Crazy Narrow Band O2 Tuning - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Maeda · 04-13-2005, 02:10 AM

OK so I got this crazy idea.
I unplugged the O2 sensors because the ecu was fucking with my tune.
It only allowed WOT tuning... Old news.

The car's tuned enough to boost but its a 'little' rich... and by a little I mean a lot.

Narrow band O2 sensors seem to be reasonable under WOT conditions when the ECU isn't constantly fucking around with the a/f...

My O2 isn't hooked up to the ECU so it can't fuck with the a/f...

So a narrowband O2 would be reasonable for my scenario?

Or am I high?

Flame on!

PS
I understand that the only way to fly is with a wideband, but I have a few extra narrow band stock sensors laying around and i'd like to datalog them for fun if they're worth anything....

orion::S14 · 04-13-2005, 08:39 AM

You're high...

It has nothing to do with the ECU messing with anything. A narrowband is affected by temperature in such a way that it can read a couple TENTHS of a volt one way or another depending on how hot it is.

So under cruising you may get it up ~1300F, then do a WOT pull...it reads 0.95 volts. You think..."good, that's nice and rich and safe".

But when you are just driving around town not boosting much, it may be at ~900F...then you do a WOT pull and it reads 0.75 volts...and the motor blows up and you walk home. Because you tuned when it was at one temp, and now at another, you're getting the *real* A/F and it was lean.

...and the relationship may work the other way, I can't recall (hotter temp of the sensor = reads more lean)

But either way, it CANNOT be relied upon for tuning, at all. Wideband has 5 volts to use, so better resolution, and not that dependent on temp of the sensor (plus they have internal heaters that keep them at a set temp anyway, like ~1500 F)...so it's accurate and consistent all the time.

- Brian

Ritz S14 · 04-13-2005, 09:50 AM

Err.. just a brief description on how o2 works.

A wideband oxygen sensor=lambda sensor. A lambda sensor works similiarly to an oxygen sensor but it's read differently. An O2 sensor reads from .01-.9v(sometimes they can go above 1v). A tenth(.01) of a volt would indicate the car is running lean(too much air, not enough gas) nine tenths(.09) would mean the car is running rich. When a wideband(lambda) sensor reads above "1" your car is running lean, and if it reads less than "1', you car is running rich. For a lambda sensor "1" would be stoichometric(ideal for your average cars). The wideband sensor itself can read 5volts or higher, but for the ECU to understand it, it iss divided by 5.

Most manufacturers started using heated oxygen sensors the early mid 90s(obdI going on obdII), which warmed up the o2 to reach operational tempter faster. Faster you go in to closed loop, the more efficient your car becomes..

nissantuner22 · 04-13-2005, 09:57 AM

I just learned something. Thanks for explaining the difference between the 2.

Maeda · 04-13-2005, 03:48 PM

I knew the difference. I was just trying to figure out if its worth datalogging. Even against EGT's its useless isn't it...

Thanks orion, I had no idea narrowband were effected be temperature... I know i'm stupid because in some descriptions they call them 'heated'...

Smogtech: My car is tuned in such a magical way... its always in open loop 100% of the time...

DIY Wideband it is then... Oh yah.....

And for you emanage losers out there. Do the hardware conversion(gold) + new support tool update and UNLOCK the autotune features.

(Set target a a/f then the emanage will do the rest)

04-13-2005, 02:10 AM	#1
Maeda Nissanaholic! Join Date: Dec 2002 Location: Camp Snake Bite, CA RIP Posts: 2,356 Trader Rating: (0) Rides Gallery: Maeda Feedback Score: 0 reviews	Crazy Narrow Band O2 Tuning OK so I got this crazy idea. I unplugged the O2 sensors because the ecu was fucking with my tune. It only allowed WOT tuning... Old news. The car's tuned enough to boost but its a 'little' rich... and by a little I mean a lot. Narrow band O2 sensors seem to be reasonable under WOT conditions when the ECU isn't constantly fucking around with the a/f... My O2 isn't hooked up to the ECU so it can't fuck with the a/f... So a narrowband O2 would be reasonable for my scenario? Or am I high? Flame on! PS I understand that the only way to fly is with a wideband, but I have a few extra narrow band stock sensors laying around and i'd like to datalog them for fun if they're worth anything.... __________________

04-13-2005, 08:39 AM	#2
orion::S14 Nissanaholic! Join Date: May 2003 Location: Orange Park, FL Posts: 1,666 Trader Rating: (0) Feedback Score: 0 reviews	You're high... It has nothing to do with the ECU messing with anything. A narrowband is affected by temperature in such a way that it can read a couple TENTHS of a volt one way or another depending on how hot it is. So under cruising you may get it up ~1300F, then do a WOT pull...it reads 0.95 volts. You think..."good, that's nice and rich and safe". But when you are just driving around town not boosting much, it may be at ~900F...then you do a WOT pull and it reads 0.75 volts...and the motor blows up and you walk home. Because you tuned when it was at one temp, and now at another, you're getting the real A/F and it was lean. ...and the relationship may work the other way, I can't recall (hotter temp of the sensor = reads more lean) But either way, it CANNOT be relied upon for tuning, at all. Wideband has 5 volts to use, so better resolution, and not that dependent on temp of the sensor (plus they have internal heaters that keep them at a set temp anyway, like ~1500 F)...so it's accurate and consistent all the time. - Brian __________________ www.KA24DEvelopment.com

04-13-2005, 09:57 AM	#4
nissantuner22 Zilvia FREAK! Join Date: Mar 2004 Location: Gainesville, Fl Age: 39 Posts: 1,056 Trader Rating: (-1) Feedback Score: -1 reviews	I just learned something. Thanks for explaining the difference between the 2. __________________ Current Project: Operation: N/A SR: 93 Silvia Q SR20DE Engine with go fast goodies. , "Common problems 240sx's suffer from are curbs, trees, ditches, and other immovable objects."thx247 "on the tounge... there is no guardrails."- citizen

04-13-2005, 03:48 PM	#5
Maeda Nissanaholic! Join Date: Dec 2002 Location: Camp Snake Bite, CA RIP Posts: 2,356 Trader Rating: (0) Rides Gallery: Maeda Feedback Score: 0 reviews	I knew the difference. I was just trying to figure out if its worth datalogging. Even against EGT's its useless isn't it... Thanks orion, I had no idea narrowband were effected be temperature... I know i'm stupid because in some descriptions they call them 'heated'... Smogtech: My car is tuned in such a magical way... its always in open loop 100% of the time... DIY Wideband it is then... Oh yah..... And for you emanage losers out there. Do the hardware conversion(gold) + new support tool update and UNLOCK the autotune features. (Set target a a/f then the emanage will do the rest) __________________

04-13-2005, 09:50 AM	#3
Ritz S14 Post Whore! Join Date: Jul 2004 Location: C A L I F O R N I A Age: 42 Posts: 3,586 Trader Rating: (0) Feedback Score: 0 reviews	Err.. just a brief description on how o2 works. A wideband oxygen sensor=lambda sensor. A lambda sensor works similiarly to an oxygen sensor but it's read differently. An O2 sensor reads from .01-.9v(sometimes they can go above 1v). A tenth(.01) of a volt would indicate the car is running lean(too much air, not enough gas) nine tenths(.09) would mean the car is running rich. When a wideband(lambda) sensor reads above "1" your car is running lean, and if it reads less than "1', you car is running rich. For a lambda sensor "1" would be stoichometric(ideal for your average cars). The wideband sensor itself can read 5volts or higher, but for the ECU to understand it, it iss divided by 5. Most manufacturers started using heated oxygen sensors the early mid 90s(obdI going on obdII), which warmed up the o2 to reach operational tempter faster. Faster you go in to closed loop, the more efficient your car becomes..