bertrenolds

I purchased the ebay v3 downpipes and I got j-o2 bungs and then spacer bungs, do the j spacers go on upstream or down stream o2 sensors? Also is the aes down pipe flange not perfectly square? I am looking at the new exhaust flanges and they are a weird oval shape, it says these are specifically made for aes 2.7 tiptronic engines and I have an allroad 2002 aes, I have icm's on the air box and my flanges look squared but have not taken them off yet, can anyone help? Pictures attached as well. Bringing it to a shop tomorrow to have exhaust done since I dont wanna deal with dropping the subframe and I dont wanna bring the wrong exhaust and would like to know what bungs go where.

bertrenolds

No one has a guess? Should the upstream sensors maybe have the shorter spacers since the j pipe spacers might be to much of an angle from where the upper o2 sensor threads in?

5v/cyl

Shape looks right. The oval is to accommodate the wastegate of the turbos. See the second pick in this article: AudiWorld Tech Articles
Not sure about the spacers, but I would guess the shorter go to the upstream sensors. Actually not sure why you even need the spacers. Personally I would have the downstream sensors tuned out in a performance tune of the ECU.

transman

I'm every car I've ever used the o2 spacers, I only used them for the downstream sensors. The point is for it to read a certain value to keep within parameters of catalyst efficiency. If you put the spacers on upstream sensors, you are going to possibly have a poor running car. If it came with two sets of spacers, they are most likely used so that if the shorter ones throw a CEL, you can switch to the longer ones. Hope this helps, Connor.

bertrenolds

****, so you think I shouldn't even use them on the upstream? Now would be the time to do it since I have passengers side pipe on and am about to finish the driver side. you got me thinking now since the upstream is the most important and gas millage is effected by it. also the sensor normally sits in front of the upper cat anyways but I wonder if it might throw a code since it wont be as hot with the upstream cat gone. Thanks for the reply!!!

This how to article only has him putting them on the rear o2 locations so maybe I will only do downstream then, hopefully this is right because its a bitch to do the drivers side o2 or the exhaust for that matter.

For anyone reading this and thinking about getting the V3 audi allroad exhaust kit off ebay, I would get it off amazon since its $300 it is doable and it is a bitch. I did not have to drop my subframe and I did it on jack stands and the exhaust fit perfectly. My exhaust did however fall apart at the flex pipe making the pipes easier to maneuver so if yours don't fall apart I would suggest cutting them at the flex pipe. Also its a PITA to get to both upper exhaust flange bolts but you can do it with normal tools, you just have to maneuver the heat shields in such a way to get to the inside bolts next to the tranny. I pushed both heat shields as far as possible towards the outsides of the car to create enough room. as for the top 2 bolts on both sides use the hole in the heat shields to get those. This is a pain of a job and you will probably hate life but you will be glad when it is done. my arms are cut to **** but thank god I am almost done!

transman

Ya, do not put the spacers on the upstream sensors.