Ok I dont know why Ive done all the mods I have and havent really noticed a gain in power. So Im ready for a "real" mod! Next on my list Im either going to do a really nicely researched cold air intake, dynomax cat back, take the cat off, or a chip. Which one do you guys think I should do. I will have about $200 to spend. Thanks!

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

Dynomax cat back and catco high flow converter would eat all 200 up and be a nice gain.. If you could toss out 35 bucks more you can have it installed...

 

So you think I should hold out on the cold air??

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

Don't run a car without a cat. Why put out 10 times the pollutants for 1 hp? A cat is not as restrictive as everyone thinks. Do what Brian said....get a Catco.

------------------
Jason E
'89 Camaro RS 2.8
Hypertech chip/K&N filters/Accel 8.8 wires/RapidFires
Eclipse CD and 100x4 amp/Boston plates and 6x9s
Alpine Alarm w/ Keyless entry
IROC tailights/tinted windows

 

What would sound better? No cat or high flow cat? Im thinking no cat.

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

just get a car also you will save your self hasstle when it comes time for smog and aslo it will reak with out a cat trust me

 

Hi Flow!!

------------------
Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O. Automatic

If u are in the Central NJ area, possibly for sale:
89 RS 2.8
60,000 miles on engine
T-Tops, new stripping
235/60/15's
AR rims
newer muffler with 2 1/2 pipes, high tempature aluminum painted
hatch tint
lots more
Nice Car

 

cat...u wonder why it gets so hot now? Because of dumbasses with no cats making global warming a factor

------------------
88 Firebird 2.8
MODS (either coming or on):
Flowmaster 80 series, Random Technologies Cat, 3" intermediate pipe, Accel 8.8 wires, MSD Coil, MSD Ignition Module,MSD 6A
Currently Working On:
t5 swap
Next to buy:
Slp dual cold air intake!

 

Thank you Graemes!! It gets me so pissed to see other states having no emissions laws at all, and seeing people run with no cat. There's no reason for it! Me? I gotta pass emissions for AT LEAST another 5-7 years, depending on how the laws change.

Monkie, you will feel NO performance benefit from taking the cat off completely. It WILL smell more, and it will be a bit louder. Thats it. Go spend $50 on a Catco, save the environemt a lotta **** and if you ever need to pass the sniffer, there won't be nearly as many problems.

[This message has been edited by Jason E (edited November 14, 2000).]

 

As my mechanics teacher has told me, a cat, no matter the make, if in good condition and operating as it should, will not impact performance whatsoever. If it is clogged, or you have been running a rich mixture, this will cause it to partially block exhaust flow. As long as it isn't clogged, your stock cat will operate just as well as a brand new "high flow" cat. And it will filter more, too. I have been told this by numerous people, including my teachers and the guy at the exhaust shop I go to. Think of a "high-flow" aftermarket cat as a really shiny, big fishing lure that costs a couple more bucks than the others. They are made to sell to people, and probably aren't everything that is advertised. Now I am not saying you shouldn't buy a new cat, but only do it if you really need one. Otherwise, keep it on and do all of us asthma sufferers a favor.
Vman

------------------
1989 Camaro RS
2.8 V6
K&N's
700R4 tranny
Cragar Street Pro rims (old Series 30)
Pioneer DEH-P3000

1969 Camaro SC
350 HO from a Vette
Turbo 350 tranny
In the process of being restored

 

I agree, get a cat-back exhaust as the next mod. Dynomax #17493 is what you need.

High-flow catalytics are part of the "throwback" to the old days. When cats first came out, the automakers didn't know what they were doing, and made the internal catalyst very restrictive. All they were concerned with was dropping the emissions of the "current state" of the motor. 70's hot rodders felt a dramatic increase in HP with the cat either removed or gutted.

After the late 70's/early 80's hell, the automakers realized that they could decrease emissions by making the motor run more efficiently. They constructed cats to flow better than the original smog-bog equip, which made the motor breathe better, which reduced emissions on it's own.

Hot Rod Mag did an article a year or so ago comparing the emissions & power output of a big block 502. They ran it without any cats, with a GM cat, and a high-flow cat.

HP didn't drop that much when they went from no cat to a new GM stock cat. It improved slightly when they switched the new GM cat for a high-flow unit-- and I'm talking 1-2 HP.

They did discover that emissions dropped dramatically with the GM cat! The street-legal, CARB approved high-flow unit let one stat (I believe HC?) go into the 1000's. The GM cat dropped it to under 100!

That was going to be my last resort if my car didn't pass the new IM/240 emissions test- I would've dumped my high-flow unit for a new GM cat. The problem is the price, of course... $300 or so.

Besides- a gutted cat goes from a pipe, into an empty box, and back into a pipe again. It seems to me that would inhibit exhaust flow.

By the way, I have a Product for Power (Dynomax) high-flow cat. I'm not sure if those are sold anymore, I only hear of Catco units.


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Dont ya just love South Carolina!!!???

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

Geeze you guys dont bite my head off!! I was just ASKING a question! It seemed good at the time to just take the cat off. I mean what $150 for a high flow one VS free to take it off. The free part sounded better. Actually it was my dad's fault. He told me that he could get a guy to take it off for free since we're gonna have to replace it soon. And since his 69 maro doesnt have one then he figured it would be a good idea for me. AND YES YOU GUYS IM GETTING A HIGH FLOW ONE!!!!!!!!! HAPPY!!!!!?????

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

odd.. i havnt a cat on my 2.8 and havnt for the past 3 years, pass emissions with flying colors each time.. and PA emissions are pretty strict, matter of fact within the next two years you will be on a dnyo pulling a load while the emissions test is taking place...

 

hey scoob...but think of one thing, in 5 years ur going to wonder why its 3 degrees hotter than it was before and thats the answer..im just doing what i can to help performance without killing the o-zone

------------------
88 Firebird 2.8
MODS (either coming or on):
Flowmaster 80 series, Random Technologies Cat, 3" intermediate pipe, Accel 8.8 wires, MSD Coil, MSD Ignition Module,MSD 6A
Currently Working On:
t5 swap
Next to buy:
Slp dual cold air intake!

 

i agree with keeping the cat ON. i think today's cars are designed with the cat in mind. advancments in technology have allowed vehicles to produce power and still be "clean". back in 1975, engines weren't made with cats in mind, so the very first cats were VERY restrictive.( not to mention very prone to catch on fire )

------------------
Dan
100% stock 1990 RS 3.1L
and VERY slow
edit:soon to be 99% stock with a flowmaster but still very slow

 

Monkie,

No, I DON'T like South Carolina at all if they don't even make you pass a simple emissions test. That's pure irresponsibility on the government's part.

Graemes is right...people should take responsibility for the environment. Here I am having to pass the same standards as CA, and states like SC, MI and NH have none whatsoever!

Here in New England, (and maybe Tom in NJ knows about this too) we have a major problem with acid rain. All those states out in the midwest that don't do a damn thing about air pollution are what causes that. Know why? Because all the sh*t those states puts out gets caught up in wind and clouds and blown east. Then when it rains down in the NE, all the shi* lands on us. For those of you that don't have such problems, you oughta see what acid rain will do to an unwaxed car. Not pretty.

Sorry Graemes, I know this ain't tech, but it pisses me off every time I read about it. Just trying to give others a little ecology lesson

 

I think we have acid rain, too- that might explain why my barely-waxed car looks so faded

I'm funny- I think cats should be used, but AIR pumps should be garbage. I don't see the point of an AIR pump- it pushes fresh oxygen into the exhaust. Well, duh! Isn't that diluting the percentage of pollution?

They say the fresh oxygen converts NOx into N2 and O2. Okay, well, where's the most fresh oxygen? Outside of the tailpipe, where the exhaust hits the atmosphere. If pushing a little fresh air through the exhaust is so good, why not measure emissions by hanging the probe by the exhaust pipe? Same thing.

I'm so glad 85-86 2.8 Automatics didn't get an AIR pump. If I can pass emissions without one (thanks GM!) then why should an '87-up need one?


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

you know, i just don't understand that. there has to be a good reason. my '90 has an auto tranny and i have an AIR pump but my co-worker has an '89 5 speed and NO pump.


------------------
Dan
100% stock 1990 RS 3.1L
and VERY slow
edit:soon to be 99% stock with a flowmaster but still very slow

 

when it comes to global warming, ill be pointing at all theese damn deisels putting out black carbon that have NO emission controls.. or that ******* down the street that took his cat off a car that would barely pass emissions with it.. if your car is running properly the cat isnt doing a whole hell of a lot...

 

Not so...want proof? Check out Tom's post above about the 502 test Hot Rod did.

I do agree though that it is very imporant though to keep the car in a good state of tune in order to keep emissions low. But you gotta have the cat too!

BTW CaliCamaroRS....my '89 has an air pump. Isn't that odd? 5 speeds didn't need it but autos did...go figure

 

God knows we have plenty of those!!!! But Im glad to say Im not one of them. And I know Im from the south and all but I think this whole "rebel flag" thing is so damn stupid! You should see how many are around here! Its about impossible to find a car without either the actual flag or sticker of the flag on it.

Anyways about the cat thing. Here is the answer! Ok you take the cat off, gain 4HP. So 4 years later the world is 7 degrees warmer. Not only have you lost HP cause your "cold air intake" is no longer functional. Make sense?

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

*SIGH* Gotta defend the diesels now...

That black soot you see coming out of a diesel engine is mostly carbon related material, not the crap that really tears up the environment. Diesel engines are actually CLEANER and BETTER for the environment (when properly tuned and cared for) than a gasoline engine of the same power ratings.

Diesels are more efficient (why else would they be in all the larger trucks on the road?), more reliable (less moving parts in the engine, no ignition system either!), and cost less to maintain over the life of the engine compared to gas engines.

BTW, it doesn't matter what state you live in if you remove the cat... It's a federal emissions law. Just because people don't have to go in for emissions testing doesn't mean they're street legal. I'm sure that won't bother the people who don't live in areas where they have visual inspections of the emissions equipment, though.

 

yep totally right...my truck is a diesel!

------------------
88 Firebird 2.8
MODS (either coming or on):
Flowmaster 80 series, Random Technologies Cat, 3" intermediate pipe, Accel 8.8 wires, MSD Coil, MSD Ignition Module,MSD 6A
Currently Working On:
t5 swap
Next to buy:
Slp dual cold air intake!

 

BS. If you are too loud around here and you pass most of the cops they will pull you over, get on the ground, and look under your car. When they see no cat or muffler, guess what... Your *** gets a ticket. LOL I know it happened to my friend when I was riding in his *****. He had taken the cat and muffler off and put a tip on. He is loud as hell! I swear you can hear him a mile away (no joke). It does make the exhaust smell like **** though. And I dont even think it sounds all that good. Atleast not on a 4 banger.

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

Ok....

Lets see here, gutting my cat made a HUGE difference in my car, and it was in perfect tune, 75K miles when I did it, I could show you chunks of the cat to prove it wasn't clogged.

Yet, when I gutted the cat, the car was alot faster, hmm...

Global warming is a hoax, ever hear of junk science, go do a search on the internet for it.

My car has no AIR, no Cat, a big exhaust leak, no THERMAC, an open element, bumped timing and will only run well on 93+ octane.

Guess what, it's fast, for a 305 TBI, and not a gross polluter.

My 79 will have NO emmisions whatsoever, and it's supposed to...

All that greenhouse **** is just that, something to keep the hippies busy so they don't find out how horrible everything else is...

Monkie, gut your cat, I dare you, I bet you feel a difference.

BTW, my state has NO inspection whatsoever

 

I would but I dont want my car to smell like eggs. So Im just gonna get a catback and a high flow cat. Better in long run.

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

 

Monkie,

I was saying it wouldn't bother the owners who took their cats off if they lived in a place that doesn't do visual inspections... They won't care if they're breaking a federal emissions law when there's a good chance they'll never get caught.

Obviously (as you stated in the case with your ***** friend) there will be exceptions.

 

But still. Its not worth it. Sometimes Ive heard you even loose HP when you take it off. Like you guys said a high flow one would be better.

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

Kills:

95 (****) Probe GT
94 4.6L Mustang
91 CRX (dont ask me why he raced me)
More to come

 

I had mine off for about a week. I got a high flow though. You can't hear a thing inside the car without it. What's this rotten egg smell though? I never noticed any odor coming from the exhaust.

 

Ive heard that if you gut the cat then you smell a rotten egg smell.

------------------
1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust
8.5mm MSD Ignition wires
TB Coolant bypass

Kills:

95 (****) Probe GT
94 4.6L Mustang
91 CRX (dont ask me why he raced me)
2nd Gen Z28 (350) haha to you V8 guys!
More to come

 

Mac, THANK YOU!!! i dont know about emissions testing in other states but now in pa when you take your test you get a printout showing your exact emission specs as far as pollutant output.. i bet if i showed you a sheet from before i gutted the cat and after the numbers are so close you wouldnt be able to tell..

and as far as the rotten egg smell, a gutted cat wont do that considering its the catalyst that the smell is coming from.. hollow cat = no catalyst...

 

Ok, if cats don't do that much, then why is it Tom shows proof from Hot Rod that it does???? C'mon guys, lets be real. Gutting a cat doesn't make sense. I know guys who have done it, gone to the sniffer, and got rejected immediately. And I laughed my as* off at them for thinking it was such a bright idea. By the way scoob, MA has to do the same test as PA, and has the printout. And my 2 friends who did this had graphs WAY off the charts.

And Mac, how the HELL do you know your car isn't a "gross polluter" if you don't have to pass a damn test?? Just because you don't see it doesn't mean it ain't there. I ain't a treehugger by any stretch...I just know the facts. And I just think its foolish to wreck the environment for no reason.

And BTW Mac, if global warming is a "hoax", why is it in New England here, we have record warm winters almost every winter? Why are the polar icecaps melting? A hoax?? Sure...

 

The way I look at it; catalytic convertors are so much less restrictive now, that it makes no sense to gut one.

I will say tho, that for 3 years, I passed inspection (at the state's testing center) with a gutted cat. When the thing rusted off, and I went to replace it with my high-flow, that's when I noticed it had been gutted by the previous owner.


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Which one of the 'rags' just did a header test? On the last pull, the put a set of 3" cats in the exhaust system. Motor lost something like 1#tq. I would say its not enough to worry about. Besides, it takes some of the "drone" out of the exhaust sound. Don't wanna sound like a Mustang do you??

------------------
1992 Pontiac Firebird 350/Six Speed
1987 Toyota Pickup 383/500+ HP

 

i dont have a scanner but soon as i get a chance im headed to my buddies house to scan my emissions test printouts with and without cats.. if your failing without a cat something evidently isnt right inside that motor..

 

Mark W Winning is correct about the cat reducing the sound level of the exhaust. I had a car which developed a hole in the muffler and it didn't sound too loud because I still had my cat.

If I had a choice between no cat and a muffler vs a cat and no muffler, I would go with the cat and no muffler. The muffler is far more restrictive than the cat, even if it is a low restriction muffler. Personally, I like to stay on good terms with my neighbors, so I leave BOTH on.

 

I believe I am with the majority when i saw EVERYONE keep you cat! I live up in Ontario, Canada and I love my country so I'm going to keep our planet beautiful. Please everyone do theeir part and feel good doing it. Thank you.