Cobb Accessport - ECU Tuning - Stock vs. Stage 1 vs. Economy Tune

[jedi_sol]

Since the SG2 is assuming the same stoic AF ratios regardless of the tune, what do you think might be causing the SG2 to read higher mpgs with the economy tune vs the stock tune?

Any suggestions on how to test the claim that the AP achieves higher mpg vs stock?

[ncs]

The sg2 is a guess, and you just change a lot of parameters. For closed loop, the timing was changed. If you stay out of boost, you will likely see a legitimate improvement, but you might have adjust the sg2 again to match.

Once you hit enough boost to go into closed loop, results become pretty random. You'll still be better than before, but the gauge will read inaccurately, possibly in both directions depending on how you drive. Open loop comes on a lot earlier than naturally aspirated cars, which doesn't help the accuracy.

The stock map is very rich, so with either AP map, you've gained something, even if it doesn't show up on the SG2. You might get a pleasant surprise at the pump.

Kinda weird about the 8 psi. The old wrxs like mine have a wastegate pressure of 11 before the ecu can even do anything.

You really should learn to tune. These ecus are completely open at this point. It an be really entertaining to try out different approaches to making power. Also the off the shelf maps leave quite a bit on the table.

[serialk11r]

At heavier load the AP map is definitely going to be way more fuel efficient. Factory maps are always super rich for cooling purposes.

The problem is since your engine is turbocharged, leaning it out further could be pretty dangerous (whereas an NA motor's pistons are harder to melt even when running too lean). That said, often times the off the shelf maps have the VVT maps ruined for "response" (which really isn't an issue with e-throttle) and you can pick up a tiny bit of gas mileage by returning them to stock.

[oldtamiyaphile]

Originally Posted by jedi_sol

Since the SG2 is assuming the same stoic AF ratios regardless of the tune, what do you think might be causing the SG2 to read higher mpgs with the economy tune vs the stock tune?

Any suggestions on how to test the claim that the AP achieves higher mpg vs stock?

I seem to recall you having a MPGuino? While not perfect, that would give you a more meaningful result.

If you have more power, you're going to run at lower load (which SGII will read), so it will record slightly improved MPG. It doesn't take into account the tuners leaner AFRs, so you'll probably get a bigger gain than the SGII shows.

[wdb]

Originally Posted by ncs

The stock map is very rich, so with either AP map, you've gained something, even if it doesn't show up on the SG2. You might get a pleasant surprise at the pump.
[...]
Also the off the shelf maps leave quite a bit on the table.

Originally Posted by serialk11r

At heavier load the AP map is definitely going to be way more fuel efficient. Factory maps are always super rich for cooling purposes.

I have a 2005 STi with Cobb AP. The Cobb maps are super rich too, so as not to pop any motors. I'm at stage 2 and my gas mileage is down from stock no matter what OTS map I use.