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Is 3" cat back big enough for 240-250rwkw?

I hae a 3.5" SS Kakimoto catback but now with the highflow a little noisier and around 2-2500rpm if loaded a little up a hill it gets a little droney.

Was thinking 3" mild steel might be quieter. It has 2 mufflers on it.

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When I first got my car was told it was 3" from the cat back into a jasma muffler and compliance cat and it was a tad loud but not booming loud. Sounded just right.

Last weekend I installed JJR split front/dump pipe and Xforce high flow cat and also noticed my exhaust is 3.5" from the cat back into some kinda resonator then into the jasma muffler and now its sounds good. Not loud at all and not quite. Id prob be a lil under the DB limit and I love it.

I have the exact same system as you and I can tell you that its way over the db limit. I got epa'd for it and had to fit a standard system for the test, which still came in at 90.4 db for a 90 db limit. The standard system was a lot quieter than the one you have.

  • 4 weeks later...

Anyone know if a silencer will get rid of a bit of drone.

My kakimoto 3.5" is a little droney when you back off or go up a hill pulling 2500rpm.

Thinking of making a silencer to add for longer drives. Will this reduce the drone at all?

It has got a little louder since the hi flow turbo.

It has a big centre muffler..and rear

I'm running the same exhaust on the R32 gts-t. It is indeed very quiet and full stainless steel. The exhaust is 3.5".

For what it's worth I run an HKS Silent Hi-Power system and was very surprised at how quiet it was. The 'Silent' in the name isn't just a marketing ploy. It seems they are rated at 98dB but I would be very surprised if it's louder than 90dB.

This is on a GTT with HKS dump and Front pipes as well... x-force cat. It sounds wicked as hell when you open it up. Surprised no one else is running this system.

  • 1 year later...

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