cinders

Right guys, just built my own AFR (10 LED) and I need some advice in setting up the led's so they light up correctly at the right voltages. I have seen two articles that contradict each other, so haven't got a clue what should be right...

According to John Banks AFR meter instructions as boost increases I want to see a 5% mixture getting richer... this equates to 840mv (5% 13:1) so this is how i was going to set it up

1000mv BLUE (RICH)
980 BLUE (RICH)
960 GREEN
940 GREEN
920 GREEN
900 GREEN
880 GREEN
860 GREEN
840 GREEN
820 RED (LEAN)

However, I have found on

http://www.j-w-racing.co.uk/acatalog...io_Meters.html

that the settings for these are different, and that green should start from 940mv on WOT and anyting under 900mv is too lean

Can anyone help me set my AFR up?...

This is on MY98 UK Turbo

Thanks,
Matt

greasemonkey

Too many LED's Matt. You only need four or five at most, monitoring the range from 0.8 to 0.9 volts. Anything more than that is gilding the lily and will make the thing difficult to read.

cinders

Thats why I'm using different colour LED's and not a bargraph so I can easily spot when the mixture is out... I might remove a few LED's as well...

I just want to know what voltage I should start the green lights at?.... 840mv as John says, or around 940mv as J-W Racing....

MBScooby

Cinders you can get multicoloured bargaph's from RS components if that helps at all

greasemonkey

Even so, with so many green LED's, you'll find it difficult to tell them apart at a glance. Mine is set up with one green LED in the middle. On the rich side, there's one yellow and one blue, and on the lean side, one orange, and one red. That way I can tell just by the colour which one is lit, no need to work out which green it is, which is the problem you'll have with your proposed design.

Hell, are you sure the JW racing one is that high? Your blue LED should be on at 900mv!

John's suggestion of 840mv or so is in the ballpark. Exactly where you want your green depends on how much boost you're running, but assuming you're standard-ish, and your lambda sensor's in good working order, you'll be looking for an ideal of between 840 and 850mv, yes. Anything higher than 850 and you should be using another colour LED to signify that you're richer than ideal.

Henrik

iTrader: (5)

Where can I find information on how to build this?

john banks

You probably want to see 880-920 on full boost, but these narrowband sensors are not terribly accurate. The previous AFR info I took from the Link manual. 870 on some cars can be quite lean.

cinders

OK - I think a good idea here is for me to remove 5 LED's from my meter and set it up like you have described above...


Yeah I'm positive, if you have a look at this page it explains what they set their Dawes AFR's to:

http://www.j-w-racing.co.uk/acatalo...tio_Meters.html

First light: Red= .78 to .90v
Second light: Yellow= .90 to .94v
Third light: Green= .94 to .98v
Fourth light: Blue= .98v and up

I thought it was a little high myself....


Now it's getting confusing!... John has stated 880-920 on WOT, You state 840-850 and JW state 940-980mv.... Argghhhh..... he he....

Anymore information on the ideal voltage would be great... Does anyone have any weblinks to any DIY AFR meters or any weblinks to any sites that might help me with %CO and mv output graphs from Lamdba probes?

I'm running a MY98 UK Turbo with Std Boost and Full Decat.

Matt.

P.S. I have designed a PCB for this meter which I'll be mass producing soon, so if anyone is interested in one of these units once I've got the voltage/led settings done I'll work out a price for them. Very simple to connect - only 3 wires.

Butty

iTrader: (2)

There was an excellent thread on SN from John and others on the PCB build needed to build an AFR working off the OEM sensor readings - unfotunately there is no longer a link.
I seem to remember that JW did two AFR meters, accounting for different 02 sensor voltages. The .94-.98 v range may be for the non-Scooby meter?

GM is pointing out the colour that green could start at to show something like 2-5% CO for normal running whilst Johns range is a higher CO at WOT to avoid contributing to det.

I would change the bottom couple of leds to amber to show a transition zone IMO

Nick

john banks

Standard cars often run 910-930, safely very rich. The response from narrowbands is unpredictable and unreliable though so you can't read too much into it.

If your car is healthy see what it runs and then set things accordingly, then you will see a change if there a significant deviation from this.

cinders

OK... This is the voltages I've decided to go for on my AFR. I'm using the 10 led's for now, but am going to remove half of them later once I start playing around with it a bit more.
mv led colour
820 RED (LEAN)
840 RED (LEAN)
860 GREEN (OK)
880
900
920
940
960
980
1000

cinders

OK... This is the voltages I've decided to go for on my AFR. I'm using the 10 led's for now, but am going to remove some of them later to reduce the size of the display once I start playing around with it a bit more.

mv led colour
820 RED (LEAN)
840 ORANGE (LEAN)
860 GREEN (OK)
880 GREEN (OK)
900 GREEN (OK)
920 ORANGE (RICH
940 ORANGE (RICH)
960 BLUE (V.RICH)
980 BLUE (V.RICH)
1000 BLUE (V.RICH)

What do you guys think?....

Matt.

john banks

Should be green or orange on full boost then. You will probably never see the blues. Even the bottom green on WOT is too lean.

cinders

John, what would you suggest yourself for my AFR?

820 RED (LEAN)
840 ORANGE (LEAN)
860 ORANGE (LEAN)
880 GREEN (OK)
900 GREEN (OK)
920 GREEN (OK)
940 ORANGE (RICH)
960 BLUE (V.RICH)
980 BLUE (V.RICH)
1000 BLUE (V.RICH)

Thanks,
Matt.

cinders

John/Greasmonkey/Anyone.... Can you tell me if you think the above setup is within the correct range?....

Or John could you write me out a chart like I've done? Please mate?.... 8 )

I'm running a std MY98 UK Turbo with std boost, however after fitting my Knocklink I want to increase the boost to about 1.1 / 1.2 bar....

Sorry to keep pestering you, just want to get my AFR meter right!

cinders

Cmon', someone must be able to help me fine tune this thing?... I've just spent 2 hours on the web looking for information on 02 sensor voltages outputs and what the Subaru expects, but have drawn a blank...

john banks

Sorry Matt just seen the thread again. The last scheme you show looks fine, should be showing green on full boost.

cinders

Hi John,
Thanks for the reply mate!... Can't wait to build it up and wire it in this weekend!...

Matt.