I want to straight pipe my 1990 with a 305 i have a nice set of magnaflows now im putting on flowtech headers and want to know if anyone has an opinion on straight piping the car.

this is the link to the muffler and exhaust i have now:
http://www.magnaflow.com/02product/s...zone=all&id=79

 

straight pipe as in no cat? just go with a high flow cat, not much restriction and environment friendly

 

yes as in no cat. will it still be loud?

 

yes it will still be loud. maybe not quite as loud but you wouldn't be able to tell the difference.

 

idk though man ive heard some without cats and there loud lol. also i have an exhaust manifold leak thats pretty bad could i be losing power?

 

the volume(db) of the exhaust is mostly determined by the muffler and outlet pipe size. if you had two identical cars with no mufflers except one had cats and the other didn't, you wouldn't be able to hear the difference. if you hear a loud import with nothing but a "fart can" it will usually have 1.5-2" exhaust with cats for and the muffler usually has a 3" outlet and up to 6" tip. that's where all the sound comes from. not saying that's the sound you're looking for, but the same can be achieved. My car has dual cats, approx. 3" mandrel bent cat back and some x brand muffler with dual 3"out and 4" tips (don't know brand or anything it was on the car when i bought it). it is definitely louder than a car with just 3" pipes because the exhaust note resonates in the tips and gets louder. basically what I'm trying to say is the cat shouldn't affect overall sound because it's not what controls the sound, the muffler and back is.

exhaust leak will cause some power loss but the biggest concern is raw exhaust leaking into the passenger compartment can cause carbon monoxide poisoning and even knock you out if it's bad enough. sleeping at the wheel is never a good thing but replacing the gasket/manifolds is fairly cheap and easy if you're just going with stock

 

Loud does not equal power.

Loud can equal tickets. And removing a catalytic converter does equal Federal Emissions tapering.....There's your ticket.

Get a good quality hi-flow cat, stay legal, and don't worry about the 2hp (if that) loss.

 

Cats definitely affect sound, hell headders vs manifolds are usualy louder.

 

thanks guys ill take yalls advice and get a high flow cat

 

If your in a emissions state then yes, you should go with a high flow cat, if your not its cheaper and in my opinion sounds better without it. Even high flow cats still restrict flow to a degree and effect sound. Really its up to you either way it will sound great

 

I say pipe it. I have no cat on my car and could feel the difference in pull right off the line. Magnaflow hi flo cats are terrible and usually fail etest anyway. The smell is another story because your car smells like a 60s/70s muscle car without the cat. I don't mind it.

 

#1....Taking a catalytic converter off is illegal in any state, because that is tampering with a FEDERAL law.

#2....My Magnaflow catted, 180,000 mile (at the last test) passed so clean, they couldn't believe it & started questioning their machine.

My cat was 1 year old, no smog pump, no AIR tube, and my #s were almost non-existent!


High Speed-2692rpm
HC 220-maximum.....4-my reading
CO% 1.20-maximum.....0-my reading

Idle
HC 220-maximum.....16-my reading
CO% 1.20-maximum.....0.01-my reading

Looks pretty good to me. Not "terrible" at all.

 

Compared to say China's polluting of the air the 0.1% difference we make is not going to matter in the end. In fact it is not going to make a lick of difference.

That's great but not everyone has had that experience with that product. I have been told by more then one person they are not all that great for passing etest. Not that I care my car is exempt.

If etest is not an issue a pipe is cheaper then blowing money on a high flow cat.

 

I'm just sharing my personal, first hand experience against your second hand, word of mouth.

As for China? Who cares? Nothing we in America can do about it anyways, so what does it matter, regarding our cars? Maybe it isn't going to make a difference, when we have way too many people bypassing the law & not doing their part to help. For every 1 person who says theirs won't make a difference, another dozen people will agree & take theirs off too. Added up, they start help create the problem.

With new cars making in excess of 500+ horsepower, what excuse do we have at the 200/300 horsepower level?

No e-test does not make it legal to pull off emissions parts. I still wonder how states can not perform tests on Federal stuff. I know it is like that for some states, but it makes no sense to me.....

 

well what if i say i want to put headers on then header mufflers? will it be bad compared to no cat? its a muffler and still restricitng but it gives my car a good idle from what i hear and my car doesnt go through emissions so i dont think it would matter, besides the authorities, but cops dont mind any MAN with a SWEET looking,sounding, old car

 

yes straight pipe sounds amazing and my cars an historic so i dont care about emissions i just want my car loud as hell.

 

The majority of loudness comes from the muffler selection. I've seen 350 Camaros with headers and no cat into a stock IROC muffler that sounded quite tame. Not stock sounding. But nothing that's going to annoy the neighbours or alert the police. I'd describe it as mildly modified exhaust.

Just a catback alone on stock exhaust manifolds and stock cat will (depending on brand) sound much louder and aggressive than the above.

Now add headers to a car with a loud catback, and that's where it goes from being loud to being loud and huge. The kind of exhaust you hear for miles away.

Headers are where the horsepower is going to be. Everybody (myself included) goes about it backwards. Starting at the rear of the exhaust (muffler and intermediate pipe) and working their way forward towards the engine (high flow cat and then headers). We all do this because we want the sound and ease of installation rather than the horsepower.

Catalytic converters have gotten so much better, that the 1970's idea of them "choking" the cars just doesn't exist anymore. I seem to recall Lingenfelter taking the cat off an LT1 and he only gained 4 HP. That's less than what the throttle body bypass mod will get you. Less than what a K&N Filter will get you.

Personally I prefer running a catalytic converter. You don't get that gassy just mowed the lawn fuel smell build up in your arms and garage after you pull in. Catted cars tend to sound smoother although they can still easily be loud. My exhaust is louder with a cat than my old Flowmaster was without a cat. It's also smoother sounding and doesn't smell.

 

The point is with countries like China polluting at such levels makes the 1% carbon pollution over here meaningless. They say have cats on all cars yet places like China can pollute all they want and our little 1% is going to make a difference? Not a chance. You think your making a difference think again. Half if not more of North America could run straight pipes and it wont make a difference at the end of the day considering what's being pumped into the atmosphere by others.

 

yeaa headers i need to do with my exhaust leak i have short flowtechs

 

I have a simple solution. Just buy exhaust electric cutouts. i know there expensive but its better sometimes than going through the trouble of cutting your cat off. I have the dual cat system on mine and just wanted to get rid of them, but when i put my the new magnaflow catback on, with the electric cutout, that was just loud enough for me. so now i dont even have the thought of just cutting them anymore. Yea they will need replacing it, but i like the fact of keeping my car different from the rest of the third gen that just have the single pipe cat, into a normal basic catback. I like the look of the dual cats, and plan on making a custom y pipe soon (meaning BIGGER) pipes into a bigger high flow cat into my magnaflow. Headers will be another story for me, just u lucked out with just having the single system.

 

Can 1 country eliminate world wide pollution? Not a chance.

Can 1 country SLOW DOWN world wide pollution SOME? Yeah, by not contributing to the pollution.

Can 1 country make IT'S OWN air cleaner & better to breathe? Hell Yes!

Do you want to breathe this?


or this?


In the end...I still wonder why some people strive SO HARD just to hit 300hp, claiming that their cats are robbing them of their potential....When there are 500hp+ horsepower cars producing clean air!

I would love to run some of the European exotics (like the Bugattis, Ferraris, Lamboghinis, etc.) through a smog test to see what they put out, with their high horsepower.


Single cat vs dual cat won't make any difference to the headers. Only the y-pipe is different between the two setups.

 

According to http://tonto.eia.doe.gov/ask/environ...aqs.asp#US_CO2 the US produces 5,833 million metric tons (19%) of carbon dioxide compared to China's 6,534 million metric tons (22%) yearly. Remember that China also has 4 times greater population than all of the US, so person per person the US produces much more CO2 than China. 1% of 5,833,000,000 is 58,330,000. That is a huge amount of CO2 that could be kept out of our atmosphere every year if a 1% margin was achieved.

It is personal choice to run one's car with or without a Cat. But it is unwise to start making opinions that being environmentally responsible is pointless because a another country doesn't care (which I'm sure they do)

 

Good points on the % numbers. Only 3% more population despite 4 times the population!

Keep in mind per person, a LOT of people in China ride bicycles EVERYWHERE, don't even own cars, or just ride mopeds (wonder what the #s are on mopeds?). So even the possibility of them producing as much pollution as the USA is, well.....impossible! So the "Well...Other countries pollute so why should we care?" doesn't carry much weight.

 

edited to move away from air pollution topic.

 

edited to move away from air pollution topic.

 

i did not want to start talkin bout pollution im closing this one

 

Never mind.....You only hear what you want & ignore the rest. Face it. You'll never be right so you can make up all the what-ifs you want to.


Let's just drop this....You will not convince & apparently, no matter how many facts we give you? We won't change your mind one bit. OK?

As for my "extremely dated engine design"? I'll put my 23yr old car up against any 2011 gas powered vehicle. Test results vs test results. Same day, same time. Back to back. If I don't WIN? I'll bet $ that I'll be I'll be within 1%.

 

Straight pipes = pollution, so s discussion about pollution is completely on topic. Besides.....A member/YOU can't close a thread, only a Moderator or Administrator can. You can ASK, but that doesn't mean it WILL be closed.

 

Take it to PM if you want to debate further. Bring your facts

 

Well I believe I have done that already . If you go to the same website I mentioned earlier you see the larger percentage of the CO2 emissions comes from the transportation sector (cars, trucks, trains, planes).

Back on track, I apologize to camaroguy19 for diverting the subject of your question. I was merely countering The_Wraith on his opinion that deleting the cat is ok because others in the world are doing a lot worse, which I have proven is not the case. It has been mentioned by others in countless other posts that no significant hp or sound is gain by removing the Cat.

However, if you are short on funds and can't replace the Cat and your location doesn't have strict pollution laws then it's ok to replace with a straight pipe. Since you also seem interested in just having a loud car my next suggestion would be just to keep the Cat but lose the muffler and fab up a turn down or duel exit pipes. This way your car will be extremely loud and if you ever get pulled over for excessive noise you won't get an extra ticket for not having a Cat.

 

If you read that post again correctly you will see I replied to Stephen

 

In my opinion when I took my cat off its sounded much louder and had that horrible gas smell. I put it back on because I could not stand the smell at stoplights and it sounded better with it on. I don't want my car making so much noise its annoying. I would rather have my car make noise because of whats under the hood, and not trying to remove items like the cat to try and make noise, because of the lack of power under the hood.
my

 

Me too, loud doesn't equal Good/powerful. my car currently only has a cat, no muffler at all, and I hate it. I would much rather a 2.5 inch true dual with turbo mufflers. I'll do it once I get my LT1 buttoned up. (with a few mods to the suspension)

 

That is totally not true!!!!!!!!!! If you had two identical cars and both had no mufflers, yet one still had a cat. Then the one without the cat would be so loud that you would not be able to drive it on the street! Trust me , I have tested this theory. The cat has everything to do with keeping the car quiet. Plus do you want to contribute to the destruction of the ozone layer and thus the domination of small engine vehicles?

 

That is absolutely not true. On our thirdgen cars. The CAT provides an extreme amount of noise reduction. If you remove it, your car will be so loud and sound so horrible that you would not be able to drive it down the road. Now, running a ypipe and a cat with no catback or even a muffer and it would still be loud , but not even a half as loud as with no converter. Trust me , i ran mine with no converters and then added a cat. Much, much more tame with a cat and sounded 95% better too. Plus, do you really want to contribute to destroying the ozone layer and not to mention violating your federal laws? It's not worth it.

 

??? what isn't true?

 

You must have some really weak ears. I've run a gutted cat with no muffler & with the pipe after the axle running straight back on the passenger side....On my Daily Driver.

Legal? No.

Never even got pulled over. I just didn't floor it in neighbors or near cops. Play right & you can get away with a lot.

That was the only car I've run without a cat on, so don't start on me about the gutted cat. Read around & you'll see that I am very pro-cat. I was 19, that was my first 3rd gen, I was dumb then & it was a 305 TBI. It needed every extra horsepower it could get!

 

Gee........... from some of these comments and a few of you folks running around
with cobbled/no cats or mufflers/straight pipes or generally LOUD exaust systems
all contribute to most folks opinions that only dumb axx rednecks/trailer park trash
and scumbags drive old Camaro and Birds !

 

LOL

 

I think your bridging that gap from loud, to obnoxious. First of all straight pipes on a stock 305 car, whether they are 1" or 3" pipes sound like ******* garbage... Why get rid of the cat? It will add some resonance, and save a tree from suffocating a horrible death. I for one enjoy the smell of fall when the air is clean, and hope people can in 100 years. Not because a lot of uneducated people had to gain 1whp.

 

Weak cars? not mine. I am running a high 13. What I am saying is I noticed a significant drop in power from my car when i had no cat.. period. I have found from my experience that a full exhaust with a catalytic converter a catback and a muffler yielded the best performance. I think you may be giving up a little power running without a muffler. Most guys feel that they lose a little on the low end.

 

I am highly confused with the obsession of loud exhaust, I prefer to hear my engine. Most cars I see on the road that are loud don't really move because the owner seemed to believe if he could make it loud he would have power without doing anything else, I do have fun quietly flying past them though. very few adults are even impressed with loud but if you want 14 year olds to think you're cool I guess that will do it. To each his own but if you live next door to me and start your straight piped car at 3am we would have a problem

 

Again, what isn't true?

high 13 isn't really much to brag about IMO.

that's why I like turbo mufflers, nice relatively quite idle, decent tone, and not as raspy as many of the other options.

 

i dont think obnoxiously loud cars that also stink are cool, thank you.

 

here is a straight pipe that works w or w/o cat. stay legal though. or just keep cat on and knock all the crap out of it. its still there but is breathing freely. on stock exhaust it made a huge difference. then upgraded to headers y pipe and 3in catback power gains and sound was a huge difference.

http://www.hawksthirdgenparts.com/ha...stsystem4.aspx

 

Sometimes I don't understand why people want their cars to be so loud but on the other hand loud is nice but not too loud, that is just awful. Just because a car is loud doesn't mean it's fast as heck. But sometimes a car is real loud and it's just as fast as it sounds too!

 

Straight pipes are nice. I have straight pipes on my 1985 Camaro Z28 with a fully rebuilt carbed 350. I have headers and the pipes come from the headers, no y pipe,no cats, just straight pipes and I have 2 flow master mufflers and the pipes go all the way back. It actually sounds beast. It idles nice, sounds good when you put the pedal to the metal! I have heard people with their own made straight pipe set up but with mine I haven't really seen yet and I really think it sounds good. I don't care about pollution because we pollute every day no matter what. The exhaust sounds good with straight pipes but no matter what man its you decision. to me I think you should straight pipe it.

 

When you can make 400 RWHP and still pass CA's emissions test, then come talk to me about whether you should keep your car street legal or not.

 

I have Edelbrock 3 Inch RPM Cat Back, with 2.5 Outs, I also have there coated Headers with 2.5 Inch y Pipe I do not have a cat.
I have tried Cats, Hollow Cat's and Straight Pipe, I hated the cat's on the car, I liked the sound of the hollow cat's the best, But the straight Pipe did make the car seem snappier and it is a bit louder then the Hollow cat's.
I have the staright pipe on at the moment

 

305 bored .30 over with Crane cam into Edelbrock shorty headers into Banks exhaust with the cat cut out. Honestly the car is definitely more mean sounding without the cat, but sometimes just cruising I think it's too loud when i'm not even getting on it. Feels slightly quicker.. but I am sure the HP gain from removing the cat is negligible...

When the new engine goes in a few years from now (LSx or stroked out 350) I will have all modern equipment including a true dual with dual cats... but since i'm running the old built up 305 I figured screw it, i'll add some noise lol