Hi all, after discussing the possibility about decatting and putting in a different down pipe I have been looking into it but have a few questions I need to ask....

1/ what sort of sound will I get? Will it be a constant drone or is it something I could live with and people not think I am a pikey

2/ with the cat gone, will me mpg drop?

3/ with less back pressure, is it likely to blow out my back box

4/ does the cat detach or would it need to be cut free? And if it is cut free, how far along does the pipe go straight for and have no sensors. Because I may just get a long pipe to replace it.

Regards,

Damian.

Decat made my exhaust note a little deeper but no droning and not loud.

MPG should increase if anything? I noticed no difference.

Less back pressure is good on a turbo

cat has to be cut free but the restriction is the tiny downpipe not the cat itself.

There's a sensor in the cat and one in front of it.

Pics here:

http://www.pimpmysko...ngine/Decat.htm

So if I leave the cat in place, would I see any difference if I gat the down pipe as well, or if I am doing that, should I get rid of the cat as well?

When it comes to down pipes, what am I looking for?

What difference does a miltek system have against doing these bits?

Full Milltek would mean you dont have to swap a cat in come MOT time... or know a friendly MOT tester...

Full Milltek would mean you dont have to swap a cat in come MOT time... or know a friendly MOT tester...

Or get a sports cat welded in to new system

or know a friendly MOT tester...

I know one of them.

So what am I looking for in a DP

This is all I would need, isn't it?

http://www.ebay.co.uk/itm/SEAT-LEON-1-8T-20V-TURBO-EXHAUST-DOWN-PIPE-DECAT-DP7402-/190657063941?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c640bec05

I wouldn't need any more piping than that?

yep that looks a lot like mine.

Then using that coupler thing I could switch the cat back in when needed?

Would there be any benefit to this one?

http://www.ebay.co.uk/itm/GOLF-AUDI-A3-TT-20V-1-8T-STAINLESS-EXHAUST-DECAT-DOWN-PIPE-/270960564196?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f168217e4

This one does have the silencer, does it. Would the silencer make much difference.

I noticed this one has there bolt holes and the other has 4

Full Milltek would mean you dont have to swap a cat in come MOT time... or know a friendly MOT tester...

Is that really the only benefit

Well that and the fact that a full Milltek/Blueflame system will be all the same diameter, material etc and tested to ensure optimum flow. If you're leaving the standard back section of the exhaust on and using a reducer then you're still going to get restriction from that part of the exhaust (albeit not as much as the restriction the standard downpipe and cat have). It doesn't seem to say on the ebay advert what size the downpipe and decat section is? You need at least a 2.5inch one to make any difference over the standard 2.25 inch.

Ok, I plan to go for just the de-cat unless a member can get back to me. When searching I came across this one...

http://www.ebay.co.uk/itm/AUDI-A3-96-03-20v-1-8T-TURBO-EXHAUST-DOWN-PIPE-DECAT-/150604272066?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3ASkoda&hash=item2310b6d1c2

But like all the other it says it doesn't fit the octavia. Is this true? I cant see it being any different from the other 1.8t engines?

All the 1.8ts have the same downpipe as far as I know.

Mine was advertised as being for Golf Mk4 and Bora Mk4 only and it fit fine.

Well i had that exact pipe fitted to mine for a couple of week before i took it off,

It fitted really well for such a increase in size compaired to standard pipe, its just abit tight getting nuts back onto turbo,

The second lamba is abit tight round the heat shield but i got a 90 degree angle spacer to life probe out of exhaust flow so it don't put light on

This is the spacer i got altho took pipe off before i fitted it

http://www.ebay.co.uk/itm/230712006719?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

When I connect the pip to the existing system, will it slot in or will I need a coupler. If I need a coupler where would I get one from?

Well i had that exact pipe fitted to mine for a couple of week before i took it off,

It fitted really well for such a increase in size compaired to standard pipe, its just abit tight getting nuts back onto turbo,

The second lamba is abit tight round the heat shield but i got a 90 degree angle spacer to life probe out of exhaust flow so it don't put light on

This is the spacer i got altho took pipe off before i fitted it

http://www.ebay.co.u...984.m1497.l2649

What happens after the Decat? How did you attach it to the existing pipe? Why did you remove the pipe?

It slots into either standard system or into milltek reducer adaptor.

Got 2 stripped turbo to downpipe studs to fix so took it off, plus its abit noisy for me