Loan Wideband lambda sensor

[bill shurvinton]

Just in case anyone is interested i am just finishing the assembly of a spare WB lambda system that will be available for rental for a small fee (£10 a week).

For those who have no idea what a wideband is or why they would want one I'll try and post something over the next day or so explaining why these are so good and why those cheapy AFR displays you buy are like a chocolate teapot.

To give you an idea, you can buy a unit like this from Demon thieves, but it costs £1200.

Bill

[Fish]

Or the Motec wide band units come in at around the 5-600 quid mark.

Dan

[bill shurvinton]

True, but I have a sneaky (and possibly wrong) suspicion that you have to buy the sensor on top of that.

[bill shurvinton]

Ok the promised few notes on how it all works.

A narrow band 02 is only really any good at measuring a stoichometric condition. Stoich (14.7:1 Air:fuel ratio or AFR) is good for catalytic convertors and therefore emissions. Not good for power, not good for economy and deadly with boost.

A wideband contains an ion pump. This allows it to measure the partial pressures of the ionised gas everywhere from 20:1 to 10:1 AFR. Or more than you will ever need (although I built one for Pip at WGT and one of his turbo cars was running so rich it pegged out).

It is an incredibly useful tuning tool. Not the only tool, but it has the advantage over a 4-gas or EGT probes that it reacts within about 0.1seconds and can be taken with you wherever you go.

What it won't do (yet) is work with water injection. The water reduces the partial pressure of the exhaust gas and changes the measured AFR. As I am planning water injection on my car I will fix this at some stage.

What is will also not do is protect you from doing something silly and blowing up your engine. It will let you know exactly what the fuel curve is though, which is (IMHO) invaluable.

Bill