Pre-Cat delete O2 sensor mod

[theeld]

I have read conflicting reports on where to place spacers when gutting only the pre-cat and maintaing the main cat in its stock form. I have nailed down that a CEL can be avoided by the application of o2 spacers applied in pairs on each set of downpipes. However when only gutting precat where do the spacers go, in the pre-cat o2 sensor position or the main cat sensor position? a definitive answer would be much appreciated as my Audi is in pieces in the garage.

[Justincredible]

To fix the CEL and need no spacers. relocate the rear 02 bungs to just behind the main cat. Or put the spacers in the rear 02 sensor spot if your not going to relocate the bungs.

[beemercer]

To fix the CEL and need no spacers. relocate the rear 02 bungs to just behind the main cat. Or put the spacers in the rear 02 sensor spot if your not going to relocate the bungs.

Exactly. If you can't weld just get the spacers.

[buffalony]

link tp spacers

[joeycuccaro]

http://vastperformance.com/shop/prod...products_id=68

[dylanbike1]

I went with a cheaper option: http://cgi.ebay.com/ebaymotors/O2-SE...Q5fCarQ5fParts

Using these it caused the back side of the O2 sensor to be almost rubbing the other O2 sensor. Since the stock DPs have a little play- you can wiggle them around enough to avoid any problems. 4 months of "driving like i stole it" and no CEL. They seem like nice build quality too... Just make sure you put some anti-seize on the threads in case you ever have to remove them.

[fitzisboss]

I went with a cheaper option: http://cgi.ebay.com/ebaymotors/O2-SE...Q5fCarQ5fParts

Those work great for so cheap

[dylanbike1]

I went with a cheaper option: http://cgi.ebay.com/ebaymotors/O2-SE...Q5fCarQ5fParts

Using these it caused the back side of the O2 sensor to be almost rubbing the other O2 sensor. Since the stock DPs have a little play- you can wiggle them around enough to avoid any problems. 4 months of "driving like i stole it" and no CEL. They seem like nice build quality too... Just make sure you put some anti-seize on the threads in case you ever have to remove them.

[SquiddyB6S4]

Right angle O2 spacers FTW.

[madkimchi]

I went with a cheaper option: http://cgi.ebay.com/ebaymotors/O2-SE...Q5fCarQ5fParts

i used two of these too and no CEL and works like a charm.

[jfunkey]

The right angle ones from time to time cause lean codes

[SquiddyB6S4]

http://www.bigdaddiesgarage.com/angled-cel-fix.html

I haven't had any problems with mine. The only way I could see that happening is if you had insufficient flow, but maybe with a 350bhp V8 there's plenty enough flow? Or maybe I'm just lucky. But they sure do fit a lot better; I tried the two cheap stacked spacers way and the sensors were REALLY close to each other, and they didn't thread all the way in.

[Justincredible]

Some cars like the angle spacers some don't. It depends on the year of the car and the season. They work better then straight spacers fitment wise.