I know I'm resurrecting an older thread here, but I'm wondering if anyone found good modifications that quite this system down a bit? I just installed the Kooks LT headers and 3" TD non-catted on my car, and I can agree it's just too loud. Would like to quiet it down a little.

 

I replaced the kooks bullets with a pair of magna flow bullets.

Quieted down quite a bit but still loud enough to enjoy the cubes.

 

Good to know this works. that's what I plan on doing when I install the kit I bought. Did you cut out the kooks mufflers and weld in the magnaflows or bend new pipe and get new tips so it was just a clamp in replacement?

 

If you have a big stall, this exhaust is loud as hell. It's not too bad in the car though.

One thing you can do - add hushmat or something similar under the carpet. It'll reduce heat and noise.

 

If memory serves, my shop just cut out the R300 Kooks bullets and just welded in the new Magnaflow bullets in place.

Retained the Kooks Tips.

There's actually a decent amount of space on both sides to swap in a variety of bullets but I like the Magnaflows; and the exhaust note turned out fantastic.

 

Hmmmm....I must have the quietest Kooks system on the planet, or I'm going deaf, lol. I think its getting louder, but nothing like what you guys are claiming.....

 

It's not the volume that's so bad for me, though it is pretty loud. I feel bad when I drive through quiet little neighborhoods. But it's the rattling. There's something rattling down there and it drives me crazy. Plus it's very raspy, though I've heard that putting cats in should fix that. I'm considering doing that.

 

Any sound clips?

 

Sent you a PM.

 

Bringing this back to help out a few of us having the " Way Too Loud" issue.

Now: my build will never, ever, never Ever Ever be stealth or remotely quiet. It will never even be civilized. I like volume & a little rasp as much as anyone. But this was obnoxious. I'm not talking about some Prima Donna " I cant have hear my wife yell at me while I'm driving" complaint. I'm talking about exterior bellowing that made every hard hitting pipe welder come out of his shop to see " what the hell is that racket".

I know some are quite satisfied with the volume & tone. However, for me it must have much to do with the cam, no-cats & the high HP level. Either way I finally got it down to something l can live with. NOT AT ALL quiet. Certainly ( for me) a livable volume & the sound is what it should be. A smooth, deep & powerful Kooks sound. The one we love on all the You Tube videos.

Including the original R300's, I've been through four sets of mufflers in the past three weeks. Please keep in mind that we are speaking about a build that is O/R & supercharged ... so this is not a bash to Kooks. This is directed to the crowd that has a bit more HP, big cam & complete O/R set up. All in an effort to help.

I will say that this Kooks system is a work of art & the fitment was spot on. Flow rate & X-Pipe are a giant upgrade from the typical Y-Pipe system.

#1. original Kooks R300 mufflers:
I was a bit disappointed. The result didn't have that smooth & rasp free tone that Kooks is known for. My build turned out sounding like a farm truck. Sitting still & free revving was deceiving as it had all the qualities you would expect. However, once on the road it took on a very obnoxious tone. Much rasp at low RPM & a sheer volume that could raise the dead. I was the guy ( we all know this guy) who's car was so loud that even us motor heads would cringe.

#2. I chose Billy Boat C7 ( second generation) Bullets for the replacement. The size is 6" round ( which is only 1" larger than Kooks R300). They are exactly the same 12" in length. I wanted the smooth sound without drone. I know they are known for sound canceling qualities & every Vette I've ever heard them on was simply perfect. Not quiet at all. Something you can hear from 50/100 yards away. Very aggressive. Well, my car is not a Vette. It obviously couldn't convey the same acoustic. It was drone free ... but nearly the same bellowing volume as the R300's ( in spite of larger size, sound canceling tech. & packing material). They also produced harsh rasp at low RPM throttle burst. I couldn't get into the high revving harmonics at any RPM, the attention drawn by both systems was mind boggling.

#3. Pro Series Hushpower Shorties ( Flowmaster):
I know Flowmaster gets a bad rap ... but after seeing (a few posts back) that someone had moderate success with them I decided to research. The laminar flow technology seemed interesting & I was convinced that they would stifle Godzilla. They were the exact same size & shape as the BB's. So ... get out the torch !
No good. The sound was a hair less in volume. ( I know, you say with that much muffler how can it be) I don't get it either ? None the less, they were a bit toned down on volume but the drone was insane. If anyone has experienced drone & high volume you know what I mean. Drone hit hard at 1,400 & carried through to about 2,000 ( which isn't bad as you can control it by gear). Its just getting through the gears which was eyeball vibrating. The volume .... still way above any street car worth driving. Again, low rpm rasp which sounded like a hammer.

#4 ( for the win !!!) MagnaFlow 12219 oval muffler:
Limited in choices with 3" in/out. I started to realize that no bullet or round muffler on the market was going to cut it. I've had great success with Magnaflow in the past. I wanted desperately to install the very simple MagnaFlow bullet but the only one that stood a chance was 18" in length. Never going to fit. The oval race mufflers would have left me in the same exact position I was in at that point, too small & not enough packing to absorb the volume, combined with the straight thru design it leaves no sound canceling attributes. I went with the straight thru 5'x8' oval series. The case is 14" long. We were able to seat them vertically and squeeze them in place. They do show a bit lower than the rear Qtrs (view from the side) but you have to be at ground level to see that. ( for reference: 8" set vertically would actually add 1.5" top & bottom to the size of the R300)
The sound was right !
The volume is few decibels lower. Still a loud car by all account.
The tone is smooth ( like you would expect from Kooks sound). I can finally hear the smoothing effect of the Xpipe.
No Farm truck ( Hammer Rasp).
Idle is still surprisingly loud & distinct. ( it did not muffle out the cam chop).
No drone ( other than what could be expected from a 3" & still quite loud system)
At cruise 1700 - 2100 RPM ( like all MagnaFlow) it mellows just enough to finally hear the radio. ( before this ,,,, I'm not joking ..... the stereo system at 1/2 volume was none existent & no such thing as a conversation with another human being).
WOT screams like a demon. ( No stopping that nor did I want to).
Down shifts still burble & pop. Not as much as I would like but I can live with that trade off.

At the end of the day I'm satisfied that the sound is closer to what I expected.

Know this: On a heavily modified build ( which most of us ... who are looking at a 3" dual system are), nothing will make this a quiet system. If you need a No Cat, full header with a cam system you are looking in the wrong spot for anything remotely stealth.

I'll get some install pics & sound clips shortly.
Hope this helps.

 

Still tuning.
Idle & 3,500 revs

 

Video / sound clip attached

 

That's way more mellow. lol

 

That sounds pretty good. A cam on a 111lsa vs a 115lsa will completely change the sound of this system though. That sounds more in line with kooks tds on a bolt on car.

 

Short 3k pop.
Still breaking in the clutch so I can't lay into it, but you can still get the basic tone.

 

Sorry to bump this back up, but Its still an ongoing problem for people. Magnaflow 12219 Sounds good in the videos! Im trying to decide between magna flow 12219 and flowmaster DBX now. I was going to try borla xr1 but I think those will end up still too loud.

 

That sounds good.

What about a resonator where the Cats would go?

I only really have an issue at 1600-1900 or so in my setup. Which is cruising RPM for me. But mellowing it out overall may not be bad with a loose 4k stall that revs to 3k+ in normal traffic.

 

For me the resonator is not an option as I'm too low. I know it sounds crazy .. Even another 1/2" would be an issue. I had to wiegh the look & stance I wanted over the sound options & I chose to go this route. With that said, I'm not sure why others (without hieght issues ) don't try it ? I also contemplated a resonator in the "old stock" muffler location. That only covers the drivers side. Where do I put the passenger side resonator. ( on my car, after the x is the lowest point).

There are a few very low profile resonators out there. One of which is made by SMW. Smooth tube. I thought I could use this one because the outer dims are only 3.5". But I believe the effective inner diameter is only 2.5". So that went out the window for me.

 

Selfishly I hope you do try the XR1's. Those were on my list of potentials but I felt the same way, the probability of them being just as aggressive as the others was very high. I'd love to hear the result.
While I like what I have ( to Jakes point) it is a bit civilized. Not melow , but I do miss the violent & angry sound. The problem being every vehicle is different.
LT Headers, Cam, no cats & lots of air ...... Change the game as it pertains to exhaust note & overall sound.

 

The fact that the xr1 mufflers are over $500 for a pair really makes me not want to try it considering the fact that they more than likely will still be just as loud, but maybe a better exhaust note. I think the magnaflow mufflers sound awesome on your car and looking at your sig my setup is very similar to yours. The flow master DBX laminar mufflers look like they would quiet it down more than the magna flow since they aren't a straight through design. Really wondering if i should try those first. HMMMMM. They are expensive also though.