HFC X-pipe w/ OEM Axle Back

[CravingBavaria]

Narrowing down the route I want to go with my exhaust. Looking to keep the OEM axle back and get an X-pipe with HFC's in the secondary slot. SYT_Shadow recommended the Bimmerworld catless X-pipe and separately buying MF 200 cell cats to add to it.

Any thoughts? I imagine there are plenty here with a catless X-pipe and OEM axle back. The goal is affordable power, but less smell and noise as compared to the full catless system, hence adding the HFC's to the unit.

TIA

[GORDON.M3]

My buddy Embolus*M3 has AA (100CEL) HFC's on his OEM x-pipe. Sounds great and virtually no smell at all. If you can smell it with the driver side windows down, that mainly means you have a leak. The BW x-pipe is tricky to get a perfect leak-free setup. If you want perfect leak-free, I'd cut the flanges and weld them all.

[CravingBavaria]

Originally Posted by GORDON.M3

My buddy Embolus*M3 has AA (100CEL) HFC's on his OEM x-pipe. Sounds great and virtually no smell at all. If you can smell it with the driver side windows down, that mainly means you have a leak. The BW x-pipe is tricky to get a perfect leak-free setup. If you want perfect leak-free, I'd cut the flanges and weld them all.

Noted, didn't even think about the BW pipe leaking, why is it difficult on that specifically?

Was also looking at ESS and Evolve's already HFC setup, $1,800 and $2,650 respectively and that's just too much for what I'm looking for. Even though the BW with HFC's separate could end up being closet o $1,800 when said and done.

[GORDON.M3]

Originally Posted by CravingBavaria

Noted, didn't even think about the BW pipe leaking, why is it difficult on that specifically?

Was also looking at ESS and Evolve's already HFC setup, $1,800 and $2,650 respectively and that's just too much for what I'm looking for. Even though the BW with HFC's separate could end up being closet o $1,800 when said and done.

Many members here have been slight issues with the BW xpipe. I've heard the fitment is the greatest.
If you are looking for a cost effective method, adding an HFC to the test pipes is a very good route to go with the OEM xpipe.

[CravingBavaria]

Revival of this thread as I do more research.

I am leaning towards the ESS or IND/RKP/Challenge Sport with the 200-cell HFC's in the secondary slot.

This seems like my best option for the most power gain by removing the primary, and the reduced smell/noise with the HFC secondary.

Outstanding question; I imagine this throws the CEL and I already have an Alpine tune so no worries, but curious if this passes CA emissions? I haven't seen a concrete answer browsing the forums. If the answer is no, I assume that people have HFC's in the primary slot with a secondary delete to pass emissions (or maybe even HFC's in both positions (?) which both of these scenarios defeat the real purpose of the x-pipe IMO and don't seem worth it with my intent to increase power more than anything else.

[DanMpower]

Originally Posted by CravingBavaria

Revival of this thread as I do more research.

I am leaning towards the ESS or IND/RKP/Challenge Sport with the 200-cell HFC's in the secondary slot.

This seems like my best option for the most power gain by removing the primary, and the reduced smell/noise with the HFC secondary.

Outstanding question; I imagine this throws the CEL and I already have an Alpine tune so no worries, but curious if this passes CA emissions? I haven't seen a concrete answer browsing the forums. If the answer is no, I assume that people have HFC's in the primary slot with a secondary delete to pass emissions (or maybe even HFC's in both positions (?) which both of these scenarios defeat the real purpose of the x-pipe IMO and don't seem worth it with my intent to increase power more than anything else.

It seems like Vibrant discontinued the 200CPI cats that RKP uses to make their Sport X-Pipe, from what I read RKP has switched to 400CPI cats for all their later batches. 400 cells might a bit restrictive.

If you want to make your own, I suggest getting a Macht Schnell X-Pipe and adding Magnaflow 200CPI cats to it, the Magnaflow cats seem to be better quality than the Vibrants anyway, I heard the Vibrant cats had a high failure rate especially in higher HP applications.

You will not pass CA emissions because your smog monitors will never set with a Stage 2 tune, the tune effectively "turns off" your secondary O2 sensors from reading that you're missing primary cats. The best thing to do is keep your OEM X-Pipe, swap it back in and flash it to a Stage 1 or OEM map before smogging.

[Richbot]

Stock secondaries are already 200-cell. If I were you I would save a grand or more and just do test pipes if you're going to do that. Spend a little extra at a good shop and have the stock cats and the TP's vbanded to swap back in for street use

Removing, as opposed to replacing with an equivalent, emissions device is, still, something that can subject you to pretty hefty fines. Beware the assumption that they'll never come for you. They've already come for the shops designing deefeat mods, and in some jurisdictions, the shops installing or selling mods. I think there's an argument to be made that some of the HFCs out there actually ARE oem-equivalent, just superior in performance (and therefore flow better despite less restriction) because they're superior to the parts chosen by the OEM who doesn't use them ebacuse it'd be expensive. I don't think there's much argument to be made that just binning the cats is within the spirit or letter of the rules.

/dire warning/winter is coming for decatted cars

[CravingBavaria]

Originally Posted by Richbot

Stock secondaries are already 200-cell. If I were you I would save a grand or more and just do test pipes if you're going to do that. Spend a little extra at a good shop and have the stock cats and the TP's vbanded to swap back in for street use

I don't want to cut my OEM exhaust to put test pipes, and would personally rather pay for a brand new x-pipe than buying a used OEM x-pipe to cut up and put test pipes on which at the end of the day will still cost $1,000+

[Scharbag]

I have owned test pipes and other x-pipes and I am back on test pipes. Been a journey but I find test pipes with Dinan cans to be pretty sweet.

Cheers,

[Richbot]

Originally Posted by CravingBavaria

I don't want to cut my OEM exhaust to put test pipes, and would personally rather pay for a brand new x-pipe than buying a used OEM x-pipe to cut up and put test pipes on which at the end of the day will still cost $1,000+

The aftermarket catted x=pipes don't necessarily fit or work any better than somebody else's cut OEM xpipe with TP's installed. Luckily you're in CA where these cars and the people who mod them grow on trees