dump pipe vs turbo back

does a dump pipe with catback = turbo back?

i know catback doesnt gain any performance....
so does that mean, for stage 2 tuning, dump pipe is all i need?

Correct - the stock dump pipe is horribly restrictive with 2x dense cat convertors.

The dump pipe is a necessity, whereas the cat back is optional for looks/extra noise.

in that case, i might as well keep the stock exhaust.
i avtually prefer no noise...just pure performance.
next question is... what size is stock gti piping size? do i need to get a dump pipe that fits?

Quote:

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Originally Posted by Lucas_R

Correct - the stock dump pipe is horribly restrictive with 2x dense cat convertors.

The dump pipe is a necessity, whereas the cat back is optional for looks/extra noise.

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Stock exhaust diameter is 2.5inch. All the dump pipes are 3inch and then taper down to 2.5inch to join up to the stock catback.

does that mean it requires modifications?

Quote:

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Originally Posted by alphabeatsco

does that mean it requires modifications?

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If you change the DP you will need a new tune.

Depending which DP you get most will fit up to the existing stock exhaust (unless it's specifically designed to fit to a custom exhaust).

What sort of modifications you were meaning?

If you replace the dump pipe and dont change the tune, you will get a CEL (check engine light) because the free flowing catalyic convertor will tell the ECU that something is wrong with the exhaust/emissions system.

So you should get a tune to accompany a dump pipe and the tune will code out the CEL.

i actually mean tmodifications to make it fit with stock catcback.
i dont wanna weld the exhaust...i want a dump pipe that is bolt fitted to the existing catback...

Quote:

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Originally Posted by Lucas_R

If you replace the dump pipe and dont change the tune, you will get a CEL (check engine light) because the free flowing catalyic convertor will tell the ECU that something is wrong with the exhaust/emissions system.

So you should get a tune to accompany a dump pipe and the tune will code out the CEL.

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What car do you drive?

Most aftermarket downpipes will mate to the stock cat back as you can see here by our SPM GTI DP. It comes with a reducer section

As for sound. That depends on the car you drive. A GTI wont be much louder with a DP but a Golf R generally will be.

http://www.vwwatercooled.com.au/foru...gtidpgif-2.jpg

Since I can't see a flange on that end. Does that mean it needs to be weld? I have gti mk6