Why you should stay catted

[Mr_Draco]

Originally Posted by EnvyTerra

I beg to differ, off road pipes have been used for years and do gain HP over cat's it's just proven over and over...

running no cats and tuning for it ALWAYS gains power, I would like to see proof that it doesn't.

This is true for MOST vehicles.

However there have been tests done by Janetty Racing on the Camaro comparing no cats and high flow cats. Their results are posted somewhere here on this forum but they showed that no cats with a tune offer no gains over high flow cats and a tune.

[The_Blur]

Originally Posted by Apex Paul

I don't think that is correct. The law does not bar replacement of parts with aftermarket products. It goes to intent; is the product you are replacing intended to defeat the emission process. If it flows better but is still effective, then I think it could be said that the item is legal.

From section 203(a)3B it is illegal:

"for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use;"

One way to interpret this is that any item can be installed on the exhaust so long as the intention is not to render ineffective emissions equipment. In other words, if someone produced an item with increased flow and also increased emissions performance, the law would not apply.

[Huck1974]

some of our states only have visual inspections. Im not saying I condone the removal. It can be argued that the sniffer sees little to no change with or without them. I have seen it first hand.

[3min3m2]

The law does have a provision that replacing damages factory components with aftermarket ones is ok I do believe.

That's how A lot of people get by with it and how some kits are 50 state legal.

Just clog ur stickies and throw high flow ones on there and make everyone happy!

[Hicompression]

OK I'll sum it up:

1.) A straight pipe does not have much gain over a high flow (200 cell) cat.

2.) A "high flow" cat does show a gain over factory cats (400 - 600 cell).

3.) Running one "high flow", 200 cell cat will show a significant gain over a factory set-up consisting of two "standard flow" 400 cell cats that are plumbed-in back to back in the exhaust on each side of the motor (factory setup).

[PsshPlzz]

Does going with straight pipes N/A have a big effect on back pressure with the ls3? If they are as efficient and non-restrictive as stated I would imagine not.

[DieselNuts]

Originally Posted by Apex Chase

Very little, the cats on the Camaro are almost like straight pipe. Dyno tests run before and after cat removal have shown basically no gain whatsoever.

Can you post this dyno chart?

Originally Posted by EnvyTerra

I beg to differ, off road pipes have been used for years and do gain HP over cat's it's just proven over and over...

running no cats and tuning for it ALWAYS gains power, I would like to see proof that it doesn't.

I'm with you on this.

[hot ss]

Originally Posted by 2010 SSRS

legal, what is that, lol, LT's and Corsa Exhaust on mine and I love it.

ditto, if i stay under 20 tps., any more, and it might as well be wot.

[The 2010 Sin]

How come everyone including myself that takes the god forsaken restrictive crap off makes alot more power to the tires.. its not because you were holding your mouth right when they dyno'd it.. they are restrictive crap.. I have 200 cell count now.. with my JBA longtubes.. now those are efficient.. but thats not what we have stock.. its two 400 cell cats per side.

[Apex Motorsports]

After going back and looking at the info I think the test I was referring to was high flow versus straight pipe. I suck again!

[LS3SSRS]

too late my cats are gone! i have a few more ponies now too, according to my butt dyno...

[jtzako]

High flow cats (200 rating) are showing 20+ RWHP gains without a tune using stock mainfold and exhaust. That is definitely not trivial. Complete removal is illegal but I've never seen anything say what the minimum rating is for 'legal' cats.

[Cam 427]

I don't mind running cats, they are suppose to reduce harmfull emissions. If the aftermarket equipment is as good or better than OEM, it shouldn't be against the law to install them.

[SGOS252382]

Originally Posted by Cam 427

I don't mind running cats, they are suppose to reduce harmfull emissions. If the aftermarket equipment is as good or better than OEM, it shouldn't be against the law to install them.

Aftermarket equipment (high flow cats) aren't designed to work (reduce emissions) better than OEM. They're designed to flow better (make more Horsepower).