Lately I have witnessed several stock RX-8 (when I mean stock they may have a free flow filter element at most) that they appear to have rich mixture specifically at top end. I know that all renesis are using rich mixture however this mixture seemed to be richer than normal. This was identified with the help of wide band sensor.

So what do you think is the cause for such a situation? I can personally think of a problem that has to do either with the MAF or the CAT. I do not think so that the free flow filter is responsible for the rich mixture.

What do you think?

 

Mazda set it that way to meet emissions. Have you changed your air filter?

 

If you lean it out, wouldn't you, probably, lose emissions and gain a couple HP?

 

Well I mean that the stock RX-8s that I have seen with the rich mixture are richer than other stock RX-8s.

 

Check the coils, weak spark=rich mixture.

 

As I recall the car has new coils and plugs ! Could it be the spark plug wires? Or is it possible that a free flow element to induce a richer mixture because MAF will see the extra air?

 

Hi again,

I have noticed that after an ECU reset the car performs better special in high RPMs and in 4th, 5th gear. I have checked this after drag racing several times with stock RX-8. But let me explain you better what I mean.

My car has a Revi + Ram Air and at a drag race with stock RX-8 it seams that the stock RX-8 has a small advantage when at 4th gear. However, when I reset the ECU and I drag race again my car performs better and the advantage of stock RX-8 disappears.

Is it because after the ECU reset I run lean and this helps me at high speeds , high gears?

 

i thought it was common knowledge that rx8s ran pretty rich...

 

^^Yup, rich bitches. Get a flash tool to get those AFR's to mid/upper 12's. Put that bitch on a diet!

 

Only way to fix the rich condition is to buy the Access Port from Mazda Maniac

 

Explains a lot of the cat problems

 

Ok , My question is that after an ECU reset are you running leaner for a while and as you put some miles you are getting richer and finally you remain richer???

Is this statement correct?

 

possibly. after a reset the car is trying to "re-learn" how you drive. that may have something to do with it.