ED30 Decat - General Exhaust System

[pazz]

First of all.....hello everyone. Recently purchased an ED30 3-Door. Couldnt really afford the S3 so ED30 it was. As usual I have a few questions:

1) I've read that the exhaust system is a 2.5" bore on the ED30? Can I just have this confirmed?

2) I'd be interested in getting a full 3" system from the turbo back but from looking at some of the prices a 2.75" Milltek cat-back looks like its not going to be a cheap option once after I've added a decat and downpipe into the mix.

3) I know of a good custom exhaust shop where I've had work done before, but from past experience it usually takes a few trips back to the shop to get it sounding reasnoble. I tend to find you have problems with it ending up being a little too loud and also looking rather chav-tastic.

4) For the time being I'd be really interested in just decat'ing the car. (For track use only).

[KRL]

Hi,

1.  Yes.
2.  There is an excellent offer on the forum for Blueflame exhausts at the moment if Milltek is going to be too expensive.
3 & 4.  Why don't you just do the downpipe on the car for now?  It will give you 95% of the performance gains, no chavtastic sounds and half the cost 

[pazz]

3 & 4.  Why don't you just do the downpipe on the car for now?  It will give you 95% of the performance gains, no chavtastic sounds and half the cost 

Think your maybe right. The stock 2.5" system after the cat wouldnt really effect the sort of power I'm after.  250-260bhp is my goal to be honest. And thats hopefully gonna be coming from just breathing mods. It's more the torque at top-end that I'm interested in.

If anyone's removed the cat on a turbocharged engine before, you'll know what I mean by top-end torque! On my 200SX it was the difference between night and day.

[tony_danza]

A decat downpipe is actually cheaper than a sport-cat DP, around £330 delivered from Milltek with the adapter pipe for your existing 'zorst. I think a sportcat DP is around the £500 mark??

You'll need a decat specific map from the likes of Revo, this will have to be a version of stage 2 and it fools the ECU interpretation of the 2nd lambda sensors signal, I'm pretty sure Superchips have that capability too. Otherwise if you try just running it on a normal/stage 1 map, it'll have a fit and put you in limp mode.

Oh, and you obviously know it's illegal and won't pass an MOT on emissions, so track only - mwhahahaaaaa! 

[pazz]

You'll need a decat specific map from the likes of Revo, this will have to be a version of stage 2 and it fools the ECU interpretation of the 2nd lambda sensors signal, I'm pretty sure Superchips have that capability too. Otherwise if you try just running it on a normal/stage 1 map, it'll have a fit and put you in limp mode.

Really? A 2nd lambda sensor - what would be the point of a second lambda sensor? Are you sure its just not an EGT (Exhuast Gas Temperature) sensor? Stage 2 - no thanks, pretty sure it can be done as a seperate ECU tweak.

Oh, and you obviously know it's illegal and won't pass an MOT on emissions, so track only - mwhahahaaaaa! 

Illegal, yes I'm aware of that. Its also handy to know your local MOT tester! 

[tony_danza]

Fairly sure it's a second Lambda, I have no idea why? Not sure it can be played with in VCDS either, you'd need someone who can hack into the ECU??

I've just re-read properly, you've an ED30 and you're just looking to get 260bhp with an intake and a de-cat DP. You could just have it remapped and get 300bhp and a load more torque on your standard kit, it'd be less money.

JonnyC would be a decent person to ask as he swaps his DP for a decat one on track days & 1/4 miles (doddle to do), I'm pretty sure Revo have given him a specific map for doing so. 

[pazz]

My apologies Tony, you're right about the second lambda sensor. Just spoken to a tuning company that I've taken previous non-VAG motors before who are actually VAG specialists.

He explained that the car runs a lambda sensor on the turbo outlet and a second lamdba further down. One monitors upstream with the other the downstream flow. Remove the cat and you put the system into limp mode as it records an imbalance in the up/downstream flow from stock.

So basicaly you have to map it to fool the lambda sensors.

[tony_danza]

No need to apologise, but I knew it wasn't a simple "fix", which is a shame sadly.

There may be some other way around it with a dummy lambda which just gives a constant signal of whatever the ECU expects, I couldn't find much detailed info and I decided against it.

[pazz]

I couldn't find much detailed info and I decided against it.

Well I can understand why, the bloke I've been speaking to just recommended I get a stage 1 map and if I come across some money go for a full system with high-flow cat.

Trouble is I didnt really want to damage the MPG as the car is a daily driver to work. So debating the whole modding idea now  A full system would be nice but then theres the fun of attracting buyers with an "aftermarket" exhuast.