A/F Numbers

[toolttime]

What is the a/f number for a lean or to rich ratio.????? On my nexus gauge it always in the 13.5 to 15.5 range

[redfire427]

I think the key number is between 11.6 and 12 when you are wide open throttle. At the lower rpm's a leaner mixture seems to be the norm.

When I had my car dyno'd this past Friday, it was wicked lean. If you look at my first dyno graph in this link:
Dyno wood

After all was said and done, it was right around 11.9 -12 across the power curve.

[toolttime]

Originally Posted by redfire427

I think the key number is between 11.6 and 12 when you are wide open throttle. At the lower rpm's a leaner mixture seems to be the norm.

When I had my car dyno'd this past Friday, it was wicked lean. If you look at my first dyno graph in this link:
Dyno wood

After all was said and done, it was right around 11.9 -12 across the power curve.

Is 11.9-12 lean or rich???

[1Bad06Roush]

Originally Posted by toolttime

Is 11.9-12 lean or rich???

At WOT it's niether. That's just about right on.

[toolttime]

Originally Posted by 1Bad06Roush

At WOT it's niether. That's just about right on.

Soi if mine is at around 14.0-14.5 at wot then it is rich???

[redfire427]

Originally Posted by toolttime

Soi if mine is at around 14.0-14.5 at wot then it is rich???

Big time rich. The air/fuel ratio is dependant on a number of things. The leaner the tune, the higher the octane required to prevent detonation. Lean also generates more heat which leads to detonation. Higher boost levels require a richer tune as well.

[toolttime]

Originally Posted by redfire427

Big time rich. The air/fuel ratio is dependant on a number of things. The leaner the tune, the higher the octane required to prevent detonation. Lean also generates more heat which leads to detonation. Higher boost levels require a richer tune as well.

It will be interesting to see the the number with the new 2.57 pulley on it.

[pachary]

I think you guys have this backwards. The larger the number, the LEANER the tune. I don't want to alarm anyone but 14.0-14.5 at WOT is wicked lean. That is actually extremely detrimental to your engines health. A/F means divide air by fuel.

The larger the fuel amount, the smaller the final number. Mine is 11.5:1 at WOT.

I am sorry if I have offended anyone.

Paul

[toolttime]

Now I am really confused Maybe then when I finish installing the gt500 dual pumps maybe then Ill get a richer mixture.

[13 MIKE]

Pachary is correct. 14.7-1 is the "perfect" stoichiometric mixture for NA. Thats 14.7 parts air for 1 part fuel. If you have the preferred mixtuer of 11.5 to 1 for boosted applications, you can see there are less parts of air per part of fuel. It can be confusing.

[redfire427]

Originally Posted by pachary

I think you guys have this backwards. The larger the number, the LEANER the tune. I don't want to alarm anyone but 14.0-14.5 at WOT is wicked lean. That is actually extremely detrimental to your engines health. A/F means divide air by fuel.

The larger the fuel amount, the smaller the final number. Mine is 11.5:1 at WOT.

I am sorry if I have offended anyone.

Paul

Pachary is correct. I should have said you are big-time lean, you need to go rich. My appologies. Maybe I should stop drinking at lunchtime.