Audi RS2 - exhaust cat-back recommendations

[Crasher]

Jetex still do that system, I have used in on a 3L 12v VR6 turbo Golf 2 I am slowly building with a mod to the rear silencer over tube to remove a rather excessive, unnecessary and restrictive, clearancing dent. The axle and 280mm rear brakes (yes, 280mm) are done now.

[JonRS2]

Thank you for these very helpful responses. There are two things I am not clear on.

First, If I keep the front part of the original RS2 exhaust (up to and including the original cats), get a new Y piece fitted from after the original cats and then have a new Jetex 43-H5DR cat-back fitted to that, is that likely to drone at motorway speeds?

Second, does SuperSprint not do a cat-back exhaust for the RS2? Why does it need to be turbo-back? Or would it be possible to buy the SuperSprint turbo-back system, only fit the rear cat-back part and try selling the unused SuperSprint front part? I am wanting to keep the front part of the Audi RS2 exhaust up to and including the original cats, if possible. But I don't like droning either. I am wondering how much better the Supersprint would be over the much cheaper Jetex.

[K Simmonds]

As far as I recall the Supersprint set up consists of a downpipe joining at the base to a full length system to the back of the car with a single cat and no other joints... I've fitted one once and was seriously impressed by the design and weight. It's basically an optimised system for a combination of power increase as well as no extra noise

I guess they designed it that way to do away with the somewhat over complicated duel cat and Y sections and to remove restriction as I seem to recall they dyno very well for a 2.75" system as well as weighing sod all compared to the stock Audi system which is seriously weighty.

If your existing system isn't structurally rotten I'd leave it well alone, as long as all the hangers are all solid enough I wouldn't worry about surface rust, it could easily last another 20 odd years especially if you either don't drive the car in winter or pressure wash the underside at least weekly if you do which is good practice on any older car.

If your cars been mapped then you'd gain maybe 5-10bhp BHP with the Supersprint if you were really lucky, the main improvement would be spool up time, but again the difference would be pretty marginal on a stage one (@360bhp) remap. To make the most of it the car would need to be live mapped again with it fitted which is now pretty much prohibitively expensive.

For the money the off the shelf Jetex looks hard to beat value wise and with cats should be drone free.

[JonRS2]

Thank you very much.

It looks like keeping the existing Audi RS2 exhaust would be the best / cheapest short-term option, but since the front subframe, suspension, heat shields, straps, etc are all being refreshed, it probably makes sense to refresh the corroded rear half of the exhaust with a new cat-back now too.

The Jetex does look like the best value option, but I am also looking at Supersprint - having now found Supersprint part numbers for the rear exhaust / silencer and the middle exhaust / muffler (i.e. excluding the Supersprint downpipe). If I choose those Supersprint parts, I would then need to figure out which Supersprint part would connect the Supersprint muffler / silencer to the original Audi RS2 exhaust (including original cats).

[Crasher]

What you have to bear in mind with SuperSprint is the RS2 system is made to order and the price is high BUT the quality outstanding, beyond compare.

[K Simmonds]

Thank you very much.

It looks like keeping the existing Audi RS2 exhaust would be the best / cheapest short-term option, but since the front subframe, suspension, heat shields, straps, etc are all being refreshed, it probably makes sense to refresh the corroded rear half of the exhaust with a new cat-back now too.

The Jetex does look like the best value option, but I am also looking at Supersprint - having now found Supersprint part numbers for the rear exhaust / silencer and the middle exhaust / muffler (i.e. excluding the Supersprint downpipe). If I choose those Supersprint parts, I would then need to figure out which Supersprint part would connect the Supersprint muffler / silencer to the original Audi RS2 exhaust (including original cats).

You may find the existing system cleans up fine which would obviously be the most desirable option, they're made out a grade of stainless steel that does corrode but very, very slowly, the only thing I don't like about Audi exhausts of this era is the weight. I seem to recall weighing my entire 3B system and it came in at over 50kg's which I reduced down to about 10kg's using a Jetex back box and 3" pipe, bends and flexi joint also supplied by them, I was on a serious weight saving mission with that car, got it down to 1330kg's with an 80kg me in it and 3/4's of a tank of fuel which drastically improved performance.

Anyway random 3B ramble over, back to RS2 data. The system on my car is now 31 years old and apart from a tiny area on the first box by the hanger has no serious issues and I'm perfectly happy to repair mine myself with a 1" patch, it would pass an MOT as it is but I'd like to sort it out to prevent further corrosion. The rest of the system cleans up pretty much as good as new with a wire brush

I may be wrong here but I do vaguely recall looking a data sheet online for the Supersprint I fitted and seem to recall the separate section's listed still require doing away with the twin cat set up... It's basically the same system just with a couple of joints so you'd still need to change the lot unless I'm wrong and they also do a cat back system which would suit your needs perfectly... Or a decent exhaust fabricator could adapt the rear part's of the single pipe system post cat's easily enough with a two into one section.

As Crasher say's above the quality is second to non, you really do get what you pay for. The one I installed fitted perfectly first time with brand new OE rubbers. They also sound lovely, just a little deeper note than stock and no drone at all. I know you said you'd like to keep the twin cat set up but if I was in your position I'd seriously consider fitting the entire system.

[JonRS2]

Thank you. Understood re: preference for the full Supersprint system, but I am wanting to preserve the original characteristics / DNA of the RS2 as much as is reasonably possible. Mainly because that is what I want, but in part because I think it may appeal more to others when eventually I come to sell it - whenever that may be (25 years of ownership so far and unlikely to be soon). There is then the matter of the MOT and changes to MOT legislation. If my car retains its original cats, will it pass an MOT more easily in the future than with a full Supersprint turbo-back system with HJS single cat? Does a new Supersprint turbo-back system come with all necessary certifications to sail through an MOT when fitted to an Audi RS2? I don’t know the answer.

[K Simmonds]

I fully understand where you're coming from with wanting to retain the car as close to stock as possible as that's pretty much the same goal I have with my example, hence me patching the original system. I do all my own work apart from ECU mapping so don't mind spending extra time fixing things a lot garages would simply replace. My example was tuned by MTM with a flowed head and much larger turbo from new under warrenty from Audi and I never want to change anything about the car, I don't intend to ever sell it but still want to retain as much originality as possible just in case I have to...

But to answer your question regarding the MOT any car registered after late 1992 simply has to have a catalytic converter or if you're cheeky even something that looks like a cat will do. As long as the car passes the emissions test it's entirely up to you what exhaust is fitted as long as it's safely supported preferably on the original hangers and has said cat... We're quite lucky in the UK as parts don't have to be TUV approved like in Germany or some of the other EU country's so we have the freedom to do anything we want to our cars as long as it's safe.

[JayCab]

The “keep as close to stock” desire is a vote to keep the original exhaust. If you want it stock and you have a functional working genuine original exhaust that can be weld repaired well into the future…
…you’ve answered the question?

If storage is not a concern you could buy the full supersprint system and NOT fit it until the original is properly beyond repair..might be one option?

I would guess at that point the car will be long into MOT exempt classic status.

[JonRS2]

Thank you for the helpful responses.

I have been in touch with Supersprint in Italy by e-mail. They have said they are about to introduce a cat-back exhaust for the Audi RS2. The parts are ready and in stock at Supersprint. They have not decided the price yet. It will appear on the Supersprint website when available.

So, my plan is to defer my exhaust decision until I can compare all the Supersprint v Jetex v original Audi options. Hopefully soon…

[JonRS2]

I can now see the Supersprint cat-back pack for the Audi RS2 on the Supersprint website (product code: 764030). It looks like the muffler and silencer from their sport pack or race pack plus a short connecting sleeve-pipe to connect the Supersprint muffler to the original Audi exhaust (somewhere behind the original Audi RS2 Y-pipe).

Does anyone know the outer diameter of the original Audi RS2 exhaust at this point? Does the short connecting sleeve-pipe look like it is for the S2 Avant rather than the RS2 Avant? It looks to me like a connection to a thinner pipe rather than a pipe of the same or larger diameter. Thanks

[K Simmonds]

I don't know the outer diameter of the exhaust at that point without measuring it but after the downpipe S2 and RS2 exhausts are the same diameter, so if it fit's an S2 it's also going to fit an RS2. It's only the downpipe itself that's larger than and S2, the RS2 use's different Cat's but they're interchangeable with S2 items.

I'm going to be using decat pipes from an ABY on my RS2 as my car isn't supposed to have Cat's according to the MTM spec and I can get it through an MOT without any.

[JonRS2]

Thanks very much, Kit

After a lot of thought, I have purchased the Supersprint cat-back pack 764030. It comprises a new sleeve-pipe (no part number yet), muffler (764003) and silencer (764006).

Supersprint have told me the dimensions for their new sleeve-pipe (to connect between the exit from the original Audi RS2 Y-pipe (i.e. the exit from the "right intermediate pipe") and the entrance to the Supersprint muffler 764003) are: 130mm length; 65mm entrance diameter; 70mm exit diameter.

Fingers crossed that it all fits.

[Tractor Dave]

I think you have chosen wisely. Post some pics when it arrives

[rustybullethole]

Hi JonRS2, I have a full cat back original RS2 system, if youre interested? Its not new but appears to be in fairly good condition