I have an 09 g37x coupe that I want to rework the exhaust on. I really like the look of dual exhaust but am not a fan of having to buy 2 cat converters - also heard single exit gives more power.

I was wondering if it would be possible to get Y shaped headers that lead into a single cat, and then exit the cat through another Y pipe to keep the dual exit.

Any help or ideas are appreciated. Thanks!

 

I always assumed the coupé had two cats, like the sedan. Doesn't the coupé have two pipes coming into the single muffler?

 

I think you would have more money in trying to make that work than it would be to buy the catalytic converters. I don't think there are headers readily available for the X and even if you're able to track some down they'll be expensive. Then you'd have to deal with the o2 sensors as there is a sensor in each catalytic converter so you'd have to try put them both into a single converter and hope the ECU doesn't take issue with it. Then you'd have to hope that you don't run into emissions problems for deleting the original equipment. You also start to run the risk of impeding the performance of your car if you're doing a lot of redesign to the flow of the exhaust.

If it were me I'd just go with a nice set of aftermarket cats and then whatever exhaust you like best, if you really want to save money you can delete the cats altogether and use test pipes however you'll again potentially run into emissions issues depending on where you live... or leave the OEM cats in place and just do a nice catback exhaust until you save up to replace them later.

 

Get yourself an ISR Y pipe and ISR eingle exit exhaust. Thats all you would need to convert it.

 

I have an S coupe and I run Ark Grip with Z1 stainless test pipes, but what I recommended for you should work in turning it into a single exit

 

Curious if you ever went down this path? Would like to see/hear it!

 

The same can be achieved if you buy test pipes and a custom Y pipe with the cats

However the question would then be why?

It would require you to also install the O2 sensors after the cat which might be even more work.
Rasp will still happen and electrical work and possibly custom work required and it will sound very similar to what's out there.

Keep your cats or get HFCs. You can experiment with your Y pipe after.