Having just installed a Hi Flow Cat,

I cant comprehend how you guys can stand the noise output with a mid pipe

I already got a few middles fingers pointed at me by the neighbors

 

now wait till you supercharge it and see how loud it gets! But thats half the fun of the rotary! only problem is the cops can hear you coming from miles away!

 

Just shoot some flames at them.....unless a highflow cat won't do that....then I'd say you're SOL because the sound and flames would be the only benefits for me to get rid of the stock cat.

 

And my supercharger getting installed now O.O

 

a well designed midpipe with a resonator does not sound overly loud. But when you mash on the throttle.. oh boy is it different... in a good way.

 

all sorts of wierd noises are coming out now with hiflow cat, some sorta of low vibration metallic rattle. Its confirmed its not the heat shield from the muffler
Dunno what, thinking something bouncing against the promaz coil bracket at the moment =/

 

Were all the gaskets installed when you replaced your CAT?

When I installed my RB mid-pipe this weekend, I forgot to install the rear gasket where the mid-pipe connects to the cat-back (the connection with the springs, not sure what it's called). This caused a nasty vibration that resonated through my entire car.

I ended up salvaging the old gasket from my stock CAT and installed it on my new mid-pipe, couldn't believe the difference it made, no more rattle and the exhaust is now much more quiet. It's actually not much louder than it was before I installed the mid-pipe.

Not sure if this is what you are experiencing, but I thought I would share.

 

Hi flow cats shouldn't be as loud as you're describing. You must have a bad cat or you installed it wrong.

 

I havent posted the vid or write up on it yet, but... I bought the Rx7 store hi flow cat, installed it on my mazdaspeed dual can exhaust with Mazdaspeed intake and i agree... It was terrible. I sounded like someone handed me a coffee can with rice and pennys in it with a Honda Civic pushing it down the road.

I went and had a resonator installed on after the cat, just like the stock set up and now, WOW!!!!!!! I cant complain. Its deep and throaty. LOVE IT! So before you consider tossing it, consider toning it to your liking. I notice the difference when its on or its off. Just last week i put the stock mid pie back on so i can go to the dealer for some work and boy did i notice the difference.

 

It has a resonator on it

The rear gasket, the rear has nol gasket at the moment i think, didnt check when i picked it up. If i remeber correctly the flange has nothing in between and is held together by two bolts with a spring on them, is that right?

Regards
Jason

 

There should be a round lead gasket that goes between the midppe and the exhaust (in between the flange and the conection where the bolts with springs are. and up front there is a crush ring between the header and mid pipe.

 

What size resonator?

 

my Rmagic cat is about 3-4db louder than stock cat, but the sound is definately deeper and sexier!lol
it's not that loud at all. rmagic says its 95db with rmagic muffler.

 

it is a very low frequency vibration that occurs
when i go from neutral to drive or reverse.

It makes a loud metal on metal vibration,
whilst driving i believe it makes a higher frequency metallic rattle

i can only hear it when i drive next to a object like a wall or something.

At the moment my mechanic reckons its the coil bracket

However i swear to god its coming from under me,

i believe its either the
cat heat shield
gasket

i dunno.....

 

ok now the rattling is getting really loud at 3k rev
My mechanic its becomes my ignition bracket is broken..

But i never had this pre cat installation.

Therefore it MUST be the cat right?

Regards
Jason

 

There are 2 cross support brackets that are under the mid pipe. My rear one was a little close to the pipe and when i put a load on the engine, the torque made it move just enough to slightly touch the bracket. I bent the bracket down and it went away. Could be? Also, you really need to get the gasket put in.

 

My exhaust would rattle around 3.5k. Turns out, one of the hangers were pushed in too far and the tone was just right around 3.5 to vibrate it enough to hit the metal. Bent the hanger out and its fine now.

 

Had a similar issue. Installed hi-flow cat and noticed a horrible rattle at idle. finally narrowed the sound to the rear driver-side exhaust hanger. Apparently the new cat was a bit different shape and caused the exhaust to rattle just around the hanger area. A bit of hammering and bending and there is no more rattle.

 

sweet, i think this is the same problem i'm having.... i was getting a high pitched rattle and thought my cat was going bad. i remember the support brackets being really close to the pipes. back under the car i go. lol

 

thanks for the help guys, dropping car off tomorrow, will tell him of these issues.

Will post whether it worked or not

 

Good luck.

 

it's the cross members (as Rota II) pointed out.
I have the RP high flow cat paired with Racing beat header and Racing Beat exhaust; LOVE IT!

 

Ok, apparently my coil bracket was broken and i had the first trialing coil floating around in my engine bay.......

 

That could be good!

 

well engine rattle gone now....

The exhaust one is still there, ive put spaced on the cross members maybe its not enough...

however it sounds like its coming from behind... i dont know.

Rattles you never know where they are coming from ARRGGGG

going to exhaust shop tomorrow