Air/fuel ratio, cheapest sensor system

Fed_up_Stag-owner · Post by **Fed_up_Stag-owner** » Tue Mar 18, 2014 7:11 am

Hi all

RV8, flapper, supercharger, with adjustable ECU

I want to check the fuelling at various engine rpms and loadings. Although there kits out there, I am a bit of a skinflint. There are heated exhaust gas sensors on that ebay for about £17 delivered, I have a small collection of multimeters. Is there any reason why I can't fit a £17 exhaust gas sensor into each of the two collector pipes, run the cables back to the cabin and measure voltages? Assuming there are tables of values for voltage outputs from exhaust gas sensors.

DaveEFI · Post by **DaveEFI** » Tue Mar 18, 2014 8:34 am

A narrowband sensor, which does give a simple voltage output, will only tell you if the mixture is 14.7:1, or below or above this. Unless you have a cat, not much use.

Wideband sensors don't produce a simple voltage output so need their own electronics to produce a linear voltage signal which can be read easily.

stevieturbo · Post by **stevieturbo** » Tue Mar 18, 2014 10:28 am

If you're looking to DIY build, this guy is maybe cheapest.

But really, given the price of fully built units, I wouldnt even waste my time

http://www.ngk.com/product.aspx?zpid=27830

Or in UK via egay you'll get some AEM or Innovate kits for £150 or so.

Narrowband can sort of be useful if you understand they arent really accurate anywhere other than 14.7:1

But in general they are fairly crap for what you want to do.

Buy a wideband

DaveEFI · Post by **DaveEFI** » Tue Mar 18, 2014 11:02 am

Having a device which only gave a voltage output would be a PITA in practice - one with a reader giving AFR is so much better.

Of course if using with a Megasquirt or whatever, the laptop display from that will give the AFR. But not with Lucas injection, unless I've missed something.

Fed_up_Stag-owner · Post by **Fed_up_Stag-owner** » Thu Mar 20, 2014 1:16 pm

Thanks for the replies, the learning curve is steep!

DaveEFI · Post by **DaveEFI** » Thu Mar 20, 2014 2:09 pm

Fed_up_Stag-owner wrote:Thanks for the replies, the learning curve is steep!

You might look at this one - it is about the cheapest available and has good reports on the MS forum.

Postage and import duty might make it less good value, though.

http://www.14point7.com/products/sparta ... controller

stevieturbo · Post by **stevieturbo** » Thu Mar 20, 2014 4:17 pm

I meant to post that earlier, just forgot to put the link in lol

SimpleSimon · Post by **SimpleSimon** » Thu Mar 20, 2014 11:32 pm

That Spartan is a great unit accurate and no voltage offset issues unlike my Innovate LM2 it just works

I dont run the gauge as I can read through Tuner Studio

DaveEFI · Post by **DaveEFI** » Thu Mar 20, 2014 11:37 pm

My Tech Edge has the choice of a floating output - as I believe did earlier Innovate products. Just why they removed this, I dunno.

stevieturbo · Post by **stevieturbo** » Thu Mar 20, 2014 11:48 pm

floating output ?

DaveEFI · Post by **DaveEFI** » Fri Mar 21, 2014 9:12 am

stevieturbo wrote:floating output ?

Different ground for the signal output from the heater ground.

DaviesDJ · Post by **DaviesDJ** » Sun Mar 23, 2014 6:43 pm

I purchased the AEM unit - it was about 140 delivered. I pondered for a while - but honestly it is the single best performance modification I made!! Without it my carb would be way off, I would have blown my pistons out - and my NoS setup would be hopeless! You guess and guess and guess, but you are almost always wrong! Take my word for it. Put your hands in your pocket and pay for a wide and system! It's like being permanently on the rolling road!

stevieturbo · Post by **stevieturbo** » Sun Mar 23, 2014 6:51 pm

If you opt for this one, it datalogs as well.

So even on a carb car, you can hook up an rpm signal, or similar which would make tuning a little easier.

http://www.daytona-sensors.com/WEGO4.html

Single or dual channel