tuning for economy and reliability
 

Know this is blasphemy, but am building an offroad-oriented allroad and am tempted to stage 1234 this thing, but honestly, am more interested being able to run on ****ty pemex fuel down in Baja and would like to extend the range this vehicle can travel between gas stations. Would be willing to give up some power to achieve something a little more... ahem... reliable? Understand that staying on top of maintenance is going to be best insurance, and this wagon's got 160,000 miles on it. Where should I start? Seems to run great. Was maintained by an Audi dealer and have extensive service records. Last major service was at 155,000 miles and the timing belt was replaced at 109,000 miles.

Nothing huh?

What do you want to know? I can cut your boost back, decrease timing, and increase knock hysterisis.

ME7 is an open book, there are no limits.

I guess I'd like to hear what steps different people might recommend if I wanted to work towards the goals stated above. Is that where you'd suggest I start? Reprogram the ECU to decrease boost and take out some timing? What's knock hysterisis?

Anything mechanical that I ought to address, other than regular maintenance?

Knock hysterisis is how the ecu reacts when it detects abnormal combustion (knock). How much timing it pulls, how long it waits to add it back. The best ways to safely run a lesser grade fuel is with decreased timing, and decreased boost. Lowering intake temps will help as well. I'd be willing to bet I could write a file that would run 87 octane gasoline without an appreciable increase in timing retard. In addition, that file could be written to turn off the rear 02 sensors, catalyst monitoring, SAI, and evaporative emissions (for offroad use only). Modifications like removing the cats and eliminating useless components such as the EGR system further aid in reliability.

Consider running 2.0 coils, they allow you to open the plug gap a bit without misfiring. The stock coils are garbage and tend to fail (as do the ICM's). As for spark plugs, one heat range colder would be helpful. If you don't mind replacing them every 10k, go with non-platinum NGK BRK7E's. They conduct electricity, and wick heat away from the combustion chamber more effectively than platinum (with the tradeoff of wearing out faster).

Consider running some logging software and monitoring how much timing is being pulled with different grades of gasoline. Useful information to have considering your goals.

Ah, thanks. Yeah I'd really like to be able to run reliably on low-grade fuel and would be willing to give up a considerable amount of power/performance to gain reliability and mpg. Would it be possible to load multiple files that I could switch between? You know, like economy, towing, performance, etc. Can we have it all?

Just purchased a vag-com and the first scan revealed intermittent misfires, but seems to run fine? Cleared the codes after saving a log and they haven't come back. But is that something changing the plugs and coils would fix?

Map switching is definitely possible. Is this something you're interested in DIY? If so, nefmoto.com.

Not sure, but thanks for the link! Appreciate all the help so far.

No problem. PM me if you have any questions (here or nefmoto, I have the same username on all forums).