tilt

iTrader: (1)

State inspection emissions can be a pain to pass with turbo cars! Thank you for those that posted their results in other threads - they were helpful. Here's my results so it can help others too.

This is on a 1.8L 1995 Miata, T25 turbo no EGR, MSPNP with high res 10g code, and closed loop turned on (wideband corrected, AFR table targeted).

Ben

iTrader: (33)

Damn, 87 octane FTW
What does the alcohol do?

tilt

iTrader: (1)

It burns cleaner than gasoline (lower HC), leans out fuel, and also has a cooling effect (lower NOx). My thought process is to target fuel a little richer than it should be then dump about a quart of alcohol to lean it out and reap the benefits. It may be overkill/unneccessary in some cases but I've had good results doing this method so far. If you do not add alcohol, I would probably target 14.7AFR @ 25MPH and 15.0 @ 15MPH.

Ben

iTrader: (33)

Interesting. I targeted 14.7:1 and left timing alone. Passed fine with a new cat.

Most people fail because of High NOx due to aging cat. Which can sometimes be remedied by going a little rich and a little hotter exhaust (retard timing).