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YOUR RESEARCHCatalytic Converter options for X51
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cats
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Hey there - I had a rattle develop in may on my 40AE that (thank god) turned out to be the cats.
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My bank 2 catalytic converter is rattling like beggar�s coin can and my CEL came on (P0420 code). A likely side effect of a season of HPDE. So time for new cats.
I have an X51 motor by virtue of having a 40th Anniversary Edition, so I�m wondering if anyone has experience with fitting exhaust modifications to these specific engines. The torque and hp curve for the X51 is vastly different in my experience, with the X51 not coming on until around 5500 rpm, then rocketing up to redline. I mostly track my car, so I don�t want to go backwards and lose this torque/hp curve which I very much enjoy.
Does anyone know how 200 cell sport cats play with the X51 motor? The X51 includes a different header design than stock. I�m considering the Soul crossover design, or the x-pipe configuration like the FVD or LN Engineering/Raby design. I know FVD offers a software flash, but I doubt this is specific to the X51.
Don�t care about sound or any other factor other than maintaining (or hopefully increasing) performance on the X51.
Stock mufflers.
If you call Rhonda at FVD, she can have them configure a tune based on the X51 and exhaust components sonce they have all of the factory programing. I would recommend FVD M&M 200 cell cats. However prices accross the board for cats have gone up $1k+ post tariffs. My FVD 200 cell cats have worked extremely well over the last 17 years without any issues at all.
Others may be able to further give you suggestions.
Congrats on the car BTW. Nice!
I think no matter the 200 cell cat you get you should see some performance improvement as they should flow much better than stock. With that the cross over cats should maintain more of the lower end grunt / torque, while the x-pipe should shift the power band a bit higher. They also sound a bit different. Might come down to how you like to drive.
FVD seems to be the most high-end option available. Nice thing about a 996 is the low cost of entry frees up the budget some.
Since you seem to be happy with it, mind sharing some more details about your setup? Did you get the �PSE� version of the cats or the �standard� one? Did you get FVD exhaust/headers also? Did you install the software? Any CEL? Problems passing emissions? Any noticeable increase in butt dyno or shift in torque curve? Any worries about annoying the neighbors?
Very happy with it. I plan on going with FVD again. Sounds great, tremendous weight savings, durable as hell, and a good boost to power. I have the 200 cell cats and sport mufflers. I did not go with headers. Back in 2007 when I put on the cats and mufflers, header technology wasn't what it is today. So I never upgraded to the FVD M&M equal length ported headers when they came out 10 or so years ago. Quite frankly, I didnt want to deal with broken bolts. But I will go with them when I refresh the exhaust system.
I did not go with FVDs software at the time because I already had REVO software which was one of the first software upgrades available for the 996. Its been great software. But I will go with FVD software the next go around due to their ability to alter the program depending on bolt on changes.
i am in Illinois, so i have to pass IL emmisions which was never a problem. But i did put on the oxy sensor extensions so i didnt have any problems nevertheless.
The only drawback currently is price due to the tariffs. However, its tough to argue with FVDs speciality amd experience with the 996 and Porsche racing in general, not to mention M&M building Porsche motorsports exhaust systems. Agreed, its the high end of exhausts.
Best of luck to you as you build out your 996. More fun than you can imagine.
I used the Magna Flow converters, I live in CA so it is either that or original equipment and the dealer was at least 3 months out at the time and 600 bucks more. They are a lot smaller, and lighter and the sound was slightly throatier, (I do have the muffler mod)
Hey there - I had a rattle develop in may on my 40AE that (thank god) turned out to be the cats. My race shop highly suggested going to 200 cell cats. I ended up going fabspeed. Car has been running great, you lose a little torque down low for a noticeable increase in power over 3k. No codes, no rattles, just nice noises. Cheers.
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