Double post-sorry

[Edited by Leslie - 5/1/2003 6:51:30 PM]

 

I've noticed that the Dawes AFR for a Scooby is set to give its mixture indications at different Lambda sensor voltages to its standard set up.

Could anyone tell me if the correct Scooby Lambda sensor produces different voltages for a given mixture strength or is the Dawes deliberately set to give its indications at different mixture strengths just for the Scoob.

Les

 

I think it's designed for displaying the mixture @ WOT

 

It says displays on WOT, but also seems to display at all throttle settings - red (lean) on lift off etc.
The problem I have with it is it is dazzling at night - to the extent that I have to put 2 white socks on it or a screwed up handkerchief so I can see out of the windscreen - the inside of the car still looks like a disco. I mounted it next to the knocklink by the "A" pillar so they are easy to see
Hope they modify it so it dims when you put lights on.

Stan

 

stuck mine down in the wee oddment tray on the right hand side by your knee

like so



not quite the dawes one but you get the idea

cheers

big sinky

 

I was thinking about getting one of these when I get my dawes, what's the consensus, good or bad?

 

Thanks for the help guys, is that the AFR from Oz BS? I would say it is well worth getting KRM if you are going to be experimenting with boost settings etc.

Les

[Edited by Leslie - 4/28/2003 12:32:11 PM]

 

I do indeed intend to play Had the car on Nobles RR at the weekend to discover it running really rich at high rpm - plenty of scope for more boost

 

I use a Dawes AFR mounted in the ashtray, I have adjusted it my self to the below metrics. Below 800mV 3%CO2 no lights to avoid the disco, only when I do WOT it light up.
During normal driving no light show up. In the morning until engine is warmed up the red light is on, but this is OK as a warning NO WOT

You need a high impedance meter og an osciliscope to do the adjustment.


Air Fuel Ratio - Lambda Meter

LED MV CO 2 AFR Bar
700
720 1,0% 14,0 : 1
740
760 2,0%
780
red 800 3,0%
red 820 4,0%
amber 830 4,5% 0,2 - 0,6
amber 840 5,0% 13,0 : 1
green 850 5,5% 12,5 : 1 0,6 - 1,0
green 860 6,0% 12,0 : 1
green 870 7,0% 11,5 : 1 > 1,0
blue 880 8,0% 11,0 : 1
blue 900 10,0%

AFR is used together with a Dawes MBC set to 1.05 bar ( 15PSI)car is a MY99. I I go to 1.1 bar AFR will no longer go green when WOT but stays on amber, this tells me that for my car 1.05 is the limit

 

Thanks for the info' Lars. I do have an oscilloscope so I can set it up with that.

Les

 

So is what they say true - it only reads "meaningfully" with WOT ???
Stan

 

Yes as I understand it now Stan, at lesser throttle settings the ecu goes into closed loop for mixture control and the lights would indicate up and down as the mixture changes slightly. The voltage change from the Lambda sensor is comparatively large for a small mixture change at around stoichometric values. This may well be changed by someone who knows more than I do though.

Les

 

Leslie - Posted January !!???
Cheers - but is that the same for all ecu's or just the std ones ?
Stan

 

Dont know why that post says January-it was yesterday.

I imagine it would be the same for any ecu Stan, The Dawes only has four leds set at the higher voltage so maybe it will not indicate at part throttle opening anyway. The Jaycar version that I have just soldered together has ten leds from 100mv up to 1.144v for the last one to light up, so maybe when it is fitted in the car it will indicate on part throttle openings as well. I have not seen one working yet and was just going by what the paperwork says.
It is the WOT indications that are important to the safety of the motor of course.

Les