Sooo I'm looking into getting some high flow cats off ebay. I don't want to go and get dirty and get under my car so what is the inlet and outlet diameter on the stock cats? 3? or 2.5?

Thanks

 

Are you going to be mounting them where the stock cats are? the stock cats are right off the manifolds and before the Y pipe. I think they might be 2.5 or 2.25 as I don't believe the Y pipe is a 3 incher.

 

Yes I was going to mount them where the stock cats are. My local exhaust shop will do the dirty work but I'm guessing that's the most logical spot...

 

Any reason why you are doing this? Just switching to high flow cats isn't going to give you much gain in hp. I would go ahead and put longtubes on with a ORY (or catted Y for emissions). Headers are probably one of the best cost to hp ratio's for bolt on's.

 

Oh don't worry I'm doing it all haha. I'm still looking at what headers to get. There is a guy on craigslist who said he has some ceramic coated mid lengths for 150. I'm gonna ask him about those because he didn't mention what brand they are. If not I'm still researching which LT's are going to be the best.

 

Any reason why you want to spend the money to get cats and get them mounted now? I would just wait and get the header/y pipe combo at one time to cut down on cost.

I'd recommend taking a look at BBK headers. $500 for their ceramic coated ones (includes Y pipe) and all the reviews and user posts I have read on them praise them of their awesome fitment.

 

I'm doing that all at the same time too my friend. I looked at the bbk ones... do they only come in shorties?

 

BBK has longtubes too. LMperformance.com and Summit carry both their coated and non-coated versions.

 

would bbk headers work with my SLP exhaust? (high flow cats, slp ypipe, slp loudmouth II)

 

The BBK headers come with the y pipe to match; and your SLP y pipe would not fit the BBk headers (BBK uses ball flanges and not slip fit). The BBK Y is catless BUT does include 2 bungs meant to be used after the cats (you would have to cut the y pipe and clamp/weld the cats in), but the provisions to run cats are all there. The catback will not affect anything really.