Pfs is quiet? Lol pfs is amongst the loud exhaust group.

I have a pfs with the stock cat and I know I wake up the neighborhood.

Im thinking of getting a high flow though because the fd is a weekend car anyway, I don't care if its a bit loud. Plus hitting boost at 4500rpm kinda sucks. And hopefully the hf cat will reduce drone.

 

OK, here's the scoop.

First off, I have owned and run at least 15-20 cat-back exhausts of all different types. Women have tons of shoes, I have tons of exhausts .

Here's some general rules when it comes to noise -

- Damn near ANYTHING is quiet with a stock main cat. It's restrictive and absorbs a LOT of sound. Many people will tell you "but this exhaust was so quiet!" but this was with a stock main cat.

- If you have sequential twins that tones down the noise a LOT. The flapper door in the exhaust manifold quiets it down a great deal. It will be louder at full throttle when the secondary turbo is online, but general driving it will be quieter.

- Straight through N1-style round can exhausts are generally the loudest. To muffle, you need volume, and less volume is less muffling.

- Oval canister style exhausts are generally the quietest. Again, more volume, more muffling.

- American made exhausts (PFS, TurboTuf, ATR) are typically VERY loud. Not sure why there. You don't see many of these any more save the PFS.

- Japanese Jasma SR rated exhausts are usually the quietest. Jasma is a third party that certifies noise levels on exhausts. They have a bewildering rating system though that has changed over the years. But, if you see an oval can style and a Jasma SR plate on the bottom, it'll be pretty quiet.

- The Racing Beat cat-back is a compromise between flow and noise. It's really not THAT quiet, the Japanese Jasma-rated cat-backs are much quieter. But, many of them are very restrictive and hurt flow.

- A midpipe is always gonna be loud. And stinky. A resonated midpipe helps, but it mainly takes some of the rasp and bite out of the exhaust note. I like running a highflow cat to reduce the stink, a highflow cat will reduce the noise SOME but a resonator helps more. SMB Australia has a midpipe with a metal highflow cat AND a resonator, REALLY nice but pricey.

- If you want to have your cake and eat it too, get an Apexi ECV. Search for my writeup on it. It's a butterfly valve that goes in your exhaust that restricts it down big time but for cruising around town, sneaking into your neighborhood, or going down the highway you can have near-stock noise levels. Open it up and the car roars again. There's also cutouts, those are crap, this is NOT a cutout.

Again, this is all first-hand personal experience with multiple systems.

Dale

 

has anyone tried a Flowmaster 70 series big block muffler on a 7?

its a big chamber muffler, i bet its pretty silent... the question is, would it flow enough to support 500+ rwhp...

 

When I ran RB single/dual with a stock exhaust, it was very quiet. As soon as I switched to the HF bonez cat + RB duals, that went out the window fast. I was shocked. The car sounds awesome though.

 

What size is stock?

 

I was worried about getting highway drone with an aftermarket exhaust, but I can report that there is NONE with a Bonz downpipe, Bonez high-flow cat, and a RB dual-tip. I almost want it louder at WOT, though.

 

Hmm any vid clips?

 

can anyone tell me how loud using an rx7store resonated midpipe with HKS Hi Flow exhaust is? Was planning to use this setup but now moving to germany due to military assignment and gotta pass decibel test, gotta be under 95 decibels at 4500rpm i believe is regulation for germany. any help would be greatly appreciated