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Plug analysis and Air Fuel Ratio
https://www.ausmini.com/forums/viewtopic.php?f=2&t=78203		 Page 1 of 4
Author:  FNQ [ Mon Aug 27, 2012 12:31 am ]
Post subject:  Plug analysis and Air Fuel Ratio
Hi



Am at the stage of 'playing' with SU carbs/ needles etc and thought i would ask people about the art of reading plugs.

I came across this article http://www.4secondsflat.com/Spark_plug_reading.html

and wondered about my set up (down the bottom of that webpage is a link to 16 plug condition pictures)

so out with one of mine - Plug 1 after a 40 min all purpose run 0 to 6000rpm, some idle and traffic some sprints some highway work and some part throttle cruising . the plugs are about 4000km old BP6ES gapped out to 30thou with a nissan elect distrib -

it runs quite well but i think it can run better , idle set 950 , timing dynamic 30degrees, is unleaded head running on 95 / 98 oct (95 in the tank for this run) ( i try to use 98 most of the time but will use 95 )doesn't ping or overheat

setup is 1310cc, twin HS4, currently running #3 needles , running a 268 cam, head/manifold maybe some work but not anything serious

Image

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So , based on these piccies ( the best i could do sorry) , give me a story

I am interested in the art of plug reading (such as in the web link) i also have an AFR sensor but i am awaiting a usb to serial connector so i can log the output properly, atm i just peek at a digital gauge that fluctuates,, so I have an idea of where to head next for AFR but will wait until i can plot the log also.



The web article makes predictions about heat range, timing (both static and dynamic) idle and WOT richness I can see some 'signs' but it looks like a pretty new plug to me.



When the serial adapter gets here i will provide info on what the electronic science says about AFR ( if not heat range etc)

Any thoughts on plug reading in general and any 'guesstimates' as to what to try next for timing needles, etc appreciated.

Darryl
Author:  drmini in aust [ Mon Aug 27, 2012 8:02 am ]
Post subject: 
Looks fine to me.
You can't really read the plugs now like we did in the old days, the lack of lead in the fuel is to blame.
If it's running too lean or the plug's heat range too hot the electrode will be white but blistered.
If sooted up it's too rich (obviously).

a wideband A/F ratio meter and running it under load is now really the only accurate way to see whatcha got.
Author:  TBOT70 [ Mon Aug 27, 2012 9:08 am ]
Post subject: 
hey doc where can you get one of those A/F meters??
Author:  drmini in aust [ Mon Aug 27, 2012 9:28 am ]
Post subject: 
TBOT70 wrote:
hey doc where can you get one of those A/F meters??

http://www.ebay.com/sch/sis.html?_kw=wi ... air%2Ffuel

Graham Russell and Greig Malaure each have an Innovate LM1 kit.
Current LM2 replaces them and has a logging function too, not sure what else..

Check the Innovate website.
Author:  TBOT70 [ Mon Aug 27, 2012 1:15 pm ]
Post subject: 
are those meters for carb or efi??
Author:  drmini in aust [ Mon Aug 27, 2012 2:15 pm ]
Post subject: 
TBOT70,
Either- whether EFI or carb doesn't matter.
The systems run off 12V, the sensor goes up the tailpipe (for portable or dyno use), or for permanent fixing they have the sensor screwed into a boss welded onto the headers.
MRC used a similar one on your car, at the ausmini dyno day. Look at the bottom trace on your dyno sheet.
Author:  TBOT70 [ Mon Aug 27, 2012 3:33 pm ]
Post subject: 
i never went, but mine is running fairly rich atm, was just looking for some kind of tool to make it more accurate and balanced
Author:  FNQ [ Mon Aug 27, 2012 3:34 pm ]
Post subject:  plug reading
Thanks doc, makes sense about the fuel differences, but a shame about the noble art form going the way of the dodos.

The AFR (innovate but waiting for log function) is basically alright . A little rich at idle-12s, mostly good but maybe too lean at WOT (14-15s) so i am going to pop the number 6 needles in. The reaction time - from when foot is planted - does give a lean second or so - so i might thin the dashpot oil just a tad - currently running 20w50.

So, I feel okay, confirming the seat of the pants feel that the mini is running okay. many thanks Darryl
Author:  drmini in aust [ Tue Aug 28, 2012 2:50 pm ]
Post subject: 
I'm considering buying the Innovate MTX-L meter setup- anybody have any feedback on this model?
$229 bought local, not checked USA much yet, probably be cheaper there.

[edit] USD199 from Innovate site. + freight.

[edit2] I've checked a few cheaper places in US but by the time they post to here I might as well buy it local.

http://adaptronic.com.au/component/cont ... e/128.html
Author:  KLAS [ Tue Aug 28, 2012 4:24 pm ]
Post subject: 
i wanted to buy a MTX-L, but than this came along http://breitband-lambda.de/ and i don't need a gauge if i can read the controler with a laptop
it's using the CJ125 chip, the same chip used in OEM applications.
not much cheaper than a LC-, you have to buy the lambda sensor extra, but much better, e.g. it don't need free air calibration
Author:  drmini in aust [ Tue Aug 28, 2012 4:45 pm ]
Post subject: 
KLAS wrote:
i wanted to buy a MTX-L, but than this came along http://breitband-lambda.de/ and i don't need a gauge if i can read the controler with a laptop
it's using the CJ125 chip, the same chip used in OEM applications.
not much cheaper than a LC-, you have to buy the lambda sensor extra, but much better, e.g. it don't need free air calibration

Thanks Klas..
But since I don't own a laptop... (unless it'll work with a Macbook air...?) I'd rather have a gauge installed...
Author:  Mini68 [ Tue Aug 28, 2012 6:52 pm ]
Post subject: 
drmini I've been looking at the mtx-l kit too. Do you or does anyone else have an opinion of the best place to put the bung? Do you think in the LCB as per the SPI Maniflow manifolds is ok or perhaps too close to the exhaust valve? Seems like a pretty convenient spot, especially sine my exhaust is out at the moment.
Author:  drmini in aust [ Tue Aug 28, 2012 7:08 pm ]
Post subject: 
IMO the best place for the bung is in the side of the Y-piece, under the car... this way you get an average reading of all cylinders.
If you stick it in the centre branch of the LCB there's no guarantee the outer cylinders are the same mixture as the middle ones.
But With a Weber or Dellorto how much difference is there, anyway.
My plugs all look the same.

[edit] reading the manual for the MTX-L it says the sensor should be between 10 o'clock and 2 o'clock. If you put it much lower, condensation can bugger it up.
Author:  Phat Kat [ Tue Aug 28, 2012 7:13 pm ]
Post subject: 
+1

Read it at the collector.. closer to the valve is better... but the collector is the best compromise.

Our LM2 is awesome. You can log with it and plug more sensors into it than I can remember. I normally just use exhaust gas, vac and ign. But it has provision for many many more. You could log everything from whats going on with your engine to how hot your brakes are getting.

Great bit of gear. Rocket industries sell them, thats where mine came from. I think I paid five or six hundred, it was a couple of years ago
Author:  KLAS [ Wed Aug 29, 2012 2:30 am ]
Post subject: 
drmini in aust wrote:
KLAS wrote:
i wanted to buy a MTX-L, but than this came along http://breitband-lambda.de/ and i don't need a gauge if i can read the controler with a laptop
it's using the CJ125 chip, the same chip used in OEM applications.
not much cheaper than a LC-, you have to buy the lambda sensor extra, but much better, e.g. it don't need free air calibration

Thanks Klas..
But since I don't own a laptop... (unless it'll work with a Macbook air...?) I'd rather have a gauge installed...

i know there is a version that works with a gauge. i hope you can see it, don't know if you have to be registered
http://megasquirt.de/msforum/viewtopic. ... &start=180
if i understood it correctly you can fit any gauge for a wideband sensor, you just have to match the firmware to what the gauge expect. a updated firmware for the shown gauge already exists.
don't know anything about macbooks, so i can not say what will work
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