HFC clogging issues? Anyone had a problem?

Draff1 · 05-21-2011, 10:17 PM

Buddy of mine Races frequently mostly drag strip stuff with a modded Subaru and he claims that his cats clog after a year or so of driving due to the rich mixture he's running. Not sure why or how rich it is but he says it's because the tune and disabling the factory O2 sensors etc.

Has anyone had problems with any of the aftermarket cats clogging when using a tune? Even turner test pipes theoretically remove the larger primaries and could potentially over power the smaller secondaries by this logic. I would hate to lose power over time and not really know it until it was totally clogged.

kitw · 05-21-2011, 11:37 PM

Don't have a crappy tune and you don't have this problem

phusion974 · 05-26-2011, 02:38 AM

Has he used any leaded race gas?

GT3 Tim · 05-26-2011, 09:30 AM

Overly rich conditions will eventually poison on clog the cats......true.

How to ensure your tune is not overly rich? Well, you could buy a ARF and monitor it....beyond that, I can't think of a reasonable way to keep an eye on it.

I installed ARF's on my previous turbo'ed cars and they are invaluable. Not only can you detect an overly rich condition, you can also see lean condition (more important). If you boost and go lean, you will melt pistons. My cousins car (Mitsu) leaned out due to one bad injector and melted a piston and turned his motor into a boat anchor. If he had a AFR, he would have seen that.

For me, if you have forced induction, you need an AFR. For an N/A motor, you would probably be fine without it as without forced induction, getting the engine into a lean condition that will have dire consequences would be hard to come by, and would be noticed anyways....I digress.

So, if you are concerned about running rich (or lean), get an AFR.

I have used PLX devices in the past and have been very impressed. Tim

Draff1 · 05-26-2011, 09:42 AM

Thanks Tim. I will look into the AFR. Since my car is basically bolt-on stuff that many many on this forum have used, I'm not sure this would be specific to me, however since there are so many of us using aftermarket HFC's with a tune, it may be interesting to take some measurements and post them.

Since there were really not too many responses, I am assuming it's a non issue OR people are unaware that cats are clogging and slowly sapping power.

It may ultimately be a question regarding a stage 2 tune or the ECU adaptation itself. Do the M3's tend to run rich after the secondary O2 sensors are disabled and cats removed? Can anyone verify that they do run rich?

Draff1 · 05-26-2011, 09:43 AM

Quote:

Originally Posted by phusion974

Has he used any leaded race gas?

He has not used leaded gas but does run 100 octane race fuel on occasion.

Singletrack · 05-26-2011, 09:53 PM

What is an AFR? You mean a wideband O2 sensor that displays AFR on a gauge? Pretty hard in my experience to monitor AFR in realtime on a gauge. You will be able to spot a bad failure, but it isn't going to be easy to identify specific rich conditions.

If you are concerned, just run your car on the dyno, again with a wideband hooked up, and see what you have.

No reported cases of clogged cats on here that I've seen.

05-21-2011, 10:17 PM	#1
Draff1 Private First Class 13 Rep 195 Posts Drives: 2009 Silverstone M3 Coupe Join Date: Aug 2009 Location: San Diego, CA iTrader: (0)	HFC clogging issues? Anyone had a problem? Buddy of mine Races frequently mostly drag strip stuff with a modded Subaru and he claims that his cats clog after a year or so of driving due to the rich mixture he's running. Not sure why or how rich it is but he says it's because the tune and disabling the factory O2 sensors etc. Has anyone had problems with any of the aftermarket cats clogging when using a tune? Even turner test pipes theoretically remove the larger primaries and could potentially over power the smaller secondaries by this logic. I would hate to lose power over time and not really know it until it was totally clogged. __________________ 2009 Silverstone II E92 M3 Coupe - DCT Dinan Exhaust, RPi scoops, Dinan Tune, Dinan Pulley, BMC filter, LCI Taillights, MS 15mm spacers, Huper Optik tint.
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05-21-2011, 11:37 PM	#2
kitw Colonel 471 Rep 2,991 Posts Drives: F91 M8, 991.2 GT3 Join Date: Jun 2007 Location: Bay Area, CA iTrader: (20)	Don't have a crappy tune and you don't have this problem __________________ DSC_3369 by Kit W, on Flickr
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05-26-2011, 02:38 AM	#3
phusion974 Lieutenant 19 Rep 437 Posts Drives: OE Tuned C63 Join Date: Oct 2010 Location: L.A. iTrader: (0)	Has he used any leaded race gas?
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05-26-2011, 09:30 AM	#4
GT3 Tim Moderator 94 Rep 1,920 Posts Drives: 2014 MB E63S Join Date: Feb 2008 Location: Sacramento, CA iTrader: (0)	Overly rich conditions will eventually poison on clog the cats......true. How to ensure your tune is not overly rich? Well, you could buy a ARF and monitor it....beyond that, I can't think of a reasonable way to keep an eye on it. I installed ARF's on my previous turbo'ed cars and they are invaluable. Not only can you detect an overly rich condition, you can also see lean condition (more important). If you boost and go lean, you will melt pistons. My cousins car (Mitsu) leaned out due to one bad injector and melted a piston and turned his motor into a boat anchor. If he had a AFR, he would have seen that. For me, if you have forced induction, you need an AFR. For an N/A motor, you would probably be fine without it as without forced induction, getting the engine into a lean condition that will have dire consequences would be hard to come by, and would be noticed anyways....I digress. So, if you are concerned about running rich (or lean), get an AFR. I have used PLX devices in the past and have been very impressed. Tim __________________ Tim <--- apparently likes "3" cars 2014 E63S -- The Rocket 2014 F30 328i -- Kids car 2008 E90 M3 -- Sold 2004 GT3 -- Sold 1997 M3/4 -- Sold 1995 M3 -- Sold
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05-26-2011, 09:42 AM	#5
Draff1 Private First Class 13 Rep 195 Posts Drives: 2009 Silverstone M3 Coupe Join Date: Aug 2009 Location: San Diego, CA iTrader: (0)	Thanks Tim. I will look into the AFR. Since my car is basically bolt-on stuff that many many on this forum have used, I'm not sure this would be specific to me, however since there are so many of us using aftermarket HFC's with a tune, it may be interesting to take some measurements and post them. Since there were really not too many responses, I am assuming it's a non issue OR people are unaware that cats are clogging and slowly sapping power. It may ultimately be a question regarding a stage 2 tune or the ECU adaptation itself. Do the M3's tend to run rich after the secondary O2 sensors are disabled and cats removed? Can anyone verify that they do run rich? __________________ 2009 Silverstone II E92 M3 Coupe - DCT Dinan Exhaust, RPi scoops, Dinan Tune, Dinan Pulley, BMC filter, LCI Taillights, MS 15mm spacers, Huper Optik tint.
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05-26-2011, 09:53 PM	#7
Singletrack 4th down; 4th quarter? Renegade. 87 Rep 3,850 Posts Drives: 09 SSII E92 M3; 19 FG M5C Join Date: Aug 2008 Location: Pittsburgh, PA iTrader: (3)	What is an AFR? You mean a wideband O2 sensor that displays AFR on a gauge? Pretty hard in my experience to monitor AFR in realtime on a gauge. You will be able to spot a bad failure, but it isn't going to be easy to identify specific rich conditions. If you are concerned, just run your car on the dyno, again with a wideband hooked up, and see what you have. No reported cases of clogged cats on here that I've seen.
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