ok, so i had a flowmaster on my 89 rs with a 305 and it sounded awsome running up through the rpm. So i got one and put in on my 86 iroc that i just put the carbed 355 in and it sounds awsome at idle and just off idle but when the rpms start to go up the thing sonds like a ******* truck with straight pipes. It pops and makes a racket, when i listen to sound clips no other flowmaster sounds like this and my rs didnt either, is it because me car has a carbed motor with headers and no cat, or do my vortec heads cause this sound, or could the muffler be old and worn out because i got it off a iroc at the junkyard and i didnt think flowmasters would wear out inside. But it sound like a cheap straight pipe job when i get on it.

 

An exhaust that sucks is great! The exact opposite of backpressure!

Seriously, Flows are an aquired taste. I'm running one, but not because I think it's the best thing out there. However, I don't hate it enough to spend the bucks to get something else, even though that would be my preference.

 

same here. my car came with a 3" flowmaster 40. rest of the exhaust is 2-3/4 sounds good. not great. i am planning on headers+full 3" soon. i wonder if it will sound better after that

 

i love the sound of flowmasters because they have a great tone, but ive never heard one pop before thats why i like em, but the one ive got on my car pops running up through the rpm and its got me stunned as to why. Ive never heard one pop like straight pipes before, ive got 2.5 and 3" pipe throughout, i dont know if the piping may be making it pop or what, but ive never heard a camaro with a flowmaster in my life sound like mine.

 

Do you have the 80 Series on your car?

 

Yeah i have an 80 series catback muffler with mostly 3" pipe, no cat, and custom made y pipe. It dosent sound bad at idle but i think there isnt enough backpressure becuase of my big pipe and no cat, i wonder if i put a cat on there if that would make it quit popping. I thought if there was a flowmaster on there it would make enough backpressure on there to not have the popping.

 

Enough back pressure to stop the popping should be enough back pressure to kill any performance potential.

You need to get it out of your head that back pressure is ever a good thing. It is not. It is true that certain induction systems are calibrated assuming back pressure, but that is only because the factory was willing to make compromises that included back-pressure-producing exhaust systems. Elimination of back pressure is a good thing, even if it requires recalibration of the induction system.

Your "popping" is being caused by something other than your exhaust system.

 

A generally accepted solution to the popping problem is to put a catalytic convertor on the car. My exhaust did that too, but only when I revved it while in park. I put the cat on, and it stopped so I believe this is correct for whatever reason.

I've also heard running extremely rich would cause this problem, but I am also unsure as to why it would cause this as well.

 

http://whitelightning2.kicks-***.org...seriesrev1.wma

does it sound like that?

 

when i rev it up i sounds like that, but that wouldnt bother me if it only did it when it was revved up, but my car does it when its in drive and im accelerating down the road. It pops really bad at about 2500. What could be causing the popping other than the exhaust, because i put big pipe and no cat to help horsepower out. I have a small header leak if that can cause it, and ive got a custom y pipe that may cause it, but i really dont know. Fuel injected camaros dont pop like this so it may be a carburated motor deal or something.

 

I've got a 3" flowmaster catback and it doesn't pop at all (I'm carbed). It used to cackle a bit at 4k and up, but that stopped when I put the cam in. I love the sound of mine.

 

the header leak can cause that...

any leaks in the system can do some seriously odd things to the sound and flow of the exhaust.

is it around the collectors, or somewhere else?

 

it is where the header bolts up to the head, my back two bolts on the passenger side came out about a month ago and i cant get them back in without taking the whole header off and starting at the back so i just let it leak a little for now.

 

My straight pipes pop life a **** when its running fat. but since a bit of tuning which leaned it out quite a bit, you have to be doing 70km/h and drop it to first to get a pop or 2 out of it.

But i prefer to have the thing sound like a machine gun when i drop a gear


So if your not for popping check your a/f ratio.

 

It was my understanding that the poping sound on a rich running engine was unburnt gas or fumes igniting in the exhaust somewhere. Especially if you had a leaky Qjet Carb. I never had that problem until I put on my Flowmaster. Now it pops on downshifts until I put the clutch in. Sounds great except on downshifting. I inspected the system and I think I hear a leak from the Y pipe to the cat. There is no gasket for that connection but I may make one or use that super black sealant. I did notice that my cat is absolutely empty except for the air tube.

 

dave good to see you on here


i'm running a 80 series on my 305, no cat 2.5 pipe, sounds crappy at lower rpms like 2k in 5th,but when i am in the upper rpms it sounds good

 

lol, i've been here for like 3 yrs... where have you been?

 

i didn't get my third gen till last year


heres a question, if i put some shorty headers on are they gonna be quiter then long tube?

since mines a basicly stock 305 should i run 2.5 from the shorties to the Y pipe or smaller?

 

long tubes give the exhaust a deeper sound, shorties are a little more high pitched. the actual noise level is similar.

i'd run 2.25 to the Y, then either 2.5 back or 2.75 if the exhaust shop has it. switch to a high flow cat as well

 

its already got 2.5 from y back and no cat, i was thinkin 3in

 

i love how mine sounds.

hooker 2055's, no cat, 3" cat-back, and 80 series muffler with 2.5 inch dynomax tailpipes.

of course, and a 350HO

 

There are 2 80 Series that are of interest for our cars. One of them is the muffler that comes with the AT system, the all 3" version. There is another that's 3" in and 2.5" out. The 2.5" out is a smaller, louder/better sounding muffler. You do not need 6" of outlet flow from a single muffler, that's bigger and produces a higher pitched, lower, more hollow sound no less. I really wish Flowmaster would use the other muffler instead.

I refuse to buy their system because of this. I'm going to buy it all separate so I can use the muffler and tips I want. These mufflers also sound better with time regardless of which you buy. They also sound extra nice with headers and a high-flow converter.

 

Popping on deceleration is usually a lean conditon or late ignition timing. Stock cats on 3rd gens are somewhat restrictive, but later model or aftermarket cats are not. They also make a major contribution to muffling, but will not remove the popping, which is happening in the manifolds (headers). Whenever you make such a dramatic change to the back pressure, you will change your carburetion characteristics.

 

the muffler does the major job of muffling the sounds. and popping can usually be taken care of with a cat because its more or less a back fire in the exhaust pipe. and its just unburnt fuel being ignited in the exhaust and a cat should most of the time take care of it

 

the 3" in/2.5 out is what i had on mine in that clip. It's on my Z24 cavalier now and it still sounds pretty mean.

 

The popping on deceleration is fine with me, it the popping i get when i accelerate reasonably hard. When i run up to about 2200 it starts to pop, it pops loud and slow. THe popping is not the quick bang bang bang, its more of a bang--------bang--------bang, it does it when i accelerate above 2200 and it stops making the noise when i get to about 2700. I love the flowmaster sound but this is pissing me off because ive never heard another flowmaster sound like this on acceleration. The one I had on my rs sounded awsome, and my rs only had a 305 tbi in it. Do flowmasters generally sound like crap on a 355 carbed with shortie headers.

 

Do you have a mechanical problem? You should never have popping while you are on the gas. Sounds more like you have a bad exhaust valve seat

 

It should not pop on acceleration. Can you describe the popping a little better?

 

The pop my car makes is like the pop vehicles with straight pipes makes. My friend has a 01 silverado with straight pipes and it makes a popping noise when he accelerates, my car makes almost the same sound but ive got a flowmaster.

 

o i hate the sound of straight pipes on trucks its funny seeing the small pipes on there too like smaller then 2in

 

@Blkmaroman: do you mean it pops like this? when i got my new exhaust it makes such a sound around 2000-2800. above these rpms its gone. dunno why it's making this

nebu.

 

yeah its very very similar to that.

 

mine makes that at lower rpms as well but as soon as i hit about 2800-3k she sounds good

 

mine popped on downshifts like crazy, but I thought it was cool

 

i like it when it pops on downshifts too, ill leave it in third and run up to about 4k and then let it run down from there it sounds pretty cool. I just want it to have a nice smooth sound all the way up from idle and it dosent do that from 2200 to 2800.