JetMech99

iTrader: (3)

lol damn guys, talk about alot of info flowing in the thread.... the reason i love this site so! Thanks for all the feedback and help on this matter, i most definatly learned something reading all of it.

There was a point brought up stating that the flaring of the muffler would slow the exhaust due to turbulence. A theory they taught us in jet engine maintenance was Bernoulli's Principle, stating that a gas traveling at a velocity comes to a pressure difference within the path its traveling, it accelerates through that contracted point.

Same as an augmentor/afterburner on a fighter aircraft, for maximum thrust, the convergent/divergent nozzle closes, speeding up the exhaust gasses providing more thrust.

So after all that rambling perhaps the sudden contraction would speed up the gasses.... or i could just be talking out of my *** lol! Thanks again all!

GuitsBoy

iTrader: (4)

It certainly would speed up exhaust velocity, which is good for lowering torque curve because the gasses have inertia which want to continue forward momentum and create a low pressure right before the next exhaust valve opens. This is the theory behind scavenging. The problem with closing the exhaust cross sectional area is that it come at the cost of added back pressure. Backpressure will lower your peak torque. This is why there is a common misconception that backpressure produces torque. Thats false, its the exhaust velocity that bolsters low end torque. You need to find a happy medium between low backpressure while keeping exhaust velocity up so the low end dosnt feel soft. Its a bit of a balancing act.

magius231

iTrader: (8)

one thing though from what I understand of exhaust flow...

It doesn't just flow through the exhaust system uniformly, it flows in pressure pulses. SO when one pulse passes the muffler, the interior gets pressurized like stated above, however when the pulse leaves it creates a low pressure zone behind it which draws out the pressure in the muffler itself in an attempt to even the two pressure areas. This leaves a lower pressure zone in the muffler. Then the next pulse comes up behind, and when it hits the muffler the pressure again tries to equal out the two zones, and thats why the exhaust gasses flow through the packing as well.

from what I understand

Droptoplt1ta

what is quieter:

a Dynomax bullet

or

a Classic Chambered Powerstick?

Let me know please

Thanks

Powerstick

If you took a dBA reading, I'd bet (my) Powersticks would be quieter - depending on the length used. The longer - the quieter (a little) = better sound to boot (more tuning). Bullets do VERY little to reduce noise - like 2-4 dBA's.

Pretty good, technical thread guys! Pretty accurate too.

Optimum exhaust flow depends mostly on correct flowpath/pipe diameter. Shrinking down the flowpath in a muffler may speed flow velocity, but it will also create backpressure which may be bad. It's very important to choose the right diameter. Too large = reduction in low end performance, too small = reduction in upper end performance. On these Firebirds/Camaros 3" seems to be the right diameter in the intermediate pipes with under 500 HP.

Funky exhaust systems on these cars for sure. When GM designed the exhaust (or floorboards!) on these cars, they did poor planning. You guys are doing the best you can though.

wannafbody

iTrader: (2)

anybody try the single in dual out powerstick in place of the regular Fbody muffler? After checking it's too long. What about making a shorter 3 inch single in and dual out that could be put in place of the stock F body muffler and repiped as a 2 on the left or single pipes on both sides?

Powerstick

I don't think that would help sound or flow any. The real help would be to run a true dual 2-1/2" exhaust.