Exhausts X-Pipe Vs Crossover

Morning, The Porsche failed the MOT on emissions yesterday. As it just scraped through last year, I have already replaced Lambda's MAF and the rather worn PSE boxes for nice secondhand Cargraphic ones. So, we think that the CATs (Sports 200 cell ones I bought seondhand from ELA a few years back) are done for..... With the option of going for either an X-pipe design, or stay with the original crossover design, I'm looking for others experiences to help me decide. The main issue is to pass the MOT. Secondary is to enhance torque and sound if possible, but bearing in mind it already has 200 cell cats, I'm not expecting much. My concern is whether the X-Pipe design experiences a loss in Low to Mid end torque. If it does, can you get round that by re-mapping? Is there a marked benefit of going to an X-Pipe on the 996.1? I know the 996.2 has a better cylinderhead and more sophisticated ECU, so really these questions may relate better to the 996.1 in particular. Any help or opinions welcome thanks.

Ive had x-pipe on mine. Sounds is different, smoother and more of an inline 6 sound. Not massively but noticeable. I like it. Power wise I went from std to xpipe with 200cel cats so didnt notice any loss in low/mid range but did seem better at higher rpms. Never had an MOT issue.

Cheers for that Coullstar. Thats useful thanks :thumb: James

when I bought a Kline for mine they change the design to an X because they consider the original system to be unbalanced.

Hi James, I have the same issue getting mine through on emissions for years... I had this issue well before i fitted my 200 cel X-pipe and after... I bought my cats brand new and have probably only done a couple thousand miles since fitting so can't be that mine are knackered so yours may not be either... I've been told a few things that might help mine, check for leaks around the exhaust flanges as they can suck air in and give higher lambda readings (I have an issue with my exhausts boxes that were supplied "faulty" from Top Gear so I know there are leaks) and also try fit a new MAF sensor as when they go they can cause high readings. I have the new MAF and some flexible exhaust paste ready to sort when i get the back box sorted next month, but won't know if either of these will work till next MOT time in March.... Hope you get sorted Mate Craig :thumb:

I've had both on my 997.1. I've not noticed any difference in power from one to the other but the Xpipe sounds much smoother and doesn't really get louder until it hits 3000 rpm. I would go with Xpipe

I've 200 cell Xpipe cats from Topgear (with their loud boxes) & never had emission problems on MOT (both before & after a remap). I fitted new lambda sensors when I fitted them to my 996.1 & made sure all gaskets were properly tight etc. The Xpipe makes more a GT3 howl IMO & does pop a little on the overrun afteda spirited drive. I didn't notice the loss of any torque by the way after fitting them.

Thank you all for your responses, that's great info. Craig, your experience matches mine entirely. I've been farting about for the last 4 years and it eventually passes when the tester puts it on the "long test". Not this time! Both the Co2 and HC's are fine, just a high lambda which everyone says exhaust leak. Just can't see one. Maybe I should have a go at splitting them down and refitting one last time but Sheesh! I don't think the tailpipe helps either. They are so large, and the probe won't go round the bend so it's half out of the pipe to start with. The tester won't let me put a rag in the tailpipe though and he's obviously scared of bending rules, even though I've been going there for the last 18 years... If I opt for new cats then thanks to all your feedback, I'll go X-pipe this time.... Cheers

I replaced standard cats with 200 cell x pipe and the engine feels very strong at higher revs, but this was fitter after an engine rebuild and in conjunction with a lightweight flywheel, so not sure how scientific that is, but it certainly doesn't feel weak at lower RPMs My only niggle is, because it joins the left and right sides together, fitting is a bit more difficult and my Top Gear X pipe wasn't a superb fit. It went on OK, but without it bolted up, the ends weren't quite aligned and required the bolts to pull the ends together. That said, it does sound great. It changes the sound from low and throaty to more of a screamer See obligatory tunnel run video on YouTube https://youtu.be/Uqx36CsOTL8

Great vid :thumb: And that's reassuring to know about the low down torque query. I have read the other thread on here about fitting issues with the TG X pipe, and it'll be the same batch so fingers crossed it'll go on ok... Though the solution of using an extra flange seems like a useful idea.

I fitted the Topgear X pipe with no issues, I did have the Valvetronic Topgear boxes too, I would say I lost some lower end torque but once at 4.5-5 revs there where definitely a power gain. All the best 🤘

Many thanks for this. Was yours the standard 55mm dia pipes or the larger 63mm Cats pipework? I've ordered and had delivered the standard dia stuff. Seems to be spot on for fit, so will see how it goes on tomorrow.. Cheers