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AFR Gauge

scam75

scam75

Well-known member
What are my options? Wideband I assume. What's the most cost effective way to do it and where is the best place for the lambda sensor to go?

Cheers

Stuart
 
It needs to go in the downpipe... For positioning Id look to see where Porsche located it in their North American cars. Of course, youll be fitting a wideband lambda, but it wants to be in a similar position.
 
I have mine where most people put it, not far from the wastegate.
I think I read somewhere that any closer to the turbo was taking a risk as wideband lambda sensors cannot bear that much heat. Not sure what this "advice" is worth though.
 
The manual for mine suggested the same, I have a Vems unit that shows AFR and EGT, has a MAP input (or any other 0-5v input), engine revs for data logging and the output for the ECU is adjustable.
It is a useful tool for a standalone ECU but being a digital gauge its a bit crap when driving as a sweeping needle would be much easier to read at a glance than a digital gauge.
 
I have never seen an original downpipe with a blank that would allow this.

The original, narrow band (less sensitive than wide band) lambda sensor is on the cross pipe, not far before the turbine inlet.
 
I have the Wideband Commander from http://www.dynojet.co.uk/

As well as a very factory looking gauge you can connect it to a laptop and do very precise logging runs against rpm and boost level, which is very handy for tuning. Once tuned you can set it to an audible alarm if you go outside certain AFR parameters.

The sensor needs to be after the turbocharger and angled downwards, so the factory bung in the crossover is not suitable
 
If doing it again I would have gone for the dynojet one purely for the gauge as the functions are pretty much the same apart from EGT and the fact that the Vems one has all the electronics in the gauge, so less clutter.

http://www.vems.hu/products/round/EN/
 
I need to get my finger out and get one of these fitted to my car ASAP as i need some piece of mind , still unsure where to place the Lambda after a couple of options have been thrown in.
I to tend to drive the car gingerly watching boost and listening for detonation which takes the pleasure out of it to a fair degree.
 
If you only want a gauge and its not for mapping, anywhere will work thats not too close to the turbo, not downstream of a cat or exhaust leak. You can even buy a clamp to fit the sensor in the tail pipe, I would imagine it would be a bit slow though.

Of course then you'll spend the whole time looking at the gauge.
 
Im surprised that theyre fitted so far up the system. Sometimes theyll burn away when fitted in the standard position on an Impreza and thats halfway down the downpipe!

With regards to the 'hole' that needs to be tapped, its usually the same as that for a spark plug.


Simon
 
Narrow band sensors rely on exhaust gas to heat them to the correct temperature IIRC and Widebands have their own heater.
Faster reaction nearer the engine and less chance of exhaust leaks throwing readings off maybe?

 
Just did some googling on this and wideband is the way to go, mounting the sensor angled down avoids condensation collecting and yes the widebands are self heating though i would not recommend hitting boost until the car is warmed up thourougly.
One youtube video shows them mounting it inches away from the turbo on the downpipe on a drift car which i presume will get quite hot.
There is another good video showing testing on a sensor basically using a fuel soaked cloth.
What AFR should a chipped turbo be running at 18 psi ?
The AEM one looks like a good bit of kit Scam
 

ORIGINAL: JamesO
Faster reaction nearer the engine and less chance of exhaust leaks throwing readings off maybe?
Click to expand...


Yes, its a balance between as close to the turbo as you can get and being far enough away so as not to fail. The original Japanese lambda melted on my Impreza, and that only made 290bhp-300bhp.
 
Well just read the other posting and high 11,s in AFR seems okay, Scam the chips you have are about 4 years old from Promax, i can get an exact date of purchase and more details as the paperwork will be in my cars history folder.
Jim
 
ORIGINAL: Frenchy

Well just read the other posting and high 11,s in AFR seems okay, Scam the chips you have are about 4 years old from Promax, i can get an exact date of purchase and more details as the paperwork will be in my cars history folder.
Jim
Click to expand...

Cheers Jim. high 11's/low 12's will be fine from what I can gather. Mine crept up to 12.8 temporarily just as the boost was loading up to near peak at 17psi. It makes sense for this to be a mechanical fuel supply issue (not chip set issue) and my 22 year old standard fuel pump will be replaced with a motorsport (400bhp rated) item which I have ordered and a new fuel filter too. If I have my AFR gauge installed it will give me on going piece of mind and will save me £60 a pop for the rolling road when making sure the fuelling is ok!

Promax already sent us up the details on the level 2 kit, cheers! Didn't know they were 4 years old though. Purchase date and paperwork for them would be great!

Stuart
 
I would run a chipped turbo at an AFR of 11.8 under full throttle at 18psi.

I used a Zeitronix wideband before and found it quite useful as it allowed for monitoring EGT, TPS and intake pressure/vacuum in real time, along with AFR (I'm selling it along with a Vitesse MAF, all wired-in a late turbo wiring loom if it's of interest to anyone).
 
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