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I have an opportunity in the next couple of weeks to pull the original catalytic converter on my 1988 C4 and gut it.
Based on what I have read here and other places it can be worth up to 20 hp and can make an older car run a little cooler.
While I'm not chasing the magical free and easy HP unicorn, I think any benefit here in airflow (30 yr old CAT must be a mess) and cooling and airflow improvements is worthwhile.
Car appears to run fine right now. No a new CAT is not on the table right now so I don't want to hear how great the magnaflow or flowmaster ones are.
Stock headers and new Walker CAT back is what it currently has.
If not you can just delete the cat period with a "test pipe" they call it that fits in place of the cat. If you want to go through the trouble to mess with your cat it's up to you. I know you could sell your cat for more than what a test pipe costs.
I was offered 150 for my main cat and 50? a piece for precats from a scrap company.
Based on what I have read here and other places it can be worth up to 20 hp and can make an older car run a little cooler.
The key phrase is "UP TO". When I say "I will personally promise to send you "UP TO" $10000." it means I can send you nothing all the way to $10000. If you cat is severely clogged, it can give you a 20HP gain because the cat is killing 20HP. I doubt it can make the car run cooler. BTDT and is makes the noise louder. That was why I reinstalled a Random Tech converter which made the noise low enough the wife will drive in it with me,.
L98s cats are pretty restrictive. Many years ago, when my car was stock I added a front without pre-cats and I hollowed the main cat. After these mods, the car was .1-.15 quicker in the 1/4.
Bigger gains were had later when I eliminated the stock system and went with 2.5" duals and long tube headers.
L98s cats are pretty restrictive. Many years ago, when my car was stock I added a front without pre-cats and I hollowed the main cat. After these mods, the car was .1-.15 quicker in the 1/4.
Bigger gains were had later when I eliminated the stock system and went with 2.5" duals and long tube headers.
Was there much if you had only hollowed out the main cat? I never tried that but on the F-body, there was only one cat, I think. It "fell" off. Don't think I picked up a tenth but it was a lifetime ago.
I think it was mostly the headers. I tried that on the F-body with headers and had them dump to atmosphere after they converged but kept the weight similar. Did a few runs with and without. No difference that was significant. A couple times the open headers gained, a couple times, they lost.
Cliff,
Yes that would seem to make sense. I am thinking the space the ceramic takes up has to have an effect, but probably small.
I have seen a lot of folks here say they disregard mods with small or minimal gains. I like to look at lots of little gains add up.
Like they say about carrying gear in the field, ounces equal pounds and pounds equal pain. I figure 2 or 5 hp here and there add up. I have read on here a 20+HP gain for a cat gutting.
Hey what is a long tube header ? Not really a car guy except for the last few months.
Someone has also said that LT1 headers are much better and direct bolt on is this true ?
I am thinking the space the ceramic takes up has to have an effect, but probably small.
I have seen a lot of folks here say they disregard mods with small or minimal gains. I like to look at lots of little gains add up.
Like they say about carrying gear in the field, ounces equal pounds and pounds equal pain. I figure 2 or 5 hp here and there add up. I have read on here a 20+HP gain for a cat gutting.
Hey what is a long tube header
If it does, it is very minimal and will probably show itself at the top of the RPM curve IF it does. Now when you are talking about racing where a thousandths of a second can mean going home empty vs winning the purse and they are talking much higher power where it becomes significant, you might be right.
Lets say it does. Why would I spend $5K added up plus time to make 20HP when there is lower hanging fruit by spending a wad of $2K and doing something significant?
If you can get 20HP from gutting the cat, it has to be very plugged up. So yes, if the cat is plugged and you don't mind hearing all that noise, gut it. I had a cat on another car that would glow cherry red after driving about 30 plus miles. THAT would give you the 20HP. If you are willing to pay for my new cat, I will be willing to put the car on a dyno, gut it and run again for you to find your 20HP. If you even get 2HP on my 383 motor, I will be surprised.
Mod worth the time ?
