A4 B7 Quattro Intermediate Pipe (Flex Pipe) Removal + Installation

[avantsline]

Has anyone here replaced the flex pipe (between the catalytic converter and center muffler) on a B7 A4 Quattro?

I am not seeing any DIY's either in written form or on YouTube videos for this procedure. Some B6 threads say that removal of the catalytic converter from the turbo is necessary as there is limited access to bolts.

Here is the pipe I'm needing to replace

https://www.ecstuning.com/b-bosal-pa...0253301ee~bol/

Not sure if this is a DIY I want to attempt or if a shop will charge a lot of labor hours. Thanks!

[Theiceman]

I did it and wrote it up.with pics
Look for threads started by me

Sent from my SM-G973W using Audizine mobile app

[Theiceman]

Basically remove o2 sensors drop cat and flex pipe together.
One nut on the turbo is a bit of a pain but very doable with the right tools..

Sent from my SM-G973W using Audizine mobile app

[Jay-Bee]

Basically remove o2 sensors drop cat and flex pipe together.
One nut on the turbo is a bit of a pain but very doable with the right tools..

Sent from my SM-G973W using Audizine mobile app

Did mine like that as well, unbolt at turbo and sleeve clamp and the one hanger spring/bolt midway and pull and snake it out as one piece then separate it. Pretty tight on tiptronic but doable on ramps with basic tools.

My Bosal pipe wasn't perfect, over sized flange and what looked like high school shop class splatter welds but hey it's holding up for the price.

[Theiceman]

Lol that's what I got too..
75 bucks but is still fine 3 years later.
And who cAres really

Sent from my SM-G973W using Audizine mobile app

[avantsline]

Thanks for the replies! Has anyone removed the pipe without removing the cat?

Interestingly enough, the ECS tuning install instruction for their high flow cat and Downpipe describes removal of this pipe first, then the cat. Basically they're showing the pipe *can* be removed without removing the cat from the turbo.

Here's a link to that instruction PDF:

http://bd8ba3c866c8cbc330ab-7b26c6f3...stallation.pdf

[Mke07]

I've done it without removing the cat (on a b6) but should be similar here. You'll need lots of extentions, u joint sockets, and lots and lots of patience. The one's at 12 and 5 o'clock aren't too crazy, but the one at 7 o'clock is very hard to see and get to. It helps a lot if you have a person up top assisting while you snake the extensions up from below. I'll add this was on a manual so unsure if there's enough room on the auto's for this method.

[avantsline]

Thanks everyone for the replies. Still hoping more gurus will chime in and confirm if the cat needs to be removed or not for this job. Any techs here have access to factory Audi service manual?

What do you guys use to see workshop procedures and labor hours for these cars?

[Theiceman]

theoretically it can be done if everything from the cat to the down pipe is not fused with heat and rust ....


by the time you do it that way , you will already be in having a beer or two if you just dropped the whole assembly.

the gurs ARE chiming in, but do what you wish .

[Mke07]

I agree it's more time consuming but been done that way by tons of people tons of times. Even the ecs diy shows it as such. But for the op if you drop the whole assembly you'll need a new turbo to cat gasket and i would get new nuts as well. Also dont over-torque the nuts, if you snap a stud off the turbo it'll become a headache.

[Mke07]

Actually i don't agree it's more time consuming. Dropping the whole thing is still a pita. I would just hit the bolts with pb blaster for a few days before doing the work and run the car in between. The heat and penetrating oil can work wonders. If it's still frozen then dropping the whole thing would be plan b tbh.

[griga]

Actually i don't agree it's more time consuming. Dropping the whole thing is still a pita. I would just hit the bolts with pb blaster for a few days before doing the work and run the car in between. The heat and penetrating oil can work wonders. If it's still frozen then dropping the whole thing would be plan b tbh.

The ECS DIY is for a manual downpipe, the link to the one he is buying is automatic. On an automatic car it is MUCH easier to just drop everything.

[Mke07]

The ECS DIY is for a manual downpipe, the link to the one he is buying is automatic. On an automatic car it is MUCH easier to just drop everything.

Good info. Only done manuals as i stated. Will be tackling this job this weekend so will keep in mind.

[Okedokey]

Get new hardware trust me and soak those bolts overnight in penetrating oil. Make sure car is cool, makes it so much easier.

[avantsline]

Thanks all for the replies. You guys are the gurus, respect!

So where the Downpipe bolts to the middle of the car with the clamp, will the exhaust move enough to slip it off without unbolting any other muffler hangers?

Or does the exhaust hanger need to be removed so it can move enough to slip the flex pipe off where it clamps, a few inches.

Edit:

I also meant to ask, since the cat has to be removed, who is recommending the high flow cat upgrade like the 034 motorsports cat? "While you're in there"...

[Okedokey]

+1 for 034 HFC, very nice, throaty tone, pedal response is immediately improved

[krewbrew]

Love the 034 HFC. Opens up the turbo and sounds good. .The downpipe can be removed by sliding the middle clamp back, no need to drop more of the exhaust.

[avantsline]

Love the 034 HFC. Opens up the turbo and sounds good. .The downpipe can be removed by sliding the middle clamp back, no need to drop more of the exhaust.

Thanks for the reply and verifying about the clamp! I will hit everything with the horrible smelling PB Blaster and let it begin doing its job.

[Plxa4q7]

Definitely remove heat shield above cat...doesn’t look like it makes more room but it makes a huge difference. Cat and downpipe can be pulled out through engine bay

[rfelker]

really not that hard. Did it on the b6 every year for emissions. Take both cat and downpipe off. those 3 lower bolts on the flange probably wont come off will need to be cut.
Just remember your going to need a new clamp for the bottom section. I use a floor jack to put that on. Also mark with paint pen so each side is even. hardest part is getting the bolts back on. I JB welded all my bolts because its a bitch getting rachet etc in those tight spots. will need long extension for the 2 bolts on the cat and will need to be done from bottom of car.

If you can have the car down for awhile and going to run a tune. Replace the cat now with HFC.(get a 02 spacer for the HFC going to get check engine light without it) Also send the downpipe back and get something in 2.5/3inch. Most of your gains are going to be with the HFC and downpipe the rest of exhaust is just for sound. You could also take the downpipe you have now use it as a template and have a custom shop build you a 3inch downpipe. thats what I did because they don't make bigger pipes for FWD 6 speeds. Can get all the parts to make the downpipe from 42draftdesigns.com.

[avantsline]

Thanks rfelker for the reply. I will begin this project today up on ramps in the driveway, PB blast several times to loosen everything up. I do have a replacement factory exhaust clamp. My biggest reservation is getting the car stuck in the driveway and needing a torch to get the job moving forward.

The hfc sounds tempting but my main car is a 335i which has double the power of the A4 which is my around-town car at the moment. Not sure I can justify the cost!

[rfelker]

how did it go?

[jgride]

theoretically it can be done if everything from the cat to the down pipe is not fused with heat and rust ....


by the time you do it that way , you will already be in having a beer or two if you just dropped the whole assembly.

the gurs ARE chiming in, but do what you wish .

LMAO!! That's exactly what I was thinking but.........I guess he's not hearing what he wants!

[Mke07]

See this here is the problem with attitudes around here. Everyone knows it all. I got this job done this last weekend and was thinking of doing a write up on the 2.5" piping i used so those with tiptronics who are interested could upgrade for a reasonable price, but some are happy running shitty aftermarket junk like the bosal pipe etc so have at it i guess.

[Okedokey]

See this here is the problem with attitudes around here. Everyone knows it all. I got this job done this last weekend and was thinking of doing a write up on the 2.5" piping i used so those with tiptronics who are interested could upgrade for a reasonable price, but some are happy running shitty aftermarket junk like the bosal pipe etc so have at it i guess.

who/what you referring to?

[avantsline]

how did it go?

Car is in the driveway, haven't began work yet. Busy with the fam during this corona! Stay safe everyone.

[avantsline]

hey guys, I uploaded a video about the car. Since most of us are stuck inside lately this might provide a few minutes of much needed entertainment



direct link: https://youtu.be/6Ao7l6qJUQM