just added AFR gauge and have questions

[BTERRY1]

Just added an AEM widebeand to my bone stock 86 951 along with an aftermarket boost gauge to start getting a good baseline an understanding of my engine prior to future modifications.

At WOT between say 5-6K RPMs I see it fluctuate between 11.8 and 12.1. sometimes as high as 12.2.

seems a bit lean from my searches. Should I concerned with readings above 12?

Should I be onsidering fqs switch adjustment or a 3bar regulator or is all ok as is

Help put my mind at ease. thxs

[87m491]

If stoich is ~14:1 and rich is higher, I'd be very concerned. Turbo cars especially should go pretty rich on WOT. What does the O2 guide say?

[kdjones2000]

You are basically capturing your current baseline, so I wouldn't worry too much about going above 12. Most of the guys who are stating that you should stay below 12 are pushing a lot more boost than your stock 10 psig.

You will notice that these cars go a bit leaner at the high end of the RPM curve, especially running the K26/6 and with the cycling valve in place.

Porsche intentionally set the car up for longevity, so with the cycling valve in place and stock boost you will be fine. You just now know how your car is behaving...

If/when you start pushing boost above say 15 psig then you should worry more about your AFR's and any lean condition.

On a positive note, by not running pig rich on boost you are actually producing more HP

Don't worry so much about it, and just use it as your baseline....

On a side note, how/where did you tap into your exhaust to place the WB O2 sensor? The stock location is a bit too close to the turbo for a WB sensor. The double-walled exhaust piping makes it a bit of a challenge (assuming that you are still on your stock exhaust).

[BTERRY1]

Thanks for all the feedback. when I first hooked up power I made a mistake and hooked it up the ash tray light. Ha! Only worked with lights on and we all know how guages act a smidge different with lights in bcs of grounds

I rewired and know Isee a solid 11.9 @ WOT

Weld is in the top of the last bend just before cat as far from the turbo as possible but not "under" the car.

[sketchers356]

Originally Posted by 87m491

If stoich is ~14:1 and rich is higher, I'd be very concerned. Turbo cars especially should go pretty rich on WOT. What does the O2 guide say?

I think that you have this backwards.

[cockerpunk]

richer is lower. WOT at full boost should be around 11.5

air to fuel ... air:fuel .... 14.7:1 is stoic ... often just called 14.7

[guru944]

cockerpunk:

Yep, I agree, 11.5 is good for +4000k rpm and higher.

Later...