Cat Converter

[xtremerevolution]

This thread is just to give me information, that is all.

 

My 95 Regal was sold in California and has been there since I moved it here. So I would assume it has what you'd call a "California Cat." What's the differenec?

 

Also, I have 188,350 miles on the car now.

 

Consider these intake/exhaust mods:

Ported LIM

Ported front exhaust manifold (which is supposedly 30% more restrictive than the rear)

CAI

2.5" pipe, no resonator, magnaflow straight through muffler

Roller Rockers

 

The last porting job I did improved performance immensely. My question now is, will I get much of an improvement going with a high flow cat? Is it even worth it?

[jake91]

the cat difference is the california cat produces less emmisions i would tell you more but thats all i could find on them

[Olds W31]

The "California" means that it will meet the toughest EPA requirements (usually has a different or additional material in the cat to conform to the more stringent standards). If you buy a vehicle in Cali, or a vehicle in another part of the US that meets California emissions, it can mean anything from additional catalyst (pre cat/post cat), additional venting/charcoal evap control, different programming, etc. It is tuning an already clean package to meet the toughest standards out there.

 

All that being said, the mileage on your cat probably means that the catalyst is breaking down. You might note some flow improvement from going standard or high flow, just because of age. The problem you may have is meeting EPA guidelines with most "hi flow" cats, as the way the achieve the higher flow is to reduce or reshape the honeycomb or bed of material. If your car passes "clean", I would consider a stock replacement. Most dyno tests of LT and LS 1s and other, larger displacement, potentially exhaust limited engines show little, if any, percentage improvement by removing the converter, except at really high rpms. The big difference is SOUND.

 

You risk not passing emissions testing in CA if you go with a "low buck" high flowing cat. Most converters are not "shaped" for optimal exhaust flow. If in doubt, drill a hole ahead and behind the converter and do a pressure test. IIRC, more than 2psi difference shows a restriction in the cat. You can always go bigger diameter thru the cat, but I would position it closer (or as close as practical) to the source of heat to aid in "light off" and allow it to catalyze as designed....

 

Just some thoughts on the subject.

[Andrew]

he doesnt live in Cali anymore, so passing the most strict emissions isnt necessary.

 

honestly, with your mileage its likely due to be replaced anyway. so might as well replace it. might see a couple ponies, but not noticeable by the butt dyno.

[xtremerevolution]

he doesnt live in Cali anymore, so passing the most strict emissions isnt necessary.

 

honestly, with your mileage its likely due to be replaced anyway. so might as well replace it. might see a couple ponies, but not noticeable by the butt dyno.

 

Well I'm not going to be replacing it unless there's a problem. If it clogs up, I'll replace it, but as it is, its a 95 in Illinois so it doesn't need to pass emissions. Hell, I'd even take a screwdriver and gut the hell out of it like I know some people have done if I wasn't afraid of the smell coming out of my car or the potential loss of torque as a result of loss of backpressure.

 

But if its just to pass emissions, I won't be replacing it. The only way I'll ever replace it is if either there's a nasty smell coming out of my exhaust or if I'm losing performance because of it.

[oldscsc]

When w had the S-10, the cat was clogged so this guy took all the honeycomb internals out. It stunk bad enough we had to turn it off in the drive thru, but there was a noticable difference on the butt dyno. (2.2 / 5 speed)

[Olds W31]

 

Hell, I'd even take a screwdriver and gut the hell out of it like I know some people have done if I wasn't afraid of the smell coming out of my car or the potential loss of torque as a result of loss of backpressure.

 

Backpressure does not equal torque. If so, we would weld the exhaust closed and have infinite torque...ok, jk.

 

If you have backpressure, you WILL lose torque (inefficient cylinder scavenging at test point = lost power)

What you DON"T want to do is "over scavenge", as that draws unburned mixture into the exhaust (cooling, lowering exhaust temps, raising emissions) as well as reducing power (less mixture = less to compress = less power).

 

The smell is not terrible, but it is different if all you have ever lived with is a cat con car. My 89 Caprice with a full 96 Impala SS and export pipes (read factory cat delete pipes for Persian Gulf countries) was fun. Louder, more authority, pulled better. No change in mileage, and it DID smell like lighter fluid at the drive in. In today's world, you could probably be imprisoned for even discussing removing/replacing ANY Federally mandated equipment....

[AWeb80]

The Cat Is Off Both My Cars, I LOVE The Smell.

[xtremerevolution]

 

Hell, I'd even take a screwdriver and gut the hell out of it like I know some people have done if I wasn't afraid of the smell coming out of my car or the potential loss of torque as a result of loss of backpressure.

 

Backpressure does not equal torque. If so, we would weld the exhaust closed and have infinite torque...ok, jk.

 

If you have backpressure, you WILL lose torque (inefficient cylinder scavenging at test point = lost power)

What you DON"T want to do is "over scavenge", as that draws unburned mixture into the exhaust (cooling, lowering exhaust temps, raising emissions) as well as reducing power (less mixture = less to compress = less power).

 

The smell is not terrible, but it is different if all you have ever lived with is a cat con car. My 89 Caprice with a full 96 Impala SS and export pipes (read factory cat delete pipes for Persian Gulf countries) was fun. Louder, more authority, pulled better. No change in mileage, and it DID smell like lighter fluid at the drive in. In today's world, you could probably be imprisoned for even discussing removing/replacing ANY Federally mandated equipment....

 

Alright, cool. At least I know that my car doesn't need to pass emissions in IL.

[pontiacmaniac94]

The Cat Is Off Both My Cars, I LOVE The Smell.

 

makes me feel fast.

 

 

 

 

 

 

 

 

 

 

 

Even if it is a lie.

[ismellrealbad]

The Cat Is Off Both My Cars, I LOVE The Smell.

 

i love the sound. that hissing ticking sorta sound. nothin beats it

[BIGBULS]

Holy shit............a thread about deleting the cat that actually has INTELLIGENT answers

 

 

 

 

 

Like others have said...........a modern catalyst is very rarely a restriction on a NON forced induction vehicle, and is usually only worth replacing if it's coming appart...........AND........a gutted cat or test pipe is usually only going to get you 1-2hp at the outside (also meaning a HIGH flow isn't going to be worth much either).

 

 

 

 

 

So yeah...........keep it on there............don't want Baby Jesus to start crying now would you?