I am building a close to 500 HP Super-Rammed 383 for my 89 GTA. I am wondering if a catalytic converter would be bad idea for this car. I know it is not a big deal when the motor is putting out 250 HP, but im putting out close to double that. My goal is to keep everything on the car that it came stock with, or replace it with a better part. For example, I still have A.I.R., EGR, A/C, but obviously i replaced my engine and transmission with higher performance internal pieces.

I want to keep the catalytic converter, but i think it would be way too restrictive. My exhaust set up includes SLP 1 3/4 headers with A.I.R., the y-pipe that comes with them, mandrel-bent 3 inch pipe to a flowmaster 80 series with dual 2 1/2 inch pipe out the back.

What do you guys think? I know that companies like Catco make "high flow cats", but high flow is relative.

 

If your not subject to emmisions, then dont run it. Id say two 3" cats wouldnt be restrictive, but youll need to make sure the engine is rich enough to shut down the cats at WOT or theyll melt in a hurry. Also, a hot cam could potentially dump alot of air and fuel into the cats at low RPM operation, shortening their lifespan.

 

Isn't that a little like saying "If no one is watching it is ok to steal?" Your not going to lose anything noticable if you use a Cat. Surely, nothing that your right foot/reaction time won't more than negate.

 

While good dual cats wont be a restriction, you have to be careful with them. Performance air/fuel ratios dont work well with cats. All the extra fuel mixed in with the residual oxygen will cause long term damage and possibly immediate destruction. Id defiatly prefer not to have it. You can run leaner, make more power, and not have to worry about reducing 150-300+ dollars worth of ceramic and precious metals to molten scrap. I have one with my 3" system. Its nice having the car run oderlessly and have clean emmisions, but I hate having to watch over it to prevent damage.

 

I run a single 3in catco on my 383. I like the less smell and also the less raspyness with the cat.