Do I need a catalytic converter
BigBlizzy
01-29-2005, 09:40 AM
I was wondering I am trying to get the best horsepower out of my truck, and was in the middle of taking my catalytic converter off, when I started thinking, if I take it off will my truck catch on fire, or will it just make it loud as hell?
MagicRat
01-29-2005, 12:41 PM
(sigh....)
It is MUCH easier to advise you if you provide the make, model and year of your truck!!
This is important because many older GM converters, (the wide, thin, 6 sided kind from the 70's and 80's are very restrictive. They use a bed of coated pellets inside.
It is possible to 'empty' the pellets by knocking out the plug at the bottom (it looks like a freeze plug from an engine block), and using a bolt - on plug in its place. Either emptying it or removing it will help power, but usually not by much, unless its really defective or plugged.
The later 'monolithic' type are less restrictive and will only provide a slight power increase....unless it has been overheated and melted inside, something that only happens if your engine has been running too rich or misfiring for a while.
Some late model trucks use two O2 sensors, one downstram of the cat. If you remove it you will get a trouble code on the ECM and the engine may not run well.
If you have a muffler in place, removal may make your truck slightly louder, but it should not be objectionable.
Finally, removing the cat altogether is illegal in most areas, and you can get a fine if caught. (and unethical.......we all have to breathe the same air......)
It is MUCH easier to advise you if you provide the make, model and year of your truck!!
This is important because many older GM converters, (the wide, thin, 6 sided kind from the 70's and 80's are very restrictive. They use a bed of coated pellets inside.
It is possible to 'empty' the pellets by knocking out the plug at the bottom (it looks like a freeze plug from an engine block), and using a bolt - on plug in its place. Either emptying it or removing it will help power, but usually not by much, unless its really defective or plugged.
The later 'monolithic' type are less restrictive and will only provide a slight power increase....unless it has been overheated and melted inside, something that only happens if your engine has been running too rich or misfiring for a while.
Some late model trucks use two O2 sensors, one downstram of the cat. If you remove it you will get a trouble code on the ECM and the engine may not run well.
If you have a muffler in place, removal may make your truck slightly louder, but it should not be objectionable.
Finally, removing the cat altogether is illegal in most areas, and you can get a fine if caught. (and unethical.......we all have to breathe the same air......)
curtis73
01-29-2005, 04:38 PM
Excellent point, MagicRat. Newer cats aren't that bad and the fact that they can be responsible for as much as 70% of the emissions reduction in a car, it makes sense to leave one on there.
I'm actually probably adding some to my 1966 Pontiac since it shouldn't cost more than about 5 hp but help the environment.
Otherwise, BigBlizzy, removing the cat won't cause the truck to fall apart, burn, or otherwise evaporate :). Depending on the year and engine controls it may cause drivability issues.
Oh, and the Violation of Federal Law part is a concern too. :)
I'm actually probably adding some to my 1966 Pontiac since it shouldn't cost more than about 5 hp but help the environment.
Otherwise, BigBlizzy, removing the cat won't cause the truck to fall apart, burn, or otherwise evaporate :). Depending on the year and engine controls it may cause drivability issues.
Oh, and the Violation of Federal Law part is a concern too. :)
joe minute
01-29-2005, 09:33 PM
If your concerned about your converter performance, it is very easy to test.
If you have an oil filled pressure gauge you can do it yourself, if not , most muffler shops do.
You drill a hole in front of the convert and put the guage on the hole, punch the throttle to wide open and see if the back pressure goes above 1.5 lbs of pressure. If it is higher than that, then replace your converter with an after market high flow converter.
If less than that, there is no point in changing it
If you have an oil filled pressure gauge you can do it yourself, if not , most muffler shops do.
You drill a hole in front of the convert and put the guage on the hole, punch the throttle to wide open and see if the back pressure goes above 1.5 lbs of pressure. If it is higher than that, then replace your converter with an after market high flow converter.
If less than that, there is no point in changing it
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