Welcome to the North American Subaru Impreza Owners Club Tuesday March 19, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

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.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 05-16-2001, 08:28 PM   #1
Kevin Thomas
Street Racing Instructor
Moderator
 
Member#: 110
Join Date: Jul 1999
Location: 1997 OBS, 1996 SVX, 1988 RX
Vehicle:
1989 1989 XT6

Question Turbos and Air Fuel Ratios

I searched but it didn't seem like we came to an agreement on this. What is the agreed Air/Fuel ratio of our cars? Is it ~.90V like the cars at DSM org or some other number? I thought I remember people posting that this was actually a bit rich for our cars. I can't find those past posts.

[This message has been edited by Kevin Thomas (edited May 16, 2001).]
* Registered users of the site do not see these ads.
Kevin Thomas is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 05-16-2001, 08:57 PM   #2
ImprezaRS dot com
over boosted again
Moderator
 
Member#: 1458
Join Date: May 2000
Chapter/Region: RMIC
Location: Colorado Springs CO USA
Vehicle:
2017 WRX Limited
15 Forester XT, 21 Ascent

Post

That sounds a little rich - 0.9 volt is about 12.7:1 A/F ratio.

I think we are shooting for a 13.2 to 13.8 which is about 0.7 - 0.8 volts.

Larry www.SubaruPlanet.com
ImprezaRS dot com is offline   Reply With Quote
Old 05-16-2001, 09:13 PM   #3
Jan Shim
Scooby Specialist
 
Member#: 6366
Join Date: May 2001
Location: Brunei Darussalam
Vehicle:
1998 WRX Wagon (Ret)
Silver

Post

A turbocharged engine requires 12.5-12.7 : 1 A/F ratio to run reliably. Depending on mods and boost levels, some even run 11 : 1 AFR for safety. If you run a LambdaLink AFR gauge, ideally you should see the middle green LED on wide-open throttle. I can tell you this, my '98 WRX ECU has a factory programmed AFR of 12 : 1 as seen on the LambdaLink. I was running a PossumLink ECU but thought I should mention that the factory ECU does the same.

13-ish is closed to stoich 14.7 : 1 which means you are running very lean.
Jan Shim is offline   Reply With Quote
Old 05-16-2001, 09:22 PM   #4
8Complex

Moderator
 
Member#: 922
Join Date: Feb 2000
Chapter/Region: MWSOC
Location: Schaumburg, IL
Vehicle:
16 WRX (white)
04 FXT (red)

Post

It is probably dependant upon your compression level, the boost you're running, etc which changes between years/models/etc. I'd say just tune by EGT and be sure of it.
8Complex is offline   Reply With Quote
Old 05-16-2001, 10:10 PM   #5
Jan Shim
Scooby Specialist
 
Member#: 6366
Join Date: May 2001
Location: Brunei Darussalam
Vehicle:
1998 WRX Wagon (Ret)
Silver

Post

Tune by EGT ?? Makes no sense !! There is only ONE way of tuning a turbo engine and that's by getting Air Fuel Ratios spot on. Even tuning on a dyno relies on an Oxygen sensor (high quality wide band unit) kit clamped to the muffler tip.

The OČ sensor in factory position after the turbo is subject to overheating and therefore does not produce accurate results. However, when placed in the tailpipe, it is not subject to temp fluctuations so you get consistent readings.

Jan Shim is offline   Reply With Quote
Old 05-16-2001, 10:18 PM   #6
98mpreziveRS
Scooby Specialist
 
Member#: 972
Join Date: Feb 2000
Post

yeah but you can't really just base it on the egt's alone..you need another factor or two to work into the equation when dealing with a "high" compression turbo motor, which is how the honda guys do it on the stock CR with 10lbs or more going through.
where should i start with a very BASIC explanation..
Let me start with the lamba.. this is a unit less # that is the indicator of the air/fuel ratio. the sensor itself functions by measuring the quantity of oxygen in the exhaust of the car. IF a complete combustion occured, it would not leave any oxygen at all, due to the "explosion and following burn" consuming all the oxygen in the air along with the . The sensor uses this measurement to determine how much fuel to pump in when running. If it is running rich (too much fuel) it can cut back on the fuel being injected and if it is running lean it'll throw in more fuel, both of which affect HP and TQ.
The traditional lamba has a hysterisis characteristic of 0.9 and 1.1. But there is another one out there which is called a wideband lamba sensor which has some nifty charaicterestics going for it. It is linear (well..has the characteristics of being linear) between lamba 1.2 and 0.7.
For a tuner you will want the wideband, because of the linear readout from not only 0.7 but also it has that necessary 1.2 ability as well.
Keep this stuff in mind, it is minor, but very important.
The nominal A/F ratio for a min. consumption engine is going to be 15.4 kg (air) to 1 kg of fuel which is a 15.4:1 ratio. This is lamba 1.05
For you max power freaks your goal is going to be 13.2:1 or 13.2kg of air to 1 kg of fuel which will develop the most power but not have the best fuel economy. This number is refered to as lambda 0.9 for you lambda heads.
MOST mfr's use 14.7:1 or 14.7 kg of air to 1 kg of fuel, for the best performance AND minimum fuel consumption which is the happy medium for most people.

IF you are on a quest for max power, there is one thing you should realize that reading of lambda 0.9 is for a NA engine ONLY. This is atmospheric pressure.
The forced induction motors have to run richer (nomially lambda 0.82) for saftey due to the higher cylinder pressures happening inside the motor. The higher cylinder pressures also add to the higher egt's which can destroy the engine if not tuned right.
By running richer it'll cool the engine by allowing the mixture to be a little heavier in fuel than air SO the burn will be cooler and a little "slower" to happen which in turn will cause the egt's to drop as well as the cylinder temps which is what you want to happen.


What i don't personally like about egt's are the false information floating around from withing groups of "tuners". There are SO many claims about that being the best way to tune the engine, but this really is a false-hood (is that a word). IF the world were perfect, the best way would be to hop on a dyno and do it there.. no if's ands or buts!
I am not denying the EGT is a god-send though, it does allow you to referance where the engine is making max torque at WOT on the dyno and get that reading.
Once you are off the dyno though, you can use the EGT to dial in you air/fuel ratio with the help of the EGT gauge. The Air FUEL ratio and gauge are really the most important factors though. Most engines make maximum power at an AFR of between 11.8 and 13 to 1 BUT in my findings and talking with tooo many people, the EGT may vary from 1200F to 1800F and is not only dependant on the air/fuel ratio, but also the turbo/sc, etc. etc.
I should hovwer mention the egt is valid on only the same engine config. as the one on the dyno that was tested. IF the timing or cams or stuff is changed, the best EGT will also change in all lieklyhood.
Take a stock subie motor, then raise the compression without anything else at all- what does it do, it drops DROPS the EGT reading.
IF you retard the ignition timing generally it raises the EGT using the same AF ratio Take motor A and motor B. Motor A on the one hand makes the best power at 1450 degrees, while the other engine, B, makes it best power with a egt reading of only 1250 degrees.
Keep in mind if you have a rotary an EGT of 1800 is normal and not excessive or high even. If you don't know what egt you are aiming for, you just wasted your money on the egt gauge IMHO...which is why that is the last gauge i'll get.
What i don't like is the assumption you should tune to acheice peak EGT for max performance. This is a falsehood (i like this word ). the peak EGT occurs around 14.6-15.0to one on gas. This my friends is Waay too lean for max power and should be steered clear of. At WOT pre-ignition or pre-det is bound to happen, which equals more $$$ out of your wallet.
What some people think is the leaner the motor the higher the EGT. This is true and false, i won't get into how it's true, just tell you as the mixture richens over 14.7:1 the egt's drop and if you go leaner than 14.5:1 the egt's also drop. Make SURE you know if you are rich or lean before you tune based on egt's. just please keep that in mind if you would.

You canfeel a lean condition of the mixture as power will be down a bit and it'll be hard to ignite the mixture. Once you get close to . 17 to 1 at WOT the engine will pre-det or pre-ignite and thus misfires..

Which gauges are better you ask..or have youfallen asleep?
The answer is..neither is better than the other. The conventional oxygen sensor and digital LED Oxygen sensor are NOT the best device by anymeans to properly tune based on the AFR in the rich range of things. They are nice because they will warn you of a lean run condition quickly and without much though from the driver's part as to what is going on. Not only that, they won't kill your money flow either, you can find 02 sensors for around 50 bucks and up, and egt's IIRC are around 75 on up
IF you combine a meter WITH a wide band lamba sensor, this is the BEST setup IMHO, due to a couple things, one is you can verify which side you're running on, rich or lean, check out your AF ratio as you tune for the best EGT's for you motor, and monitor the motor easily and very accuritly as MOST good quality wide band lamba sensors are going to be of a lab quality construction which means highly accurate and quick reading. the downsid eis of course going to be cost and sheer size, but how much is your motor worth to you?
The EGT gauge has the advantage by working long term with leaded fuel which will clog oxygen sensors..
the choice is yours..but i am going with both and a TECII for added measure.
98mpreziveRS is offline   Reply With Quote
Old 05-16-2001, 10:22 PM   #7
98mpreziveRS
Scooby Specialist
 
Member#: 972
Join Date: Feb 2000
Post

oh yeah..kevin..sorry i just realized i didn't answer your question
I'll get back to ya on that
98mpreziveRS is offline   Reply With Quote
Old 05-17-2001, 12:30 AM   #8
SuicidalLabRat
Scooby Specialist
 
Member#: 4096
Join Date: Feb 2001
Location: Constantinople
Vehicle:
noun [ ve·hi·cle ]
a carrier,as of infection

Post

Lambda/wide bands still suffer from thermal:resistance. Those v. changes effect your output, without a temp sensor built in it can be difficult to equate sensor output.

SLR-
SuicidalLabRat is offline   Reply With Quote
Old 05-17-2001, 08:37 PM   #9
98mpreziveRS
Scooby Specialist
 
Member#: 972
Join Date: Feb 2000
Post

yeah but if your tuning with a air/fuel and an EGT gauge along with some other tidbits of knowledge you can normally get it close enough to where only the max power heads will ask for more (like myself ) and go to a dyno and just tune the butt off the car
Oh yeah.. and if you don't know what your doing, please don't try this at home
98mpreziveRS is offline   Reply With Quote
Old 05-17-2001, 10:49 PM   #10
Jan Shim
Scooby Specialist
 
Member#: 6366
Join Date: May 2001
Location: Brunei Darussalam
Vehicle:
1998 WRX Wagon (Ret)
Silver

Post

some other tidbits should include a Knock meter. I have been saved by my trusty KnockLink on countless occasions. I have also learnt to recognise pings when they become audible, confirmed by the KnockLink flashing the big red !!
Jan Shim is offline   Reply With Quote
Old 05-17-2001, 11:40 PM   #11
Kevin Thomas
Street Racing Instructor
Moderator
 
Member#: 110
Join Date: Jul 1999
Location: 1997 OBS, 1996 SVX, 1988 RX
Vehicle:
1989 1989 XT6

Post

So I guess we haven't gotten an agreed upon Air/Fuel ratio point or area. I know my Jumptronix Air/Fuel ratio gauge typically is in the .7 range and at full throttle it's in the .8 range, never reaching the .9 volt. Car seems to run great with EGT's typically in the 1250 *cruise* to 1450F *WOT on warm day*. Looks like ImprezaRS.com is on to something.

I just figured that someone that's really familiar with Subarus could tell us where we should be running based on tests they have done.

[This message has been edited by Kevin Thomas (edited May 18, 2001).]
Kevin Thomas is offline   Reply With Quote
Old 05-17-2001, 11:46 PM   #12
98mpreziveRS
Scooby Specialist
 
Member#: 972
Join Date: Feb 2000
Post

yeah i just realized again i never answered your first question sorry..i'll dig into it a little more and fill up another page or so with figures to try and factor around with to get an answer..what year is your motor, and what boost pressure you running?
I HOPE to be able to come upon something just basing it on that and your egt's normally.. if not..just talk to the usual tuner friends and see what they think if all else fails
98mpreziveRS is offline   Reply With Quote
Old 05-18-2001, 01:46 AM   #13
Jan Shim
Scooby Specialist
 
Member#: 6366
Join Date: May 2001
Location: Brunei Darussalam
Vehicle:
1998 WRX Wagon (Ret)
Silver

Post

Kevin,

It's not that difficult, really. If you run an aftermarket ECU, put your WRX on a 4-wheel dyno and then you tell me if ImprezaRS Dot Com's "shooting for a 13.2 to 13.8" is not too lean for a turbocharged engine @ wide-open throttle. I've been with the Aussie [email protected] discussion list for three years and not once has any member (tuner even) talk about tuning by EGT's.

I am the ONLY member who owns a high compression WRX 9.0:1 (Japan spec, engine still stock) while all WRX and STi have low CR 8.0 : 1 engine. Still I have always aimed for centre LED on my LambdaLink/AFR gauge and that is 12:1 AFR, regardless of engine compression.

You will beat yourself to death trying to debate which is the "best" method of tuning but fact remains, in the tuning arena here, Air Fuel ratios determine the car's power. Nonetheless EGTs should always be observed but EGTs do not dictate a car's state of tune. By following the 'rule of thumb' that a turbo engine requires 12.5-ish : 1 AFR(let's not get pedantic but accuracy is still required, nonetheless), I have not blown my stock motor in 3 years, 80,000 kms. I drive my rex hard pushing it to 7000 rpm redline every chance I get boosting at 1.2 bar (17.4 psi) on stock 380cc injectors, with killer ambient temps of 91-ishșF. I guess I am doing something right here
Jan Shim is offline   Reply With Quote
Old 05-18-2001, 04:45 AM   #14
AndyHidley
Scooby Newbie
 
Member#: 1031
Join Date: Mar 2000
Location: PA, USA
Vehicle:
2002 WRX
Blue

Post

98mpreziveRS and Jan Shim and others...WOW some real "tech talk here" my hats off to ya!! A question for you... Where is the O2 sensor placed, my 2002 WRX has 3 catalitic converters. I would assume that each one makes the exaust alittle leaner, how much I dont know, What do you think the difference whould be if it were placed in front of the first one or at the end of the third one??
AndyHidley is offline   Reply With Quote
Old 05-18-2001, 05:52 AM   #15
Jan Shim
Scooby Specialist
 
Member#: 6366
Join Date: May 2001
Location: Brunei Darussalam
Vehicle:
1998 WRX Wagon (Ret)
Silver

Post

Andy,

While the '01- '02 WRX has a new shape and other new bits, fundamentally most things are still the same in design. Not having seen where the OČ sensor is mounted, I can only guess that Subaru had not repositioned it which is 3-5" from the turbo on the downpipe. The catalytic converters are post turbo so therefore A/F ratios aren't affected.

Air Fuel gauges are typically piggybacked on the ECU wires to read from the factory sensor. However, if the car is going to be driven hard all the time, EGT is likely going to be high especially on such cat-restricted exhausts. High exhaust temps tend to cause factory sensors to read leaner than it really is but when given sufficient cooling period in between runs, it is hardly a problem.

I recommend fitting an AFR gauge as it helps you see if the OČ sensor is still healthy or not. My original sensor lasted 50,000 kms. There must be a Link dealer in the US by now .. I find their LambdaLink AFR and KnockLink gauge very easy to use especially when you start to mess with aftermarket ECU.
Jan Shim is offline   Reply With Quote
Old 05-18-2001, 06:34 AM   #16
TurboXS
Former Vendor
 
Member#: 4143
Join Date: Feb 2001
Location: Gaithersburg, MD USA
Vehicle:
2002 WRX Wagon
WR Blue

Post

Andy,
I agree with Jan Shim wholeheartedly. Shooting for A/F ratios of 13.2-13.8:1 at WOT is way too lean for the WRX. 12:1 will be much safer and 11.5:1 even more so, especially if you are going to run high boost levels on the stock turbo (let's call high boost 17+ psi on the stock WRX turbo). Sorry, but I can't tell you what this means in terms of the the output voltage from either of the stock O2 sensors (I use a separate A/F sensor). I can tell you where to find your WRXs O2 sensors, however:
1. The front O2 sensor is on the uppipe before the pre-cat (Cat 1). This is supposedly the main feedback sensor for the ECM to modify injector duration to change the car's A/F ratio.
2. The rear 02 sensor is right before the rear cat (Cat 3).
TurboXS is offline   Reply With Quote
Old 05-18-2001, 06:39 AM   #17
rao
Scooby Specialist
 
Member#: 52
Join Date: Jun 1999
Location: Naperville, IL
Post

Kevin,

You can't rely on the output from any stock O2 sensor because of the extreme slope of it's response as you move slightly away from it's target range (which is likely not where you want to be with yur turbo ) If you want to know for sure you need a wide band O2 sensor and they are very expensive $1000+. Reading the stock sensor is really only useful to flag changes from previous values, not as a reliable indicator of the a/f ratio.

The front 02 sensor on 2000+ Subaru's seems to be some sort of wide range sensor, but nobody has yet figured out how to read the 4 separate voltage outputs it generates
rao is offline   Reply With Quote
Old 05-18-2001, 06:50 AM   #18
RyanC
Scooby Specialist
 
Member#: 2634
Join Date: Oct 2000
Chapter/Region: NESIC
Location: CT
Vehicle:
1988 5000 CS Quattro
Tornado Red

Post

Kevin, fwiw I set my AFR targets to 13.8:1 above 125kPa in my TEC-II. Car doesn't run lean, and EGTs are under 1500 (probe is in header behind #4). I run up to about 8.5psi, and haven't had any issues with this AFR target.
RyanC is offline   Reply With Quote
Old 05-18-2001, 07:14 AM   #19
NickSTi
Scooby Specialist
 
Member#: 626
Join Date: Dec 1999
Location: Miami FL
Vehicle:
2001 Impreza 2.5 RS
Black Diamond Pearl

Post

I think what 8Complex was trying to say was if you do not know, watch your EGTs cuz chances are you will not do any damage once your EGTs are fine.
But your a/f will depend on the engine like he was saying and there is no one fits all value.
NickSTi is offline   Reply With Quote
Old 05-18-2001, 07:47 AM   #20
AndyHidley
Scooby Newbie
 
Member#: 1031
Join Date: Mar 2000
Location: PA, USA
Vehicle:
2002 WRX
Blue

Post

Sorry guys , my question got "long winded and I lost my train of thought"!!! I have an A/F meter but it only works on 0-1volt sensors, thus I have to use the rear O2 sensor, pin 17 in the second connector on the ECU, white wire, I believe. My question is :
What do you think the difference in A/F ratio whould be if the O2 sensor were placed in front of the first cat or at the end of the third cat??
My concern is not really accuracy of my A/F meter, but reading the exaust after it has been leaned by going through three cats.
AndyHidley is offline   Reply With Quote
Old 05-18-2001, 10:26 AM   #21
Joe Hogan
Scooby Specialist
 
Member#: 699
Join Date: Jan 2000
Location: Green Mountain State
Vehicle:
2002 golf TDI
Blue

Post

I've resisted this thread fro a while now but ..... I just can't resist any longer ...

AFRs are at best hypothetical targets ... it has been my experience to use a properly placed EGT [ 2" from the exhaust port of the leanest cylinder ...#3 on the 2.5L engine with stock fuel rails], an aftermarket ECU for multi parameter data capture, and a DYNO ...

My $.02

JH

[This message has been edited by Joe Hogan (edited May 19, 2001).]
Joe Hogan is offline   Reply With Quote
Old 05-18-2001, 02:50 PM   #22
Jon [in CT]
*** Banned ***
 
Member#: 2992
Join Date: Nov 2000
Chapter/Region: NESIC
Location: Connecticut, USA
Vehicle:
02 WRX Sedan
Silver

Post

I believe that the WRX uses this Bosch wideband sensor as the front 02 sensor located at the right-hand (passenger side) exhaust manifold. The photo of the sensor matches almost exactly the diagram of the sensor given on page FU-16 in Volume 8 of the Subaru service manuals.
MoTec, among others, makes a meter (AFM-2) that can handle this Bosch sensor's signals. I'm not sure what it costs - probably very expensive.

I presume you people use these meters only for tuning purposes. I don't think that's the best way to do it. You can't make a WOT run and watch the meter(s) at the same time. The better way, IMHO, is a data logger. A simple, effective and cheap data logger is a PC-based OBD scan tool. They can be had for less than $125 for software and connectors and can log at up to 30 measurements per second. You would tell the scan tool to collect from the ECU, for instance, short term fuel trim due to the front 02 sensor as well as engine RPM. When you've finished your WOT runs, you plot/analyze the collected data at your leisure.
Jon [in CT] is offline   Reply With Quote
Old 05-18-2001, 04:38 PM   #23
Jan Shim
Scooby Specialist
 
Member#: 6366
Join Date: May 2001
Location: Brunei Darussalam
Vehicle:
1998 WRX Wagon (Ret)
Silver

Post

Rao, Joe, Jon et al.

In an ideal world, tuning is best left to the professional tuner who have the right tools for the right job. Then there are some of us who have no access to either a tuner or dyno but have the sheer enthusiasm to learn, share and improve. Sadly, I fall into the latter category. This is not to say we have no access to reputable tuners from overseas but just that we dont have one here permanently; JUN, Haltech, PossumBourne (Link), Autronics, Bozz Speed to name a few have visited us and exchanged ideas.

I run a Link computer that allows me to map boost, fuel and ignition timing in 500rpm increments including cold/hot starts fuel enrichment, Knock threshold, boost solenoid & wastegate actuator control while the LambdaLink, KnockLink and K-type thermocouple probes give me the necessary feedback from my tuning.

Kevin, if the US WRX runs a wide-band sensor and your AFR gauge cant run off it then you have no choice but to get one that can. For accuracy, AFRs must be taken post turbo but having said this, most dyno tuners use a tailpipe kit so perhaps the cats do not affect AFRs? Most of us run a turbo back straight through 3" pipe without any cat as it is not mandatory here.

Ryan, 8.5psi=0.58 bar. Given that this is a very conservative figure (my wastegate actuator rod preload has the same boost pressure if I run without a boost controller), you could perhaps run 13-ish AFR without leaning out while this is reasonably dangerous territory if one ran at say, double the boost. The increase in boost=increase in air supply necessitates an increase in fuel supply to maintain the target AFR. If you increase boost from 8.5 psi to 12 psi, the AFR will without a doubt leans out. We tend to push our WRX/STi to the limits of factory internals and run proportionately higher boost that what the factory dictates. STi's have standard 17 psi boost while the Type R does 18.5 on 100+RON fuel. Due to my high CR engine, the factory boost is 10.7 psi but i have managed to push it to 17 psi running IHI VF24 turbo. Intercooler, increased fuel pressure, and constant monitoring of vitat statistics such as AFR, Fuel Injector duty cycle and knocks are of paramount importance.
Jan Shim is offline   Reply With Quote
Old 05-19-2001, 12:55 AM   #24
ImprezaRS dot com
over boosted again
Moderator
 
Member#: 1458
Join Date: May 2000
Chapter/Region: RMIC
Location: Colorado Springs CO USA
Vehicle:
2017 WRX Limited
15 Forester XT, 21 Ascent

Post

I have some new 5V Rich/Lean Meters that I will be selling as soon as I finish the documentation and instructions and photos. They will work on the front 5V O2 sensor of the 2000+ models and the 2002 WRX, and are very accurate. They will be in the $100 neighborhood. (I will also be selling some converter boxes at half that, which let you use a regular 1V A/F meter, like the autometer phantom, on the 5V front sensors).

The middle "stoich" yellow light will be on from about 14.8 to 14.4 to 1 and then go off when outside that range.

Then the first rich light will activate and stay on from 13.9 to 13.2 to 1 and go off.

Then the second green light (a different shade from the first green) will come on from about 12.9 to 1 and stay on as long as you are richer than that.

It will show one or two red lights if the A/F ratio is more than 14.9:1 and too lean.

Between values, two lights will be on.

However, I know that I never see more than 0.8V on my rear O2 sensor (with OBDII monitor) when the car is running strong, and EGT's (#3 cyl) at WOT are between 1350-1475 depending on load and speed. Since that is about 13.2:1, and the rear sensor is supposed to read richer than the front, I suspect the front O2 sensor would indicate I am leaner than that and in the range I stated earlier. I am always open to gentle correction.

FYI - I curently have a dedicated 1V O2 sensor mounted in the turbo up-pipe with a Autometer Phantom Rich/Lean meter in my gauge pod. The sensor location was chosen since it is about the same distance from the head that the factory O2 sensor used to be when the car was NA. I have no documentation as to which LED is what O2 sensor voltage on the autometer, like I do with these other ones. But, I keep it about midway in the green zone and it runs great, and EGT's look good. This is richer than my friend's NA car with same meter, using and intake, exhaust and S-AFC. When I did this mod, I would have prefered a $350 analog A/F ratio meter with lambda sensor instead, but none that I found would fit the gauge pod (and I didn't have that much money left at the time).

This new meter that I will be selling is nice because at least you know what A/F ratio you are at according to which LED is lit up. It is about 2"x2"x1/2" in size, and can mount in the ashtray, or on the dash, etc...

Larry
www,ImprezaRS.com
ImprezaRS dot com is offline   Reply With Quote
Old 05-19-2001, 12:56 AM   #25
ImprezaRS dot com
over boosted again
Moderator
 
Member#: 1458
Join Date: May 2000
Chapter/Region: RMIC
Location: Colorado Springs CO USA
Vehicle:
2017 WRX Limited
15 Forester XT, 21 Ascent

Post

PS - I got my numbers of 13.2 - 13.8 for max power from having glanced at a book on Bosche fuel injection a few months ago.

The designer of the new A/F meters is the owner of the book.

Larry
ImprezaRS dot com 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
Autometer Voltmeter and Air Fuel Ratio gauges bmwmotorsports Interior/Dressup/Audio & Security 3 10-02-2008 07:12 PM
Autometer cluster bezel with oil pressure and air/fuel ratio gauges gingertooth Interior/Dressup/Audio & Security 31 01-28-2008 08:23 PM
fs/ft autometer boost and air fuel ratio afr schiarelli Interior/Dressup/Audio & Security 1 12-17-2007 04:44 PM
Autometer LUNAR SERIES ~BOOST and air/fuel ratio gauges.. JT's06sti Interior/Dressup/Audio & Security 1 06-09-2007 09:26 PM
Boost gauge and Air/fuel ratio install? eswrx Newbies & FAQs 4 10-27-2002 02:21 PM

All times are GMT -4. The time now is 06:46 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.