Settle an argument between 2- 85 GT owners of V-6's One took off his cat converter and has no problems, the other says taking the cat converter off affects performance. Whats your opinion.
As a stock Fiero has no post-catalyst oxygen sensor, the presence or absence of a catalyst should not have much effect on engine operation. The ECM is not aware of the catalyst.
If the catalyst was in good shape, removing it will remove some restriction and free up some small amount of power.
If the catalyst was clogged, removing the catalyst can make the engine go from not running correctly whatsoever to running fine.
if your cat is old and plugged up with 30 years of crap, taking it off will improve performance and help you fill the world with NOX and carcinogenic particulate. Replacing it with a new cat will improve performance an equal amount and improve the environment. Your choice.
The new cats are a hexcel matrix that creates no real backpressure- so removing it only makes for more pollution...If the cat-less guy likes pollution, tell him to take up smoking 10 packs a day!
The older cats created some back pressure- which would appear to make removing it an improvement- But most computer-controlled engines are tuned/programmed to have some back pressure- so contrary to "Common knowledge", removing a cat could HURT performance!
All monolithic cats have very little to no back pressure. Fiero V6 has them but many are plugged or worse for engine burning oil and other problems.
Fiero L4 and others regardless engine displacement had (Some still have) "Pebble Bed" cats that does cause some back pressure because of cat design. Has several names over time but all are based on Pellets in them. Years ago Pebble Bed units could be reloaded/rebuilt by installing new Cat Pellets thru a hole in case w/ a new plug in the hole after.
Burning oil, run rich or lean, "burning" coolant, and other engine problems will plug or poison the cat. Coolant leaks from intake manifold problems etc. are common cat killers. Type of Engine Oil and Additives you might add to the sump matters too. Cats get poisoned w/ Zinc (AKA ZZP) and other things sim to having Lead Gas before was banned in most places. Is why new(er) API SJ SL SM and SN have less Zinc. You adding more zinc to current oil types are not good because most use way too much, more then obsolete SF and SG oil or even older classes.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
To answer your question: Had an 86 SE (2.8L) without the cat, straight pipe, but OEM muffler. Put a high flow MagnaFlo universal cat on it. Piping was all stock size. All I noticed was the raspy ness of the exhaust minus the cat was gone after installing the MagnaFlo. Tone was nice with the MagnaFlo. As for mileage or performance there was ”no noticeable” difference! This was on a perfect running 2.8L (37,000mi).
The previous owner of our car reported to her mech that the car had no power going up hills. The mech removed the cat and put the straight pipe on. On our inspection of the old cat, which was in the trunk when we picked up the car, looked good visually. However, you can’t see the center of the cat so who knows if it was good or bad. the straight pipe was the mechs fix. It was nice though that we had the OEM cat. We turned in the OEM cat at a metal scrapper for $100 which payed for the new MagnaFlo (approx $70) and the cost to have it welded on that straight pipe ($30). Ended out being a win/win, new cat and better exhaust tone!
Having the cat will make the exhaust smell better while idling, if ya give a hoot. Who cares about the guy behind you, if he can smell your exhaust he’s to close anyway.👍
[This message has been edited by Kevin87FieroGT (edited 10-02-2019).]
Catless, no mufflers install a j-pipe to tune the sound on each side. I use to have a video of mine setup with that I'll see if I still have it when I get home later.
Mine sounds awesome with no convertor. Stinks to high heaven and pollutes the air. I imagine I will put a new convertor on when I get to it. Getting older in years and wouldn't mind a cleaner, quieter system.
I am all for running with a catalytic convertor. I believe that I am wrong and would like to correct that one day.
Catless cars stink up the general area. Has nothing to do with anyone following too closely. My neighbor and his kid doesn't deserve to have to smell my exhaust on his own property, but he will if start the one I own which was bought cat deleted from someone here. It'll give you a headache or a smell you can't get out of your clothes, hair and nose hair. I have property in a poorer section of town and the cars in that area make the whole neighborhood worse with their smells. Stop signs, red lights (even after they're long gone) parking lots, drive thrus. It's not just me who thinks that people who drive them are not the sort of people I would trust to tell me I dropped 5 dollars at the convenience store register. There's usually dents in the car, mismatched rims and red tape over the cracked tail light, but plenty of money for cigs and tattoos.
How's that for profiling?
[This message has been edited by sourmash (edited 10-03-2019).]
Originally posted by sourmash: How's that for profiling?
Wow..LOL. I took mine off when i redid the exhaust because the car came with a straight pipe and i wish i had just put a high flow cat on instead. I plan on dropping the whole thing out of my formula and sticking it in another 88 base we have this winter. When it comes out it'll get a high flow cat before going back in. My opinion is that the performance gain, if any isn't worth the smell or pollution.
Add that most Silicon anything kills cats too not just O2 sensor. So Don't nearly all Silicone Sealers and lubes anywhere in the engine exposed to gas or oil or air going thru it. Only use "Sensor Safe" sealers.
Bought mine catless with a huge can. Absolutely hate it. Wakes up the neighbors and smells like **** if I have to do work with the engine on. The moment I can afford a new exhaust or find one at a scrapyard I'm putting it on. A little louder is fine, but it's just too much.
My experience has been that there is no justifiable reason to remove a catalytic converter on a car designed to have one. A functioning catalytic does not slow you down at all, and greatly reduces the pollution you produce. A new catalytic now is less than $100. If a person can't afford $100 to keep the environment much cleaner and be considerate of drivers behind them, perhaps public transit would be worth a consideration...
[This message has been edited by cam-a-lot (edited 10-17-2019).]
On a Fiero CATS are a fire hazard. One oil leak and there's a fire. I don't use em!
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Guys, Don't go by just what text on a DMV web site because Most only have bare minimum of the fully state laws/rules. And don't think is a joke or whatever when you read people dropping emissions and/or safety equipment.
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Originally posted by Dennis LaGrua: On a Fiero CATS are a fire hazard. One oil leak and there's a fire. I don't use em!
What a load of crap. Anything hitting or dropping/dripping on any exhaust parts in any car can be a fire hazard. A plastic bag you drove over last few days, grass/leaves parked over, and more likely have started more "Car Fires" then oil leaks. Is no more dangerous then most cars including recall cars made in last 5-10 years. Is far less problem compared to recalled Takata Air Bags that hurt or killing people even for very minor accidents. Many current recalls are for Electrical fires unrelated to battery problems for E-cars.
34 years old cars Would either car manage to put 100whp down on a dyno? Replace old cat with a modern cat, or even better put both cars on the same dyno and validate if there is a measurable difference.
Related Note: EPA is now going after many "Off Road" scammers selling Diesel "Delete" hardware and ECM/PCM reprogramming services needed to use the hardware.
In Very Short, Diesel "Delete" is removing the Diesel "Cat" and part using DEF liquid.
I was always surprise they didn't stop "test tube" makers/installers to eliminate cats for decades. Has been illegal to remove emissions equipment since at least 1975. NY and others using private inspections have been fining or arresting inspection shop owners/staff for selling stickers for fail safety inspection or emission tests for 40+ years. Most only get a sound bite in the local news when that happens is why most don't hear about them. Too bad US DOT(NHTSA) and many others don't go after selling/installing crap "upgrades" for cars.