The wide band is the precat 02 sensor on the 2001+ cars.

If adding a wide band gauge then the answer is yes you will have to add a 3rd 02 sensor to your down pipe. You can not splice into a wide band 02 sensor to use it for 2 different things.
This is why wide band gauges are sold with its own 02 sensor.

 

ill take your word on that Mike cuz your like the A4 Guru.. but that makes no sense at all.. all the gauge does is read what the sensor is putting out just like the non wide-band does.. and you can splice into it... so why cant you do the same with a wide band.. i dont see how it would make any difference.. and 200$ for the kit is ridiculess IMO.... if possible can you explain why you cant splice into a wide band O2 cuz that just makes no sense to me... and i would use VAG com. but i cant get the stupid program to work right to save my life.. i can get it to reset the radio but thats it.. with a CEL on and i run it and nothing comes back as being wrong.. i have a feeling im just gonna end up paying the 200$ to take my car to this place in MD about 2-hrs from my house and having them tune it and be done with it..

and another thing.. if the non wide band O2 sensors are for NA cars then why the hell are they on our cars? cuz that would mean they are pointless on our cars all together.. would it not??

i love how this car makes ZERO sense

 

The wide band gauge setups are $200 because there is way more to them then just a simple 3 wire gauge setup.

The DB innovate setup includes the digital gauge, an LC-1 wideband controller, bosch wide band oxygen sensor, bung, and the award-winning LogWorks engine-tuning software.
http://www.innovatemotorsports.com/products/db.php

So as you can see it is way more then just a blinking gauge that just says lean or rich.


Ok it seems you didn't ready my post. I said the narrow band 02 "gauges" are not designed for our cars and this is because during WOT the 02 sensor in your A4 1.8t is not used by the ECU to adjust fueling at WOT. It is only used during idle and part throttle. The wide band cars use the wide band 02 sensor 100% of the time which includes WOT.

You can use the Vagcom to look at AFR readings on block 031, but they are not going to be all that accurate. Narrow band 02 sensors only use a 0-1 volt signal, while the wide bands uses a 0-5 volt signal. The Narrow band 02 sensors are only really good when the car is running at 14.7:1 and this is why the ECU stops using the input signal once you go WOT.

Now on some WB 02 sensor gauge setups they can come with a anolog output that can be used in place of the stock narrow band 02 sensor.

 

ok cool.. thanks again mike... now i understand how the thing works.. i guess ill just figure something out.. there is no way the wife is gonna let me blow 200 on a gauge.. so i dunno what ill do.. guess ill just set it at 15psi and be done with it till i get it tuned..

And CCA4 lol ill be putting pics up soon.. just waiting on the new front mount core.. i might put pics up tonight.... lol who knows.

 

Ok well Idk if I'm supposed to tag into threads but I've an 01 1.8tqm iv got a k04-15, tt225 injectors, 3" turbo back exhaust, "ghetto intake", and sikky intake manifold gasket . My boost is completely uncontrollable with n75 my boost spikes and surges crazilee boosting and then dropping pressure I've used different n75 valves and gotten the same results I put an mbc on and now I only get 11psi max and I'm chipped uni stage 2 with my homemade mbc and n75 ran online together I had consistent 15psi I've checked for leaks and can't find any vac or pressure someone help please

 

Car might be stuck in limp mode.

 

Other than soft limp mode wouldn't that throw the cel on and I have boost it just doesn't ever do what I want it to do which is 18-22 psi I get ten now with a turboxs mbc cranked all the way up n75 gets me 17 max but it surges and spikes terribly and is generally very inconsistent. I hold pressure so no leaks and my vacuum at idle is like 17.5 in hg could it be my software???