Hi Everyone. Long time reader, first time poster. I have a 1986 camaro. Did the 3.4 swap which went very well. I have rebuilt the front end, 115 speedo, new headliner and soon rear springs. My converter gives off the rotten egg smell and I believe it has a hole/crack in it.

Should I put a new converter on or a straight piece of pipe? Will a straight pipe cause the check engine light to stay on constantly and or set codes constantly?

I am positive from past experience that converter removal increases gas mileage. However, I have never removed a converter from a vehicle with an oxygen sensor.

Also, I have seen on ebay a $39.99 "universal" converter for camaros. Anyone ever try one of these?


Thanks
Rick

 

I have a high flow converter. I lost power down low. After 65, I saw MINIMAL GAINS.
I have raced others with no converter at all AND WHOOPED THEM.

In all honesty, I would do a stock replacement converter. They are anywhere from 30-50 at most parts stores. But yes the smell is the converter.

 

A universal convertor means that it won't bolt up. You'll either need to weld it in place, or find some kind of adapter kit. I believe that's what the local parts stores sell; a universal convertor and a $20 adapter kit.

We're all OBD I, so the car will never know if there's a cat on it or not. Our oxy sensor is before the cat. OBD II (4th gen f-bodies) has an oxy sensor after the cat, so they either need to keep the cat or get one of those "fake" oxy sensors.

Also, one thing to keep in mind- what years have your past experience been with? Early cats were pieces of crap; they choked the motor. Newer GM cats flow just as well as a high-flow cat- except a new GM cat is about $300. Aftermarket high-flow is about $100. Plus, most original 82-92 cats have had their pellet bed break up by now, causing a clog...

 

Ditch the cat. Went from a 17.4 to a 17.07 with a little extra timing, and removing that cat, in combo with a good TomP Tune Up.

 

Just do what I did, and get rid of it. It does not cause the check engine light to come on in my car.
Plus I think I have more power now. Actually it feels llike I have more power now, I mean I can just burn out now without power brakeing. So I guess i'm the lucky one.

 

I have a question. I have a 88 firebird 2.8 wiht what i believe to be the stock cat. Should i replace it or no? My echuast smells rich and i know the car is running good. Could that be my cat? Also when you stand by the passenger door the exhuast sounds tinny and it is very loud by the cat. What you guys think?

 

if the cat is leaking, replace/remove. your choice.

TomP My experiance is comparing the car before and after. Down low I can no longer grab 3rd, before I could. Yeah it squats, but no chirpy like before. And yes same tires on rear before/after.

The car I was racing was a semi built 2.8 auto.

 

350man, I believe you need to know that the only way the cat affects the air/fuel mixture is that is gets super clogged when the engine runs rich, so it gets destroyed in a sense, and exhaust flow slows down. Look for leaking injectors, have the ECM tested, etc. And if the exhaust is louder by the cat, it probebly has a hole in it.

Got my new cat for $65 and change at my local AutoZone, and it is a "direct fit", meaning you remove the old one and put the new one in without welding or any problems unless someone modified the system previously (DPO did so.. going to get him one of these days ) or if the system is seriously rusty...

 

Thanks, ya that will be the next, i will take a look at the cat today and see if there is a hole it in or not, not sure to be honest with ya. Just sounds very tinny. So the rich smell is not the cat? Thanks again.

 

NO, its not the cat, but it may destroy the cat if left unchecked, not to mention that if you are forming carbon chunks in the exhaust stream, you can clog it and lose a lot of power...
Forgot also that you were going to be replacing your flange gaskets at the manifolds. Take care of those first before worrying about the cat.

 

The original designed cat convertors will do exactly as Maverick H1L says.
My "Original style" replacement cat did that on the Firebird I have. When the cat dropped to the cement floor, BIG small chunks dropped out. I laughed.
I replaced that Firebird cat wth the AC Delco Cat Convertor one I scored when I purchased the 3.4 now in the Blazer. The Blazer has a 50,000 used 3.4 in it. I scored the 50,000 mile "Y" pipe & CC with the engine purchase. These exhaust pieces look brand new!
BEST CC I've ever used, this AC Delco. And performance made a hugh jump forward! That includes 3.4 powered.
My Blazer may need one, after this 3.4 installation, too. I replaced that factory issued CC back in 1990/91 with a universal 2 1/2" that has lasted to present date and with over 100,000 miles on it, too. Will see IF that old universal CC passes the next smog test, too!
Try to score a very low milage CC from a 4th Gen F Series. "Almost" any engine size, but you'll find one, easy. IF ya hold the AC Delco CC up to sun you see right thru the "guts" to the sun. That's the sign of a very good CC Hi Flow feature. Try the same trick on a factory issued pancake flat CC from 1975 - late 1980's. You'll never see the sun!
My 1975 Vega, brand new, first year of US auto maker issued CC's. I NEVER SMELLED ANYTHING SO BAD AS THAT ROTTEN EGG SMELL, especially on a humid, no wind air flow, suck in traffic situation. And your windows are down due to no AC. Oh it is fowl smelling.

My 1995 used 50,000 mile 4th Gen V6 F Body CC I installed on the 1985 factory issued exhaust system?
Bolted exactly as if it was made for that spot, not a single "alteration. AND NO rotten egg smell.
Pace Setter Exhaust ALSO MAKES Cat Convertors.
Besides having made our V6 60* 3rd Gen F Body Street Legal Headers, too!
Contact fgerle@pacesetterexhaust.com for a part number and vendor for purchase.

 

I removed the converter from my 91rs (305) which gives it a better sound with the flowmaster. Don't know if it raised the hp but it sure feels better. Anyway, I think the 02 sensor is bad due to really,really bad gas mileage. I think the cat and 02 sensor work together. When removing the cat does it mess up the 02 sensor or does it even work anymore. I hear with no cat there is a "fake" 02 sensor which plugs in the electrical and corrects the false reading which guzzels the gas.

Any one know about the fake replacement for the 02 sensor ?????

 

The O2 sensor is before the cat and removing the cat does nothing to it.

 

If it's bad is it affecting the mileage

 

At $30-ish, it's certainly a cheap enough experiment for a solution.

 

That only applies to OBDII cars ('96-present). Those cars have O2 sensors before the cat for fuel control and O2 sensors after the cat for catalyst montitoring. If one were to remove the cat, the rear O2 sensor would know and the SES light will come on. If you replace that rear O2 sensor with an "O2 Sim" it will simulate the readings needed to keep the SES light off.

 

you guys got any links of where i can get a high flow cat for my 3.1 i seem to only find ones for 5.0

 

www.pacesetterexhaust.com
For a specific application number and more personal service of Pace Setter Exhaust products (including the street legal headers for our V6 rides and yoru desired Cat Convertor)
send a short email to
Mr. Fred Gerle
fgerle@pacesetterexhaust.com
He'll be happy to assist ya!

 

If it's cloged up at all you will see big gains.
I would gut it or replace it with a pipe eather way I would lose it.
It won't set off the "light" neather one of my cars have one.

 

How about emissions? Would a car without the converter post a problem passing? Esp. with the sensor they put in the tailpipe.

 

i would think that a good portion of this would have to do w/ how stringent your emissions testing is. If it's really strict, then you might not pass, if it'sn ot so strict, than you might pass. Around here in missouri, they're thinking about restricting emissions testing to 96+ vehicles, and all they'll do is plug the obdII into them and make sure everythings working, if it is, then they pass, if it's not, then you don't. So essentially, if ur check engine light isn't on, then you're good to go, that'll really help a bunch of us folks w/ older cars.

 

A car with no converter will fail any ASM test.

 

My 92 Camaro V6 RS runs like **** after converter was taken off