Is going all catless on a na fa20 motor such a good idea? - Page 2 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Captain Insano · 09-09-2013, 09:45 PM

Quote:

Originally Posted by Dephective

Rasp isn't necessarily caused by lack of cats guys. Add another resonator and the same effect of reducing rasp can be found. It has a lot to do with the frequencies that vibrate the materials. Also, shitty made mufflers can rasp with or without cats, and may only present the sound AFTER you go catless, i.e changing the frequency of the exhaust.

If you ever plan to autocross your car, you definitely want to keep a cat.

Totally agree. Resonators can eliminate rasp as much as cats. Single biggest factor is what kind of catback you are running including the midpipe. I believe the N1 may not have that much rasp because it has a very large resonator in the catback midpipe. I am now running a Q300 and a catless resonated frontpipe as well as an aftermarket overpipe. With the large midpipe resonator, and the frontpipe resonator, I have zero rasp/drone right now. I have no concerns when I make the catless header leap...

Argento_FR-S · 09-09-2013, 10:24 PM

Running RevWorks UEL with SRT headerback no cats with 1 big resonator and all I have is no torque dip with loud awesome sounding scubie burble. No rasp or drone at all. Oh and with a few simple weight saving mods and this setup I average about 3-4 mpg more per tank. Seems like less emissions without cats to me...

BRZ? · 09-09-2013, 10:34 PM

Quote:

Originally Posted by Jive Turkey

full catless will not only not net a benefit, but it will sound so raspy.

lmao i love it when people talk shit!

Gen · 09-09-2013, 11:50 PM

When I added my turbo, header was replaced (and consequently the cat is gone). Front pipe was replaced with a high flow. Catback is stock. There has been absolutely zero impact on exhaust note. It still sounds very much stock.

6speed_Sam · 09-10-2013, 12:26 AM

Quote:

Originally Posted by ShadowSeraph

I am running Full catless with the Borla UEL and Perrin 3" catback exhaust... no rasp.. no fartcan.... all growl. Power seems fine... if i could only find where a dyno is around my area.

Exactly. Mine's 2.5 resonated but still. Sounds awesome.

Astroboy · 09-10-2013, 02:40 AM

Is that on e85 or 93oct? And do you have any dyno numbers on it?

Astroboy · 09-10-2013, 02:41 AM

Quote:

Originally Posted by Argento_FR-S

Running RevWorks UEL with SRT headerback no cats with 1 big resonator and all I have is no torque dip with loud awesome sounding scubie burble. No rasp or drone at all. Oh and with a few simple weight saving mods and this setup I average about 3-4 mpg more per tank. Seems like less emissions without cats to me...

Is that on e85 or 93oct? And do you have any dyno numbers on it?

Fast_Freddy · 09-10-2013, 03:08 AM

Interesting, yet not even remotely surprising, that so many forum "experts" agree that OEM 400 cell ceramic core cats are not at all restrictive and should be left intact when modding for increased hp and tq. Not even a mention of cell density or substrate material... typical FT86club...

sw20kosh · 09-10-2013, 03:15 AM

lol no rasp.... ya right...

Astroboy · 09-10-2013, 10:33 AM

Quote:

Originally Posted by Fast_Freddy

Interesting, yet not even remotely surprising, that so many forum "experts" agree that OEM 400 cell ceramic core cats are not at all restrictive and should be left intact when modding for increased hp and tq. Not even a mention of cell density or substrate material... typical FT86club...

You sound like a forum expert yourself

SkAsphalt · 09-10-2013, 11:48 AM

Quote:

Originally Posted by StormTrooper

False.....

It does stink and it won't gain any power though, so no real good reason.

Catalytic converters take nitrogen dioxide out of the exhaust (plus more harmful gasses) these gasses when mixed in the atmosphere at critical levels react and if it happens to rain, that rain will be corrosive.

Nitrogen dioxide reacts with OH to form nitric acid:
NO2 + OH· → HNO3

So in short, suck a D

ihaskrayon · 09-10-2013, 12:11 PM

So the entire city will have acid rain because I put a catless midpipe on?

Jive Turkey · 09-10-2013, 12:33 PM

Quote:

Originally Posted by BRZ?

lmao i love it when people talk shit!

excuse me?

its easy to see who the adults are that post, and who the teen ricers are, carry on

SkAsphalt · 09-10-2013, 05:01 PM

Quote:

Originally Posted by ihaskrayon

So the entire city will have acid rain because I put a catless midpipe on?

Sadly, yes. /s

09-10-2013, 03:15 AM	#23
sw20kosh Senior Member Join Date: Jul 2012 Drives: 2013 Black FR-S Location: SF Posts: 3,030 Thanks: 881 Thanked 2,014 Times in 990 Posts Mentioned: 153 Post(s) Tagged: 1 Thread(s)	lol no rasp.... ya right... __________________ 86DRIVE Challenge

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
FA20 + Boring holes = bad idea?	gt8613	Scion FR-S / Toyota 86 GT86 General Forum	19	08-20-2013 02:36 PM
j2 catless pipe	sosick	Engine, Exhaust, Transmission	28	07-31-2013 11:32 PM
Catless Vs HFC?	Koolkiid	Engine, Exhaust, Transmission	14	05-28-2013 09:03 AM
Going to track with stock setup good or bad idea?	evasquez7	BRZ First-Gen (2012+) — General Topics	11	08-21-2012 03:33 PM
Considering selling my BMW 335i to get FR-S... Good or Bad idea?	iBurnTires	Scion FR-S / Toyota 86 GT86 General Forum	112	08-02-2012 09:46 PM

09-09-2013, 11:50 PM	#18
Gen Senior Member Join Date: Jun 2012 Drives: Scion FR-S Location: Under a rock Posts: 1,060 Thanks: 75 Thanked 552 Times in 270 Posts Mentioned: 39 Post(s) Tagged: 0 Thread(s)	When I added my turbo, header was replaced (and consequently the cat is gone). Front pipe was replaced with a high flow. Catback is stock. There has been absolutely zero impact on exhaust note. It still sounds very much stock.

09-10-2013, 03:08 AM	#22
Fast_Freddy Senior Member Join Date: Jul 2012 Drives: Passat Location: East Coast Posts: 626 Thanks: 331 Thanked 188 Times in 130 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	Interesting, yet not even remotely surprising, that so many forum "experts" agree that OEM 400 cell ceramic core cats are not at all restrictive and should be left intact when modding for increased hp and tq. Not even a mention of cell density or substrate material... typical FT86club...

09-10-2013, 12:11 PM	#26
ihaskrayon The Comedian Join Date: Jun 2012 Drives: SWP BRZ Limited Location: Irvine Posts: 969 Thanks: 94 Thanked 642 Times in 266 Posts Mentioned: 12 Post(s) Tagged: 0 Thread(s)	So the entire city will have acid rain because I put a catless midpipe on?

User Name		Remember Me?
Password