X-pipe cats vs standard

I have searched a fair bit about the x-pipe/standard difference (expecting to have to change cats relatively soon) and can come to no conclusion other than sound. But is there any dyno evidence? I'll comment on my current belief but would love to have more informed comments. Ok my current belief is: - 1) If x-pipes were a benefit then Porsche would have built them that way. 2) I have heard comments like "x-pipes make 996s' sound like M3s", well toddle off an buy an M3 then, I like my flat 6 sound. I'd love to hear some educated opinions, tbh if it still sounded like a flat 6 but a little more "screamy" with no loss of engine characteristics/performance then I'd be interested.

Have a search on here but from memory, nxi has discussed this before and from memory, x pipes rob the car of abit of low down torque but make up for it when at full chat.

That's it, I didn't seem to loose any low end torque on my 996.2, once up to 4.5k revs it sounded awesome and seemed to pick up better 👌

Yeah, of course I did search but found nothing to stop me still asking the question. Thanks for the responses guys.

I went through the same phase as you, searching for an answer that has been discussed many times but that hardly ever leads to a clear conclusion. I wanted my 996.2 GT3 to sound more like a 997 GT3, and the single best ingredient to achieve that is thorough an X-pipe. I therefore decided to go for a Cargraphic R system that includes Header, X-pipe and muffler (I went for the middle version i.e. Sound version). The end result is very satisfying from a Sound perspective, whereas from a performance point I have a feeling that I lost a bit low down torque, yet do not really perceive any potential gains at the top end. The car was not on a dyno before/after, but I am fairly convinced that a good remap would be able to smooth out the low end torque "issue" while getting the best out of the top end. I am considering doing this, but atm I find it quite hard to justify spending 1'800-2'000k for a remap (on the dyno). Hope this helps Cheers

Thanks Denf! Yes I'm getting the feeling that the general consensus is a "screamier/straight six" sound and a loss of mid range torque, the jury appears to be out on the top end although there is the "seat of the pants dyno" which will always make a racier sound feel faster. My original thought was that if x-pipes were better then that's exactly what Porsche would have done so i'm leaning more and more to 200 cells with standard crossover pipes because in standard driving mid-range torque creates a lot more enjoyment to me than absolute flat out BHP even if there happens to be a minor improvement, which I doubt.

I too am having this dilema and it is leading to serious analysis paralysis! Cargraphic do three types of cat - non-linked X pipe, linked X pipe and standard cross over. I think I will end up going with the crossover with some of their sound (mid noise) back boxes I was thinking about the kline route as the few examples I have heard sound amazing but worried about the x-pipe design

This should help. Custom built inconel, titanium linked X pipe, no cats : And a small clip of the above for demonstration purposes : https://www.youtube.com/watch?v=NaxtAinCsiM :grin: And a Manthey K400, M&M linked X pipe with 200 cell cats : Along with another clip for demonstration purposes : https://www.youtube.com/watch?v=w3J8HeIfJwc

Thanks for the post slippydiff, great videos and great sound! Trouble is :dont know: it leaves me feeling the same. Xpipes just seem to make the flat 6 not sound like a flat six, did these cars go faster/slower? more or less mid range? Perhaps people like them because they make the modest 7000 rpm revving M96 sound a tiny bit closer to the high revving Metzger lumps. For pure sound though I really appreciated these videos :thumbs:

I think that above sounds amazing. At higher revs I love my xpipe, the Kline system on my old 996 was sublime.

Truth be known, yes, there was a reduction in low/midrange torque, but it was by no means a deal breaker, insofar as I never felt the loss was catastrophic, the flip side being that it uncorked the top end of the Mezger engine in a Mk 1 996 GT3 in a manner that made that small sacrifice completely worthwhile.

Ever since I fitted the Cargraphic system I noticed a reduction in tourque between 2.5k -3.5K rpm. I was of the opinion that this could be smoothened out with a remap. Is that not so? Or in other words, did you ever drive a 996.2 GT3 where the DME was remapped to match the exhaust? If so, was this not enough to compensate the loss of torque?

I've not driven a Mk2 with a modified exhaust/remapped ECU, so I can't comment. But I'm pretty sure a decent mapper such as Wayne Schofield (ChipWizards) in the UK would minimise any torque losses and smooth the power curve out at the same time.

Yes those x piped GT3 sounds amazing but they are being driven a manner very different to how I drive my car. Mine is never tracked and I often have two small kids in the back so it very rarely ever sees the redline. The 3.9 is built to be a road biased torque focused engine and that's what I want to preserve. I have contacted Cargraphic so will see what they come back and say. I am also interested in whether I should opt for a 997 exhaust as that is closer in capacity to my engine.

Might be worth a chat with Wayne Schofield in terms of optimisation, as he will have mapped your Hartech engined car, and could probably give good insight.