Custom downpipes

[Ski]

Is that a milkek spanish? will one of them fit right onto my s2 or will i need these weired peices of metal which go by the name of "flanges" and "downpipes" ?

[The Spanish]

Thats Marco full custom 3'' job.
The downpipe you cannot see it in the picture but it finishes in the Cat you can see. Thats what Marco is producing. Then you must fit a Cat, a straight pipe and a custom back box.

If you don't want a custom job these are the possibilities i see (only for coupe, avant is much easier):

1. Get a full Milltek 2,5 inch turbo back exhaust.
Favour: Is a bolt on application
Against: It is very expensive for just 2,5 inches and it has a
very strange :wacked: 1-2-1 split. (Check my thread about
Milltek downpipe and Cat)

2. Get a SuperSprint downpipe with Metal cat (70mm or 2-3/4
inches) and then www.bn-pipes.de 70mm center silencer +
back box for the coupe
Favour: Very good quality and semi-bolt on application
Against: Very expensive (Check thread about
SuperSprint)

3. (My Choice) Marco's downpipe (in 70mm) then a race cat then a
70 mm pipe wich connects it with the www.bn-pipes.de system
Favour: Good quality for medium price and an easy
installation.
Against: Still expensive (Cheaper than the Turbo back 2,5 ''
Milltek system though). I got the 70mm Center Silencer and
Back Box with a nice discount, to that add 250-300 for
downpipe and 250 for Cat

For info Bn-Pipes are based on Inglostad and they produce parts for MTM. They do have a 70mm downpipe with twin racing cats but they only sell the downpipe through MTM and because it has two cats I don't want to know the price

Cheers,
Rafael

[Pisobiker]

Hi all,

As I sayd I'll build first downpipe for Rafael (in 70 mm external = 66mm internal) as soon as I get the flanges.
Then I'll post some pictures of it including the tryal fit on my "mannequin" S2.
I'll be able to make them in many different diameters (70-76-80mm) and standard K24 (also 7200) and S2/RS2 EM + WG. Other custom applications for different EMs and Turbochargers might be possible as well, but this will eventually be evaluated afterwards.

The deal with it is to have a single pipe going back, so it will just come out of the engine bay around and under right side axlearm aluminum shield, horizontally towards the back (and with all the needed clearances with engine, gearbox, chassis, engine sub frame and whatever else). Of course I'll place a threded insert of the right dimensions and at the right position for the Lambda probe.
I was not planning to provide a threded plug for a "post turbine" EGT, because best position for it is on the EM, and also because usually each probe has its own thread dimensions, so, if needed, anyone can drill a hole and weld a SS nut of the right size.

anyway just wait for the first one, then you'll decide if it is good enaugh for your needs.



Marco

[Ski]

Spanish

miltek is 2.5 inches.. and the rest are 70mm.. which is better?

also, i dont have a garage and the knolege/equipment to do any mods to an exhaust (even fit one) so i take it my only option is to get a bolt on application or go for a custom build by some company?

[Pisobiker]

From my calculations the original S2 system Ø62mm internal is good for up to 300-310 Hp. Although original ceramic 400-450 cells catalytic converters start to be too restrictive well under that output.
OEM RS2 system with Ø66mm internal (70mm external) and OEM 200 cells metallic cats, should be good up to 350-360 hp.
Ø72mm internal and sport cat should flow enaugh for up to 430-440 Hp, while Ø76mm internal can go as high as 480-500 Hp.
From there up to 600-630 Hp better use a Ø85 internal but once there it will be almost impossible to find a single racing cat converter suitable.


Marco

[Pisobiker]

Quick update:

today got the flanges, bends and all the tubing.
Will start with the building of the first downpipe this weekend, so I might be ready to post some pictures and numbers for the next one.


Ciao

Marco

[SteveH]

Nice one Marco...can't wait to see your first prototype

[S2central.net]

Marco - You the man !

I also can't wait to the finished article. I reckon a 70mm diameter is plenty enough for my needs - can you recommend a good sports CAT that would be a good fit. I'd like to get a custom system made of 70mm stainless to fit behind that. Someday.....

I don't want something massively loud, but my CATs are dying and I'd like to extract a little more oomf from a less restrictive system. Will dyno the results eventually for a before and after with my chipped setup.


Paul

[Pisobiker]

Yeah Paul,
I actually have found an Italian company who sells 150-200 cells metallic sport cat-converters. I'm sure you will be able to find good ones at the right price over there too. I posted some mesurements also over internal cross sectional flow areas of 3B-ABY-ADU cats in the "Guides and Top-Tips" section ("Downpipes and cat stuff" was the thread) to compare with.
The one I bought here should be only slightly bigger (in cross sectional flow area) that the two RS2 ones, so I think If I'll go over the 400 Hp I might need to have a bigger one.
If I remember correctly I payed about 270-280 Euros for it.


Marco