Lonewolf95

Hi guys, I just got an used 13 A8 4.0t, now I noticed that the efficiency program in DIS has not been enabled. I tried to code it with VCDS, like I have done on my B8 A4, but the instrument cluster model is different that I couldn't find the option for enable efficiency program.

Has anyone ever done that before? Or is it not an option for pre-facelift A8?

Another question is, pre-facelift A8 does not have "active" line assistance (the steering wheel only vibrates as a warning). Does anyone know if it is possible to retrofit the "active" line assistance on pre-facelift A8?

the_duke

Newer models have electric power steering and that's how the active lane assist works so there is no way to enable it on your '13. No clue on the efficiency program.

derfA8L

Duke is correct. The lane keep assist function is dependent on having electronic steering which was implemented in the A8/S8 beginning with the 2015 MY. Cannot recall anything having to do with activation of an Efficiency Program, other than the 4.0T's cylinder deactivation setup which is autonomous, and is itself a fuel efficiency feature of the engine.

MP4.2+6.0

Efficiency program can be activated for more recent ones at least, and is on top of cylinder on demand (COD). How to is buried very deep in the "old"/lengthy Audizine C7 VCDS mods thread. It is not included/active in the U.S. spec models. Not sure if you can activate it on one without COD, and not sure about pre-vs. post facelift split. That is, COD may be a pre-requisite. But it is more than just COD. It affects the various systems that the other MMI settings do (Comfort, Auto, Sport), but in a different mix and match combination. May also affect a few other things like A/C cooling strategy and coast down shifting.

Level of detailed info and knowledge about it here is low as best I can tell. I asked about it in the past, and likewise got very limited information. It is used in Europe, but I couldn't find much info there either, albeit searching only in English.

LexusLSguy

What does the program do?

MP4.2+6.0

A variety of tweaks to subsystems to emphasize fuel economy at the margin. So it follows the "auto" setting strategy under "CAR" that lowers ride height at highway speeds for aero efficiency, which the comfort setting does not do. But then it follows the comfort setting on various others that would be associated with more powers or harder driving. A fair amount of it you could replicate by using the "individual" settings in MMI, but some like the shift down strategy (more likely to shift down on a coast down in efficiency IIRC), the supposed lightening up of the A/C, and backing off the throttle somewhat more than the comfort setting, probably not.

Silver_Solid

That sound accurate. The D1, D2, D3 etc in the instrument cluster is replaced by E1, E2, E3, etc. Does change things a bit including the cooling strategy, shifting map, throttle sensitivity, as MP has mentioned.

I've not tried it further than the parking lot due to the overwhelming heat (100F/40C+) in this part of the world and would prefer to stay cool than save gas since its closer to $15 for a tankful here. Maybe when winter comes around.

the_duke

Below is what I have found. I have not tested this yet but I plan to try and enable it this evening as I have a 500 mile drive to Monterey CA tomorrow. I've traveled about 1100 miles so far with my cruise set at 90mph most of the time (avg. speed of 78mph) and this has resulted in 25.5 mpg. I'm pretty happy with that. Unfortunately I won't be able to compare fuel mileage with the rest of my trip as the speed limits have been 80mph up to this point and they will be lower in CA.

09 - Central Electronics
Security Access - 16
(enable)
Adaptation - 10
Read channel 66
change from 15 to 47
Test / Save

MP4.2+6.0

If you do it, I expect you won't see any gee whiz sort of mileage improvement. A guess is this is 1 or 2% type stuff, so it can easily lost in noise of wind speed and direction, tire pressure, etc., let alone average speed differences.

As far as subtle or little discussed effects, see if you pick up a difference in coast down downshifting. My experience playing w/ it is it is a bit more aggressive on downshifting, which I view as a good thing. You feel a little more connected with drivetrain then you get with an 8 speed prone to stay in upper gears a lot and with little spacing between any one of them. I'm guessing the economy strategy is to use the alternator charging backfeed to recover a bit of the energy. Sort of counterintuitive, but here "efficiency" can actually be a bit more "sporty." Also see if you think COD cuts in a bit more (via watching display for it), or more reliably on flat highway runs at 70-75. Somewhere in there COD sort of fizzles out in the standard ("D" mode) at least in my S8, even though HP needed to move car on level ground at those speeds remains a small fraction of what is available even from just the four cylinders. By 80 COD seems pretty much disabled.

Yep, throttle back in CA. The novelty the CHiPpie's found with laser a couple of years ago seems to have worn off some, but just takes one hit hiding in shadows, onramps, etc. More than 25 over is also a mandatory court appearance--can't just pay the (steep) fine.

the_duke

I passed 7 highway patrol cars on I15 in several states on my way to Vegas this weekend with the cruise set at 90mph and they didn't seem to mind. But I'm going to keep it to 5 over in CA as I've heard bad things about getting tickets there. I watch my COD display a lot as there isn't much else to do so it will be interesting to see if is stays on a little longer with the efficiency program.

My mileage on previous long trips has been better but that was with the original tires (265's) with about 50k miles on them. I just had new tires (275's) fitted so I expect that impacted my mileage some.