OH DEAR LORD! Why is the CAT directly on the turbo?

[AnmanIndustries]

Short story:

Never having dealt with a CAT being used as a dump pipe, would a massively oversized cat work as a dump pipe? Excluding all the computer confusion.

Long story:

So Im sitting here thinking to myself about my b5, every one else is like, the cat and the dump pipe are the biggest restrictions in the exhaust. So i was like, ok fine, change cat, put on 3x 15" resonators and Im done (no muffler needed with a small dump pipe). Cheap and easy.

But no. NO. I look up the diagrams and Im like oh ok, there is a split exhaust. Wait, no wrong. Wrong car, I have a Single, Oh ok, thats fine. Wait, what is this third diagram? OH MY SWEET MERCIFUL JESUS IN HEAVEN, WHY!? Confirmed, same in my car.

So this has thrown my cheap exhaust plan into a frenzy and I doubt I'll be buying new wheels any time soon as this will probably eat up most of my budget. Will a massive CAT suffice as a dump pipe?

[h100vw]

Short story:

Never having dealt with a CAT being used as a dump pipe, would a massively oversized cat work as a dump pipe? Excluding all the computer confusion.

Long story:

So Im sitting here thinking to myself about my b5, every one else is like, the cat and the dump pipe are the biggest restrictions in the exhaust. So i was like, ok fine, change cat, put on 3x 15" resonators and Im done (no muffler needed with a small dump pipe). Cheap and easy.

But no. NO. I look up the diagrams and Im like oh ok, there is a split exhaust. Wait, no wrong. Wrong car, I have a Single, Oh ok, thats fine. Wait, what is this third diagram? OH MY SWEET MERCIFUL JESUS IN HEAVEN, WHY!? Confirmed, same in my car.

So this has thrown my cheap exhaust plan into a frenzy and I doubt I'll be buying new wheels any time soon as this will probably eat up most of my budget. Will a massive CAT suffice as a dump pipe?

So they heat up fast for efficiency.

audi a4 b5 exhaust | eBay

Hardly worth making one at ebay prices from the states

[AnmanIndustries]

So they heat up fast for efficiency.

audi a4 b5 exhaust | eBay

Hardly worth making one at ebay prices from the states

*scoff* Damn europeans with their silence and emmisions over fuel enconomy and functionality. And power.

Hmm. That is interesting. Never bought an exhaust off ebay before. My original idea of just adding 3x $30 resonators and a straight pipe at the muffler would have been much cheaper. But with the CAT in it I might as well consider it.

So, going by your search there, I can assume the audi has the exact same exhaust.

[h100vw]

Never assume, but nearly everything is interchangeable

[AnmanIndustries]

Never assume, but nearly everything is interchangeable

Yes, that is true.

I however was lucky in that I was not able to find any CATs that I thought would be suitable under the a4. However, the same applied to the b5.

Im going to have to take a look at the turbo diagrams and see what I can do in the event of not being able to find an aftermarket one. Ill just move the cat behind a large pipe.

[h100vw]

This is a 1.8T isn't it? Don't try and reinvent the wheel.

If you're planning on tuning it? you need to know what ECU type it has. Some are too hard for some tuners to work on.

[AnmanIndustries]

This is a 1.8T isn't it? Don't try and reinvent the wheel.

Nah, its easier and cheaper to just get a large pipe and weld a flange to it and then use a generic CAT. But because the engine is facing the wrong way I will need a whole bunch of other bends and that adds more welding costs.

If you're planning on tuning it? you need to know what ECU type it has. Some are too hard for some tuners to work on.

Nah. Im going to do the exhaust, open up the intake and change the recirc bov. Possibly change to front mount intercooler. I have a spare one sitting around, but I originally used it for a big turbo daily car, so its short and fat and might not suit this car.

Im on a tight budget, but I have a LOT of spare parts to use. If I have to get a CAT to suit this car it will destroy my wheels budget. Which looks like it will be the case.

[h100vw]

That's a lot of wasted effort if you're not going to change the software.

[AnmanIndustries]

Not really. Bov change, after work. Intake, already have some bits to mess around with, after lunch on the weekend maybe to pull it apart and inspect my options and put back together. Design something during the week and slap it in on the weekend. The exhaust IS now the only time and money thing that has come up. And by time I mean, money, as I wouldn't have spent much time collecting the parts and I wont be installing it as Im a crappy welder. I dont even have a welder.

I reckon I will spend more time replacing the fuel latch lock than I would fitting the intercooler. Excluding any trips down to the hardware store to buy any bends I might need for the pipes.

Its a daily car so for all intents and purposes the core of the engine will be unchanged. Sure, I could gain a large bit of power from a chip like every one else on the international sites say, but I only have $1000 to spend.

[h100vw]

The whole point though is it won't make any extra boost without a tune. At best a handful of HP due to improved intake temps if you do the intercooler.

[AnmanIndustries]

Im happy with stock boost. Im more after fuel efficiency, holding the boost longer and spooling faster. I think I read somewhere that the wastegate actuator is adjustable, I might adjust it ever so slightly for enough of an increase to not freak out the computer.

Oh I also want loud noises and cool turbo noises. If the car is going to look 100% stock, it might as well sound other wise. Ever since I took my last turbo apart and my wifes evo needed serious repairs, I've just not felt the same.