bugzy530

iTrader: (1)

Hello all,

I just read the thread below bout Mufflers and that didnt quite answer my question, so i will ask it here. I want to put mufflers back on my car and delete the resonator, reason being is that I went and got my car HP Tuned the right way and it saying i am only making about 255 to the wheels, which I felt was horrible.

So my questions is what muffler is the best muffler to put on my car, I like loud so could anyone tell me????? Any help is great, I was looking at this website but dont know which one would be best, any suggestions?????

Or if not on this website can you provide one so i can see and buy them? Also, i think backpressure is another reason I lost power. What do you think?

http://www.car-stuff.com/store/?N=99...588+11920+9164

06 SS

you have to define what you consider the word 'best' to mean. You say you want it loud, is cost a factor? i.e. replacing the mufflers with straight pipe would be loud and cheap, do you want a stainless muffler that will last a long time or are you planning on getting rid of the car in a few years? 'Best' will be different for everyone. The way you have asked your question will only get you the opinion of what everyone feels is 'best' for them. Just swapping out a muffler will not gain you much, likely not even enough to make up for the error factor on a dyno. Probably even the stock muffler will flow more than the 2" pipe that feeds it.

bugzy530

iTrader: (1)

Hello,

Sorry let me rephrase my statement, I took the mufflers off my car so i have none now, so i would imagine im losing back pressure needed for more power. My mufflers, yes i want them to be stainless, I want them to last, I want them to provide an exceptional amount of flow and sound loud. Does anytype of high performance muffler fit this description?

Panther427

What fuel do u use?

bugzy530

iTrader: (1)

i use 93 fuel all the way man

Mgpeagle

iTrader: (6)

Here is a great link that gives each muffler their own cfm rating so you can narrow it down for what you like.

https://ls1tech.com/forums/generatio...-mufflers.html

Hope this helps.

-Mike

06 SS

Listen; I am a mechanical engineer, I am extremely familiar with fluid flow characteristics and with engine intake theory. Back-pressure can make a big difference in low-end torque production (lower) with HIGH overlap cams, the kind that will not pass emissions and that GM definitely did not put in the LS4. It can cause reversion and start sucking exhaust gases back into the combustion chamber and cheating you out of a good burn. That is why cams with a tighter LSA (which has a huge amount of influence on overlap area as opposed to duration) are very sensitive to back-pressure. Now...as to our engines; Same story, just not as severe. Back-pressure will lower net torque output at all times vs less back-pressure Now most will chime in about how they have dyno proof that their torque went down when they opened up their exhausts. I have no doubt that they do, but it is not because of less back-pressure, it is because they have bigger pipes.

Bigger pipes will usually lower back-pressure, this much is true, but the engine only cares about one thing when it comes to filling the combustion chamber. The lower the pressure on the outlet side (exhaust valve), the more of the incoming air/fuel charge will get into the chamber, promoting better filling (and that is the key to torque).

With bigger pipe, the gas flow will slower, think of a garden hose where you put your finger over the end. Water speeds up, now, take your finger off, water slows down, true story, I promise. Slow exhaust flow out means it is pulling less in. That means lower pressure difference. The gist of that is that bigger pipes should lower net torque and therefore power at all times. It is true, they will. At least at lower engine speeds. As you raise speed and push more gas out, the back-pressure will come up very quickly and pumping loses from trying to push against that extra pressure will lead to even less net power. It is a balancing act. With bigger pipes (less restriction), you get less power until you get to the point where the smaller pipe would have started (sooner, as it has smaller pipe volume) to have a real problem with back-pressure. At that point they would be equal. Confusing, I know, I know numbers better than words, but my conclusions are valid if you want to skip to that part. So after this 'equal' point where the back-pressure of the smaller pipe slows the flow of intake charge until it is equal to the slower (due to less vacuum with the bigger pipe). After that, the back-pressure will still increase more rapidly on the smaller pipe and choke the engine. As the volume gets larger in the big pipe, it starts to move faster without so much back-pressure and starts pulling in the intake charge faster (when there is less time for the engine to gulp it in at higher RPM.) More power higher RPM and less at lower RPM with the larger pipe. Exhausts will have a sweet spot based on size and other factors. Same principle for headers and downpipes and the like. You trade high end power for low end. Just like picking a longer duration camshaft

The other factor in exhaust pressure/speed is temperature. As the gases flow towards the end of the exhaust, they cool. As they cool, they contract, take up less space. Less problems with back-pressure, they can move to smaller pipes/mufflers towards the rear and still not have that be the bottleneck point. The key to changing back-pressure is to get as close to the engine as possible with whatever changes you want to make.

Mufflers do one thing (aside from certain frequency sound cancellation at some RPM). They turn sound energy into heat by diverting them, but having them expand into large chambers, etc. This is why in a passenger car, changing the mufflers has little effect on back-pressure at the engine. The gases have cooled and take up less space, so less is needed, plus the real restricion in an exhaust is usually right at the engine itself. Even our puny 2" pipes after the Y will flow better than the 2.5" or whatever it is up to the exhaust manifolds. The only reason to change the muffler, is for sound. If you really are worried about back-pressure, get a larger downpipe, it will be the (until headers are available) biggest help in that area. It will decrease back-pressure and help net power production everywhere.

Now that you are a bit more clear on spending for some quality and that you like it loud, I suggest you go look at Spintech mufflers, I think it would be just what you are looking for, but just know, it will do pretty much nothing for back-pressure, even the stock muffler probably flows better than the pipes in front of it and that back-pressure does not increase low end torque, bigger pipes decrease torque! Consider the garden hose again, the same amount of water comes out with your thumb over it or not, regardless of the speed, however think of how much pressure is against your thumb, that thumb is backpressure, that is how much extra work it takes to pump that same volume of water out a smaller hole. That work is why back-pressure lowers net engine output at all speeds. Also for the same reason, putting a muffler close to the engine in the space where the resonator lives might increase back-pressure as the gases are still hot and expanded.

Mgpeagle

iTrader: (6)

Excellent read! Extremely informative. This IS the type of stuff I LOVE to read. Nice job, Doug!

-Mike

MCSS07

But with the amount of TQ these cars have, I dont think it would be a bad thing to lose some of it to gain a few extra HP's

bugzy530

iTrader: (1)

Wow talk about a detailed description man i really appreciate that now i really have to get my mufflers put back on, thank you so so much

beznich

I've had Flowmaster and now have Magnaflows. When I had the CAT I liked to sound of the Flowmasters, but once I removed the CAT it was a bit too loud, so I switched out to the Magnaflows, it's a nice deep mellow tone. I have a Youtube video of my car with the flowmasters (search beznich on youtube) - I'll post one of the Magnaflows ASAP.