Challenge to find HFC´s!

[Nightauditor]

H Guys,

I haven´t posted here in about 2 years or so, and I come back with a problem I possibly need your help with.

I am still happily running my APR B8 S4 with quite a few juicy mods, and due to one of the supercharger coolers leaking, I was running on 5 cylinders for a while.

Long story short, that has all been fixed, but due to the unburned fuel, my cats are damaged.

So, I have to switch the cats to get everything back to normal, and as I have to do that anyway, I was looking into HFC´s.

I have read all I could on the web and on this forum here, but I am still confused about a few things.

Aren´t the stock cats integrated in the downpipes? But as far as I can tell, the usual downpipes you can buy are without cats. I have not been able to find anything cat related anywhere. Closest was a cat-delet testpipe from 034 motorsport.

I have heard that 034 has HFC´s as well, but I can´t find them anymore in their website.

Then I read about problems with o2 sensors after install of HFC´s which raises the question if the cats are a usefull upgrade anyway.



So, here is my question: Would you guys go for the OEM cats, or would you install HFC´s? And do you know of ANY HFC´s for our car?

Thanks for your help, it´s nice to be back.

Oh, just another little thing, there is a new AWD dyno near munich, so as soon as she´s completely fixed, I´ll post a dyno vid here.

[Nightauditor]

Update: Decided to go with the stock cats, everything else is too risky at this point.

I´ll post the dyno results as soon as they are in in a new thread.

[chaos2984]

how many miles do you have on your car. Whats your warranty over there for cats. We have a 8yr/80K mile warranty over here in the usa

[Nightauditor]

how many miles do you have on your car. Whats your warranty over there for cats. We have a 8yr/80K mile warranty over here in the usa

Hi there, thanks for the reply. I now have 62.000 km on the clock, which should be something around 40k miles.

I just talked to my guy at the shop and the situation is as follows.

I could replace the oem cat on one side only, or I could custom weld hfc's into the stock downpipes. The O2 sensor issue is known here from other engines, and could be dealt with by welding a little shield over the sensor, and basically taking it out of the equation.

Apparently there are two sensors for each side, one before and one after the cat. The one before the cat does the important measurements and the one after the cat is not strictly needed.

Well, while I am all for getting all the power I can get out of the car, I still think I will just replace the oem cat on one side.

Warranty is out of the question, but that is not really an issue.

[GrkA4]

Doesn't JHM have both a TP and HFC option for us?

[DGVR6]

Yep, but I think the gains are questionable, and I've heard of failures where the DPs separate from the cats.
Not worth the risk IMO.

Edit: Sorry that was 034's that had the (possibly isolated) problem.

[infinkc]

per your sig you have an apr tune, apr has a catless option for their tune, have them load that and gut the cats and you dont have to worry about your 02 sensors triggering.

[jran76]

per your sig you have an apr tune, apr has a catless option for their tune, have them load that and gut the cats and you dont have to worry about your 02 sensors triggering.

That's not usually an option in Germany. Their emissions testing makes it hard to pass with non-approved HFC's, much less no cats. Think Cali times five.

[RWD2quattro]

Call HJS, they have a 200 cell HFC HD #9095 0165 that meets euro 5 standards. I just bought a set to add to EC headers.
At least I feel a little better about the environment, trust me, I'm no tree huger