Hey Guys,
I wanted to know how hard would it be to remove the downpipes on my Audi a6 3.0 fwd? The ultimate goal to gut the precat and the main cat. The set up is very similar to the b6 s4 and I just feel like they are causing a major power loss in the 3.0’s. Anyone have thoughts on this?
there is a downpipe specific discussion thread in this section. Check it out. I believe CountVohn said he was going to put together a video of DP removal once he figures out the best way.
A video would be great, cause i found it to be the biggest PITA
A little update on this.
I am making a video its already been shot. I have to go back and grab a few more clips and some more pictures. I think after I edit it you guys will feel comfortable doing this.
To make it more real I didn’t use a hoist. I did it on the ground in my garage as many of you will be doing.
I have to replace an o2 sensor so this should help me out big time. Thanks count!
Awesome work count…
Scale of 1 to 10 how hard and how painful did you find it. Also did you have the entire car on stands or just the front
You’re gonna want the whole car on jack stands, but the rear is easy to jack up as you can just use the nub on the rear diff as your jack point to bring the whole back end up at once.
I’m gonna say based on the S4 DP removal, the most difficult aspects are:
A)getting the right angle/extensions/etc to get the socket on the bolt (which is just something to play around with that you’ll get eventually)
B)PRAYING that you don’t break a stud. I don’t know how the studs are designed on the A4, but the S4 they’re pretty shitty. We have 3 8mm studs, Jason from JHM was telling me how the B5 S4 had 4 10mm Studs and how much better that was b/c you almost never had to worry about breaking a stud.
C)Plenty of penetrant spray and time. It’s almost guaranteed that the studs haven’t been touched before, and if you have a high mileage car that’s seen salt before, then this is where part B really becomes a truth. So it’s important to soak the bolts, then come back, soak some more, then leave and come back and soak some more. I’ve heard of some guys just taking a day to soak them before ever putting a socket on them. And heat can be your friend as well.
I’m not trying to scare anyone off by any-means, I did my own, twice (I put the O2 spacer in the wrong spot after doing piggie pipes and had to pull again to swap, DOH!), but just wanted to give you some honest/realistic advice for what you could get into. A LOT of the S4 guys do this on their own, so if it was just awful you would hear more complaints about it.
Also I think Count’s Video/writeup will really help you get a better understanding. Like everything, doing it the second time is always a lot easier, so hopefully his info will make you feel like you already have a grasp for it and you’re not going into it blind.
I think A video would be very helpfull. Much more so then just a DYI with pictures.
I was reading and if my memory serves me correct. The 3.0 has just one 02 per side rather then the standard two 02’s per. This may cause issues with no cats.
Not sure sounds like the count would know more then me
well I have a 2002 and I know that I have TWO Oxygen sensors on each side and 2 cats on each side. I do not know what other models have I can only speak for my own. Maybe some other years can chime in if they know for a fact what their cars have?
Mine is '02 and has one per side??
ummm ??? … maybe we need to be more specific, I think I am a late 02? maybe I am wrong but I could of swore I have 2 becuase I just bought one from ECS tuning and turned out I didn’t need it so I ended up mailing it back and will be using the credit for hopefully a RS4 rear sway bar 
It seems the 3.0 A4 was a bit of a parts car for the Audi assembly.
Going over some dealer notes. It seems you could have gotten 1 or 2 cats per DP on some cars and it looks like 1 or 2 02’s as well.
There seems to be a bit if this and then a bit of that in the cars
Yeah that is exactly the case, My 02 A4 has 2 cats and 2 o2’s per DP and B6Joe’s A4 just had one big cat
I dont think we have been able to nail down which cars have 2 cats per DP and which ones have 2 cat per DP.
People with 1 cat per DP may want to see if they can source the secondary cat when they go catless DP’s if they are concerned about running catless.
What effect will the secondary cat have on the tune? is worth looking at getting a HFC on the secondaries
Up date. I had the pleasure of having countvohn and Justin help me remove my Dp’s. man they make it look simple. Ill let countvohn say more
Team wise. It took 3hours and only a few swear words. On my own for a first time test on my car, it took about 6hours and I was looking to strangle puppys and kittens. At one point I think I was speaking in only swear words. Im doing my best to make the video and DIY very user friendly with lots of tips. I feel that when Im done most anyone with the right tools can do this.
At some point Ill start a more dedicated thread to this.
The cat hornet and I had in our cars is huge.
http://audirevolution.net/addons/albums/images/117355872.jpg
This was the biggest issue there was and one of the reasons were going to do what ever we can to make the price of these 3.0 Dp’s so cheap that no one will have to try and put this back in.
What your looking at is a picture of how big the cat is. Even with the rear sub frame down all the way its still not enough to get this big hog through
http://audirevolution.net/addons/albums/images/683789852.jpg
daaamn that thing is freekin HUGE! So i’m guessing and hoping that the reason they switched to 2 was to have 2 smaller cats vs 1 monster??
And hopefully if thats the case it will be easier to remove the DP’s on cars with 2 since they are hopefully smaller?
And on a car with 2 cats does the exhaust on each side ever cross paths?
What i’m getting at is you know how some cars have dual exhaust but at some point in the piping it crossing into 1 which I was told defeats the purpose of having dual exhaust. So what i was wondering is if there is only 1 cat on some of the 3.0’s doesn’t that mean the exhaust gasses would at some point all have to be fed thru that 1 cat ? And then on the cars with 2 are they completly seperate assemblies or do they cross paths at some point? Sorry if this is a dumb question but I don’t know much about this stuff.
Is this just the case for TIP cars?
I thought it looked like there was decent room to get them out when I looked at them on my 6MT car
Ya the 6speeders have it much better room wise.
The Dp removal should be much easier on a 6 speed car. There is still going to be lots of work but the over all amount of work will be the same. The struggle to get the pipes out will be different.
on a good note here is more information on the Dp’s.
http://audirevolution.net/addons/albums/images/692489696.jpg
While the hogpipe (with this cat Im calling it the hogpipe) mod will deffinitly help. Still there is much room for the 2.5 aftermarket dp’s to do quite well. The stock opening that I took a picture of is less then 2in.
That is amazing how big that cat is
Count’s
http://audirevolution.net/addons/albums/images/117355872.jpg
Vs Mine
http://audirevolution.net/addons/albums/images/347679784.jpg
Is that 2 o2 sensors in you hogpipe
http://audirevolution.net/addons/albums/images/692489696.jpg
Count are you able to shed some light on the tune in terms of the cat.
For people that have the hogpipe and then get the new dp’s they will obviously have no cats, and hence very good for tune wise. What about the people that have the 2 cats per dp will the new dp’s remove both cats or just the pre cat, if it only removes the pre-cat will the secondary cat affect the tune. If so should people gut the secondary cat?
A43Zero - to answer your question, the exhaust does converge at the rear of the car. The cats are placed at the end of the exhaust manifold, some 3.0 have 2 hogpipes 1 per dp and some have 2 cats per dp. Hope this clears things up.