Anyone running cats with their front mount turbos? While I do like the gas smell, I would rather not have it on my daily driver. My DP is 3.5" and I was thinking of just running 3.5" the whole way with a big muffler and cutout right after the downpipe. I would like to place a cat or two after the cutout. Anyone have issues with cats failing? I can't decide if they would get too hot, or too cold from being so far from the engine.

Any particular type to go for? There are more 3.5" cat options than 4", mostly metal matrix ones for diesels. Or would doing a full 4" system be better? Aiming for around 600rwhp.

3.5": http://www.summitracing.com/parts/MPE-59920/
3.5": http://www.summitracing.com/parts/MPE-60010/
4.0": http://www.summitracing.com/parts/MPE-60011/

 

Cats will fail pretty fast with FI.

 

I've heard of them lasting awhile as long as the tune is in good shape. I'm sure the rich AFR in boost cuts down the life, but the other 99.5% of the time out of boost they should be okay.

 

Dont the factory FI cars have cats?

I was planning on putting a vband at the end of my DP so I can swap my cutout with a cat depending on what Im doing/inspection. I have a 3" DP and cutout and was going to go with a 3.5" cat to make sure its not much of a restriction. catback will be 3.5 as well.

 

Cats need heat to work properly. I would install after Dp.
Keep in mind you will ne increasing the back pressure and could loose some performance.

I would do the largest dia.

 

Yep, use the largest one you can get and flare up to it if you have to.

 

Thanks for the tips! What I may do is flare the end of the DP to 4" and run it into a 4" cutout and then into a 4" cat. I wonder if fresh air would come in through the cutout and damage the cat? I'm planning on putting a turndown with some piping on the cutout, not sure how long though.

 

I'm running the 3" Magnaflow Cat for the last 4k miles. So far so good.

 

A single 3" cat? Metallic or ceramic?

 

Metallic

This one:
MagnaFlow 59959 - MagnaFlow Universal Spun Catalytic Converters - Overview - SummitRacing.com