Removal of Catalytic Converter

[ricka]

Hi Tuners
Just visited a mechanic who recommends that I remove the catalytic converter on my galant 4g94 engine to minimise carbon build-up and improve fuel economy. Any thoughts on this.

[rollingstock]

Don't really see the sense in his statement, the carbon build up will be on the catalyst itself and doesn't pose a problem as this is it's function, unless the catalyst is severely clogged. Removal will gain a minuscule gain in power, but may actually cause you to lose fuel economy, reason being a less restricted exhaust. If you want to cut down in carbon build up in the engine and gain better fuel economy i suggest removing the egr valve, no burnt exhaust gas will be pumped into the intake thereby keeping the injector cleaner resulting in less gas being burnt.

[Alpha_2nr]

Hi Tuners
Just visited a mechanic who recommends that I remove the catalytic converter on my galant 4g94 engine to minimise carbon build-up and improve fuel economy. Any thoughts on this.

Yep...two thoughts:

1) Does your mechanic work under a mango tree with a large hammer as his primary tool?

2) Have you ever considered changing from said mechanic? Frankly it makes no sense what he said. Your cat converters actually help keep the exhaust cleaner. And as for fuel economy, having a "free flow" exhaust on a modern day car help fuel economy is near impossible. The only way this would happen is if your stock cats are clogged/damaged....HAVE YOU ASCERTAINED THAT?

Your "mechanic" is clearly a shade-tree trained pleb who should perhaps be limited to hammering bodywork and applying bondo to cars, rather than working on engines.



My 2c.

If you want to cut down in carbon build up in the engine and gain better fuel economy i suggest removing the egr valve, no burnt exhaust gas will be pumped into the intake thereby keeping the injector cleaner resulting in less gas being burnt.

Please. EGR is used to IMPROVE low end economy in some cars.....mainly for NOx control in others.

Furthermore, that is NOT how removal of EGR woudl affect fuel economy.

Removing EGR essentially makes the inlet air stream PURER (non-diluted), which means that to move a given mass of oxygen into the combustion chamber now requires less throttle opening than WITH EGR on. AIR=POWER. Hence technically you can get a little more power for a given PEDAL APPLICATION with the EGR removed.

NOT because of keeping injectors cleaner

[rollingstock]

Alpha_2nr, i get what you're saying, but from my personal experience after removing the egr i had to clean my injectors a lot less, i took them out and they had remained clean unlike the buildup that was present when the egr was installed.