fuel-efficiency-economy-thing... With doing all you did but stopping short of 'turning it up', you ran the race all the way to the finish - and stopped 1/2" shy of the tape.... Trust me on one other thing --- once you do turn it up, you will never-ever turn it down!

 

Honestly JD, you are right and completely misleading.

First thing is first, yes a 300+hp tune WILL net much better fuel economy than a 150-250hp tune. And yes, if you are easy on the noise pedal you "should" be fine. But, that said these trucks already have major piston issues and running a high hp tunes means elevated cylinder pressures. The biggest impact is on the pistons themselves... These trucks are known for cracking pistons even under stock hp levels. When you start adding fuel and messing with pilot injection you really start limiting the life of your pistons.

Second, head gaskets... Now, before I go farther on this. A 6.4 doesn't just blow head gaskets. Unlike a 6.0 they aren't prone to HG failure. The bolts are MUCH stronger and they don't have the same oil cooler restriction on the egr coolers. The problem that the 6.4 has goes back to cylinder pressure. it is the same reason this motor can build so much damn power. Something as simple as driving when cold is no big deal for a 6.4... But it leads people to driving "normal" and never letting them warm up. When diesel doesn't burn (I am talking cold) it is still a liquid. This means it can't be compressed the same as if were atomized properly. Guess what happens over time... Yes, elevated cylinder pressures over stress the tty head bolts and boom goes the dynamite.




Now, a high hp tune makes both of these issues 10x worse. With a 200+hp tune you really shouldn't be going over 2k rpm EVER unless you are at or above 160* eot/ect. The motor just can't take it... Remember the 6.4 was never designed to be run at the hp/tq levels that ford tuned it to. The motor itself is quite solid but emissions and tuning are what gave it the problems that it has in stock form. If you delete you are getting rid of the regen cycle and the oil dilution, but you are adding power to a motor that was never properly designed to take it. Not to mention that Ford royally screwed up on the piston casings...

 

Sorry Crazy - but you're overstating the situation... SCT flash - turned wide open, dpf delete, egr delete, cat delete, straight pipe, Valvoline DOT blue premium full synthetic since day-one, 3 radiators (replaced each time one leaks), one oil pump, 5,000 mile oil changes, 10,000 mile fuel filter changes (religiously), bypass to the damnable crank-case vents (plug the line to the intake and take 1-1/4" hose to the frame-rail), fuel treatment in every single tank (religiously - I keep gallon jugs in the bed), regular trailer towing with two ATV toys on trailer -- oh, and did I mention 233,000 miles and counting?
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Oh - and then there's U-joints every 75,000 miles, tie-rod ends and ball-joints every 75,000 miles, top-gun front bumper/grill-guard, hammerhead armor rear bumper, tire rotations every 5,000 miles, new tires every 85,000 miles, new vacuum seals on the 4wd every 75,000 miles, new front and rear main seals on the transfer case every 75,000 miles, new rear main seal in the transmission every 75,000 miles, new rear-diff and front diff fluid every 100,000 miles, rebuilt driver's door latch mechanism to get interior ligths to work, new thermostats at 150,000 miles, plugged-in on timed heater circuit in the garage for any temps below 45 deg ambient, K&N washable air filter for the past 175,000 miles ---- even replaced the seat-foam in the driver's seat at 150,000 miles - just to restore the ride comfort....

Of all of it - the EGR delete and crank-case vent bypass did more to reduce temps than anything....