My cat is toast, I would like to put a test pipe in with the heat shield welded to it. My only problem is that I have to pass a dyno sniffer test and I'm not sure if it would??

------------------
1987 Formula 350, headman hedders, Accel supercoil, cap, rotor.
MAF screens removed. 160 degree stat and manual fan switch.

Best ET: 14.745@91.317mph-Stock
Best ET: 14.418@95.51 mph-Modded
Ridiculed Founder of the Traction Impaired Crew

 

Your engine has to be really freakin' clean to pass with no cat, but it can be done.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

I passed with a gutted cat and had lower numbers than with it. However,I did run a bottle of G2P in it before I went to get tested.

 

Forgive my ignorance, but I'm assuming "G2P"
is a Brand of dry gas??

 

Its a product called "Guarenteed 2 Pass", available at your local auto parts store.

 

YES! you can pass with a gutted cat. I did, but lets just say I did a little tuning first! after I was done it was cleaner than with the cat on it. (i realize this is only because of the tuning and it is not always this clean). I will be buying a high flow cat when I replace my exhaust because i feel guilty about contributing to the pollution problem more than I should. by the way I didnt gut the cat, the previous owner did.

------------------
84 Firebird with Trans am ground effects- 350 4bbl GM crate motor (LM1), T-Tops, automatic, K&N filter, 180* thermostat, ram-air hood scoop, flowmaster muffler, Accel cap & rotor, MSD Super Conductor Wires. Coming soon: new interior (grey), rear end work, subframe connectors, polyurethane bushings

 

I've been doing emission testing in Atlanta for about a year. It's rare but if your EGR system is working good...it could happen. But as for the test pipe...i don't know how they do it there, but here there is a visual cat test so you have to have a cat, gutted or not. Unless you are blocking off the EGR system completely, running w/o a cat will eventually cause EGR problems...so in my opinion I would say just bite the bullet and get a high-flo cat.