musicmandan13

New member here but have been using the forum for information for years. I have a question and would like advice. I just purchased Speed Engineering longtubes and a Madhammer/gmmg catback exhaust. My question is can I use a reducer to run the stock y with cats? Or should I really go for a catted y like the tsp one? I live in california and wouldn't mind possibly being able to pass emissions when it comes up. I like not scraping over bumps and also wouldn't mind saving some money for other mods. Couldn't find this exact question in a search. Has anyone run longtubes with the stock y? Thanks for any help.

HCI2000SS

iTrader: (2)

You'll need the matching y-pipe to fit the longtubes

musicmandan13

Right on. I've heard the tsp catted y will fit with a little fabrication but is it absolutely not possible to just run a reducer to stock y is my question. Is it just a bad idea or is it just a lot lower with the longtubes or what? I know the tsp will flow better of course but was just seeing if anyone has run lts into a stock y using a 3" to 2.75" reducer.

black sky

iTrader: (3)

In hindsight, it might have been a better option to just purchase TSP headers and TSP catted Y considering fitment. You might have a tough time finding people who purchased high flowing headers, a great catback, and retained the stock y pipe. Really defeats the purpose. Of course, I do not live in CA but I would think cam choice would be more detrimental to emissions than adding a catted y to an already enlarged exhaust system. Not to mention the bottleneck it would cause.

musicmandan13

Totally get it and thanks for the reply. I was going to go with the tsp lt's but decided on the speeds due to solid reviews and unbeatable price. I'm just gonna go with the tsp catted y and mock it all up before I install. Had heard that the stock y wasn't as restrictive as most say, but there's always people on both sides of any conversation regarding flow rate. I'd much rather redo the whole damned thing while I'm doing it anyways. Gonna be a cool project either way. Cam will be a ways down the road for me anyways but I'll figure emissions out when I get there. California is pretty lame with that sort of stuff. Thanks again for the insight. I'll post up some pics when I get it in.

HCI2000SS

iTrader: (2)

Why not just go with the SE y-pipe? It's obviously going to fit best with their headers. Of course any aftermarket y-pipe will have a little less clearance than the stocker, but is no big deal usually

musicmandan13

I haven't seen an SE catted y. Or I'd definitely go with that. I want cats because I know how raspy the gmmg can be with lt's and I am not a fan of rasp. I have heard(via a tsp rep in the forum) that the tsp catted y will hook up to the SE lt's but if anyone has heard different I am open to a different alternative. Or maybe go with a bullet? Just really want to keep that awesome gmmg tone.

HCI2000SS

iTrader: (2)

Ok I didn't know if they had a catted one or not. You could also run a SLP LM1 bullet resonator as well, and that would help kill some rasp

black sky

iTrader: (3)

I think SE just has the ORY type. Having cats will lean in your favor, and not just with emissions. The GMMG can get pretty rowdy with headers and an ORY. Not only loud, it can promote more rasp. Cats will calm it down some.

musicmandan13

Thanks blacksky. I've read that too. Excited for the new sound but would love to just get it all done with in one shot rather than dealing with rasp and going back to the drawing board. Exhaust is stock at the moment. I'm gonna do as much research as possible and see what catted y handles that rasp best before buying anything.

BeatonZ06

The SE headers fit perfectly with TSP y-pipes. I have the TSP catless y-pipe on my SE headers, and have installed TSP catted Y-Pipes onto SE headers. No modification required. The stock y-pipe won't work because the longtubes are so long, that you'd end up just cutting off the cats anyway, and would be stuck with some little baby y pipe haha.