So I've decided against a testpipe and go with an HFC. I run a Greddy Ti-C and was wondering for your recommendations? Before people start talking about power I want to be very careful about emissions and would rather not be swapping things back and forth for DMV visits. Another factor that comes into play is the sound where the local cops aren't too forgiving. The other thing is... I plan on 350 at the wheels no more and no less for my spirited DD. I plan on adding an 02 downpipe and 3.5" intercooler also in the future and I feel that even with an HFC this should be easily obtainable after a good tune from Ivey. I am really stuck on what manufacturer to go with. Please advise! I think I may want one with a fouler bung too just incase.

Also is there a power difference between 100 cell vs 300 cell just out of curiosity?

 

Just get the test pipe and swap the cat back in when you go for inspection.

 

i think greddy ti c going to drone with test pipe

 

Even with a HFC, you probably won't pass emissions. Hell, you can still smell the gas smell with a HFC. Might as well go with a UR mini muffler test pipe for the most gains but also to cut down on the sound and then swap the test pipe with your stock cat for emissions.

 

There might be a slight power difference between a 100-cell and 300-cell catalytic converter, but it would hardly be noticable.

There's a lot of good HFC's to choose from, and I personally went with the Mil.Spec HFC. It's been great so far, and the company has a very good reputation with almost negligible differences in power between their HFC and a test pipe. The only complaint I had was that the O2 sensor bung was on the "wrong side" without anything to hold the O2 sensor wire, though that hardly proved to be an issue. I have also heard good things about the ETS 200-cell HFC if you're looking in that direction.

As far as sound goes, unless you add a resonator/muffler or something along those lines to your exhaust, a HFC does very little to make your exhaust less noisy than a test pipe, especially if it flows well. If you add a HFC or a test pipe, expect your exhaust to get at least a little bit louder.

Regarding emissions, it depends on what emissions tests your state has. If your car has to have the sniffer test done, you probably won't pass with a HFC. In Pennsylvania, all I needed was the OBD-II scan test for my county, and I had no issues in passing, so keep that in mind. I got a fouler bung for extra security, but I'm not sure if I actually needed it.

 

Mil.Spec 100-cell if you're willing to custom fab it yourself to fit (cheap testpipe + cutting & welding), otherwise the Cobb 200-cell is a nice bolt-in piece.

*edit*
Unless, does Mil.Spec offer a direct bolt-in HFC for the X? If so, that's easily the winner.

 

I think Mil.Spec offers a bolt-in app for the Evo X now.
One thing to note is that there have been a few cases of plugged HFC's on Evo X's recently. Not saying it's a common occurence, but it's worthy of looking into at least. I think GST has had at leat two or three cases recently (maybe more) where they were tuning customer cars and had issues with plugged HFC's.

 

What ever you do, DO NOT buy a Perrin HFC. It will fail on you quick and make your car run like crap. I speak from experience, and I am not the only one.

 

Did you not read what the OP wrote. He does not want to deal with the hassle of switching parts back and forth.

 

I think a HFC is a nice compromise and tradeoff between power and cleaner air. In Texas they just do a check to see if your OBD has not thrown any codes. I have the Cobb HFC which I believe has a metal (not ceramic) catalyst, and on E85 the car is at 363 whp / 372 ft/lbs. I was using it with an anti-fouler, but it still ocasionaly threw a code on cold mornings, until the AccessPort tune disabled the codes. I have passed one inspection so far on my 2008 Evo X.

 

^^^ That's it on E-85? I would be expecting more power? are you still stock?

 

Mil.Spec does offer a direct bolt-in HFC. That's what I ended up purchasing because of almost the same reasons as the OP. The noise wasn't too big of an issue for me, but if I ever got pulled over for the smell or noise of the exhaust (and yes, the HFC still smells, just not as bad as a test pipe), I've at least got a catalytic converter for the police officer to look at under my vehicle.

I put about 40,000 miles a year on the X due to my commute, and my Mil.Spec HFC is still going strong.

 

This is going off-topic, but on this dyno it's a respectable number. The point is that with a HFC the tradeoff is not that bad.

 

Yep. I've had friends with heavily modded cars pass no problem since the 'check engine light' was not on.

 

not only is this stupid and environmentally irresponsible, it is a federal crime. keep the test pipes on the track please.