Wideband lambda delay?

Hi everyone! I have heard that using a sniffer type lambda with vacuum pump is worse than using o2 inserted directly to exhaust pipe in terms of time delay. Is it true?

What's better to use mechanical vacuum pump or based on venturi effect compressed air pump?

You can measure the time delay at a given RPM if your wideband is connected to your ECU, and you can do live tuning. Just change the fueling by 10% and either in your logged data, or your live screen (if you can stop and zoom in), note the time required for the Lambda to change by the same 10%.

Personally I don't think it matters, you can only use tailpipe sniffers when there is sufficient exhaust flow (so not useful for idle tuning), and then both system are probably adequate.

I read a good article about that comparison long time ago and Indeed there was some delay in displaying but it was very minor - something that can be disregarded on average tune.

As far as vacuum pump goes- it should not be usee on SD systems as it may effect on the tune if it is not working in closed loop throughout the entire fuel table.