Downpipe for stage 2

[CCmk6]

need help on making a decision.
2010 mk6 gti currently stage 1 tuned with intake installed.
want a downpipe with it to go stage 2.

any suggestions?
a relatively cost-effective but yet reliable product would be ideal as I don't want to spend a big chunk on just a steel pipe.

cheers

[RS4]

What cat-back do you have (if any) and did you want high-flow cat, or go to de-cat?

[GLIDN]

I'm guessing he is still running stock,

seeing he is currently asking about a downpipe only?

[RS4]

He's asking about stage 2 which has to include a catback as well, so naturally he would have a cat-back if he was going to add a downpipe. You wouldnt do downpipe and no cat back .

[GLIDN]

He's asking about stage 2 which has to include a catback as well, so naturally he would have a cat-back if he was going to add a downpipe. You wouldnt do downpipe and no cat back .

Stage 2 only requires intake and Downpipe to be classified as Stage 2, along with the correct Stage 2 tune.

All you get with the Cat Back is the great sound too.

[RS4]

We have seen significant gains off cat back and i would never class a stage 2 car still having stock cat-back system in place.
Freeing up one part of the system while the other remains restrictive doesnt make tuning sense

[M]

We have seen significant gains off cat back and i would never class a stage 2 car still having stock cat-back system in place.
Freeing up one part of the system while the other remains restrictive doesnt make tuning sense

Any figures to back that up?

[80 Vert]

Probably on the seat of the pants dyno 

[RS4]

why dont you visit our premium suppliers of exhausts website:
www.akrapovic.com, www.supersprint.com
V10 R8   +14bhp just with cat back
Late model lancer  +11 bhp
BMW M3 E92  +13bhp
They are what we have done here, but there are heaps of other data on the,. Plus why would you possibly want to do a downpipe with de-cat or high flow cats and the restrict the back section. just doesnt make technical sense.

[Turbo]

milltek cat back systems on the b5 s4 can increase 20+hp on the stage one tune. and 7% torque increase.

as RS4 says, leaving it stock doesn't really make sense as you've freed up everything pre cat, but left the restrictive resonator and mufflers to slow it all down again.
like widening a hydroslide so a fat bloke can fit down it but leavening the exit point tight.

[CamB]

Doesn't that depend a little on whether the back section is actually restricting the car in question (with or without a high performance downpipe)?

Akrapovic claims 4hp (maybe a little more in the range) for catback:

http://www.akrapovic.com/car-exhaust/products/volkswagen/model/golf-vi-gti-2009/slip-on-32582ab009/

I think supersprints site is saying you get 9hp with everything - how much is downpipe and how much is catback?

http://www.supersprint.com/en/prod-p-7079-10385-8-vw_golf_vi_gti_20_tsi_211_hp__09_E28093E280BA.aspx
(as an aside, they see only about 20hp difference between GTI and Golf R - stink for me)

Perhaps the better question is, how does that change when you factor in more boost for stage I / II? If a Stage I GTI 35 can support about 300hp (and the catback is the same - I dunno), presumably the catback isn't much of a restriction...

[RS4]

Remember for most people the cat back is also about the change in sound, not just power. If you look at the suitcase systems at the back of mk5/mk6 golf there is no way they can breath properly.
Having had ed30, mk5 and mk6 gti, i know form my experience that i would never do just the front section and not the rear.
Even if it was only 4-6 hp for the cat back, wouldnt you do it for the sound also?
Its about complimenting the other mods, air intake, intake pipe, dv, etc etc. It all adds up.

[CamB]

I am sure the sound sells a lot of people!!

[Turbo]

Doesn't that depend a little on whether the back section is actually restricting the car in question (with or without a high performance downpipe)?

yes, true.
i believe anton put a milltek cat-back system on his mk4 and it actually lost power.

and the previous S3 saw minimal gains as its system was already pretty free-flowing.

taking out the cat's or putting in DP with hi-flow cats would probably yield good gains but not as much as if it were combined with cat-back.

stage 2 typically involves the entire turbo-back system so there must be sound reason.
but a popular thing to save money in S4's is to go cat back only but gut the cats, as they're really the only restrictive part of the DP's, might be a similar case with the golfs?

but with the freer flowing system you do could lose a bit of lower end power in order to gain more at the upper end.
just have to weigh up what type of driving you're likely to be doing and where the most usable power is required.

[RS4]

I have seen no evidence that any car loses power on a decent branded exhaust.
Milltek and others do extensive testing and research to make them flow as they should and not lose power.
Would be interested to see data on it if someone has any.

Different story for pod filters in the wrong applications