high power-low db prototype muffler - Page 4 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

wparsons · 10-05-2015, 01:05 PM

Quote:

Originally Posted by CSG Mike

Those other "quiet" exhausts are not quiet enough for our requirements.

What sound level are you trying to hit? Assuming you're trying to hit the sound requirement fully catless, right?

CSG Mike · 10-05-2015, 01:06 PM

Quote:

Originally Posted by wparsons

What sound level are you trying to hit? Assuming you're trying to hit the sound requirement fully catless, right?

Correct!

We want to be under 90db from 30 feet away, 30 degrees offset to the passenger side, without cats, boosted.

Even with this hard requirement, the muffler will NOT cause a power loss with an NA car; it flows more than enough. The challenge for us is to not lose any power with a FI (supercharged) car

wparsons · 10-05-2015, 01:58 PM

90db is a lofty goal, but if it works out that'll be awesome for tracks with tight requirements.

BRZoomTX · 10-05-2015, 02:36 PM

Quote:

Originally Posted by CSG Mike

Correct!

We want to be under 90db from 30 feet away, 30 degrees offset to the passenger side, without cats, boosted.

Even with this hard requirement, the muffler will NOT cause a power loss with an NA car; it flows more than enough. The challenge for us is to not lose any power with a FI (supercharged) car

I'd imagine that goal would be much easier on a turbo car. This is a very attractive muffler for me as I am over loud exhausts. Will there be a full 3" version?

The tips need to be raised up as well. They are very low IMO and make the rear look very "off".

churchx · 10-05-2015, 03:30 PM

If 10db is twice perceived loudness .. 90 vs 96 of +6db is BIG difference and harder bar to hit. Anyone knows stock or Q300 levels for comparison sake at similar 30ft/30deg offset/catless/boosted?

CSG Mike · 10-05-2015, 05:43 PM

Quote:

Originally Posted by wparsons

90db is a lofty goal, but if it works out that'll be awesome for tracks with tight requirements.

It's not a lofty goal; it's mandatory to run at Laguna Seca.

There are a TON of creative solution you see there, and many series have "Laguna Seca Spec" or "Laguna Seca Special" mufflers that they run ONLY at Laguna Seca, and many of these cars have higher output than we do.

It can be done

CSG Mike · 10-05-2015, 05:43 PM

Quote:

Originally Posted by churchx

If 10db is twice perceived loudness .. 90 vs 96 of +6db is BIG difference and harder bar to hit. Anyone knows stock or Q300 levels for comparison sake at similar 30ft/30deg offset/catless/boosted?

without cats it is over 100db.

CSG Mike · 10-05-2015, 05:48 PM

Quote:

Originally Posted by BRZoomTX

I'd imagine that goal would be much easier on a turbo car. This is a very attractive muffler for me as I am over loud exhausts. Will there be a full 3" version?

The tips need to be raised up as well. They are very low IMO and make the rear look very "off".

It won't be released until it's perfect

A turbo car will absolutely be quieter than a NA or SC car.

3".... if there is enough demand, possibly, but I'm not sure we can hit 90dB with a 3". From other platforms, we already know that a 63mm exhaust can support 500+hp with virtually no power loss on a NA/SC car. Turbo cars, love large exhausts, and somewhere a compromise will need to be made.

BRZoomTX · 10-05-2015, 06:17 PM

Quote:

Originally Posted by CSG Mike

It won't be released until it's perfect

A turbo car will absolutely be quieter than a NA or SC car.

3".... if there is enough demand, possibly, but I'm not sure we can hit 90dB with a 3". From other platforms, we already know that a 63mm exhaust can support 500+hp with virtually no power loss on a NA/SC car. Turbo cars, love large exhausts, and somewhere a compromise will need to be made.

No big deal if it weren't able to get 90db on 3". This still seems to be one of the quietest aftermarket mufflers (potentially soon to be) available so far.

I would definitely be interested in a 3" option regardless of what actual sound level you are able to get out of it. The CX kit came with 3" back to the cat-back position so its just a preference to keep the exhaust all 3". Otherwise I agree 2.5 would be sufficient.

If you guys need a catless turbo car with full 3" exhaust for sound level testing....

mav1178 · 10-05-2015, 06:55 PM

Quote:

Originally Posted by Jrdad

How does this compare to the stock muffler?

Quote:

Originally Posted by olsonpg

Yeah does anyone know stock exhaust sound level in db?

Stock is (quoting Fujitsubo site):
http://www.fujitsubo.co.jp/prods/det...04741/00001474

Idle 61dB
5250RPM 82dB
3000RPM 73dB
4000RPM 80dB
2000-4000RPM "response" 87dB (most likely revving engine in this range)

churchx · 10-05-2015, 11:30 PM

mav1178: any numbers should be accompanied by nfo how loudness was measured. For example for this Fujitsubo data how can one know distance (which can change measurements a lot) at which those numbers were seen? Hence one cannot gauge what these dBs mean vs 90dB mentioned earlier.

Wepeel · 10-06-2015, 10:04 AM

Really interested in this. Is it safe to assume that with a fully catless setup, a Perrin 2.5 resonated or Q300 would exceed 90dB?

CSG Mike · 10-06-2015, 11:14 AM

Quote:

Originally Posted by Wepeel

Really interested in this. Is it safe to assume that with a fully catless setup, a Perrin 2.5 resonated or Q300 would exceed 90dB?

It's not an assumption; I've seen cars fail the sound check at Laguna Seca.

Jrdad · 10-06-2015, 12:52 PM

Fwiw a stock c7 with dual mode exhaust hits ~96db

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10-05-2015, 03:30 PM	#47
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,086 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	If 10db is twice perceived loudness .. 90 vs 96 of +6db is BIG difference and harder bar to hit. Anyone knows stock or Q300 levels for comparison sake at similar 30ft/30deg offset/catless/boosted?

10-05-2015, 11:30 PM	#53
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,086 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	mav1178: any numbers should be accompanied by nfo how loudness was measured. For example for this Fujitsubo data how can one know distance (which can change measurements a lot) at which those numbers were seen? Hence one cannot gauge what these dBs mean vs 90dB mentioned earlier.

10-06-2015, 10:04 AM	#54
Wepeel Senior Member Join Date: May 2012 Drives: '13 BRZ Ltd Location: PA Posts: 458 Thanks: 265 Thanked 229 Times in 117 Posts Mentioned: 8 Post(s) Tagged: 0 Thread(s)	Really interested in this. Is it safe to assume that with a fully catless setup, a Perrin 2.5 resonated or Q300 would exceed 90dB?

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