AFRs (Air/Fuel Ratios)...?

[AutoXRacer]

What are the desired AFRs (Air/Fuel Ratios) for our cars...? (huh)

I've been thinking about this recently released reflash from Mazda which lead me to look at my AFRs... Prior to my Cork Sport CBE install, my AFRs were peaking in the 9s and settling in the 10-11 range. Post install, I have noticed I am now in the 12 range...not sure if its low, mid or high 12s...but definitely in the 12s.

My question is, is this safe? Were do we want to be in AFRs?

Thanks for the help!! (2thumbs)

 

[shaodome]

12:1 is ideal for max safe power. Lower than 12 and your giving up some power for a minimal gain in knock resistance due to a cooling effect of the fuel.

 

[mcb]

over 12:1 is looking for trouble... zoom zoom BOOM

 

[Darksun280]

if you have the boost turned up from stock i would try to keep it in the mid to high 11's.

 

[spec2k5]

according to my scangauge, I am always in the 13s and 14s and sometimes in the high 12s in boost. I just got the reflash yesterday and it did not change much. I only have a mscai.

 

[AutoXRacer]

if you have the boost turned up from stock i would try to keep it in the mid to high 11's.

Nope, stock boost... 20 spike, settles 16.56...

I'm thinking about a fuel pump now...would that help lower the AFRs back to 10-11s...?

 

[Darksun280]

Nope, stock boost... 20 spike, settles 16.56...

I'm thinking about a fuel pump now...would that help lower the AFRs back to 10-11s...?

yup yup. Mrlilguy is having a group buy right now. I know i hopped all over one. I wouldn't mess around with running too lean on these car i really think they can't take as much as a beating as some other cars.

 

[AutoXRacer]

yup yup. Mrlilguy is having a group buy right now. I know i hopped all over one. I wouldn't mess around with running too lean on these car i really think they can't take as much as a beating as some other cars.

What is your reason for getting one; just wondering?

I thought I was going to sneak by this fueling issue since I live in Florida with the warm weather and all.
I'm still confused on how a CBE changed my fueling needs like that... (huh) (scratch)

 

[Darksun280]

What is your reason for getting one; just wondering?

I thought I was going to sneak by this fueling issue since I live in Florida with the warm weather and all.
I'm still confused on how a CBE changed my fueling needs like that... (huh) (scratch)

Im getting the pump because down because its been recorded that if the fuel pressure stays above a certain number the throttle plate wont close as early. Also I'm tired of running 14 a/f's till 4800 rpms

 

[AutoXRacer]

Im getting the pump because down because its been recorded that if the fuel pressure stays above a certain number the throttle plate wont close as early. Also I'm tired of running 14 a/f's till 4800 rpms

AFRs of 14!!!!(shocked) Really...? Damn, I feel dumb now...here I am worrying about 12s and you're in the 14s... (bang)(lol2)

Wow...

 

[AutoXRacer]

I might have jumped a little too soon on the fuel pump thing... I was tracking my AFRs and fuel pressures today...warmer temps (mid 70*s) than the rest of the week (low-mid 60s)...and my AFRs are back up to 10-11s...though my fuel pressure is in the upper 1500 mid 1600.

Any comments on that...still think I need a pump?

 

[Darksun280]

I might have jumped a little too soon on the fuel pump thing... I was tracking my AFRs and fuel pressures today...warmer temps (mid 70*s) than the rest of the week (low-mid 60s)...and my AFRs are back up to 10-11s...though my fuel pressure is in the upper 1500 mid 1600.

Any comments on that...still think I need a pump?

Was the throttle plate open all the way when you had 10's-11's? no knock or detonation anything that would make the plate close thus raising your a/fs back up. thats whats happening to me I'll do a pull catch some knock and the plate won't open all the way to keep the car running rich.

 

[AutoXRacer]

Hmm, I've never monitored the throttle plate...

Interesting thing that happened this morning, for the first time, I experienced my fuel pressure drop to 1200 at 5700-6400 RPM and felt the engine power reduce...nothing drastically noticible like traction control kicking in...it was a very smooth transition into reduced power. My AFRs were still in the 11s.

What the hell was that!!!???http://****************.org/forum/images/smilies/Smilies/06.gif

Out of 5 pulls, it did it 3 times... Weather conditions were in the 52* range.

(scratch)

 

[Mid_Life_Crisis]

It was pointed out in no uncertain terms by Matsuda that the reflash has nothing to do with AFR targets. The purpose is to rework the algorithms that control the fuel pump so that it can better meet the fuel demands of the engine under load. In your case, that sounds like it might be a good thing to try before spending the money on an upgraded pump. If it isn't enough, you can always add the new pump anyway.

 

[AutoXRacer]

Cool!!!! (2thumbs) I think (scratch)... (lol2)

At least now I have an excuse to get the reflash... LOL

But why now...? Its never happened before... I still have a hard time thinking all this is cause to the post-CBE install...

 

[shucky]

Autox, as I posted before, my car personally does not like anything below about 53-54F outside temp. Believe it switches maps or something because my car is significantly slower under this temp. I've even been running 100 octane straight for 3 weeks to see if it was bad gas previosly but no change in the colder temps. Above say 54F the car rips, sounds different, pulls hard, etc. My car does same as yours, you can feel reduction in power high rpm during that temp (52'ish), this along with it not pulling as hard in general. I dont even have as many mods as you and my car does this. Good luck though....

 

[astraelraen]

I might have jumped a little too soon on the fuel pump thing... I was tracking my AFRs and fuel pressures today...warmer temps (mid 70*s) than the rest of the week (low-mid 60s)...and my AFRs are back up to 10-11s...though my fuel pressure is in the upper 1500 mid 1600.

Any comments on that...still think I need a pump?

All things similar, warmer temps = less oxygen in the air = less AFR.

You would think the ECU would compensate for this and add/pull fuel depending on ambient temp to reach its "required" AFR but it doesn't appear so all the time. During the winter I can easily run 13/14s all day long when its <35F outside.

 

[shaodome]

for those of u supposedly running lean...have you verified this by pulling plugs? I don't have the highest faith in the scan tools ability to read the factory wideband o2 output. Do we know if its a linear output? If not, do the scan companies or are they assuming the scaling of voltage to lambda.