GBX

Anyone have real world experience w/ sport cats in our cars. I know very few run them in favor of a bypass....but I have no desire to bypass the cat. With that being the car, is a sport cat worth the money or should I stick with my OEM cat?

Vandit

The problem with the 964 sport cats on the market is that they're stupid expensive. They're like $600. I was trying to haggle a used Fabspeed Sport cat off of Craigslist but the seller wouldn't go lower than $400.

I mean, you can get a universal metal core Vibrant race cat for $100 (200 cell, 578 CFM). Then find a competent muffler shop do the rest. I've been meaning to do this but no time, and since I'm barely driving the car, no urgency either.

GBX

I don't mind spending a few extra $ for a good sports cat but want to make sure they actually flow better then stock and increase power....

Fabspeed actually seems to be the only reasonable one at $645...they go up from their.....FVD's is almost twice that for a 200 cell.

kreeshp

My 964 came with a cat bypass and primary muffler bypass (cup pipe) and stock secondary muffler.

I found the exhaust note obnoxiously loud for city driving and wanted to quiet it down a bit without compromising the performance too much.

Located a barely used 100 cel sport cat (Maxspeed, 6 lbs 10 oz., with heat shield mounting points) sold here by a forum member for $250 and now the exhaust sounds just right to me.

Vandit

Regarding if there are gains with using a sport cat.

Bill Verburg posted some really useful stock 964 exhaust stats in this Pelicanparts thread.

http://forums.pelicanparts.com/porsc...des-964-a.html

Section Flow Rate (CFM)
Catalytic Converter 442
Primary Muffler 396
Secondary Muffler 462

GBX

I probably reread this info weekly and its great info. The thing is that its really only half the story. Flow rates are important. Increasing flow will make more top-end power, but it wont necessarily be usable power. My goal is to only make exhaust mods to achieve usable power, which is why i'm leaning towards a secondary bypass, since Steve Weiner has proven dynos that this increases power on the lower end of the spectrum, which to me is usable power.

I'm obsessing, I know.....

mrmandmman

I've got a fabspeed, wanted higher flow but not too totally destroy the planet.

ChaoticBliss

I am running the Fabspeed sport cat. I actually started with the Fabspeed bypass but didn't like the additional smell so switched to the sport cat. I can't say I noticed any seat of the pants different in power between the two (I am running a Steve Wong chip) so I am happy with the sport cat and no smell.

Mr.Alex

A good 200cel cat should still flow at around 90% similarity to a bypass.

cobalt

I have a Dansk 100 cell cat and magnaflow muffler. It looks identical to the factory cat for DOT purposes (Dansk makes the factory cat and muffler) and offers a considerable increase in performance and sound. I found mine on ebay years ago cheap but it is worth the $600. With a chip the car puts out 290 BHP and 281 torque making for a very strong enjoyable experience. Best yet it passes smog testing with very low emissions similar to modern cars today.

stimpy32

What mods do you have supporting this power output? And where were these figures taken from?

stimpy32

Do you have a link to the results of the secondary silencer bypass pls?

I presume here it was just a G pipe?

GBX

I see that dansk currently sells a 100 cel on automotion. How about a 200 cel. How do they compare? Fabspeed's 200 cel is $650 vs $900 for the dansk unit, although it doesn't have brackets for the heat shield. Which is better?

I don't. But if you search gpipe and Steve weiner's user name you will find something.

cobalt

The car started out with 1-2% leak down and 170-175 compression. Mods are simple cup air box, K&N filter, dansk 100 cell cat, magnaflow 3" in 3" out muffler. Installed by Protosport and tuned using a proprietary chip of their design to optimize power.

here is the dyno sheet. I also dynoed my 928 GTS the same day which was previously dynoed on a dynapac with similar results the GTS showed nearly perfect factory numbers both tests. My assumption since dynos can vary is that the GTS showed similar factory results in both instances on two different occasions I also trusted both facilities which are known for their testing, therefore I must assume these results are accurate. The car pulls very strong and currently has only 60k miles. It had 50k when this was done.

Sorry had my numbers confused earlier it was 291BHP 279 torque calculated using 15% drive train loss which is standard for these cars

I am including the GTS as well which has factory numbers of 345 BHP and 369 torque it had 50k miles during this dyno pull and is in pristine condition. The dynapac actually showed the GTS to have more but the temps weren't as hot.

GBX

Interesting. Would have expected closer to 265 wheel with these mods.