exhaust question

[audi-tone]

Hi Fellas, thinking about getting a custom downpipe done on my 1.8t; my question is do i need to install a hi flow cat aswell to get the best gains or can i get away with just the downpipe, and if anyone has done this does it make a noticeable difference; also 2.5 or 3"??

cheers

[h100vw]

3 inch is very tight fit. I had one on my A3 due to the JBS04 turbo I was going to fit. 2.75 would be a good compromise if you are keeping the standard turbo.

I would go with a hi-flow cat too.

Gavin

[No457 Snowy]

2.5" with a high-flow cat is plenty if you are sticking with the standard turbo.

Cheers,

Snowy

[audi-tone]

anyone know roughly how much something like that would cost??

[JVLR32]

Find someone that can custome make one....u will be better of
Some of these known brands i reckon are over rated....
Some cats are overrated as well with the amount of coin u throw at them the gains are minimal

[audi-tone]

yeh recently asked an exhaust shop about all this and they said if i'm doing the downpipe i had to dget a hiflow cat and the full exhaust aswell. all custom but was gonna cost about $1100 which is just too much and i really dont want this car to be loud.
i've been reading and the general consensus is that i can do the downpipe and leave the cat and cat-back exhaust and i'll still see gains appossed to doing the catback which is marginal or jsut a hiflow cat and catback.
i think i'll go for 2.5/2.75" over the 3 as its overkill for the stock turbo (from what i've read)

can anyone reccommend an exhaust shop northside brisbane? i'm gonna call a couple tomorrow and see what the g-o is.

thanks for the replies fellas,

cheers.

[JVLR32]

yeh recently asked an exhaust shop about all this and they said if i'm doing the downpipe i had to dget a hiflow cat and the full exhaust aswell. all custom but was gonna cost about $1100 which is just too much and i really dont want this car to be loud.
i've been reading and the general consensus is that i can do the downpipe and leave the cat and cat-back exhaust and i'll still see gains appossed to doing the catback which is marginal or jsut a hiflow cat and catback.
i think i'll go for 2.5/2.75" over the 3 as its overkill for the stock turbo (from what i've read)

can anyone reccommend an exhaust shop northside brisbane? i'm gonna call a couple tomorrow and see what the g-o is.

thanks for the replies fellas,

cheers.

stick to 2.5 and leave the cats alone m8......

[fuzion]

stick to 2.5 and leave the cats alone m8......

as jvlr said.. you dont need to touch the cats.

3" dp and 2.25 through and im still bit more than most of the k03/k03s guys.. a k04 is only slightly more then me so figure that one out .... hmmmmmmmmmm

[audi-tone]

hey fellas, got a 2.5 downpipe installed today, when i picked it up it spools much faster but i have a slight crackling sound when boosting and backing up boost.. i'm taking the car back in the morning so they can check it but has anyone else seen or heard of this? i'm dreading my turbo is failing.. but was fine and had none of these sounds with the stock downpipe.
also getting vibrations from 1500-1700rpm aswell as from 3300-3800rpm.

this normal?

cheers

[geoff_gti]

When you say crackling, where does it come from - back end or the front? I can make mine pop out the back, esp changing from 2nd to 3rd, if you boost up to around 3500-4000 and hold it without the bov venting so the pressure stays up which sounds like what you're experiencing. Slight blip on the throttle as I'm changing seems to do it. I suspect it's dumping a bit of unburnt fuel into system so maybe you can hear it more now with the bigger pipe than before???

I also had to get my dump pipe repaired some time ago as it had actually cracked, so all the noise was coming from the front like the exhaust system had been cut off lol

(I try to pop it deliberately sometimes haha, sounds cool but might not be so good for the system... although I have 3" with K04 which would make some difference too)