I want to install an airfuel meter but am having some trouble with a few decisions. I know the audis use wideband AF sensors and most AF gauges are narrow band and trying to splice in the gauge doesnt have good results. Ideas around this?

There is also the option of having a dedicated o2 sensor welded in but I am concerned that it might not give truely accurate readings if only 1 pipe is being monitered. I dont know if it matters because the air is mixed in the y pipe before being combusted. For diagnostic reasons, I am thinking about installing a dedicated sensor for each side, thinking it would give me an idea of how the combustion of each side is progressing. Perhaps just a supremely over thought way to find bad coil packs lol.

I am planning on install the glowshift combo boost and AF gauge if only 1 pipe needs to be checked. Am thinking about a triple column pod with boost in the middle and each bank on a side. Honestly, I am at work and I have nothing to do but think about this ****, so I apologize if I sound like the mad scientist

 

Are you talking about aftermarket o2 gauges? If so, most are wideband. Not much sense in reading a narrowband sensor since it only really gives you rich vs lean condition, rather than an actual a/f ratio. Aftermarket a/f readers come with their own wideband sensors which is really the only way to go.

also "the air is mixed in the y pipe before being combusted." im not sure what youre talking about here, there is no combustion going on in the exhaust.

 

The fuel is added to the air just ahead of the intake valves and that works on a per cylinder basis. To be the most accurate, you would have a wideband sensor and gauge on each cylinder, which would let you know how each cylinder was performing and would let you know if an individual injector was having issues. Next most accurate would be one per side. Lastly, one on one side. If I were going to the trouble of removing the downpipes to weld in additional O2 sensor bungs, I would do one on each side and gut the pre-cats while I was at it.

Bob

 

also "the air is mixed in the y pipe before being combusted." im not sure what youre talking about here, there is no combustion going on in the exhaust.[/QUOTE]

What I meant was that each cylinder bank is fed from the same air source. Other crazy mods I've thought up include repiping the intake so that each bank has its own intake. The idea being to reduce effort needed for the engine to pull air into the cylinders.

As far as a/f gauges, yes I know there are a great many aftermarket wideband options, but I don't think I really need that much info. I trust the ECU to make the right decisions about the mixture, I just want to keep an eye on the rich/lean status of the exhaust for early problem detection. I dont see the need to spend 200 bucks to know the mixture stoichiometry if I don't plan on any radical mods. Maybe if when I do the k04 upgrade, but for now its a restore and rebuilt sort of operation. I was everything nice and proper before I move to upgrades.

 

and to bob, I agree its a compromise between absolute accuracy and ease of implementation. There is a muffler shop here that has done some crazy work on some serious cars. www.hanksvillehotrods.com I have been considering an exhaust that merges the 2 downpipes into a large (3 or 3.5 inch) straight pipe with a single cat and muffler before splitting back near the read to keep the same stock look on the tips.

As far as gutting the precats I have now... its on my to do list