AFR ratios, whats too lean.

[Mad Hatter]

hate to bring up this old dog again but went to the dyno on Saturday and got these results.....

This was taken at 1800 ft elevation on a cool 12C day. Is this about normal for a stock boss with Kooks lth and xpipe and nothing else??

Gas was stock 93 approx octane. Just in case it was 403 hp at 6500rpm and 380 torque at 3500rpm

 

[SlowJim]

Looks good to me. What tune?

 

[Mad Hatter]

Thats with the stock tune still. Now with my dyno test and compression test ok not quite sure what to do. AED is closed to me so maybe try a Lund tune and log again at the dyno.

 

[SlowJim]

Yep, Lund is awesome. I run their tune and it pulls much harder than my Steeda one did. You'll pick up a solid 10-15hp

 

[Mad Hatter]

My Lund tune arrived today and will install it this week end with a new O2 sensor for passenger side. Can't wait to log it and see the difference. Was reading that Kooks LTHs can make the car 4% lean. So my lambda 0.83 could go to a more sane 0.79? That and some Sonoca!

 

[WinterSucks]

Glad you got this figured out. I am tempted to start treating my O2 sensors like consumables every other year or two just to avoid issues that ruin a track day. Seems like bad O2 sensors are becoming a frequent answer...

So if the answer to the question is not "Miata" it's "replace the O2 sensor"? ;D

 

[Mad Hatter]

"Miata" is a term frequently discussed..... That is, before and after the track day.... never during.

 

[Mad Hatter]

Well, hopefully its tie to put this long story to bed. My apologies for keeping this post going!! Got a Lund Racing tune for the car. Very quick response and got the tune next day.

https://www.facebook.com/photo.php?fbid=10206132391647528&l=de33bbd538
Here is the screen shot.

I logged the car and sent it back to them right away to check as I am getting paranoid about running lean! Jon Lund senior answered back saying the Log was good and stop trying to read logs and go enjoy the car!!

Which is what I intend to do!!