Currently have O/R Mac prochamber and Mac catback. I really want to quiet the car down some. I'm thinking of ordering two Magnaflow obdII compliant cats and having them welded in to the prochamber. My question is: How much quieter will this make my exhaust? If it's barely going to make any difference, then I'm not sure I want to do it.
Will high flow cats quiet my car down?
- Thread starter mjh78
- Start date
It will definitely make a difference. The exhaust won't be as raspy and the tone will be much more smooth and defined. MAC mufflers are loud anyways. I had the MAC o/r h and the flowpath catback at first and it sounded sweet but I got sick of the noise, so I installed a magnaflow catted x-pipe. The after installing the catted x, its still loud especially when you're on the throttle, but much more bearable and IMOP a much higher quality exhaust sound.
Get the cats welded in, and if it is still too loud buy a pair of Magnaflow mufflers
Get the cats welded in, and if it is still too loud buy a pair of Magnaflow mufflers
SteedaGT9150
Advanced Member
It will definitely make a difference. The exhaust won't be as raspy and the tone will be much more smooth and defined. MAC mufflers are loud anyways. I had the MAC o/r h and the flowpath catback at first and it sounded sweet but I got sick of the noise, so I installed a magnaflow catted x-pipe. The after installing the catted x, its still loud especially when you're on the throttle, but much more bearable and IMOP a much higher quality exhaust sound.
Get the cats welded in, and if it is still too loud buy a pair of Magnaflow mufflers
what this guy said pretty much.
It will definitely make a difference. The exhaust won't be as raspy and the tone will be much more smooth and defined. MAC mufflers are loud anyways. I had the MAC o/r h and the flowpath catback at first and it sounded sweet but I got sick of the noise, so I installed a magnaflow catted x-pipe. The after installing the catted x, its still loud especially when you're on the throttle, but much more bearable and IMOP a much higher quality exhaust sound.
Get the cats welded in, and if it is still too loud buy a pair of Magnaflow mufflers
yep, what she said......
I went with and o/r X pipe with my LMIIs and switched to a MRT catted H.......Much better sounding, quieted it down some, plus a much more better muscle carish tone, Raspyness is completely gone.
yep, what she said......
I went with and o/r X pipe with my LMIIs and switched to a MRT catted H.......Much better sounding, quieted it down some, plus a much more better muscle carish tone, Raspyness is completely gone.
I AM NOT A SHE *adjusts bra*
Thanks. I'll give it a shot. the cats should be here tomorrow. They are the compact ones as not much else would fit on the straight section of the prochamber. Just tired of the damn noise. The drone at around 2K rpm is just stupid and I'm tired of everyone knowing exactly when I leave and arrive at places. And another thing....shortly after taking a drive when I put the prochamber on a couple years back I thought to myself....damn, this car really feels different off the line...sluggish. Now I've heard everything from "it's in your head" to "it pulls stronger up top so it feels weaker down low in relation" to "its louder now so your mind is telling you the car should feel faster, but it doesn't". I'm sure there's no way the actual #'s with the cats on and off can be significant at all, but I honestly was disappointed in the way the car felt after putting the prochamber on...and it was NOT in my head, I could tell an immediate difference. I truly think there was a loss on the low end with the cats removed. but I loved the sound and it was a PITA to put it on so I was like ah screw it, Ill leave it on.
There's probably some truth to what you experienced. I've heard from others that completely freeing up the exhaust after the stock manifolds will cost a few ponies down low, but it more than makes up for it in the higher RPM's.
Honestly if you hate the drone, adding cats wont really make much of a difference. On my car the drone is slightly less intrusive, but still present w/ flowpaths and the magnaflow catted x-pipe (compared to the o/r mac h-pipe). If the noise really bothers you, I bet a pro-chamber w/ welded in cats and magnaflow mufflers would sound f'n awesome
Something you may want to consider.
rispoli_23
Member
- Jul 7, 2008
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Well the cats did the trick. The car is far from whisper quiet, but it's much much better now with the cats. Just much smoother and the drone is drastically better too. And sure enough right when I pulled out of the shop..the car just flat out felt different, to my delight. It just seems to pull a little stronger right out of the gate with the cats on there. The O/R pipe is just not my thing. I was really starting to get annoyed with my damn car. I enjoy driving it again now.
When you remove the cats on your car, you eliminate all the back pressure you may have had. No backpressure means no low end torq. With the loss of back pressure, it requires you to not build up enough pressure until higher in the rpm range which is why overall you do gain more hp with an offroad pipe but unless you have something to compensate for the pressure losses then your car will feel much slower accelerating.
HawkX66
Member
7 year old thread, but what you say isn't necessarily true. Back pressure needs are relative to what the big air pump under your hood needs. On a bone stock car, you might be right, but with any mods at all I'd say not. My 4.6 has a Flowmaster system, X pipes and no cats. It sounds excellent (other than the rattle I'm chasing lol...) and I doubt you'd notice any low end torque missing. If you put headers on that are too big, that's another story all together.
