hungryhippo

Just curious on your experiences with high flow cats on a car that does 10-12 track days a year. Do they last? It seems to me that they're not that durable.

SouthernSon

It really depends on the oil that one uses. High ZDDP racing oil and you can kiss them goodbye in short order. Otherwise, with typical walmart brand, you can expect long life. However, the engine would prefer you get rid of the cats and go racing oil or, at least, high ZDDP content.

mountainbiker2

Your not going to past smog with used high flow cats. Ones that you're going to be racing with.

RDnomorecobra

depends on where you are. not all states insert the sniffer thingy. some just validate that you have cats and there's no codes being thrown.

Sidney004

My expensive experience is that if you track the car, you are going to reduce the efficiency the cats, regardless if their OEM, aftermarket, whatever type of oil. At wide open throttle even with a stock tune, the engine runs rich(am I right or wrong here?) and this hastens their demise. In my case(2 times) the cats just weren't working efficiently enough to pass the sniffer test without replacement(and I tried all the tricks too!) Nowadays, I have taken my functional set of cats off and replace them every 2 years. If you don't need to smog until 2013, you may be OK, no sniffer test next year. http://forums.corvetteforum.com/sout...ffer-test.html

Cobra4B

When I built my car in 2010 I left the cats in place (removing them costs points for NASA PTA racing). I finally removed them this spring. They looked fine with no signs of deterioration or clogging etc. My H-pipe had come off a lower mileage 2004 Z06 when I got it. FWIW I ran Amsoil XL 10w40 and 93 octane pump gas.

hungryhippo

Thanks gor the input. I have the stock parts for smog. I was thinking about putting the catted X back on to quiet the car down. I'm worried that they will get blown out or plugged up.

Wicked Weasel

Mine and a friend's cats both plugged up from being on the track. I gutted mine.

AU N EGL

8 years and no problems. RandomTech high flows here.

I use 15-w50 oil too.

SouthernSon

7k to 8k track miles with Random HiFlow and no problems either. However, I switched to a more dedicated track oil (extra ZDDP) and decided to gut the cats since they would not be expected to last much longer with the extra zinc. The reason most oils have dropped the higher concentrations of the ZDDP is for catalytic convertor longevity. The engine, as I stated above, likes the extra additive.

C66 Racing

FYI - that is a "low" ZDDP oil complying with API SN limits so probably didn't put the stress on the cats like a high ZDDP racing oil like I use.

Also note that the high levels of phosphorus in racing oils doesn't "plug up" the cats -the phosphorus slowly poisons the cats and prevent the catalytic exchange that allows them to function properly. The only way to really verify this is on an smog testing rig.

Clogging of the cats is common on track cars, but I believe this is caused by the full spectrum of engine exhaust byproducts, not specifically phosphorus. Thankfully for me, the SCCA changed the rules for my class many years ago and my cats are long gone.

mcar00

Same here.

ZedO6

My solution to clogged/overheated cats on track cars. Between the catalytic heat, and the computers COT cat overheat protection scheme (which dumps fuel to cool off overheating cat's), I chose to remove the cats for track use.

I run this setup on a spare H pipe and keep my low mileage catted H pipe on hand for smog. Obviously I'm not running headers. This is a cheap and easy solution, reduces engine heat, and I tuned out the COT feature from my ECU.

GeorgeZNJ

I'm the friend, hi flow cats and long tubes from ARH.

varkwso

No problems with the cats that came with my dynatech headers. Probably 300 track.days on them.

Bill Dearborn

Can't say anything about high flow cats and all NY does is check the ECM for Cat codes but I haven't had to have any Stock Cats replaced in the last 15 years except on the Tahoe that tows the Vette and when the engine blew on the Vette last year and destroyed both cats (220 degree coolant being dumped into them when they were running at least 5 times that temp).

Bill

Sidney004

Just to make sure we are all on the same page, does Georgia(NC and TN) have a functional sniffer smog test like they subject us to in California? I've never had any mechanical problem(obstruction or otherwise) with my cats, just couldn't pass the sniffer test and get the thing registered. The car was primarily driven to and from the track in addition to the track usage.

varkwso

Most of the states no. Just in certain counties.

Wicked Weasel

Blew the cats in my trailblazer SS too. Maybe it's me.

AU N EGL

OBD II testing in NC. and VISUAL inspection. So any cars that spend even a little time on the road, need CATS.

Most states us OBD II testing.



NOTE: NC is or MAY change the OBDII testing requirements, to cars OLDER then 3 current years models or more then 70K miles.

But if the car is OVER 25 years no testing is required, just visual inspection for safety.