Hey guys. So I'm replacing my cats but have a dilemma. I have straight through exhaust from the cat back and don't want to add any rasp when I replace my cats. SO. FI RHFC's, FI HFC's, or Test Pipes? What to do, what to do… opinions?

 

Resonated test pipes did me well back in the day. Resonated HFC's would be the best of both worlds.

 

if you have a straight through I d go with RHFC

 

Thanks man. Which RHFC's do you recommend? I've seen a lot of people use Fast Intentions. Open to any suggestions though

 

Any recommendations?

 

I think FI is the only company that makes a resonated HFC.

 

No, the ARK cats have a Helmholtz resonator tapped in right next to the catalyst. It's a pretty funky design.



And this isn't a cat, but MXP has these double-resonated test-pipes. Kind of steam-punk looking.

 

As far as volume goes, what will be the quietest guys?

 

I forgot about ARK's. I'm considering their resonated test pipes vs Motordyne's.

From the general consensus I have seen here, the RHFC will be quieter than the test pipe.

 

I had FI RHFC with the OEM catback for 12 months, and you could barely tell the difference in sound. On a scale of 1:10, where OEM is a 3 as compared to most cars, the cats move that up to a 4, which was noticeable by me, but no one else. Whereas the FI catback ratchets that sound up to a 7.

Hows that for completely BS numbers?

 

I went with Stillen HFC's (which are non-resonated) and it's suppppperr raspy and loud as hell. I love the rasp and hissing so I didn't care but I've heard cars with RHFC's and they're much much better with the rasp.

 

I have rasp with Fast Intentions HFC's on hard acceleration.

 

Is the rasp from the HFCs on stock exhaust? Or do y'all have other exhaust mods on yer Gs as well?

Getting some Magnaflow HFCs installed Thursday and all this rasp talk is making me a bit cautious about going forward with it. Maybe i should just save up a little more and do a full CBE and leave it at that...

 

AroundTheG37 has the FI HFC and 2.25" FI catback w/12" resonators.

I have the FI RHFC and 2.50" FI catback w/18" resonators.

He has vastly better hearing than I do. I say that literally, because I'm deaf in one ear, and he's hyper-sensitive to noises many people wouldn't notice. So if he says there's a noise, then there's a noise. That's a fact. How much that noise bothers you vs. him is another matter, and a personal valuation.




As a side note, AroundTheG37 would benefit from having a sig-line of mods that provide context to his comments.

 

My cats aren't resonated and yeah yeah, I'll do the sig one day John. LOL.

What's funny is Fast Intentions guarantees no rasp with their full system. LIES!, lulz.

Here's the quote from their page.