It depends on your mods,bigger turbos will suffer more so..Also cat size/design will matter....

Yes, 100 cats will quiet it down a bit and change the nature of the sound a bit, too, but the muffler design is more important. If it's an overly loud muffler/system design to begin with, adding cats will only do so much. Listen for the tonal change from cats to no cats in the video below...

Our SpeedTech 3.0 X-Flow muffler design does a very good job of attenuating the sound, while retaining a full 3" flow and an agressive note at the same time. Without cats, our 3.0 sounds very raw and race-like, but it's not over the top loud. IMO, it's actually pretty nice mix - loud & raw, yet comfortable at the same time. But I wouldn't go flooring it by police :-)

I have a video comparing our 3.0 Loud with and without cats, so you can get an idea of the difference cats make and hear for yourself...

SpeedTech 3.0 Loud - 100 cell vs. catless video:

Haha! Nice shot Paul!

I couldn't really hear it over your loud stereo jammin Justin bieber

I would do something without cats that you can add to later if you wanted. Does sound sick without but it may get old depending on you and how much you drive it. Oh and the cops.
Nice roads John, sounds great!

I had a 3" catless, mufflerless x-pipe on my car for the last 6 months. Was using it as a daily driver on a 25 mile bridge for a little while. It was crazy loud at startup, but once the engine is warm it was not loud at all.




The sound of the turbos in a tunnel was hair raising.

..Nice...That is the MagnaFlow X-chamber??..Did you have it made that way.....Good Job and I bet reasonable....

Sam,

For the sickest sound, we have a modular straight X-Pipe that allows the cats to be swapped with bypass pipes. It includes mirror polished tips, too...Here is a picture with 100 cell cats installed

Hey guys,


Don't want to go off-topic here, but I've tried to contact member Lysoleverywhere to find out about his exhaust setup, but haven't gotten a reply. I remember reading about it here on on 6speed, but can't find the threads anymore.

I really would like for my car to sound exactly the same. I remember it being a custom 3" x-pipe exhaust, but not more (cats or not etc). Does anyone know who built this system?

Thanks for the help!

As far as my contribution goes, catless on these cars is not half-bad. you'll be fine.

Best regards,
Yannick

I have GMG's catless X-pipe exhaust on my primarily street GT2. To me the sound is perfect. No droning on the highway, but racy. I have not noticed any bad smell other than what I would consider normal fuel smells for a serious performance car.

i have a fabspeed gen 1 exhaust, catless.
its one of the loudest cars ive ever heard (on cold start).

will NEVER do it again.

HEY,Have you seen the way Protomotive does his X-pipe.??It is different then everyone elses...Since you are into the flow thing,as I am,check it out...I believe his way is very good also......

We use Protomotive 3" X-Pipe on stg1, modded vtgs, Alpha 3076, GT3076R's and +1200whp 3.8l w/GT35R's and it works damn good!

Im pretty sure thats the exhaust I had. If I remember correctly, Lysol sold his car and I bought the exhaust from the new owner.

Ive got a PSI exhaust that's catless. It's not an x-pipe design but I have had a few turbo and NA cars in the past which I removed the cats on. Here's the scoop, on cold starts without cats is very loud for the first 30-60 seconds until the air pumps kick off (I believe) after that sounds tame. You will get a bit more raspiness without cats. Yes you will notice more of an exhaust stink going catless than having cats but not sure how much of a difference with the 100 cells as I've never ran a high flow cat ever. My two cents are if your modding a turbo car running catless is the only way to go:
1) Quicker boost and throttle response
2) Option of running leaded high octane race gas/mix which gives the car a few more ponies
3) Less expensive than buying cats (few hundred $'s to go towards your flash)
4) Hearing the turbos spool is pure ecstacy.
I would try going catless first and if you don't like it slap some cats on it just tell your exhaust guy to make it so it will be the easiest for him to modify to cats if you don't like it. I love every aspect of a catless turbo car why spend more money for less performance? Hope this helps with your decision. Good luck!

This is why X design is a must.