MikTip

I ran a test-pipe on my A4 for nearly a year, with the K04. With my Thermal exhaust, it was loud! I thought I could sneak a HJS HFC out of Germany,(but found out after the fact, HJS sent their cats to the UK, to the same people who weld up and fabricate the Milltek cats) so I installed the Milltek(AKA HJS), and it quieted my exhaust down, and slowed the turbo's spool up ever so slightly, compaired to the test-pipe.

The main advantage of the HFC, is it pass's USA emissions tests and still flows exhaust very well! NO CEL!

In the state I live in I'm OBD tested every year.

Fail it, the state fines you! Especially if they catch you "altering the emissions system".

If you have ever tried and swap out the test-pipe every year, and have the turbo bolts sieze on you, you will be thankful for the HFC. Even DIY'n the test-pipe or HFC is a PITA, and to do it every year.....

Lots of folks bitch about the price of the Milltek HFC, but those of us who have'm, "know" how they perform.

Yes, you may not get any higher numbers on the dyno, but is driving a street driven car all about numbers on a dyno?

I've posted here several times, about the results of the HFC on my K04 equipped A4. For me it makes a noticable difference, especially compaired to the OEM CAT, or test-pipe.

If I could I'd take all the nay-sayer's for a test-drive, so they could see for them selves, what a difference the HFC makes.

Where's TigerClaw when ya need him? ;o)

A4darkness

where is Roman?

My bad for not STFA. Now that I think about it, I'm sure you posted something about this. Thanks for clarifying.

I'm in CA and don't plan on monkeying around w/test pipe removals when I have to get a Smog Inspection so it's HFC or OEM for me. But it seems that unless I'm running a giant turbo, there's really no need for a HFC.

diagnosticator1

driven setup. I don't know if the tests done comparing a HFC with a stock cat, considered this. BTW, it seems "tgrclw" has forsaken us on this forum, haven't seen a post in a long time now.

EBG 18T [Eric]

pulled out in a couple weeks as it appears to have gotten broken or melted as my temps have gone up since the past couple track days. I don't think that HFC's and trackdays are always the best combo.

A4darkness

a particular setup. Like installing a really oversized FMIC will decrease spool up w/a K03 or certain manifolds will smooth out the torque curve with a K04.

And as for The Clw, I have faith he'll return in good time.

MikTip

the larger ATP exhaust manifold smooths out the torque curve ;o)

A4darkness

034 has their own and is doing some custom ones as well.<ul><li><a href="http://www.034motorsport.com/product_info.php?cPath=28_61&amp;products_id=784"> 034 Motorsport Manifold</a></li></ul>

MikTip

ATP has a new and improved version of their old manifold. Then suddenly tuners starting selling the ATP look-a-likes as their own...Hmmmm?