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Old 01-07-09, 03:42 PM   #11
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Default Re: AF ratio

No, not accurate. It's for closed loop fueling. Basically non-WOT driving.

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Old 01-07-09, 05:39 PM   #12
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Default Re: AF ratio

Not only does it not read richer than low 11's AFR, it reads that in many cases where you're leaner than that. For example, I've seen the stock sensor read that when I'm "really" at 12.0 AFR as per a wideband.

A good wideband controller with a wideband sensor that's in good working order and properly calibrated should always be used for accurate tuning and monitoring. The stock sensor is acceptable for a course idea of AFR while at idle and while cruising or decelerating.
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Old 01-07-09, 08:07 PM   #13
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Default Re: AF ratio

Quote:
Originally Posted by Shamoo View Post
The stock oxygen sensor is not very accurate and is pretty much only good enough for closed loop operations. I believe that the lowest it will read is around 11.1 (atleast that's what mine does).

I'd look into an aftermarket wideband for accuracy.

Cmon now, that's not exciting. I love knowing my a/f could be anywhere from 10-14 when I'm at 19.5 psi. Sort of like russian roulette...
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Old 01-08-09, 01:05 AM   #14
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Default Re: AF ratio

What's a good aftermarket oxygen sensor?
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Old 01-08-09, 03:16 AM   #15
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Default Re: AF ratio

AEM - Gauge-Type Wideband UEGO Controller
This is the one i ordered and seems like most people are running this.

Gauge-Type Wideband UEGO ControllerFAQs...A wideband UEGO sensor controller accurately monitors Air/Fuel ratios (AFR) during the tuning process to prevent a lean fuel mixture, which could lead to engine damage. AEM has combined its single-channel wideband UEGO controller and gauge display into one unit, uniting unsurpassed AFR accuracy and control with an easy-to-read interface. AEM’s Gauge-Type Wideband UEGO Controller features a digital LED display and sweeping LED “needle” that changes colors as AFR changes from rich to lean. The unit’s 52mm (2-1/16”) gauge housing fits in most gauge pods and can be remotely mounted virtually anywhere.
Ideal AFR monitoring tool for EFI and carbureted applications, and engine dynamometersDoes not oscillate AFR reading like narrow band sensorsNo laptop required for monitoring!Bosch sensor includedAccurate to 0.1 AFRReads in AFR or Lambda via a switch in back of gauge housing24 Color-coded LED display lights provide immediate reference to engine’s air/fuel ratio (AFR) or Lambda ratioIntegrated three-digit display reveals AFR or Lambda in real timeUser-programmable 0-5v analog output included for use with data loggers and virtually any engine management systemSerial data stream included for output of AFR (RS 232)
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Old 01-08-09, 04:29 AM   #16
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Default Re: AF ratio

Quote:
Originally Posted by Inn-Tune View Post
A good wideband controller with a wideband sensor that's in good working order and properly calibrated should always be used for accurate tuning and monitoring.
On this note, how does one make sure that the WB system is properly calibrated and showing accurate numbers? Actually, the O2 sensor is probably the piece that is most likely to fail with time, so my questions is - how to you tell that your WB O2 sensor is reading accurately?
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Old 01-08-09, 05:09 AM   #17
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Default Re: AF ratio

^^^

To make things even more dfficult, the sensor should be placed far enough away from the turbo so the heat doesn't affect it in any way (not just the reading, but heat can also damage the unit). I believe they usually say at least 14 inches from the turbine discharge, although I often see them only inches away.

ALSO, the sensor should always be angled upward in the exhaust pipe to prevent moisture from collecting on and damaging the unit.
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Old 01-08-09, 05:12 AM   #18
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Default Re: AF ratio

great so i guess i should get a wideband to make myself better by seeing more accurate no. thanks for the info guys
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Old 01-08-09, 11:17 AM   #19
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Default Re: AF ratio

If the o2 sensor needs to be 14 inches away from the turbo why does cobb put so close?
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Old 01-08-09, 11:19 AM   #20
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Default Re: AF ratio

Quote:
Originally Posted by SRH_STi View Post
^^^

To make things even more dfficult, the sensor should be placed far enough away from the turbo so the heat doesn't affect it in any way (not just the reading, but heat can also damage the unit). I believe they usually say at least 14 inches from the turbine discharge, although I often see them only inches away.

ALSO, the sensor should always be angled upward in the exhaust pipe to prevent moisture from collecting on and damaging the unit.
I though it was 6in or so. (That's what she said...). There's actually a nice LC-1 instruction manual available from their site, I believe that talks in great detail about this.
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