Ditto. No cats here with a SpeedTech 3" X-flow system. The cross-flow design takes nearly all of the drone/obnoxious noise out of the exhaust. It's only loud at WOT when I want it. Cruising is beautiful - perfect melody. Ditch the cats.

 

Add me to the catless bunch. I love the sound of the 3" X flow catless.
Just burn race gas and it smells wonderful

Ohio guys, alls you have to do is get collector plates and you dont have to emission test ever.

 

Mikegr yes my car has an epl stage 2 flash. If you don't have a flash or o2 bung extenders you will get a cel. But the car will run fine and won't go into limp mode. As well I hear the o2 extenders work for awhile and then a cel will come up causing you to clear it periodically.
Plus a flash is by far the best bang for the buck.

 

Cats will straighten the airflow coming out of the turbo, especially due to their proximity to the turbine on these cars. Doesn't necessarily mean a lack of flow, but you can definitely hear a not cat system spool vs a cat'd system. Keeping the air spinning is never a bad thing. I will go catless for sure when it comes time to put a system on my car.

 

I had a catless 2.75" cross system and would roll up windows at light due to the smell. Not as bad as my straight pipe adventure- that was just stupid.

My pick would be 3" cross with high flow 100 cats.

But the spool sound with straights was incredible!

 

I am running the FVD race pipes (straight, no cats) for 95% track work and would offer you the following.

Would NOT recommend it for primarily street use.
Cold start very loud and obnoxious
Heavy drone at 1500-3500 revs
Throws CEL's for rear O2 sensor when running on the street (not when on the track)

Having said all that I LOVE the set up for the track. The noise actually helped the driving as another input, and the weight off the rear really brought it to life.

 

I'm on a cat less fabspeed gen 1. Smell is not noticeable. The sound was barely louder after I went cat less. No check engine lights. My vote is catless.

 

I did the 100 cell cats, but w/o an X-pipe or muffler. It is LOUD! The only reason I have the cats is to quiet it down a bit. I have an X-pipe in my garage, but my exhaust guy said "It does not make sense to put an X-pipe on a turboed car because there is no pulse from side to side, and the exhaust will flow better w/o all the extra bends".

I may still add the X-pipe though, because I would like to tone down the noise a bit more. It's confusing because I have heard the X-pipe can help and hurt HP??? I guess it's the system as a whole that makes the difference.

I have never had issues with the smell on my other turboed cars w/o any cats. That would not be an issue, I'm guessing. Sound and air-flow should be the determining factors IMHO. If you don't mind the noise, go catless is my vote. Your tune should be able to delete any CEL issues.

 

In Arizona, you will have to have collector car insurance, or live out of the main city's to avoid emissions tests. Grundy is a great ins co. I had a drugged up woman force me off the road once and caused some damage to another car I own, and Grundy had my full payment for repairs to me in 3 days....The police report was not even written yet. Grundy allows unlimited mileage as well!

 

I'm also rocking the fvd pipes and I do not have drone from 1500-3500 thats straight absurd! I have drone from 2200-2700ish that's it. While criusing the pipes sound great, cold morning start they are loud. Not for the faint of heart, not for people living in association equipped homes lol, not for people driving at 4 am. I love them.
I love hearing my turbos spool up and spool down like jet planes. Wife got use to it.

 

If you go catless your car with have an exhaust smell like real cars used to. People forget what cars used to smell like so might freak out. If you don't have emission testing they go for it. You will have to get a flash to override the second set of O2 sensors.

 

Still not yet installed on my own car, but thanks again for the great sale transaction. I look forward to being able to answer this question soon!

 

How much performance loss are we talking here about going to 100cell cats?

And sound wise do they quiet it down a lot? I went to listen to a 3" Xpipe exhaust today with no cats. It was pretty loud.....

 

What smell, I must be deaf and have no sense of smell. What are you guys smelling, I smell nada.
who in this thread actually has straight pipes???

 

Also depends on what turbos you are running, when we ran I had the catless 3" xpipe race system with K24s

Since you had lots of time behind me during the run. You should have a great idea how it sounds