Dual Wideband/O2..

[ericburnby]

How do I use VEMS on a V8 engine where I have dual exhaust? Can VEMS use 2 widebands? How can I monitor the A/F bank to bank since VEMS only has a single wideband? Do I need to get an external wideband and assign it to one of the other input channels?

[mattias]

There was once provisions to use dual wideband sensors, it won't happen with the current hardware any more.

If you suspect any difference in combustion between the two banks, just move the sensor between banks and compare the signal between  pulls performed under the same conditions.  On an engine which is highly tuned and maintained properly it shouldn't be required to monitor the two banks, anyway it's up to you as a human to watch the two signals and compare to see any potential problems - and that is the biggest problem because we're usually quite busy driving and forgetful.

If you just want to rest your eyes on a gauge to watch lambda, by all means - get a VEMS round with an extra sensor. Or whatever equivalent product you fancy.

[ericburnby]

This is for a customer who isn't going to be monitoring much of anything - they just want to drive the car (regularly) and not have to worry.

I'm just worried about having the wideband in one bank, and having something go wrong with the other bank (fuel supply issues, for example) and the ECU wouldn't even know to make corrections. So the bank with the wideband would have the correct A/F, but the other bank could be running lean.

[gunni]

When you looking at each bank then who knows if one injector fails and then the others will start to run rich to compensate the mixture.
So ideally you´d monitor each cylinder.

The wideband should only have a slight adjustment range anyway, as the sensor can fail and lead to the same over rich or overlean situation.

I´d say to tune it, run closed loop on one side for overall compensation. And if the customer feels any irregularities to have it checked.

[GintsK]

It is possible to configure VEMS WBO2 (aka Round) so: on top you see one bank (passive - directly from sensor) on bottom - lambda transferred from VEMS unit by serial datalink.

Again in newest firmwares it is possible to feed analoge signal from passive WBO2 unit (Round) and convert this signal to lambda or AFR. Thought - it would be usable just for datalogging, not for closed loop control.

Gints

[fphil]

Hello everybody

This is an old topic which coul be re-opened following what is announced with the 1.1.98 firmware version:
"both WBO2 channels are displayed in VemsTune (and captured in vemslog).
 - when ordering assembled controller, request in order comment that both WBO2 channels are tested (otherwise some pins like heater2 might be used for other functions, like analog input channel)"

Because my biturbo engine has 2 banks, last week I plugged two sensors, one on each exhaust pipe, and I am puzzled because I did not understand what this announcement means in practice.
Indeed I do not see in the 2011.11.15 VT version any reference to any 2nd wideband channel and the actual controller data sheet says nothing about possible dual sensor.

I hope that some one from the forum has some insight about this issue ! ....

Philippe

[rob@vems.co.uk]

I guess its their announcement that there's the option on new VEMS units to drive a second wideband.
It may be possible to modify your system to work with the new firmware, but that will require some help from one of the development team...

[GintsK]

PCB has second WBO2 circuits from beginning. Some parts may be missing. On my latest boards - two resistors from first look. Statement why second channel will never be implemented was some microcontroller related details.

Now  we have supprise.
BTW 1.1.98 with 2011.11.15 VT seems has some traction control capabilities, but as Philippe wrote - no any mention for second WBO2...
Mattias? Emil?

[Kamuto]

PCB has second WBO2 circuits from beginning. Some parts may be missing. On my latest boards - two resistors from first look. Statement why second channel will never be implemented was some microcontroller related details.

Now  we have supprise.
BTW 1.1.98 with 2011.11.15 VT seems has some traction control capabilities, but as Philippe wrote - no any mention for second WBO2...
Mattias? Emil?

maybe you know when 1.1.99 will be launched?