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Stock muffler question


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rico750sxi:

 

Well I hooked up the shop-vac and let it blow through the stock exhaust through both inlet’s and It appears to be a dual exhaust muffler. I still have the Y-pipe on the exit end and air blows through no matter which inlet pipe the air blows through. So since I don’t know what the internals look like on the muffler I would say it doesn’t have a dummy exit on one of the pipes.

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Hey Blackhawk, I was just thinking, if the muffler only had one real exhaust outlet and the other was a dummy then the air would blow out no matter which inlet you put it in, right? Thank you for doing your test, I appreciate it.

 

Anyone hacked off their tailpipes yet? I'm still curious if anyone has seen the exit side of their stock muffler.

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If you reduced the backpressure by running an aftermarket muffler(s) or even straight pipes, it moves the power peak higher in the rpm band, but sacrifices the low-end torque.  No longer do you get the exhaust gas pressurizing the intake charge, but low backpressure exhaust systems do allow the engine to efficiently expell gases at high rpm.

Sorry dude, doesn't work that way. Any improvements in exhaust scavenging increase volumetric efficiency. Torque peak numbers may be raised or lowered in the rpm scale by increasing the collector volume and length, but the back pressure is generally a bad thing.

 

The circumstance you just described is known as "Reversion" That is when the residual gasses in the exhaust are reintroduced into the combustion chamber by a low pressure situation such as when camshaft overlap occurs. If the exhaust "supercharged" into the combustion chamber as you described it would contaminate the fresh intake charge (air/gas mixture) and reduce power output potential.

 

An engine is nothing but an air pump. The more air you get in the more you need to get out to make power. Improvements in exhaust flow have always been the first place to look for more power.

 

Remember, torque is what moves you off the line, horsepower is what maintains your speed such as when ascending a long grade. Torque and horsepower come hand in hand. Emphasizing torque is done by altering rod length to stroke ratios, camshaft profiles, gearing etc...

So reduce your backpressure, allow a fuller denser air/fuel intake charge to invade your combustion chamber and watch your power and torque both increse proportionally

These are great trucks, keyword "Trucks" not drag trucks, just a nice street truck! If it's max acceleration you're after, buy an old 69 Camaro like mine, and gut the interior, put a healthy small block or big block under the hood and drop in some 4:56/1 gears and hold on tight! That's what it takes to satisfy your neck snapping needs! Believe me! Drive the truck home from the races, and look good doing it.

You know, the right tool for the right job! :thumbs:

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either way if you loose alot of back pressure on any new chevy engine it will loose power. oh it sounds awsome but the power loss if noticable. learned on my 00 silverado. i ran the ss with no muffler for about 6 miles from my house to muffler shop. sounded freaking awsome but ran very poor. so if the exhaust is too free flowing it can be a bad thing

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