High Flow Cats

[loveskiing]

Hi All,
I've attempted to do my research on HFC that have no odors and have been unable to find any one that gives you what you want in terms of performance benefits that doesn't have some residual gas fume odors. I understand that to some, it is a trade off that they are willing to take, but I value my lungs and am hopeful that there is at least one manufacturer that makes something that gives you the benefits without the drawbacks. I'm mainly looking into this because I understand to go the SC route one has to make changes to the exhaust system. Any thoughts/suggestions/recommendations?

[pbonsalb]

Several of the x pipe makers offer cats. Try AA, Macht Schnell, maybe Mastermind, maybe Challenge. You won't get the same flow as catless, but should get more flow than stock. You also won't get the smell that you say you don't want, and to you that is worth some compromise in flow.

[whats77inaname]

I'm running HJS 100 cell cores. I warm up my car in the morning for 10 or so minutes prior to leaving, and I don't smell anything out of the ordinary. There may be a slight smell prior to the cats getting warm, but I really can't discern it. Next time I drive the car, I'll try to be a bit more cognizant and will report back, but I can honestly say that I haven't really noticed anything, and none of my passengers have ever mentioned anything.

[Hujan]

Originally Posted by whats77inaname

I'm running HJS 100 cell cores. I warm up my car in the morning for 10 or so minutes prior to leaving, and I don't smell anything out of the ordinary. There may be a slight smell prior to the cats getting warm, but I really can't discern it. Next time I drive the car, I'll try to be a bit more cognizant and will report back, but I can honestly say that I haven't really noticed anything, an none of my passengers have ever mentioned anything.

That's a hell of warm up! 30 seconds idling seems like an eternity to me.

[whats77inaname]

I'll get up first thing in the morning and play the "moving the vehicles" game and get it out of the garage, and then go back inside to get ready. This way, I'm not sitting in my car waiting for it to warm up. It takes me about 10-15 mins to get out the door in the morning, so by the time I'm ready, the car is, too

[Raek]

Active Autowerke all the way. No odor, great sound and 30-60 sec warm up is lovely when the cold-start happens.

[loveskiing]

Thanks to all who responded!
I'm wondering if there are any other recommendations?

[Cbozz]

Originally Posted by loveskiing

Thanks to all who responded!
I'm wondering if there are any other recommendations?

are the secondary cats 200 cell?

[Dave07997S]

Originally Posted by Cbozz

are the secondary cats 200 cell?

Yes they are 200cpi metallic-substrate..

Thats why the cheapest as well as one of the best xpipes is the OEM pipe with removed front cats.

There is a little smell when cold and first started up, but I actually like it. Especially when you run race gas.

Dave

[8600RPM]

Dave although everyone assumes they are 200 celk, what evidence is out there? I've never seen a shred of data to support this. I think it's more like they are 400

[Dave07997S]

Originally Posted by 8600RPM

Dave although everyone assumes they are 200 celk, what evidence is out there? I've never seen a shred of data to support this. I think it's more like they are 400

The fronts are 400, from what I read and what Malek said at MRF the rears are 200cpi. You are correct though, I don't know anyone from BMW that confirmed what cpi they are.

Dave

[Hujan]

Originally Posted by 8600RPM

Dave although everyone assumes they are 200 celk, what evidence is out there? I've never seen a shred of data to support this. I think it's more like they are 400

The evidence lies in the fact that there is little to no difference in power between test pipes and a system like the Akra Evo with 100 cpsi secondary cats or even a full catless x-pipe. This wouldn't be true if the OEM secondaries were 400 cpsi.

Not to mention that on every other recent BMW that I can think of, the primaries are much more constrictive than the secondaries.

The OEM secondaries are 200 cpsi.

[Honda]

There is also FABspeed HFC

[Dave07997S]

Originally Posted by e90-335i

There is also FABspeed HFC

I had these before my test pipes on my 2011 M3, they would drag on every speed bump no matter how much I tried to tuck them in. Thats why on my 2013 M3 I went with the test pipes.

Dave

[whats77inaname]

Originally Posted by loveskiing

Thanks to all who responded!
I'm wondering if there are any other recommendations?

As promised....I drove the car today following my typical warm up routine. During the warm up, the car smelled a little more "exhausty", which is to be expected having HFC, but by no means did it stink.

[Dave07997S]

Even with test pipes keeping the OEM rear cats, I do get a little smell on startup and when its cold. Once warm I don't smell anything.

Dave