Air fuel ratio guage

  • Thread starter heaven is a gtir (bry)
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K

kizzyturbo4x4

Guest
I know a fella that makes them,
it aint to difficult.
you couldnt convert it, you would have to make it for 0-1,6v scale.
mayby i could get him to make some.... :wink:

these leds that lit up all come with different OHM resistance that makes
them lit at different voltages)
so you would have to get the correct leds in different OHM`s and different colours to make up a scale from 0-1,6v.
and the more leds you have, the more accurate measurement.

i will talk to him and maby get som 0-1,6 A/F gauges made.
 
G

geetee

Active Member
I think you could be onto an earner if you organised a group buy on an AFR gauge that understood the R's 1.6V Lambda.

I am sure saw a thread on the voltage ranges for Lean/Stioch/Rich before, but it is too late to go rummaging.

But then maybe not

Cheers
GeeTee 8)
 
K

kizzyturbo4x4

Guest
im someone could get the full spec of the R`s lambda probe.
from fex. bosch? then we could see how to make the gauge.
when making a A/F ratio gauge you want to place 12 (or more)
leds within the stoich voltage area of the probe. that way it will show very accurate readings even for a narrowband probe. and would be usefull indeed.
 
O

Olly

Guest
Flat out 2nd, 3rd ,4th side by side with some chief in Red R33 GTR last night nr horsham, 1.3 bar,uprated pump,forge fmc kit,aquamist, that autometer guage didn't back off one bit, bit like me. 8)
 
C

chrislloydus

Guest
kizzyturbo4x4 said:
you want to place 12 (or more)
leds within the stoich voltage area of the probe. that way it will show very accurate readings even for a narrowband probe.
Click to expand...
I dont want to rain on your parade - your logic is flawless - BUT the narrowband probe is highly inaccurate under boost and high EGTs. Your gauge would be excellent for tuning out of boost, or for getting good cruising mpg but it would not make a tuning tool.

geetee - im not sure where you're getting that the R uses a 1.6v lambda from ? Industry standard is 1v, and the GTiR workshop manual says it uses a 1v lambda. The only mention of a 1.6v lambda i could find was in this thread :D

The stock narrowband doesnt offer the resolution required to read anything accurately. The difference between a 12:1 ratio (good ratio for making power under boost) and a 13:1 ratio (lean under boost with a tendancy to det) is LESS THAN 0.01 volts. The difference between 14:1 and 12:1 is only 0.02 volts. This is without varying EGTs mucking with the results too.

Im not trying to pi$$ you all off, im just asking you to do a search on Yahoo, check it out, and spend the money on a wideband if you must have an o2 display !
 
G

geetee

Active Member
There are several threads on this forum about the voltage range of the R's Lambda being non-standard and running to 1.6V

If you don't believe this, run the sensor to a datalogger - I did, it was returning up to 1.77V :shock:

Maybe it is a standard sensor but the higher EGT's cause whatever funky reaction goes on in there to be a little more excited?? :) (Well seems like fairly sound chemical / catalyst logic to me - always quicker at higher temps??)

I don't think anyone mentioned tuning their car on boost based on the output of the AFR gauge did they?

Cheers
GeeTee 8)
 
K

kizzyturbo4x4

Guest
simply to get whats possible out of the narrowband probe. at a low cost. a broadband isnt cheap as chips so..
(but i got on on my list so calm down, thats for mapping)
 
G

geetee

Active Member
Wideband probes are far more expensive and don't last too long.

If you are going to the effort of drilling and welding a boss into your manifold for an extra sensor you may as well fit an EGT.

:roll:

why has this gone on so long??

Cheers
GeeTee 8)
 
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