2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Well, I got my A/F meter in. here is what I've discovered

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Old Mar 8, 2002 | 11:18 PM
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Well, I got my A/F meter in. here is what I've discovered

I put in my air flow meter this afternoon, I used the 1 year old O2 sensor that was already in the manifold. I simply tapped into the wire the computer uses about 4 inches from teh sensor.
My meter is a 10 bar LED type graph.
1 bar is 16.2:1 -lean
4 is to be perfect
7 is 13.2 - pretty rich
10 is 11.7 - really rich
When the car is first started it is very lean (0 bars) then in a second or 2 it is rich (7 bars)
drive when it is cold and it is always 9 bars
after it warms up idle is 4 -5 bars always
under acceleration the bar reads a steady 8 bars
at cruise an aprox. 1/3 sec fuctuation of 8 bars to 1 bar constant while at 60 MPH - 90 MPH cruising. I don't understandd the last part why it would bounce like that.
and sadly my car is never close to 4 bars unless at idle only. My car runs way too rich.
I know some of you will start the rich is better speech, but the people that know, say that the 14.7:1 mix is the best for these cars too. that makes the most power, and is the best milage. it is only when they run lean can you get problems. a litlle lean is even okay on the n/a's. turbos should never fall below the 15.2;1 mark because of teh pressures in the chamber. but the n/a can take a bit more abuse.
anyway this is only informative. I will keep you updated on teh performance benifit of going to the right mix. I am going to make some runs as is and then after ever adjustment leaner.
I will run now at 12.2:1 mix
then at 13.7:1 mix
last at 14.7:1 mix
Three runs each to get an average.
No other mods to the car will be done to keep accurasy.
No dydno, this is the only alternative.
later
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Old Mar 8, 2002 | 11:25 PM
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It shows real lean when cold because the sensor isn't hot yet so it reads wrong. When you're cruising, and it goes boing boing boing and jumps around, that is because the ECU is in closed loop mode, and it is continually adjusting the A/F ratio for maximum efficiency/minimum pollution. (that's most of the point of having one in the first place, since under WOT it is using pre-set fuel maps and the o2 sensor input is ignored)
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Old Mar 8, 2002 | 11:37 PM
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umm, 14.7 is too lean for WOT!... I'm not sure what N/A's should be but it's probably around 13. turbos run 11.5-12

the o2 sensor and gauge will not work when cold, just ignor it, the readings mean nothing.
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Old Mar 9, 2002 | 02:02 AM
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Don't be using that to fine tune stuff...

http://fc3s-pro.com/TECH/MODS/EL/afr.htm




-Ted
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Old Mar 9, 2002 | 02:34 AM
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Originally posted by RETed

http://fc3s-pro.com/TECH/MODS/EL/afr.htm

-Ted
heh, don't normaly see anything about split sec. nice gauges but $$$. love the dimmer wire but the voltage seems to be backwards from the dash lights LOL. brigher dash = weaker gauge. but it does turn down when lights go on which is the most important part. I got it on a group buy, much cheaper also like that it has another ground wire for the 02. now I just need a 2 wire 02 sensor...

http://www.1300cc.com/mycar/IMAGE014.jpg

Last edited by Scott 89t2; Mar 9, 2002 at 02:36 AM.
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Old Mar 9, 2002 | 04:35 AM
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I knew about eh cold O2 thing. I put it in for accuracy.

I did replace the stock sensor with teh wide band type. I noticed an improvement when I did it in the feel of the car. I know why my car runns rich, I made the mods to do it. It is easy to go back and beyond.
Now it has rained too so the roads and track are not going to be dry for a day or two. this may have to wait until next week.
The design of this meter was suposed to compensate for the non-lenear readings of the sensor. How I don't know but it is said to be more accurate with everything else being equal. anyway the track test will prove what gains can be had.
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Old Mar 9, 2002 | 04:43 AM
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Ok. You've tweaked my curiosity. What is the name of this WIDEBAND sensor and meter, please??????
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Old Mar 9, 2002 | 07:51 AM
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http://www.techedge.com.au/vehicle/wbo2/wbo2.htm
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Old Mar 9, 2002 | 09:26 AM
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http://www.scuderiaciriani.com/rx7/AF_meter.html
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Old Mar 9, 2002 | 12:09 PM
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Originally posted by tweaked

I did replace the stock sensor with teh wide band type.

first post you said you have your 1 year old stock sensor. now you have a wide band??? if you built a standard A/F gauge it will not work with the wide band, and if you tryed to hook the wide band up to the ecu you could have just fried something
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