200 cell cats ?

Has anyone done a before and after dyno run with 200 cell cats ?. I'm thinking of getting a set of the top gear ones , I don't want to go to that expense if they don't really provide any gains . I know the difference won't be huge but a few extra horses is always nice , the original cats look rusty as hell so are probably not in great condition inside either . Would be interested in your opinions on this

No Dyno test, my suspicion is that they actually lose you a little torque lower down, but they sound great and look nice so I don't care.

I had the top gear big bore 200 cell cats on my gen1 and they were great , I have cargraphic 200 cell cats on my gen2 also great. my gen2 has been remapped and has a full cargraphic exhaust with 200cell cats and its given the car 4% gain in BHP but a much better power curve especially in the low mid range. :thumb:

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I did a lot of research before going for 200 cell cats and the reason was that I was able to find evidence on the net from multiple sources that backed up the modest but very real power gain. All in all, I would say that it's a worthwhile investment, and probably the only cost effective proven power upgrade you can do on a naturally aspirated 996. Loss of torque lower down is something that stems from there being less 'back pressure' due to the freer flowing nature of the 200 cell cats. This is utter cobblers and 'back pressure' is not something deliberately designed into exhausts. Torque depends on efficient evacuation of the exhaust gasses from the cylinder. Partially blocking the pipe that they go down will harm rather than aid that process. If anybody tells you anything involving back pressure as a genuine 'thing' in exhaust design then kick them in the balls (hard) and walk away. The bore of the pipe has an effect, and at different revs, different bores of exhaust give the fastest gas flow, this is why different designs of exhaust give different torque characteristics. Smaller bore gives faster gas flow at lower RPM and therefore better torque low down. Bigger bore prevents the flow from becoming 'choked' at higher revs where there is more gas to evacuate.

Cheers for the replies guys , your opions seem to agree with was I've read on the net , that it's one of the few mods that will make any difference . I just hope the old ones come off ok as the bolts will be rusted solid ! It has milltek back boxes at the moment , I reckon with the new cats the car will sound even better , if it sounds better it will feel faster , even if it's not 😂

If the bolts at the manifold ends are original then you'll almost certainly need to cut them and then drill or hammer out the studs from the manifold flange. Use stainless replacements from Ebay, or titanium bolts from Ebay if you're feeling flush.

On my car I have tried a few variations of exhaust and cat, I'm now on Carnewal modified cats and there exhaust modification. The car now sounds superb if not better than that. Personally I thought pse is how a Porsche should sound, the Carnewal is a step up and it keeps the proper Porsche sound

I too fancy a set of 200cel cats so good to hear comments on this mod, Drew1209- Would you mind letting me know the details on your system? PM me if you like don't want to go off topic on this thread too much, I have DANSK silencers that came with the car although they sound nice I miss my old PSE from the one I sold, It sounded like nothing else and I don't fancy paying out the price a new one is! so would be very interested in what you have for the same PSE sound??

I have what looks like 200 cell cats, definitely not standard, along with manifolds and ss boxes of unknown origin. My car dyno'd at 296hp and 254lbs ft I think. Few other bits but just the usual air filter in the standard box, sure fire coil packs and iridium plugs. Early 3.4 car with 74k and good history. I was very happy with the hp results as most I googled were 270-280. Torque was down on standard though. I have no before results, just the one session. Dyno results are obviously only a guide as the results will vary depending on where you go. I'm thinking of making my own exhaust with decats, x pipe and a centre exit. It's on the to do list but it's a big list. Would I feel the difference? Who knows. Any actual hp gains on a car like this are going to be brutally expensive. If ya want noise then go for it. Just don't be expecting a big boost in performance

I have what looks like 200 cell cats, definitely not standard, along with manifolds and ss boxes of unknown origin. My car dyno'd at 296hp and 254lbs ft I think. Few other bits but just the usual air filter in the standard box, sure fire coil packs and iridium plugs. Early 3.4 car with 74k and good history. I was very happy with the hp results as most I googled were 270-280. Torque was down on standard though. I have no before results, just the one session. Dyno results are obviously only a guide as the results will vary depending on where you go. I'm thinking of making my own exhaust with decats, x pipe and a centre exit. It's on the to do list but it's a big list. Would I feel the difference? Who knows. Any actual hp gains on a car like this are going to be brutally expensive. If ya want noise then go for it. Just don't be expecting a big boost in performance

I stand corrected. 298hp and 239 lbs

I am also tempted by 200 cell cats. I wonder if one of the suppliers might be interested in giving a discount price if there is enough interest in a forum group buy? It looks like there are 3 interested so far, any more?

Could try Topgear for a group buy, good shout :wink:

I have Top Gear 200 cel cats and TG standard back boxes with OE manifolds and I really like the sound. The car feels much smoother and has a lovely bassy sound to the exhaust note. I am very pleased with it.The old cats were fckd and the innards were rattling around inside, so I needed to swap them out.Go for it. :thumbs: :thumbs: