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? for the Dmax tuning experts...

BKDespain

BKDespain

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Everyone complains about mpg in the winter and my PPE on lvl2 gives me the best mpg. I started messing around with the custom changes. I turned off the defuel and took the fuel out of all the tunes. I left the rpm increase in and the timing in. Level 2 felt a lot different than the normal 2 obviously. Better shifts and no power. So... in went level 4, 225 hp on mtr, with no fuel added and no defuel??? No idea what it lays down now... Better power and boost still hits around 28 psi according to the insight. At full throttle all the shifts are firm. Before, wot on the 160 tune with no changes, 5th and 6th gears would slip the tq. Now on level 4 flat footed its fine, no tq slip, obviously there is no fuel added and less hp. EGTs are waaaay lower also. Barely hit 1100* on lvl4... makes sense because of more boost and no fuel increase. Usually can hit 1700* fairly easy when rail psi drops.
I would almost tow on lvl 4 with those changes. Also fuel pressure stayed where it should and never dropped like on the standard lvl 4 tune.

This is what I have seen and understand so far....My questions now are...With these setups will I get better mpg than the standard fueled tunes? Is it better for the motor with just timing and boost added. How much HP is added with no fuel if any just from boost or timing? Finally is it safe to tow on lvl4 with no fuel added? Would lvl 1 with standard tuning put down more power than lvl 4 with no fuel. EGTs are lower on defueled 4 than standard 1 tune.

Sorry for the long post...got the wheels turning in my head tonight:D What do ya'll think haha!
 
Adding boost WILL lower your cruising MPG when empty. Timing helps to bump it up as well as reducing boost. And I highly reccomend not turning off the defuel, espescially on a mostly stock trans(a JR doesn't give you a whole lot more holding power).
 
Cruising boost is pretty much the same all the way around...maybe I will get better mpg?
 
Stock tuning does defuel during shifts.

I ran PPE for a while and I never thought it was all that healthy of a tune. It smoked way too much for me.

Generally, more boost and timing = better mileage. Your results may vary.
 
BKDespain said:
How much HP is added on lvl4 with no fuel if any just from boost or timing?
Click to expand...

Not very much probably. More boost and timing can actually cost you some HP if you don't need the added timing and boost. PPE puts those options in there for guys who have oversizedinjectors and bigger CP3's.
 
timing to an extent will help with milage, boost will hurt. generally boost comes from heat, with the non vvt turbos, heat comes from fuel, the vvt turbo heat is still needed, but to make boost down low less heat is needed due to the vvt, which in return means less fuel, but the down side is with stock vain tables you tend to offset the fuel decrease with vain position increases, creating a "smaller" turbo or bigger exhaust restriction. thus not doing much to affect mpg.

i see on average 18 mpg with either my big tune, or my mileage tune during the summer. my big tune has wide open vains at idle and on the highway cruising. it simply opebns the exhaust up a little allowing it to breathe better.

what i am getting at is taking away fuel on an other wise stock setup is not going to help much imo. technically it sounds good, but unless the programming changes turbo vain tables when you remove fuel the vains will be closing much more trying to achieve the boost levels it was set for with the big fuel shot. thus causing more restriction in the exhaust. causing you to be deeper in the throttle.
 
Thanks Stacks, that explains alot and makes sense. I think I will tow with this setup. I have been considering buying a PPE boost controller to keep egts in check. I don't think I will have too now.
It is more responsive and Egts are the lowest I have ran with this setup. MPG are the same as lvl3, a little worse than on lvl 2. A lot of idle time so its hard to tell. Getting about 150 mi for 3/4 tank.
I'm almost ready to get EFI live and be done with it!
 
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the cost of the ppe and a boost controller would put you well beyond efi live. the only issue is the selectable tunes for your year. although i tow with the big tune in the summer, as long as i can keep the egt's in check, and i now keep the plow/winter tune in all the time for the cold months. i rarely ever change the switch. so it may not be that bad of a deal for you.
 
If anyone here wants the sh******* mpg ever....tune as I did in above posts! I got 9.6-10.2 mpg over three tanks of fuel. 45miles on a 1/4 tank! I updated my ppe today. My tuner had the updates from march 2008. Updated tunes seem smoother than before. Lvl2 is getting me 16mpg! Pre-update was 14.5-15.2 mpg at best. Extreme light foot also. So if anyone is curious like me...dont do what I did :)
 
I'm getting about 13mpg with the new updates. I let it warm up for awhile and have been driving under 45mph alot so 13 is pretty good. Hwy I bet its getting 15 or so. Not much difference with the updates.
 
What happens if you go back to stock tuning. In my LBZ CC dually I get 16 in town and 18 mixed driving. I've never had it on the road without my 40' trailer so I do not know what it would get on the open road unloaded. That would at least give you a baseline to work from to see what's getting you the best milage.
 
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