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Anyone know if there is a downpipe and cat option that fits the std Exchaust? The CAT back option seems to be a waste of money by all accounts.

So far I have found

APR and Miltek options both around 1500+...any others?

Rgds

K

Hi, Only if you have the Cats back on its own
If you go for new downpipes and cats it is adviseable to have the larger rear pipework to increase gas flow, other wise ointless changing the down pipes

Don tbe tight!

Bushy

Now I'm not tight but 2K for an exhaust....! I can buy a whole car for that sort of money.

wot about a stock RS4 pipe?

K

Now I'm not tight but 2K for an exhaust....! I can buy a whole car for that sort of money

You obviusly haven't asked how much to fit it yet......hahahahhahahaha

I don't know if the CAT back option is that much of a waste of money. With MTM chipping it gives you another 15 bhp. It also seems to allow the car to rev/breath easier and sounds a little bit fruity. This extra 15 bhp and fruitiness costs and extra £535 fitted.

I agree that after that (i.e. with the sport cats) the power increases do cost increasingly more money - sort of exponential, negative returns.

As regards other options, there are some people who hand make exhausts.

Hand made route is attractive option, get exactly what you want and can't be more than 2K surely, plus VAT plus fitting for Jeff's amusement can it?

Have a look at:

www.tubetorque.co.uk

Haven't used them myself, but I met somebody who did and he seem to like them.

[quote="BlackShadow"]I don't know if the CAT back option is that much of a waste of money. With MTM chipping it gives you another 15 bhp. It also seems to allow the car to rev/breath easier and sounds a little bit fruity. This extra 15 bhp and fruitiness costs and extra £535 fitted.

I agree that after that (i.e. with the sport cats) the power increases do cost increasingly more money - sort of exponential, negative returns.quote]

I don't know if any of you read my post last year when I called Millteck about buying their CAT back option for my AMD chipped S4. In short I said I take it if and only if after a before and after dyno run I noticed at least a 5bhp improvement after much discussion they bottled it saying they couldn't accept a used exhaust. Now this was going to be bought, fitted and tested by one of their distributers. - NOW THAT'S CONFIDENCE IN YOUR product!!

CAT BACK = BS IMHO - Full System or nothing

Patrick, the cat-back system might not give any wild peak HP figures, but surely it will reduce back-pressure and thus have some effect. It's been said before, peak HP isn't everything, the cat-back *could* make +15lb/ft torque and +15bhp lower down the range (where it counts IMHO), but we all seem so hung up on peak figures.

Plus, you don't seem to get any discount for buying a full system, so buying a cat-back is a good 'deposit' towards the full system .... oh, and the noise they make is schweeeet

Nige,

I agree with you about the back pressure point. I always thought that's exactly what the CAT back system was about. After having some problems with the spot welds that held my S4 middle box together I decided to cut open the middle box and seal welded it properly. The design of the mid box offers little obstruction to exhaust gases and certainly nothing like that generated by the 4 CATs upstream of it. (2 primary CATs at the turbos and 2 main CATs under the car)

In over two years of surfing Audi sites I've yet to see/read any decent before and after CAT back dynos. I know over on Audi world one of the main contributors did some kind of hand held type dyno run which resulted in quite frankly dubiously high results.

Don't get me wrong this all the ramblings of a man who has never had a Millteck etc. So I can't give a true hands on report. I wanted a Millteck CAT back and was prepared to buy one but having talked to Star Performance who sells them and after having my car dynoed Jim thought I wouldn't benefit from a CAT back but I still wanted one that's when I decided to contact Milteck directly. I promised to promote the results on this site and Audi-sport.net and even offer myself as a customer reference. From day one, Miltecks story on the development of the CAT back exhaust was at best incomplete. They weren't sure who they used to develop their exhaust, it could have been a German tuner or a UK one. They didn't use or have any qualified fluids/engine design engineers not that that means very much) They weren't sure what typical gains I could expect. They just told me to refer to Scot at AMD as "he raves about them." I told him I know that as my car was AMD tuned and Scot tried to persuade me to buy one at the time!

Even more disappointing was the result from one of the Audi-sport.net lad's S3 when he went for a full Milteck system and got 3bhp more. Not sure what it did overall to the cars performance but he was understandably disappointed.

The thing about exhausts and air filters that make the car sound noisier is that IMHO you think your car is more powerful.

If I knew how to do it I could start a poll to gauge the experience of CAT back folks. I'm sure there have been a few hundred fitted.