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Discussion Starter #1 (Edited)
I read proposed fuel economy claims all the time. I have a 2007.5 LMM and I get 17 ~ 18 mpg real figured fuel mileage average hiway at 4100' asl. Is this as good as it gets? I don't lead foot it, and I keep good records. More power would be nice but economy both towing and empty is what I really want.

Are the increased economy claims a myth?

I appreciate honesty here please.

Thank you

Jeff
 

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The main factor would be the regens, they lower your mileage a lot. The tuner will improve your mileage a bit (1 to 3 mpg max)

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Discussion Starter #3
The main factor would be the regens, they lower your mileage a lot. The tuner will improve your mileage a bit (1 to 3 mpg max)

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Ok Thanks. I did all the deletes and tune and got no improvement.

Jeff
 

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I have kept mileage records for over 30 years on every vehicle I've owned.

I thought the regens made a big difference in my mileage. When a regen occurred early in a tank of fuel, I could watch the mpg go down steadily.

Since deleting the dpf, I've noticed very little increase in average mpg. It's somewhere between .2 and .3 mpg on a full tank.

If you want to see substantial gains in mpg, slow down. Reducing from 75 mph to 55 mph gives me 2 to 3 mpg increase over a couple hundred miles of freeway driving.
 

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I have a 45 mile one way commute, 70mph to nearest town, then 60 to 65mph, then whatever the herd feels like doing. dpf deleted. I average 15 to 16mpg, never knew if that was good, bad, or ugly.
 

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I have gotten 21 hand calculated doing 75 on the interstate. Dropping down to 65 I hand calculated 23
 

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I read proposed fuel economy claims all the time. I have a 2007.5 LMM and I get 17 ~ 18 mpg real figured fuel mileage average hiway at 4100' asl. Is this as good as it gets? I don't lead foot it, and I keep good records. More power would be nice but economy both towing and empty is what I really want.

Are the increased economy claims a myth?

I appreciate honesty here please.

Thank you

Jeff
Jeff,
I'm pretty sure I informed you last summer to not expect much if any gains with deletes. More power yes, but even driving normal you will not see much more than .5 gain if your lucky.
Towing 13,500lbs stock mine was 8-9, $3000 later towing 13,500lbs 9-10.
Solo stock city/little highway 14.5-15.0, fully deleted 14.0-14.5 tank to tank, top off the tank every fill-up 400-425 miles.
Final results, gained 1.0 fully deleted while towing, lost .5 solo.

Slow way down like eastex mentioned.

On mine, my mileage was better with just deleting the stock muffler and DPF, than it is now fully deleted.
It's a great sales pitch to claim you'll get another 1-3 mpg gain with these great products we offer.

With every mod I fell for and ended up doing with the advertised sales pitch on mileage gains, I should be getting at least 30 mpg by now.

As far as myths on mileage when anyone with a LMM claims 20+ at the higher speeds they claim, it's not a myth it's more in the line of BS.
Possibly down hill, a good tailwind or both.

There's a member on another forum that claims above 20 cruising on a flat highway @ 70.
What he fails to admint now is, he actually sets the cruise at 70 on a nice flat highway then he resets the ave mpg after driving a mile or 2 going by the mile markers, this is how he claims to be his actual MPG.

He adminted this a few years ago and truly believes this is a good way to figure and claim his awesome mileage.

What people just can't figure is when you add more fuel for more power with tuning, that added fuel is going somewhere, adding timing helps correct that a little.
Every vehicle I've owned and modded since 1968 (I don't have enough fingers and toes to count) better mileage NO, more power hell yes.

This is your honest answer. :smile2:
 

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I can guarantee you my claims are not bs lol. I have no reason to lie about the mileage I get. I am on flat ground getting this mileage
 

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Two months ago after deleting I filed up in NC, drove 280 miles on the highway and filed up in VA . I drove between 60 and 70 taking advantage of terrain and I averaged 22 hand calculated with Rob's 90econ. Granted I was trying hard to get the best mileage possible. Before tuning my best was 19.

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:wink2: :thumbsup
 

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Discussion Starter #11 (Edited)
Thank you everyone. I appreciate the replies.

D_R_C, you did indeed tell me just that and you were spot on. I just cant believe after spending 2K in deletes and tunes I got pretty much nothing. The power increase is minimal to say the least. Maybe a problem here? But I am coming around to agreeing with you 100%. I did take a trip and ran two tanks at closer to sea level and the mileage picked up. But this was after deletes and I would have to figure I would have seen the same increase in mpg before deletes since I see no increase in mpg after deletes here at home at 4000'. This is based on testing over 8 plus months.

galantea, what is Robs 90econ tune? Is that his economy tune for the LMM? If so I have that tune, and he has retuned after data logs from my truck, and it is what I run on most of the time. What year is your Dmax ? It is an LMM correct?

Thanks
Jeff
 

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Discussion Starter #12
Another question. Has anyone seen increase in economy after they installed aftermarket lift pumps on LMM's?

Just wondering since the performance gains were slim to none, if I could be having a fuel delivery problem?

That said the rail pressure stays at 26K or above at WOT. If we can believe the EDGE monitor. And I have my doubts with it as well for a number of reasons.

Thanks

Jeff
 

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2007.5 same as yours.
I don't feel a lift pump will help with mileage, I didn't gain any mileage.
From what I was told they are needed when adding 90+ HP.

Someone the other day said 60.

I put one on to have the extra fuel filteration, leaving the stock filter.
I can easily go 2 AirDog filter changes before I change the stock filter.

At the time when I installed my lift pump I was running only a 40hp towtune. Now I'm trying my 60hp TT.

They only add 8-10 lbs fuel pressure where fuel is always at the engine when needed.
 

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Discussion Starter #14
Thanks D_R_C I am with you. My top tunes have sluggish spots some times. Plus as I said, just not impressed and really don't feel I gained much power. I have my alarms set on the Edge monitor. They go off at times during WOT. Two things set them off. EGT and boost. I know from previous life experience lean conditions can spike boost. I also know you can have pressure, and lack volume causing cavitation and aerated fuel flow. Just not sure if I trust the Edge II. Its over all performance has been weak in my eyes.

I am taking a hard look, trying to be 100% honest, and will gather second opinions from guys that know more that I. Thus, I appreciate your input. In the end, I will either retune, add a pump to get it right. Or plan B, take it all off and return to stock and have the same performance and mpg as I do now.

Jeff
 

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I think I mentioned last summer to take baby steps, start off by deleting just the DPF and muffler first and get a tuner.
Then as you add stuff slowly you could see gains or no gains.
I've done just about everything you can do over about 5-6 year period doing one mod at a time.

This way I feel I can honestly say the gains I did or did not get with parts claimed to do the unthinkable with power and mileage.

Mine was best all around with just deleting the DPF & stock muffler, using Quadzilla Stealth II set on Economy NODPF tunes.
 

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Thank you everyone. I appreciate the replies.

D_R_C, you did indeed tell me just that and you were spot on. I just cant believe after spending 2K in deletes and tunes I got pretty much nothing. The power increase is minimal to say the least. Maybe a problem here? But I am coming around to agreeing with you 100%. I did take a trip and ran two tanks at closer to sea level and the mileage picked up. But this was after deletes and I would have to figure I would have seen the same increase in mpg before deletes since I see no increase in mpg after deletes here at home at 4000'. This is based on testing over 8 plus months.

galantea, what is Robs 90econ tune? Is that his economy tune for the LMM? If so I have that tune, and he has retuned after data logs from my truck, and it is what I run on most of the time. What year is your Dmax ? It is an LMM correct?

Thanks
Jeff
Yes, it's Rob's 90hp econ tune and I have a 2008 lmm. My regens were about once every 300 miles. I think the driving conditions during a regen can also have a significant impact. I have a 15 mile commute and sometimes a regen would not complete before i had to shut her down and it would continue on my drive home. It probably doesn't burn much extra fuel if you're towing due to the already high egts.

I averaged 17.8 on my last tank and it was mostly commuting and a couple 40 miles trips. 90% highway.

Do you use any additives? I know their claims are exaggerated, but I notice an improvement on short trips (commute) when the engine never really reaches full temp.

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I wouldn't say you spent 2k$ and got nothing.....you got a lot of the problem out of the truck......ill never understand guys wanting a 8k lb truck to get car mileage....I get 20 running 75......way better than my 6.2 got in my half ton.....but you didn't waste your money....you probably saved yourself some money in the long run...
 

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You're definitely improving the life of your engine by not having regens and egr plugging your intake.

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If you are not holding rail pressure it will feel sluggish... Personally my truck fuckin rips! I tow on my 60hp tune and will forget to switch back before I romp on her and 60hp feels slow lol.
 

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On your boost and egt alerts did YOU set the max to your settings or are you just going by the factory defaults ?

I understand your frustrations with everything on what you was told on the possible gains, you just gots to sum it up as typical sales pitches.

The mods you did is NOT a waste of money when it comes to the longevity for your engine.
Another suggestion that would help is to tone down your HP level, or you'll be looking at more repairs down the road, especially trans.

You'll get a little better mileage with the higher hp tunes, but your risking a lot for maybe 1-2 mpg is that really worth it?
If so, then continue on with what hp level your using.

You might try a lift pump and see if that helps please you a little knowing fuel is at the engine at all times, at least you'll know in advance that it will NOT increase mileage.
But it will aid in other areas, like I mentioned earlier.
 
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