Ryan Way

I installed my catless X-pipe yesterday to my 996 C4S with Maxflows yesterday and the ECU/DME has not relearned yet. Power below 4 grand is gone and the system is ungodly loud and not in a good Gundo hack way. I'm really displeased with the sound of the system but I have spent the money.

My question:

Should I install 200 cell cats on the x-pipe? What are some good alternative options to the spending another $1600 on Fabspeed cats?

Should I try to bolt/on tune my way out of this problem with an IPD, 82MM TB and intake and leave the cats off?

Thanks,

Ryan

dan_189

I have just added 200cel cats which made my car sound amazing but volume wise quieter. I think one of the cats had collapsed causing it to be excessively noisy (which I actually liked) but am in the same boat - made the purchase and installed so won't go back now.

Powerwise initially I thought it was down on power but I think the noise make it feel "more powerful".

IMO there does need to be some back pressure not having any moves the "power" curve even higher into the rpm range. I'd add 200cel cats or see if fabspeed will allow you to exchange the non cat xpipe for one with cats. You'll also be doing the environment a favour too...

Vipertag313

Sell your x-pipe...

There are many other options than fab$peed. Every Catless X Pipe Thread on here clams significant power loss under 3.5-4k. I debated the pros and cons going in and I would not go back for the positives it gives me now. The top end gain is worth it.. Headers and a Tune could be worth a shot but it sound like you want stock torque back. If you are looking for that low end grunt you will not find it with an x pipe setup by simply adding 200 cell cats. A tune will only smooth out the torque curve

dan_189

I feel I've lost just a bit of low end due to the x-pipe configuration I feel, it was quite a trade off to me and i'm not completely sold on it.

However in saying that what i've lost in low end i've gained in sound. Difficult trade off for me as my car is street only and I don't see red line if at all when i'm driving.

dan_189

I actually wonder what a 200cel non-xpipe setup would be like, if it strikes a balance between low and top end... Has me thinking now...

Ryan Way

Probably going to sell it. A well known CA tuner wasn't willing to touch the car without the stock cats on it so, I'm stuck having to do a mail order tune or sell the x pipe and buy a set of TopGear 200 cells (Isn't there a group buy?) or keep the stock cats and gundo the Maxflows. Either way I despise the way the Fabspeeds sound at the moment. Just thinking out loud.

dan_189

Fair point, I had one failing cat and it was loud, I think it would be much too loud if they weren't there altogether.

I'm thinking about a 200cel crossover (rather than x-pipe) to get back some low end now

Ryan Way

Anyone know the pipe diameter for the Fabspeed X pipe - considering welding in cats and not near my car for a few days

dan_189

Unfortunately can't help with the diameter but I do know Cargraphic use the German brand HJS and I think fabspeed do as well.

Is it not more economical to sell it and buy another? When you factor in parts + labour?

https://www.fabspeed.com/hjs-tuning-catalyst-200-cell-108mm-od-x-100mm-l-non-directional/

Ryan Way

I have an exhaust guy who is also a friend who has done multiple gundos. Fabspeed's sport cats (even with a discount) are not in the budget right now. Considering universal, TopGear/Gundo Maxflow or just stock and gundo maxflow and trying to make up the power with IPD/82mm TB/EVOMS V flow and a mail order EVOMS tune...which sucks because I can have it done live in CA with anything but stock cats.

808Bill

I want to buy a set of Fabspeed maxflow mufflers (motor has headers) to shave some weight and increase some sound. But post like this get me worried as I don't want any drone at cruising speeds or lose anything down low...Thoughts?

Ryan Way

808Bill The Maxflows are QUIET and low timber when you are on the gas (weak sauce IMO). No drone at all. You will not lose anything at all unless you cat bypass like I did

dan_189

It's a trade off, probably wouldn't go catless but 200cel seems like a good compromise. However I do feel I've lost just a touch of torque up until 3k and then it gets awesome

Fabspeed Motorsport

Scott from Fabspeed here, we use 200 cell HJS cats here! This system is designed to greatly improve horsepower and torque by 25 whp and 32 ft-lbs! Cuts weight and adds a better exhaust note!
Fabspeed Motorsport 996 Carrera Catalytic Converter X-pipe

Always the best option to keep check engine lights off, add exhaust note, and increase HP!! Take a look and feel free to reach out regarding forum pricing!!

Mbren1979

I can vouch too. I put some Maxflows on my 04 C4S. I was happy yet disappointed. They are too quiet in my opinion. I only have the intake and maxflows. No other exhaust mods. No drone at all and my drive to work is 25 miles with 20 of them being highway. It will make a nice noise while into the throttle but very quiet at anything less that 1/4 throttle or cruise. Truthfully i wish i went for SuperCups.