When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I’ve felt the throttle response isn’t as precise or instant on my GTS from a stop. Is this where you saw improvement?
Definitely. It's very noticeable down low when you get on it a bit. This is all seat of pants feel, btw - nothing precise, no instrumented tests - but it's def improved. I think where it was most noticeable was how it pulls now even without dropping gears from low rpms. That occurs more frequently in normal driving than aggressive starts from a stop, so it really stood out.
Dropped mine off yesterday but my mechanic found a small oil leak. Decided it was better to keep the stock cats on for now and have the dealer address the leak first.
Cats are on -- the sound difference isn't very obvious; perhaps slightly more tone and some turbo whine. When getting on it above ~4k it's def louder but not at all obnoxious. I drove most of the way home with the top down and the sounds this motor makes are just so glorious; now a bit more so.
The most obvious difference from the cats is that the motor revs more freely, leading to the improved throttle response. It also pulls noticeably harder from low rpms even in upper gears.
I had the Numeric shifter installed at the same time. It's much more precise, shifts are much more satisfying.
No CEL I assume ?
Was Numeric shifter worth the cost in your opinion?
Was Numeric shifter worth the cost in your opinion?
No CEL yet — I don’t anticipate one given explanation from stef as well as others’ experience.
Numeric .. I like it. It’s not the night and day difference I was expecting from some of the descriptions. There was a rennlister that likened it to operating the bolt on a bolt action rifle. I think that’s overstating it. Would I do it again - probably. But not a no brainer for me.
What are the HP gains from these? I do want downpipes for the increase in sound, but some manufacturers claim 30+ hp gains while others don’t mention any sort of gain.
A quicker spool up and a noticeable gain up to 3500 rpm as shown on the dyno chart:
Could someone with factory sports exhaust please do a interior cabin decibel test before and after installation of the 200 cel cats?
Both with and without the valves open?
Interesting mod, but honestly I don't want any additional noise inside the cabin, but like the idea of freeing up the turbos a tad.
Thanks!
My set should arrive on Friday. I can update with apple watch measurements - perhaps not the most accurate but better than nothing. I'll try to do inside (idle, rev to stationary limiter, 1800rpm cruising, WOT max) and outside (stationary idle and rev to limiter). I'll post in this thread once I've got it.
I have the M Engineering tune coming too, so if I'm feeling ambitious I might test the above permutations before/after sport cats and with/without the 100% valve open mode on the tune.
Normally the 100 cell cats are used for racing purpose only. The Cup cars use them and so does the 991 GT2 RS Clubsport. Emission results aren’t really important on these car, actually they don’t even have an O2 sensor so no CELs either. You won’t get really good emission results with regular off the shelf 100 cell cats.
We use Vitesco-Continental 100 cell cat cores with a proprietary coating. It’s expensive but we’ve been doing this succesfully for nearly 30 years now. Catalytic convertors are defined by their size, cell count, foil shape, washcoat and its amount of precious metals. The washcoat is a porous primer that multiplies the surface area of the cats by factor 100 to 10000 depending on the type of washcoat the $$$ you want to spend. There are several companies that apply the washcoat / precious metals onto cat cores. There’s Corning, Degussa, Johnson-Matthey, Umicore etc.
Umicore is one of the largest companies and is located in Hoboken just 5 minutes from our shop.
We’ve never used 200 cell cats really. The older 996 Turbo, 996 GT3, 993 Turbo etc all use 300 cell cats so I’ve always skipped the 200 cell cats and went straight to the 100 cell ones.
We offer a 4 year warranty on our exhausts and on the cats, on any issues or CELs.
Here’s the emission results of the stock exhaust, our 100 cell Europipe cats and a catless setup all measured at idle and near 2500 rpm.
The CO and HC are poisonous.
You have a shop near Hoboken New Jersey??? Oh never mind. Hoboken in Belgium/Holland area
Honestly, the more I drive with them, the better they get. It’s actually a crime to smother this motor’s power and sound if there’s an option not to without any significant negative effect to emissions (based on stef’s posted tests).
Is there an option to purchase just the sport cats without the mufflers for the carrera (OPF model)?
the europipe website only has the muffler+cat combination for OPF Carreras.
if there is, assuming it will fit other aftermarket slip on mufflers like Akra, and will it throw a CEL?
The sport cats will fit but they will throw a CEL for not having the proper OPF pressure difference, that is correct.
On our OPF sport exhaust we have an small area ahead of the cats that connects with the first OPF bung and subsequently with the differential pressure sensor. The second OPF tube is connected with a specific nozzle inside the muffler. The pressure difference between these two is equal to the pressure difference of a new soot filter so you’ll get no CEL.
The sport cats will fit but they will throw a CEL for not having the proper OPF pressure difference, that is correct.
On our OPF sport exhaust we have an small area ahead of the cats that connects with the first OPF bung and subsequently with the differential pressure sensor. The second OPF tube is connected with a specific nozzle inside the muffler. The pressure difference between these two is equal to the pressure difference of a new soot filter so you’ll get no CEL.
This changes things. Might really consider this over an Akra set up then. Not keen on a tune just to have to code out the CEL, and I’m thinking the sound improvement on the Europipe sport exhaust system will be better compared to just the Akra slip on (without link pipes).
08-25-2022, 02:04 PM
