What is the difference between HFC and test pipe?
 

Hi, Guys!

I think that this is a silly question, but I really don't know the difference between HFC and test pipe. I just know that HFC is more expensive than test pipe. :tup:

Also, will you recommend the HFCs and test pipes.

Thanks!

Rhet in Seattle

Hey Rhett,

HFC or (High Flowing Catalytic-Converter) is basically the same device that's already built into your cars exhaust system that converts the exhaust gasses.

An HFC is just a smaller cell of them that flows free-er letting you regain some performance lost. It still suffices as a cat for those states that require them and do emissions testing...

A Test Pipe or Resonated Test Pipe has NO cat of any sort in it. Resonated ones carry a resonator, but just to drown sound and rasp, not any sort of chemical conversion. So what comes out of your engine, comes out of your exhaust. (Gas wise)

HFC's will give you better numbers than Stock cats, and (Resonated) Test Pipes will give you better numbers than HFC's due to the freedom of gasses to flow.

Hopefully this broke it down for you enough to make a decision based on your particular situation. If you already knew most of that, I was not trying to make it sound as if you were not knowledgeable, just pointing out all the details. :tup:


Chris in Avondale :icon17:

Thank You Chris, for an exellent reply. a rep for your help.

The whole time I was writing it I was thinking...

"What would Trip say?"


:icon17: :tup:

Then you added waaay to much info, but thank you. :tup:

So I like to be thorough... whats so wrong with that? :bowrofl: :roflpuke2:

Thanks for the explanation (helping out another member). +1 rep :tup:

Thanks a million, Chris!! You are a great man! :bowrofl:

Finally!!! Someone speaks the truth everyone else knew but just didn't want to say out loud! :happydance:



:roflpuke2: :bowrofl:

Ok!! pickup your panties and Leave Now!!!

:roflpuke2:

great exp. +1

good info! i was wondering about the gains between the hfc's and test pipes :tup:

THx for info
I was wry the same thing... what about the sound???

Test pipes are going to be louder than HFCs. They will also be a good bit more raspy, and the well documented deceleration hiss will be more pronounced with test pipes.

why, muffler is not at the center of the car?? Is it Error during installation or production??
YouTube - Fast Intentions Exhaust w/ 12" Resonators - 370Z

That's just the angle of that video. FI uses two angled cannisters, not one single center mounted muffler.

BTW, I was more interested in the HFCs than test pipes, 'cause the more expensive, the better in view of performance. But, from what you said, I changed my mind. ^^ My only interest is a little bit higher performance by spending a little money. ^^

Before I order the test pipe, I want to ask you something. I am thinking the ERZ test pipe. How about this one? I just know from this forum that the ERZ stuffs(including the HFC and the test pipe) are mhch cheaper than Stillens, Berkes and so on.

Do you think what test pipe is the best? I think that this is also a silly question. ^^

Please, give me your professional opinion! :bowrofl:

Thanks,

Rhett in Seattle

I have ERZ HFCs on my G37 sedan. Love them. They were raspy with the stock exhaust, but once I installed my Fast Intentions system, the rasp totally disappeared.

There really isn't much difference between test pipes. They really are just straight pipes. Compare the materials used though. Some use better stainless steel.

As far as performance, there won't be any difference regardless of brands. I would consider resonated test pipes, to cut down on the rasp. Adding a resonator in no way effects performance, other than sound.

Thanks! But, some people inclduing Chris says that resonated test pipes give better numbers in performance than the HFCs. Now, I am a little confusing.

What he means by it not affecting performance is that adding a resonator won't Detract from your performance. Even though an HFC doesn't have as big a Cat Cell as a stock cat, it still does have something the gasses have to pass through. So some performance will be lost. Resonated or non-resonated test pipes have Nothing in the way to block the gasses. Free-er flow = more performance.

Ah... yeah between HFC and test pipes, you will get a few more HP out of test pipes. Nothing you'd really notice though. :)

Thanks a lot, Chris!

BTW why are some people excited by the HFCs even though some performance may be lost? Only reason is to get rasp sound from the HFCs with lower cost?

Thanks for a note! ^^

edit: sorry wrong thread

what is the different between w/ 12" Resonators w/ 18" Resonators
just a sound? which one is louder? What about the performance? any power gain or loss?

and what is O2bung, what is it use for? and what does it mean polished by stainless?
Any different from the normal one?? Does the carbon fiber give different sound from the normal one or just the look??

FI 12" with test pipes will be the loudest + more gains. thats the combo im getting :tup: and the Carbon finish is for esthetic's only.

There is NO performance difference between 12" or 18" resonators. The resonators only affect sound volume.

Thx you all for good informations

12" or 18" resonators is it a lot different in sound volume?
I like the one that show on the clip very much. Which one that he use?

12" is a good bit louder than the 18". 18" has a deeper tone, though.

thats what i said 12" = loudest :tup: +tp = best gains. i was looking at the dyno sheets and test pipes have a few more hp compared to the sheet with hfc's

non resonated would be louder then 12", if thats what you meant.

12" are louder than 18" right? non resonated u talking about the tp's?

and sorry if my english is not perfect i went to french school... excusez moi pour mon anglais :D

yes 12" are louder then 18" but you can also go no resonators on the exhaust. Test pipes comes in resonated or non-resonated.

True..Test Pipes do produce more HP than HFC's bu not by much...and you will only see the gains at the top end

i have the MXP Resonated Test Pipes with MXP CBE... i love my setup! you could search youtube for my dyno video if you're really curious on the sound.

it's raspy, but kinda in a good way... once cruising in 6th gea,r the in-cabin sound is surprisingly quiet!

awww sh*t thats ur z lol nice man i was looking at the drop looking real good and sounds real nice man not too raspy :tup:

so no resonaters on the exhaust + test pipes will it be too raspy with FI? i just want the best gains + loud deep tone, not too raspy ... man im asking for too much i think :ugh2: