Its showing low 15s when cruising, thats not too high?

 

air pump installed? wideband sensor located before the cat?

 

i have no cat, 40" from engine, no air pump. i just read that it should be ok.

 

factory O2 sensor good?

 

stock o2 is showings 0.8v at idle.

 

It should be bumping between 14.1 to 15.1 when cruising. This is called "closed loop" and means everything is A-OK...... when cruising. N/A's don't run any boost, so really unless you are cruising around at 17's or 19's you shouldnt really worry too much about knocking. Performance may lack however....

 

NA's don't run any boost... ever...

 

lol funny some people need to read before posting.

 

Yea..... thats.............. what i said. Thanks for re-iterating.

 

hahahahaha he thought he got you ! WRONG

 

Running at an AFR of 15:1 at cruise shouldn't hurt a thing; stoichiometric is 14.7:1. That little bit lean of peak should hurt nothing (at cruise power settings), and maybe improve your gas mileage a smidge. At cruise the peak pressures and temps are not such that a lean mixture is going to cause any problems. Under heavy acceleration it is another matter, and there you would like to be at or rich of max power, which occurs around 13:1.

 

The stock DEI manifold on the NAs produce up to approximately 2 PSI of positive pressure at the intake ports, according to Mazda.

 

a little lean is ideal. going from 13.5-15.2 is pretty much the range youll see.
what is your afr at cruise at 65mph? whats your afr during acceleration?

 

That's pretty cool...... no need to go turbo now!

 

low 15s at 65. low to mid 13s. at wot.

 

the your engine is running fine. 13-15.5 is perfect

Lloyd