Hi Mturbo.netters,

I just am a bit confused about the correct O2clamp voltage. I have my clamp dialed at 0.38 V at the moment which I read in here should be fine. Over at the mx5nutz forum there is a discussion at the moment about the EMU and the AFRs where a clamping voltage of 0.50 v to 0.47 v (stoich) is proposed.

Could you please try to explain the correct setting for me?

Thanks

 

.47 would be neutral and above that would be a rich signal, asking you ECU to shut down the injectors. You want the leanest signal from your O2 clamp to reach the ECU that is not too lean that it creates rich bogging as you go into boost. .38 volts is a good place.

 

Thanks Zaphod for posing and Olderguy for answering this question. I was getting very frustrated with my recent BRP62 supercharger (sorry) installation. There was lots of stumbling at boost transition and/or from closed to open loop. Both felt like over rich but I'd been blinded by the lean ping at WOT caused by last winter's 91 octane gas into thinking it had to be a lean problem.

I fixed the ping with colder plugs and 94 octane. Setting the O2 clamp at 0.38v (from the, as received, 0.33v) fixed the stumble.

 

0.33 is too low IMO you need to find a voltage around 0.38v to 0.42 volts. the exact voltage will depend on your base fuel maps and whether or not you get any hiccups or stumbles on transition/o2 clamp switch on/off...ive got mine set to 0.38 at the moment too