BlackZ06

OK. let's discuss .......

Would you care to expand on your claim that you tried high flow cats on two occasions and "as soon as I used the car on the track the cats would fail" ....... Yeah, I believe that .....

I have no problem with a "track only" vehicle having no cats. Trailer it to and from the track and have at it.

For street vehicles like Targa98 is talking about it is plain stupid to take the cats off, plus it is illegal under federal law and most state laws.

vrybad

First, I don't think anyone is truly trying to bash you here.

You asked about removing cats and avoiding a code issue, which tells us you may need to worry about passing emissions.

For that reason alone, most of us suggest using a good high flow cat because they don't really rob any power.

Then you can tune around the code problem, which you should do anyway to get the most from your car.

For a guy like you, that knows so much about cars and making power, you really should know that.

I agree that a good race muffler with a good tune doesn't rob power in a situation where noise limits must be maintained.

Just like a good high flow cat.

Good luck.

vrybad

By chance were you using any leaded race fuel in your car when at the track?

Also were the previous cats the ceramic type or the newer metal matrix style that appear to be much more durable?

jovette

Wow, you're certainly all that and a bag of chips................all of 20 years old and knows it all...............Suggest you show your full name, and address, and then those EPA folks you love to hate (as well as your children, and grand children, should you ever grow up and get married), can come and grace you with a friendly visit.

bigbadbevo

Got uid0

Help someone that knows what he is talking about?

Hell even i know how to make my own 02 sims

Got uid0

"the cats would fail"

How would they fail? You mean your 02 sensors would throw codes? That is not the failing of your cats that is the o2 sims doing their job. You need to program them out.

dougbfresh

What exactly do you think your gaining? You'll have to spend something to do this (SIM's, tuning, pipe(s)) for little upside. Use your money for NOS-keep the CAT's.

Bill Curlee

Well said!

Oh,,,by the way,,,most of those cars running "RACE MUFFLERS" are REQUIRED to run them because of a some local or track noise mandate! NOT just because they want to.

BC




BC

slvr76

Okay, this is already getting a little too heated, but isn't it technically illegal to alter the factory cats and/or their location in any way? While the high flow cats may allow you to pass the sniffer has anyone done any tests to see which cats, factory or aftermarket, do the absolute best job of reducing emissions. Furthermore, for those who seem to be concerned about environmental issues are you against gears, heads, cams, or other performance mods that may reduce mpg and/or increase emissions and therefore pose a greater threat to the environment?

BlackZ06

No, it is not "technically" illegal ... it IS illegal ..... from an EPA web page .....

The motor vehicle tampering provisions of the Clean Air Act apply to everyone. The Clean Air Act prohibits removing or rendering inoperative any emission control device or element of design installed on or in any motor vehicle or engine designed to meet federal standards. The tampering provisions also prohibit the manufacture, installation, sale or offering for sale of any part or component used on any motor vehicle, including motorcycles or motor vehicle engines, where the primary objective is to bypass, defeat, or render inoperative any emission control device, such as the catalytic converter, or element of design of any emission control system. The maximum civil penalty under this section of the Clean Air Act is $25,000 per violation for a manufacturer or dealer, $2,500 for any other person, . This law applies across the U.S. regardless of whether the vehicle is registered in an I/M test area

Also note the first post in this thread .... (Katech is the company who prepares engines for the Corvette C6.R and other GM Racing programs) ...... more and more vendors are starting to realize that someone soon is gonna get whacked for making/selling/installing illegal equipment ....

http://forums.corvetteforum.com/show...ight=catalytic

I'm constantly amazed out how blatent some vendors are in making and selling equipment that is clearly going on street vehicles.

As far as parts that actually reduce emissions below the level the "stock" engine produces .... that's easy .... go look up a part (a supercharger kit, for example) in the California ARB database. If the item has an E.O. issued by the CARB then it pollutes LESS than the stock parts. An example is Vortech makes a supercharger for the C5 Corvette and it is in the database under E.O. D-213-19

http://www.arb.ca.gov/msprog/aftermk...es/amquery.php

nickolbag

I thought I remember reading several times that high HP rear mount turbo cars won't run cats for fear of them blowing the insides fo the cats into the turbos. If I am not mistaken it has happened and messed up some turbo systems.

Untrue to say all cars will run better w/o mufflers. Even when tuned to run with no catback some cars have picked up power by going to a race muffler. Keep in mind we are not talking race cars here. We are talking street cars that race on occasion.

nickolbag

To the OP. It is pretty simple. Get an off road pipe. Tune out the 2 rear O2s. You are good to go. Its that simple.

Since you are in Jersey you will either need to know a guy that will overlook no cats or get a set of high flows to swap for inspections.

I would expect somebody with an impressive resume such as yours to know all this already.

vrybad

I don't disagree with this.

He had stated his cats failed when he tracked the car.

I was just wondering about the type of fuel used, and the type of cats that were in place when they failed.

Ceramics have been know to come apart more readily than metal matrix.

peterc5oz

OKAY..Here is what happened on the track.
Car is a 99 C5 with LS6 ,STROKED ,FORGED BOTTOM END,DISC PROCHARGER 10lbs boost .etc.. RUNNING 98 OCTANE FUEL .Dynatech long tube headers with Dynatech high flow cats.
After a day on the track I heard a rattling noise which in the end was the internals of the right hand cat.(had come loose)
Replaced both cats AND again next track day the same problem this time it was the left cat that internals came loose...Again after a full day of track work..Noticed the rattling the next time I drove the car. CATALYTIC converters were both high flow high performance expensive units .My deduction was that the extreme heat generated by the conditions of use had caused the failure....If someone can guarantee "cats" that will last more than a day on the track I will buy them.I am aware of the environmental issues and the legalities even though I am not in the USA , as these are world wide.
My daily driver is a 2008 SAAB linear sport 1.9 turbo diesel (Still GM )which runs on the smell of an oily rag.The VETTE uses more fuel in a track day than the SAAB uses in a month.
If we were all truly concerned for our world we would ride bicycles but we are human with our own selfish needs and mine is "THE NEED FOR SPEED".
GREAT FORUM GUYS ....Peter , Australia.

BlackZ06

A turbo is mounted in the exhaust stream BEFORE the cats ... not after, and even if it was mounted AFTER the cats, the turbo is using the exhaust to "compress" the INTAKE air .... it doesn't alter the exhaust flow other than, when spooling up, it will create some added back pressure to the engine side of the system.

I think you're confusing back pressure in the exhaust (which mufflers, cats, and turbos can all add to) with a "tuned" exhaust.

If you look at a Top Fuel dragster, for example, it has 8 pipes coming off the engine. No mufflers. BUT ... those pipes aren't just a random length ... they are "tuned" in length to actually help scavenge the cylinder on the exhaust stroke. If you look at the gas flow in one of those single pipes ..... it is not a constant flow of gas ... it "pulses" with each exhaust stroke ... and even during the time the exhaust valve is open the gas flow is not constant ... there is an initial "burst" of exhaust as the valve first opens and then the flow tapers off somewhat. A "tuned" pipe has a length so that the initial "burst" of exhaust is exiting the end of the pipe at about the time the exhaust flow is ending in the cylinder. This rush of the initial gas charge out the end of the pipe accelerates the gas flow behind it and helps "draw" the remaining exhaust gases out of the cylinder and pipe.

The MOST efficient exhaust system is, as you will see on any true race car, without impediments to gas flow (no mufflers), and the pipe or pipes are "tuned" for the engine. Even race cars that have turbos on them (such as the now gone Champ Car race cars) have a tuned exhaust. Headers are "supposed" to allow you to tune the exhaust better because the pipes are theoretically all the same length (which is why the pipes often have those odd bends in them) .... they collect the exhaust gases and deliver them to a single pipe. The end of that single pipe can now be measured and cut to an "ideal" length that again should be of such a length that a charge of gas is exiting the end of the pipe as another cylinder is exhausting into one header pipe. If the exhaust pipe is long enough there may be several cylinders worth of exhaust "pulses" flowing down the pipe at the same time. Take a look at a NASCAR set up and you'll see no mufflers and a tuned exhaust length.

The reason some people see a decrease in power when they remove cats and/or mufflers (and therefore mistakenly think that mufflers add power) or see an "increase" in power when they add a race muffler is that the change has altered the tuned length of the exhaust system and/or the characteristics of the exhaust flow.

VIPERBLUELX

There are more than a few "idiots" on this board that don't run cats, myself included.

nickolbag

Thanks for all the info...but my car is not a top fuel dragster nor a Nascar race car. I'm more interested in how it will effect my car. Say me running open headers vs me running an x pipe with race mufflers vs me running an aftermarket catback.

Any input?

I've seen cars bolt on race mufflers on an open exhaust and pick up power, I've also seen my car on the dyno without a catback and lose power. If you are saying that it is simply the length of the pipe that matters and as in Nascar can hold several pulses of exhaust, wouldn't only the header length matter and the rest of the straight pipe be meaningless? Why would it matter how many pulses are traveling thru the pipes as long as the header is of proper length?

BlackZ06

Peter .....

I'd take the issue up with Dynatech ... their catalog specifically says these cats are:

"NOTE: These products are intended for racing and off-road applications."

http://www.afabcorp.com/exp/files/re...5_dt_other.pdf

(It is under the product list of cats on page 30 of the catalog)

Sounds like they should replace the cats for you ... or you should find another vendor ..... clearly their product is not living up to its claims.

peterc5oz

THANKS FOR THE FEEDBACK...I will look into this.
Appreciate the constructive comments.