Standard Audi 90 and Couple 7A Exhaust info please

[RS2]

Hi,

In an attempt to get rid of a horrible drone that my 7A produces in my VW Transporter Tristar, I'm trying to find photos and info on original Audi Exhaust systems.

Does anyone have photo or even an original exhaust system kicking around from either an Audi 90 20v or Coupe 20v?

Thanks

MG

[Bowie69]

Starts with:



Into the Cat:



Then into middle box:



And finally over the rear axle into the back box:



These are all Coupe parts, but the 90 is pretty similar to be honest. Pipe size at join between cat and middle section is 65mm IIRC.

There is an option to have a cast manifold, these are a little quieter than the bag of snakes, but do tend to crack quite happily.... but once you get to the cat the system is the same as the earlier one.

What system do you have on it at the moment?

[RS2]

Ok thanks,

My engine came with the later cast manifold and I've fitted the earlier bag-o-snakes header.

Did the earlier engines (that came with the bag-o-snakes header) have cats also or was this just the later cars?

I was expecting a long centre box just after the downpipe.

*typing one handed as my little finger is surrogate feeding until 'Mum' gets home*

MG

[Jamin]

My 90 20v is one of the earliest and has the tubular manifold and cat system like Bowie69 posted.

[RS2]

My 90 20v is one of the earliest and has the tubular manifold and cat system like Bowie69 posted.

Ok that's good info, thank you.

So I'm probably looking to create a three silencer system to get it quiet!

Do any of your cars have the 5 cylinder drone at 2,000-2,500 rpm?

MG

[Bowie69]

Yes, it is all coupe's that had a cat., from the cat-manifold downpipe flange back I believe they are identical systems.

The coupe is only 2 boxes, one big central one and the big rear box -the cat does little/almost nothing in keeping the noise down.

My middle box is pretty much toast I think, most of the baffles have disappeared inside I reckon, but then it is 23 years old, and I can't really complain. It does resonate here for me too, but as I say it's not exactly 'fresh'.

What have you got at the moment?

The other option is to take it to a custom exhaust shop and say 'make it quiet' and they will, for surprisingly little actually, certainly less than a new genuine Audi middle section(!).

[RS2]

I currently have the bag-o-snakes, then a one off downpipe going to 3 inch followed by 2 chambered 3 inch silencers.

It was built out of what I had left from other projects rather than planning this exact spec.

I am limited to some extent as to what I can do as the van is rear engined so you have to be 'creative' with where the exhaust can go. Also, I'll be converting it to 4WD and off-roading it later in the year so the exhaust can't just hang underneath the van. It has to be tucked up out of the way.

http://www.thesamba.com/vw/forum/viewtopic.php?t=530085&postdays=0&postorder=asc&start=0

When the van was too low.. the exhaust was waaaaaaaay too low



I've added another silencer since the above photos.











The Tristar.



I'm looking at the 034 motorsport tuning bits for it at present.

MG

[_ShurikeN]

Pipe size at join between cat and middle section is 65mm IIRC.

Is it outer diameter? I wonder why OEM catalog says that connection clamp is 60mm. Inner diameter meant?

[Bowie69]

Got a clamp in my hands, says 60.5 on it, so IDRC

[SA BOY]

You'll need to go more freeflow on the exhaust to get any real benefit from the 20v, go forward and then out the back like the SA vans do. Nev.

[RS2]

I think that I'll probably re-hash the exhaust at some point in the future.

This will involve cutting off the factory flange so that a) I can move the whole system further up and have more clearance and b) I can have a slightly larger diameter flange to start off with.

It should only mean moving the flange up by an inch but that will mean moving the lambda sensor as it's very close to the factory flange.

I'm probably looking at 2.75" (70mm) as this should free up the exhaust enough while still providing enough enough back pressure and sound deadening.

I may look at a different routing if possible but with off-roading in mind, this won't be easy.

I would like to borrow a completely standard exhaust to see just how much quieter it is.

MG

[SA BOY]

Been looking at your samba build you not scared of work! Exhaust system can be nicely tucked away doing it the SA way, I've got a complete system here, can get some pics if you need. Has only 2 silencers and is very quiet maybee too quiet.

[RS2]

Been looking at your samba build you not scared of work! Exhaust system can be nicely tucked away doing it the SA way, I've got a complete system here, can get some pics if you need. Has only 2 silencers and is very quiet maybe too quiet.

Thanks Nev.

The only issue with the SA setup is that it runs under the van. I'd rip it off when off-roading so I can't really have it. I'd be interested to see how quiet it is though. I'll have a look when I pop in next

MG

[UrS4boy]

...Do any of your cars have the 5 cylinder drone at 2,000-2,500 rpm? MG

I can't speak for the B3/B4 chassis I-5 20vt people but I know for certain that for the C4 UrS4/S6s, when people have built their own exhaust systems with out the middle muffler/resonator (or ordered the 034 exhaust system without the middle muffler/resonator), the engine drones badly in that range (or a tad higher, e.g. 60 to 70 mph on the highway). This is why the Stromung exhausts are good: Years of fine tuning the exhaust set-up using a single downpipe to a highflow cat, to a middle muffler/resonator to a final rear muffler. Eliminating that middle one just asked for the drone monster to come out.

[RS2]

I can't speak for the B3/B4 chassis I-5 20vt people but I know for certain that for the C4 UrS4/S6s, when people have built their own exhaust systems with out the middle muffler/resonator (or ordered the 034 exhaust system without the middle muffler/resonator), the engine drones badly in that range (or a tad higher, e.g. 60 to 70 mph on the highway). This is why the Stromung exhausts are good: Years of fine tuning the exhaust set-up using a single downpipe to a highflow cat, to a middle muffler/resonator to a final rear muffler. Eliminating that middle one just asked for the drone monster to come out.

Thanks, this is good info.

I could do with a degree in exhaust design/sound resonances right now

MG