View Full Version : Final HFC Question

10-25-2007, 02:58 PM
Hey Guys,

First off thanks for bearing with me this past week on all my HFC questions, I really appreciate it.

I think I am going to end up getting the Tantrumwerks HFC for about $260. Best deal I could find on a non-universal HFC.


My final 2 questions/double checks:

1. This HFC will work on my factory 1.8T exhaust right? From what I have read the flanges on the HFC and any stock/Borla/exhaust should be the same.

2. No welding is necessary correct? From what I understand is just bolt off old OEM cat, and bolt on the new cat.

Thanks in advance guys, just want to make sure I am getting the right part for my needs. =)


10-25-2007, 03:13 PM
1. probably, call them to be sure.
2. prolly not, i can't see why you'd need to weld anything

10-25-2007, 03:30 PM
The TantumWerks catalyst will replace your crappy stock one. It is a pain in the ass to replace so give yourself much time. They don't supply all gaskets (at least I didn't get them all). You will need a Turbo-Cat gasket and 3 copper lock nuts, cat to downpipe gasket, bolts and nuts.

Go for it.

10-25-2007, 07:14 PM
Where do I get these gaskets and things from? Can I not get them from TantumWerks?

10-25-2007, 09:34 PM
When I got mine it just came with a non-oem cat-downpipe gasket and bolts with non-copper nuts.

Go to an Audi or VW dealer and get the right hardware. Exhaust leaks suckkk

10-25-2007, 11:15 PM
lol exhaust leaks are awesome! while I was still stcok, my exhaust manifold cracked, the turbo spool sound was soooo sweet! :DD

10-26-2007, 07:28 AM
Hey Guys,

I also posted on Audiworld and they told me to use a non-fouler mod on my HFC?

Apparently even on my AEB motor, with a HFC it throws some CELs. So I have to use a press-drill or something like that. But I was going to ask and see if TantumWerks could actually bore out the hole on the HFC for me to put the spark plug extender to fool the CEL. Anyways, help please! =)


10-26-2007, 12:54 PM
Call Tantumwerks, and ask for the Audi guy. He's really helpful. He will put the spacer in for you when you oder.

10-26-2007, 01:13 PM
I've been on a Labree HFC from TW for a couple years. I put new O2 sensors in the cat during installation and it has yet to throw a catalyst code. Evap Emission codes aplenty since June. The occasional warranty void for overspeed. Nothing from the cat. I've got a set of those anti-foulers ready and waiting but I don't think they'll ever be needed.

10-26-2007, 01:44 PM
What engine are you running onemoremile? So are you saying you are getting SOME cel's though? I think the non-fouler mod is supposed to eliminate all of them.

And regarding gaskets, I located some using BusDepot.com Apparently some guys on the passatboard who also have busted cats and got HFCs, ordered their gaskets from here:

1. http://www.busdepot.com/details.jsp?partnumber=1H0253115

2. (inlet) - http://www.busdepot.com/details.jsp?partnumber=1H0253115C

Turbo Outlet:

Any of you guys have part numbers for the exact gaskets I need?


Can you share with me exactly what I need to do? And this Audi guy's name? Thanks everyone! =)


10-26-2007, 02:28 PM
I have a 99.5 AEB with a K04 and Neuspeed cat back. The HFC has been in there for at least 20k miles and has seen track days. Not the 1/4 mile kind but the 120 track miles split into 5 sessions of chasing P-cars kind. The cat has never thrown a code.

The other codes were to indicate that yes, my check engine light works just fine and yes, I check the codes when they pop up. The emissions code I'm getting is from the Evap and is unrelated to the HFC. The void warranty code pops up when I tap the rev limiter.

I stopped by the muffler shop with the HFC and asked if they had gaskets that fit. They had 3 and I grabbed them all. I can't remember if they were gratis or a fiver. A few days after installing the HFC at home I had leaks at both ends of the downpipe. I slid a 20 across the counter at the muffler place and said "tighten my shit up?". Um, ok. "trade you this gasket for the trashed bottom one that's causing all the noise?" Um, ok. Dude spent 5 minutes on it and gave me my 20 back. Been leak free ever since.

10-27-2007, 12:20 AM
^ Thats how exhaust shops should treat all knowlegible customers. I just spent $75 on flaring, cutting and putting in a pipe I provided that goes between downpipe and rest of exhaust. Overpriced!

To make you more calm about this situation, call Fast Intentions (818) 882-2788

Ask for a guy who deals with Audi. He will explain everything to you. Ask him if he includes all gaskets and bolts. If not ask them to include it at extra price so you have everything.

Here is a thread I started after I installed my HFC with pictures.