High Flow Cat questions

[Bluebird_1251]

Hi all.
In reguards to a change in sound, will a high flow cat deepen my exhaust? If so, what would be the loudest sounding cat on the market? I have a Flowmaster catback, and K&N FIPK (on the way). I do not plan on changing headers, but this hobby is becoming addictive, so, ya never know.
And are all Cats the same? Or do some perform better than others?

All help is highly appreciated. Thanks.

[Dominic]

Re: High Flow Cat questions

They're all about the same. Any aftermarket "high flow" cat does the trick fine for a v6's CFM output of exhaust. I personally like my non-airtube equipped Magnaflow 3" cat, and it does make the exhaust louder due to the fact it's bigger and offers different resonance. I counter it with a resonator in my I-pipe.

[slow6]

Re: High Flow Cat questions

will a cat deepen the exhaust? no
unless its a bigger than stock cat, my stock cat was 3" in / 2.25" out
the aftermarket High-flow cat was 3"/3"
it will make it louder though

[CamaroDude]

Re: High Flow Cat questions

Will getting a catback exhaust make that much of a difference without replacing the cat or does the cat really make a difference as far as performance?

[Bluebird_1251]

Re: High Flow Cat questions

OK, so I have stock up to the cat, and Flowmaster catback which fits onto the stock cat. What is the stock diameters of the in/out on the Cat? And do they have highflows with these diameters? or MUST I go bigger?

[slow6]

Re: High Flow Cat questions

i would definately get a high flow, even though its only gonna get you a few hp.

i already said what the stock cat size was.

[Bluebird_1251]

Re: High Flow Cat questions

I know you said Slow6, but as far as aftermarkets......(high flows) same size? or do I always make a jump in diameters. I just want to know if I order one, will I have to do any fabrications to fit.
Thanks for the patience. I'm learning. (very quickly) thanks to this forum.
Oh yeah....every little hp counts (in my eyes)...specially when its a part cheap as a cat.

[natural3800]

Re: High Flow Cat questions

This has been on my mind for awhile too. I tought that if you went up a size say from stock to 3 or 4" it would depen the sound but make it louder in the high rpms, or give it that toe tump sound. I have a question also, how can I acheive that toe thumping sound of big block Chevys? Will headers, cat delete, and 4" bullet style muffler acheive that?

[Fbody3400]

Re: High Flow Cat questions

The way for you to achieve the cam thumpin' sound of a big block chevy would require you to have a big block under your hood...

Headers, !Cat, and an aftermarket muffler alone will not make it sound like its cammin' hard unless you actually have an aftermarket cam that thumps.

[sdm1234]

Re: High Flow Cat questions

the larger diameter your exhaust pipes are, the deeper the sound will be. The better better flowing your exhaust is, the louder it will be. That's how imports get that extremely low note. The muffler is just an extremely large bellow, with a 6in diameter tailpipe. Installing an aftermarket cat will not make your exhaust any deeper, but it will help with dB ratings somewhat. Headers will help with the note, because the primary tubes are slightly larger in diameter than stock manifolds. Basically, if you want a deep note, increase the diamter of your y-pipe, intermediate pipe, and catback.

Oh yea, I almost forgot. The more packing is in a muffler, the deeper the note is. The packing gives it a "throaty" tone. For that extremely low note, I highly recommend Dynomax Ultraflos.

Below are links to my two different exhaust systems. The car is a '97 TA WS6 with the LT1, but the concept still holds true. The first link is my car with nothing done but a new Ultraflo Muffler. Notice how low and "throaty" the exhaust is. The second link is a completely new exhaust system, consisting of midlength headers, a high-flow dual-catted y-pipe, and the SLP LoudMouth1 CatBack system. Notice how loud and ear-piercing it is, but yet it's still not as deep as the Ultraflo. I hope this information and the audio clips help!

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[slow6]

Re: High Flow Cat questions

Basically, if you want a deep note, increase the diamter of your y-pipe, intermediate pipe, and catback.

doesnt the cat back come with a Intermediate pipe?

good god, that loudmouth is loud! ;) I like the UltraFlo too

[Bluebird_1251]

Re: High Flow Cat questions

Thanks for those clips and the info....much help.
But still....will a high flow cat fit stock sizes in/out? or is fabrications involved?

[slow6]

Re: High Flow Cat questions

it depends on if you have stock 2.25" intermediate pipe or whatever size...
it depends on what size the cats pipe is going out
they have to be same size
or you have to get a pipe that will merge the different sizes, I think its callled a reducer or something
good luck

[sdm1234]

Re: High Flow Cat questions

Anything to help a fellow enthusiast!
You can definitely find an aftermarket converter to fit your application. They make them all different sizes. They don't usually make different sized in/out diameters, though.

[Bluebird_1251]

Re: High Flow Cat questions

I have no clue as to what stock sizes are......but I guess I can do a search or something.