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Which cat for high HP single turbo FD?

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Old 10-10-10, 08:21 AM
  #51  
Rotary Freak

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I got everything installed yesterday and I couldn't be happier with the results. At idle the car sounds exactly the same as with the open midpipe. On the road, however, it's really quite quiet; in fact the sound of the turbo spooling is louder than the exhaust note. I also plumbed my open wastegate back into the downpipe so it really feels like a totally different car. It sounds like an aggressive factory sports car all the way to redline.

The cat cleaned up the smell perfectly.

As far as power goes, I definitely feel like some was lost. Before I was literally scared to redline it in 3rd gear, now it's predictable. I can still break the tires loose at 60 mph though, so that's good . I would guess I lost around 30rwhp over 7k, the car feels exactly the same below that. The turbo spool is exactly the same as well. Overall the car is so much more drivable that I don't miss the small power loss.

This set-up cost me $325 with welding and using my existing midpipe. So if the cat lasts, it's clearly a more affordable option that the others that are out there. It doesn't look nearly as pretty, but this is one area on the car that no one will ever see so I could care less.
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Old 10-10-10, 09:24 AM
  #52  
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wait, so you installed a resonator, a cat, and recirculated the wastegate at the same time? I'm glad you're happy with the Vibrant cat, I've had good luck with their parts.
Old 10-10-10, 09:30 AM
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I too have a resonator and a cat at the same time. It is quiet for sure. I just wonder if I'd rather have the extra ponies. Have you tried just a straight through with no resonator before? Just wondering how much louder that would be.....
Old 10-10-10, 09:31 AM
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the resonator seems overkill. just recirculating the wastegate makes a huge difference.
Old 10-10-10, 10:05 AM
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Yeah, I added the resonator, cat and plumbed the wastegate all at once. The WG obviously made a huge difference, but the resonator is noticeable; my WG doesn't open until 13 lbs and the car is definitely quieter until that point. Also,my last car had a plumbed WG and a straight midpipe - it was much louder than this. The resonator is small enough (and a straight through design) where I don't think it's a big power killer - the cat is primarily responsible for that I would assume.

So, it's probably overkill for many on this forum, but I'm looking for this car to have the volume of a factory Porshe or vette at WOT. It's definitely there. There is still a loud drone on the highway cruising, I think a different catback can clean that up. Hopefully at 16 psi I'll still be over 400 rwhp (before I was at 475 at 17psi) but it will be a while before I'll get back on the dyno.

Originally Posted by arghx
I'm glad you're happy with the Vibrant cat, I've had good luck with their parts.
Thanks for the recommendation!
Old 10-10-10, 10:08 AM
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If you're ok with the subtle look, consider an RB catback with the vibrant cat, no resonator, and recirculated wastegate. In my experience the RB exhausts have the least amount of highway drone, even without a cat.
Old 10-11-10, 07:13 AM
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I have the RB dual tip, and I get drone on the highway. It seems to go away if I get above 120km/hr though.
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