200 Cell Cats but X Pipe or Crossovers? What's the verdict?

Okay so I'm building up to follow the plenum / big throttle body / air filter / sports cats path to join up with my Dansk Sports boxes. I'm thinking about 200 cell cats and I'm probably going to source them through Design 911: I seem to have a choice of crossover pipework as OED or the X pipe arrangement. Instinct suggests that a big nasty bend is less efficient than a straighter pipe but I'm open to persuasion from those who know more than me. Presumably if the X pipe was a big disaster it wouldn't be there for sale and you guys would all be running in the opposite direction. Please guys, what's the wisdom of this forum?

Re: 200 Cell Cats but X Pipe or Crossovers? What's the verdi You are at the same dilemma point we all reach, in the states fab speed are very pro one and sharkwerks very pro the other. and both give very good reasons why , so it really does boil down to read what both say about each type and make your decisions based on that. I am not a fan of the designtek stuff from Design 911 and there are some negative reports on here and other forums about the baffling in the exhausts braking up. but as with all these things how many have been sold v the few shouted about issues. :grin: by the way I went topgear 200 cell big bore x pipe and they are fantastic, I can't remember the facts on the xpipe but its along the line of , the mandrel bent pipes create a smooth flow but at the part where the touch there is some kind of merge collector set up which is what gives it the pops and crackles and assists with the tone. but there isas equally good reason for the straights , have a look on sharkwerks and fabspeeds sites. :thumb: :grin: oh yes and great call on the Throttle body plenum sports filter set up don't forget you will need a remap to bring everything together and make sure your not running rich or lean. Didn't see the 4" underdrive pulley on the list are you not up for that. Keep us posted on what you do. :thumb: :thumb:

Re: 200 Cell Cats but X Pipe or Crossovers? What's the verdi Thanks, you make it sound like the issue is about as clear as Brexit GO or STAY. Didn't I mention the EBS Underpants, sorry, underpulley kit? :floor:

Re: 200 Cell Cats but X Pipe or Crossovers? What's the verdi :floor: :floor: :floor: yes it is a bit like that . I am obviously pro the xpipe option but each to there own and hopefully someone who had fitted 200cell straight pipes will give there 2p on it. :thumb: :grin: and good to know your looking at the underpants option also :thumb: :grin:

Dragging this up again as Im considering the Topgear 200 cell x-pipe set up. Id like to get a higher pithc and tone like my old Kline system along with a little more noise so figured this was the best way. I currently have Gemballa silencers fitted that are louder than std but a little muted as well so was going to give them a chance with new cat set up first then change out if required. Has anyone else fitted the std bore x-pipe from Topgear that could give some feedback on how the noise changed?

The performance benefit of a "x-pipe" over cross-overs is the merged point between the 2 pipes i.e. an "H-pipe" converted to an "x-pipe" will give some increase in performance, but mostly sound..... introduction of an "x-pipe" where a merging didn't previously exist is intended to create a secondary pulse scavenging effect later in the exhaust, thereby increasing flow (primary pulse scavenging effect is the collection of primaries on each manifold e.g. you engineer the timing of the pulse of each chambers exhaust stroke such that they meet there one after the other/overlap and effectively push/pull the next along, rather than all just "colliding" there) the principle of pulse scavenging (as I tokenly understand it) it to create a better "flowing" exhaust that still maintains the "right" amount of back pressure, etc .....a better flowing exhaust of this nature on a 996 will typically have more of a "howl at rising rpm", versus the "low end/idle grumble" of standalone mods to the backboxes (or an X-pipe earlier in the system of a classic front engine v8).... or this is all complete "balls"....

Haha, Ive read up on the flow characteristic but in all honesty its the sound change Im looking for and indeed the howl rather than the rumble at preset. If my wheels sell its getting ordered instantly haha. Quick Q on fitment then, can this be done with silencers in place and all bolted up i.e. do the silencer pipe and cat pipes interact or as Im assuming the sleeve serves that purpose?

with the x-pipe being a single piece replacing two cross-overs, in reality whoever's fitting will want to at least be able to loosen off basically every other section as needed... although should be avoidable with the manifolds themselves... will almost certainly involve unbolting the silencer on at least one side.... I think the engine mount nuts then needed to be wound out somewhat on my car(?) or something in that area... - swapping in a big single fixed piece basically does make the whole thing a bit more awkward, but the specific ball aches on one car to another will vary FYI - I'd recommend ordering new stainless version bolts for each flange throughout the exhaust - existing bolts are rarely ever salvaged and SS should last a bit longer than stock bolts/hardware.... (although a decent size bag of each is no terrible thing to own!)

I'll be interested to see how you get on with this, I've just bought the cat bypass pipes for mine to get some more sound (I don't mind swapping cats out at MOT time)

Oh yeah they would be getting ordered, so what your saying is there is not enough room to remove existing cats and put in the x-pipe without removing at least some of the other components? My bolts look original, i.e. not much left of them.

Demon what a bloody good explanation mate :thumb: :thumb: I cant comment on the topgear std xpipe as I used the big bore xpipe on mine.loved it :thumb: :thumb:

When i changed mine to X-pipe , just removed rear bumper and heat shields , and had the typical porsche rusted fixings to deal with on cats to manifolds

Dont forget when your ready to order call Alex the sales director at topgear in bridport , tell him your a 911uk forum member and ask him for 10% off the list price and he will do his best to assist you there :thumb:

I am looking to switch to an X pipe with 200cell cats. I have the OEM eisenmann PSE (sounds great, but think an X pipe will complete the package). I am also fitting a 997 GT3 TB, IPD Plenum along with BMC filter. Is Topgear the best option? Anyone selling an X pipe?

Top gear is highly regarded on this forum, their prices and quality are great their customer support excellent and their products come with a lifetime you own the car warranty Don't forget after you have fitted the GT3 TB/Plennum it will need a remap So suggest you either do it all together or all the bits before the TB/PLEN then get it remapped to bring everything together. Its a great set of mods you have planned had the same set up on my 997.1 and now on my 997.2 :thumb: