CLBrakesuk

Hi Guys, I am looking at replacing the stock cats on My Late December 2018 GTS 4 GTS.
Has anyone here done something similar?
It would be in conjunction with a stage 1 map, and an ITG free flow filter.
Ideally id like to see more power a little more noise (not sillly).
Here is a link to the Cats in question,

Porsche 911 991.2 Carrera Downpipe with 300 Cell Cats (topgear.co.uk)

TIA

4 Point 0

Yep. I did 300 Cell Akrapovic cats, Vektor headers and COBB tune. Noce sound difference, not too loud.

Then later Pro tune E40, and other mods.

After 3 years of tracking, the cats clogged.

Went catless. Way more sound and turbo spool and power.
Sounds mint with valves closed, not too loud. But when they open the oops an crackles go off like a gunshot.

CLBrakesuk

How come the cats clogged?

spdracerut

Heat over time on track. Good cats last longer. Cheap cats fail quickly. They all fail eventually.

DBH

Why would you buy 300 cell cats from a UK firm when you can get high quality 200 cell cats from reliable and vetted USA manufactures who happen to be recommended Rennlist members?
BTW, I happen to have Soul cats and Vektor headers installed on my "18 GTS and after ~2years I'm entirely satisfied.

NJ991

You’re on the right track as far as mods and what you want out of them. I would question the brand for the cats you linked. With you being in GB, you have access to a few popular brands. I would search around. Do the same for the tune. You’ll get quite a bit of power from the tune, that’s immediately noticeable. Good luck

CLBrakesuk

I am in the UK, this manufacturer makes them for a US firm that is very popular on this very forum!

Speed2k

Most manufacturers use a 200 Cell cat, I don't recall seeing any reviews for a 300 cell unit before. HJS catalyst units are supposedly amongst the best, these units usually cost more though.

4 Point 0

See below. On our cars the cars are very close to the turbos. Akara use the high quality HJS cores. I was lucky to get 3 years. My son killed some cheap 100 cell cats in 3 weeks.

Catless is the way if you track.

CLBrakesuk

I'll maybe do 2 a year, do the OE cats fail if tracked too?

X-PH.COM - MIKE

+1 if you want to upgrade the cats without the flaws of catless, get HJS they are the best quality cats on the market.

DBH

Didn't realize you are UK based. Please enlighten us as to who this US firm might be.

MingusDew

Why do race cars have cats? Pretty much every racing body, from IMSA to FÍA has requirements for race cars to run cats, some are required to run factory supplied parts and others use aftermarket but approved by the race series. Most of these cars have 500-600hp. Formula 1 is one exception I’m aware of where the cars don’t run cats, but it’s really the exception to what is the norm. Is it just a cost thing for tracking, i.e., the pro race teams have budget for replacing cats every season but as an amateur it’s just easier and cheaper to not deal with them?

fsmich

I too had Akra cats, and decided to go catless, after seeing pics of yours. ( mine MUST be clogged too, after 4years, 30,000mi, 60 track days) Nope, they were fine!

Put the Soul bypass pipes on anyway, and love the sound. Quiet with the valves closed, Track worthy sound when open

Here's a take on Ethanol and Cats

Ethanol and ZDDP

Your engine's cylinders never achieve an airtight seal; at best, they'll always allow at least 1 percent of the combustion gases to escape past the rings and into the crankcase, where the oil is. The problem with ethanol is that it's highly reactive with phosphorous, combining with it to produce any one of several free-floating phosphor compounds. These compounds get sucked up through your positive crankcase ventilation system, sent through the motor and then make it to the catalytic converter. Once that happens, you're looking at converter poisoning not directly as a result of the ethanol, but the way that it interacts with the phosphorus in your oil.

https://itstillruns.com/effects-etha...-12172217.html

4 Point 0

Don't zero in on the fact they are forced to have them, to cater to some made up environ-mental disorder. We are not talking about race cars or even other brands of cars. We are SPECIFICALY talking about 991.2 Carreras 3.0 TT's.

I am not generalising. Its mainly the LOCATION of the cats. They are too close to the turbo's. Most race cars are front engine and have room to move the cats as far away from the engine as possible. This has absolutely zero to do with our cars. We cannot move the cats further away. Race teams can move them anywhere they want, again zero to do with us.

IF you think you're being green by running cats at the track and constantly replacing them, then Have at it. I prefer the power and the sound. I don't wish to be fed climate crap. I also don't want to be constantly changing them. Its a waste.

FSMICH : I do believe and have seen first hand evidence that E85 and E40 significantly contributes to accelerated cat decline.