Welcome to the North American Subaru Impreza Owners Club Saturday September 20, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 04-14-2003, 01:59 AM   #1
Eric SS
Sooby Guru
 
Member#: 1914
Join Date: Jul 2000
Chapter/Region: SWIC
Location: 2013 335i, 2011 G37 coupe
Vehicle:
2000 2.5RS w/ EJ22T
swap and N20. gone. : (

Thumbs up A little info in regards to hooking up A/F meter to rear O2 (discuss!)

OK, Not sure how different the rear O2 reads between a stock exhaust Subaru vs. a Subaru with a Turbo and high flow cat but I think this is some pretty decent info for everyone.

I finally decided to hook up my A/F ratio meter to my rear O2 sensor. I have always heard and thought that the rear O2 sensor on our cars would read WAY off from actual A/F ratios because of how far it is away from the begining of the exhaust (and because of the cat). However, after hooking my A/F gauge up I have to think that (at least on my setup) that is nothing but a rumor.

My O2 meter reacted exactly how I would have expected a meter on a front narrow band O2 sensor to work. Although the delay is a little bit, probably about 1/2-1 second.

First for my readings during regular driving. This is why I believe my "spirited driving" ratios to be correct. First, let me give you a little info on my meter. This is a very accurate Haltech Narrowband meter with 30 readings. 10 Lean lights, 10 stoic lights, and 10 rich lights. ( http://www.halmeter.com/ )

After the sensor gets warmed up (about 2-3 minutes) at normal cruise at any speed in any gear (no acceleration or deceleration) it would cycle back and forth from dead lean (1st lean light) to about the 5th stoic light like a fuel injected car is supposed to do. When I sat there idling with the A/C on, it would idle at the 4th stoic light when the compressor was running and the dead lean light when the compressor would switch off. During normal acceleration through all the gears, it would stay at about the 8-9th stoic light and when I let off the gas to shift it would jump to the 2-3rd rich light and then jump to the dead lean light for a split second before going back to high stoic.

So, during normal driving, it read exactly what I would expect a properly working A/F gauge on a fuel injected car to read! I was very impressed and happy about this.

So, now came time to actually do a bit of spirited driving.

OK, so I gunned it in 4th gear starting at 2000rpm's which is 0 boost. It was at the first rich mark. sounds good to me.

I held it wide open all the way to about 6,200rpm's. By then it had cliimbed to 12-13psi (I had the wastegate spring a bit to tight. I want about 10-11psi). The amazing thing was that it stayed right there at the 1st rich mark all the way up there! That is exactly where it is supposed to be.

I tried this in 2nd-4th gear at different times (although they all didn't build to 12psi) and did 5th gear until about 4,500rpm's which was about 8psi. It held 1 bar of rich in all of them!

And this is with the EJ22T, Ludespeed stage 2 (t-03 turbo), stock EJ25 injectors, stock ECU, and S-AFC set at zero. Fuel pressure was about 75psi at 12psi boost. Not once did I see a lean condition on the A/F gauge.

So, based on this, I feel that the rear O2 sensor, at least on a car with a high flow cat, can be a relativly accurate tuning tool contrary to what we have heard.

Now, this is all subjective on my part but it is what I believe to be true from what I have noticed in my setup. Take it for what it is worth.

If you have any questions or comments, feel free to post them and discuss it.
* Registered users of the site do not see these ads.
Eric SS is offline   Reply With Quote
Old 04-14-2003, 11:08 AM   #2
BOY
NASIOC Supporter
 
Member#: 232
Join Date: Sep 1999
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
99 RS-T RIP
02 Forster-S

Default

Eric, not sure why you posted in N/A but your theory is sound. What you should do is get your hands on a wideband (try renting one from a local FWD/RWD dyno shop) and comparing/contrasting the two. Either that or get your hands on a datalogger and compare. As long as the O2 sensor is w/in its operating temp range and the meter is fairly acurate you should get a decent reading. Mind you narrow band sensors are never very acruate no matter where you place them in the exhaust.
BOY is offline   Reply With Quote
Old 04-14-2003, 11:20 AM   #3
Eric SS
Sooby Guru
 
Member#: 1914
Join Date: Jul 2000
Chapter/Region: SWIC
Location: 2013 335i, 2011 G37 coupe
Vehicle:
2000 2.5RS w/ EJ22T
swap and N20. gone. : (

Default

Quote:
Originally posted by BOY
Eric, not sure why you posted in N/A but your theory is sound. What you should do is get your hands on a wideband (try renting one from a local FWD/RWD dyno shop) and comparing/contrasting the two. Either that or get your hands on a datalogger and compare. As long as the O2 sensor is w/in its operating temp range and the meter is fairly acurate you should get a decent reading. Mind you narrow band sensors are never very acruate no matter where you place them in the exhaust.
I posted this in the AFI forum also. I thought it might be good info for N/A guys also.
Eric SS is offline   Reply With Quote
Old 04-14-2003, 01:43 PM   #4
DDMan
Scooby Specialist
 
Member#: 11221
Join Date: Oct 2001
Location: Rocklin, California
Vehicle:
2002 2.5 RS
Black as Midnight!!!

Default

I dont really believe its the wide/narrow aspect, but more the problem that there is A catilytic converter sitting before the O2 sensor. The cat completly throws off any accurate readings because it cleans the exhaust removing the extra un-burned fuel and gases and turning it into water practically (ok, im being very general here). Thing is the cat introduces other gases into the exhaust (other than what would he going through without a cat) and that throws off the readings.
DDMan is offline   Reply With Quote
Old 04-14-2003, 02:08 PM   #5
BOY
NASIOC Supporter
 
Member#: 232
Join Date: Sep 1999
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
99 RS-T RIP
02 Forster-S

Default

BOY is offline   Reply With Quote
Old 04-14-2003, 03:51 PM   #6
kturner
Scooby Newbie
 
Member#: 8225
Join Date: Jul 2001
Location: Corvallis, OR
Default

I think my narrow band Autometer works fine behind the cats for general relativistic purposes. Like Eric is doing, I can compare "normal" ranges to "spirited" ranges. Plus, it was easy and cheap.
kturner is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to hook up a 12V source to LED strip light? starcraft227 Electrical & Lighting 2 05-31-2009 12:14 AM
12v wires in dash area to hook up fire radio wgas Electrical & Lighting 6 03-02-2007 07:19 AM
What Color Wires To hook up Car setup installed in room SubaTubaru Car Audio, Video & Security 12 01-13-2002 06:51 PM
How to hook up PS2 in car? Chocobo Car Audio, Video & Security 6 12-27-2001 02:34 AM
Digital Boy in Irving TX. Wants to hook up and hang... MPREZYA Texas Impreza Club Forum -- TXIC 6 02-14-2001 10:38 AM


All times are GMT -4. The time now is 08:22 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.