89 sierra 5.0

[debo89sierra]

i have a 89 gmc sierra with the 5.0... i was wondering what would be the issues with cutting my catalytic converter off... any info is greatly appreciated

 

[1988IndySierra]

Nothing, really. Slight gain in HP. Unless you live somewhere with inspections, then you will likely fail.

 

[Molson02536]

i have a 89 gmc sierra with the 5.0... i was wondering what would be the issues with cutting my catalytic converter off... any info is greatly appreciated

Th catalytic converters are designed to reduce noxious gases that harm our ozone and contribute to global warming. If you haven’t changed heads or cam on your TBI engine, VE at 4500-4700 RPM is only 67%. On a 350 TBI engine, CFM requirement is 383-473 CFM.

A 350 with hydraulic roller camshafts, performance heads and other performance goodies, you can choose a VE between 90-100%, but I bet there is <5% of the TBI crowd out there with that engine combination lol.

What is exactly VE? Probably the most important factor influencing CFM engine requirements. CFM requirements are based on 3 factors, 1 max engine RPM, 2 intake manifold design, 3 volumetric efficiency (VE) of their engine. http://www.wallaceracing.com/intakecfm.php.

Removing the cat on a 2-into-1 exhaust system will improve power on a heavily modified engine with no questions asked. So depending on how you feel about saving our environment versus the additional expense of 2 catalytic converters and a custom exhaust, only you can make that decision.

All I can say is TBI engines with stock heads and cam do not need to remove the stock catalytic converter, unless it is plugged or faulty (or the ancient pellet-type). There is no significant change in power with or without a high-flow catalytic converter. A 1996 plus Vortec 350 engines already come with 2 catalytic converters from the factory that is more than enough to meet any performance upgrade potential.

Hope this helps answer alot of peoples questions about catalytic converter removal.

Molson02536

 

[debo89sierra]

thank you

thanks guys i am mainly wanting to do it because mine is about stopped up and my exhaust is rusted in several places.. but im planning on putting headers and duel flowmasters just wondered if it would cause any sensor issues . its not a daily driver it is my dads old truck and i jus like to get it out and ride around some..