CAT placement on downpipe???

[Oryx R]

Ok so I'm going to buy a 304ss GTI Downpipe off of EBAY and chop it up and add a nice catalytic converter into it. I have Vbands and a nice flex pipe section leftover from an old project.

My main concern is where do I place the cat? It seems like the higher priced units have the Cat in the stock location with the O2 sensor after the Cat.

Cheaper units have it down under the car and still put the O2 after with an extension. I know this is because it's more expensive to put it in the stock location because of the driveshaft. I figure there must be a reason some units go the extra mile to go stock location.

I can do either location. What do you guys think? I'll be going stage 2 of course.

 

[tjasko]

Traditionally you want the cat as close to the turbo as possible. The reason why is cats work better when heated up as much as possible.

I don't know why anyone would place it further away other than fitment issues.

 

[Slow*Jim]

I don't think a GTI downpipe will fit a golf R

 

[Oryx R]

I don't think a GTI downpipe will fit a golf R

I know it's called fabrication.

 

[tjasko]

I know it's called fabrication.

The only thing I'd be worried about is the flex pipe. It may be very close to the drive shaft as I don't know if the GTI's are the same or similar.

Other than that, I believe you should be able to fabricate it.

 

[Oryx R]

The only thing I'd be worried about is the flex pipe. It may be very close to the drive shaft as I don't know if the GTI's are the same or similar.

Other than that, I believe you should be able to fabricate it.

I have a nicer section of 3" flex pipe than what comes on the DP I'm looking to get. I would be mainly using just the tubing and turbo V band and bends from it to make a complet new DP. Some cutting and rotating of the bends can go a long way on tubing. I'm also going to make it 2 piece with a Vband near mounting hangers.

 

[Spinozaman]

The closer the cat is to the turbo the hotter it will get and better it will work taking the nasties out of our air. That's why VW put it there. The negative of course is that it does rob some amount of power. The further the cat is away from the turbo the better from a power standpoint. Most people with good (high flow) cats at or near the stock location get the best of both worlds. Lots of people with cats further away get CELs - I know some tunes deal with that but some don't.

 

[The Fed]

If you have emissions inspections you might want it to look as close to stock as possible.

 

[Oryx R]

If you have emissions inspections you might want it to look as close to stock as possible.

I live in the motor city. You can run open header and you might get a ticket for loudness.


So no inspections, lol