Hi all,

Got the following information off the http://www.18turbo.com website:

"Downpipes are a direct replacement of the stock downpipe to the catalytic converter. The theory behind a larger downpipe is much like that of a performance exhaust system, better flow. The factory downpipe is quite restrictive, therefore the addition of a larger downpipe will add approximately 8-10HP. Not only will a downpipe increase power output but it will also help the turbo spool up faster. There are two sizes of downpipes available 2.5" and 3". There is much debate over which is better, but it can be assumed that when used with the stock ko3 turbo the 2.5" is great, but for any larger turbos you should use the 3" system for peak performance. Note however that many people have used a 3" downpipe and cat mated to a 2.5" cat-back with excellent gains. It all depends on what your plans are and how deep your wallet is!"

Any thoughts on this one also does anyone know where or who does a 3 inch downpipe for the RS?

Cheers

Lloyd

I heard/read somewhere that a 3" DP would need stronger engine mounts. As there is not much room under there and with the engine moving all over the place under load, it can apparently knock the pipe lose!

Impossible Performance do a 3'' dp and sports cat.

the manifold is the biggest restriction... but if you do change it you will need a new turbo as it will flow that well the k03 will drive itself to bits....

Lloyd,

I believe you have an AmD "K04" which, I think, is more or less the same as the K03S already in the RS.......not to be confused with the K04 in the TT.

I have a custom 3" DP on my RS..

Correct SkodiRS I have the KKK (K04) turbo so does this mean I can have the 3" downpipe installed on my RS?

Lloyd

Must be pretty tight with a 3" DP -- It's already tight with 2.5" Milltek DP - I had to adjust heatshield to get enough clearnace,and will probably have to do a bit more.

Sorry Lloyd I don't know...Paul is probably right though.

Your turbo is basically the same as the K03S which is essentially why you get the same output as a remapped RS. If you had the K04 from a TT you should have expected at least 260+bhp. It would be totally worth while in this case.

Also if you had the 3'' dp and sports cat would then have to have a 3'' system made up (H&S?). If you connected a 2.5'' system to a 3'' dp/sports cat would you be nullifying (is this a word?) the gains from the dp i.e. big bore to a smaller bore?

Sorry that I haven't an answer for you and raised a couple more.

Cheers.

Adrian.

changing the downpipe is no prob.. the dowen pipe is not the manifold... using a high flow manifold can make the turbo flow too much air (not sure exactly how much is toomuch...)

Correct me if i'm wrong here but isn't the down pipe and the cat all one unit, if so how (and why) do you fit a bigger down pipe to the OE cat?

Des

u dont u lose the pussy

Originally posted by ffelan in this post

u dont u lose the pussy

Thought so, just misunderstood Lloyds opening lines.

Lloyd

IP do a Direct replacement De-cat/Down pipe for Octy (still not on web page).

Des

So it's possible to mate a 3" downpipe to the 2.5" exshaust system?

Des what is the price is the downpipe from IP?

Lloyd

I have 3" from the turbo to the cat. thereafter 2.5"

Hi Turbo2,

Have you noticed any differences in performance with the 3" downpipe?

Lloyd

Originally posted by llblake in this post

So it's possible to mate a 3" downpipe to the 2.5" exshaust system?

Des what is the price is the downpipe from IP?

Lloyd

Lloyd

Yes the downpipe is from IP, don't know the cost you will have to speak to Mike at IP, it's OK he doesn't bite.

The downpipe you refer to is better known as a de-cat pipe, I think this is what your after. Once fitted it will give you better throttle response and more torque you will defo feel the difference.

Des

Originally posted by DGW in this post

So it replaces the exhaust pipe with catalyst? Does that mean no catalyst - and no MOT pass idc?

Correct!

Hence I haven't done it.

or go milltek and keep a sports cat and pass the mot....

you dont have to use the back box... not sure how much bhp diff there.. guess me/jon/des need to meet up on the same rr on the same day to find out....

Originally posted by ffelan in this post

or go milltek and keep a sports cat and pass the mot....

you dont have to use the back box... not sure how much bhp diff there.. guess me/jon/des need to meet up on the same rr on the same day to find out....

Paul

Got the Milltek sports cat and exhaust but it's not as free flowing as a De-cat system IMHO.

Des

Don't think a 3" down pipe to cat or to 2.5" exhaust would make any diff. either.

Des

what about milltek dp with powerflow back?

is the cat the prob or the back half?

Originally posted by ffelan in this post

what about milltek dp with powerflow back?

is the cat the prob or the back half?

It's the cat thats the problem. The Milltek Sports cat is rated at 200 as apposed to 400 for the standard/OE cat, don't suppose the two boxes help either.

Des

I suppose the perfect world would be 3" pipe from turbo to back bumper, no cat, no boxes = lots of noise, lots gangs and lots of flames...........uum.

Des

So you liked my exhaust then Des