more power with muffler or no muffler?
Professional
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RE: more power with muffler or no muffler?
ive been running my truck with no muffler and a 45 deg. turn-down tip from the end of the stock Y-pipe for about a month, i can say ive lost a little down low but in the top end it feels like it has more guts..
thats just the butt-dyno speaking..
thats just the butt-dyno speaking..
Record Breaker
Joined: Feb 2006
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From: Richmond, Va
RE: more power with muffler or no muffler?
ORIGINAL: SmokeGrinder
Mopar your on the right track as for racing cut outs, for example...
At 6000 RPM with a shorter exhaust
pipe, (or cut-out open), will the torque be higher, or lower?
When you're talking about cutouts the distance is critical and will tune the exhaust to be efficient at one
RPM, with a tapering curve above and below that RPM. Now when you open the cut-out at 2000-3500 RPM
on the street, you notice a lack of power, Then everyone cries, "I lost backpressure, thats why I lost power!!!"
This is incorrect in the fact that by opening the cut out, youhave changed the tuning of the exhaust for the
RPM range you are using...the frequency of the exhaust does not decide how much power you make, it decides when the power
comes in. The pipe length in the exhaust has to do about when the power is made..... At 2000 RPM an exhaust pulse is 50 inches for example. If we cut a pipe to be "resonant" at 2000 RPM, it would need to be 50 inches. This pipe would only be resonant at one RPM, and one frequency. The reflected pulse at 2000 RPM will reach the exhaust port and create a low pressure area..... Someone driving around in the city would tune their
exhaust to this length because it would be moreefficient from 1000 to 3000 RPM with a PEAK at
around 2000 RPM .....SO based on my knowledge why would you put a huge exhaust and lose alot of torque to only have it available again at a unusable RPM??
Mopar your on the right track as for racing cut outs, for example...
At 6000 RPM with a shorter exhaust
pipe, (or cut-out open), will the torque be higher, or lower?
When you're talking about cutouts the distance is critical and will tune the exhaust to be efficient at one
RPM, with a tapering curve above and below that RPM. Now when you open the cut-out at 2000-3500 RPM
on the street, you notice a lack of power, Then everyone cries, "I lost backpressure, thats why I lost power!!!"
This is incorrect in the fact that by opening the cut out, youhave changed the tuning of the exhaust for the
RPM range you are using...the frequency of the exhaust does not decide how much power you make, it decides when the power
comes in. The pipe length in the exhaust has to do about when the power is made..... At 2000 RPM an exhaust pulse is 50 inches for example. If we cut a pipe to be "resonant" at 2000 RPM, it would need to be 50 inches. This pipe would only be resonant at one RPM, and one frequency. The reflected pulse at 2000 RPM will reach the exhaust port and create a low pressure area..... Someone driving around in the city would tune their
exhaust to this length because it would be moreefficient from 1000 to 3000 RPM with a PEAK at
around 2000 RPM .....SO based on my knowledge why would you put a huge exhaust and lose alot of torque to only have it available again at a unusable RPM??
My truck pulls hard from when the tc catchesat 2.1-2.5k all the way until I shift at 5.8, and apparently it does better than I'd like it to after 2 feet.
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RE: more power with muffler or no muffler?
I have heard that piping matters! I have heard that bigger is not always better! When choosing headers you do not buy the biggest headers! I just looked and found out that my plenum plate is leaking and that could be throwing off alot of the feel on the truck. But when i put a muffler on the truck it seemed like it had more low end power. I dont care about high end, its an automatic so im never in that range. I believe an engine needs a little back pressure on it to keep the power band consitant.I just want to know from people that have actually expereniced with open and muffled exhaust. Race cars are not equall to street driving trucks. They are always in the high range of hp & torque.
Question #2...Would a race muffler give any back pressure..lack the flowmaster series 10?......How is a glasspack or bullet muffler any different then running a open exhaust? All they do is control the sound..
Question #2...Would a race muffler give any back pressure..lack the flowmaster series 10?......How is a glasspack or bullet muffler any different then running a open exhaust? All they do is control the sound..
Captain
Joined: Feb 2007
Posts: 504
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From: Spokane WA
RE: more power with muffler or no muffler?
the reason why he's losing low end power is becuase of the piping he's using as stated in one of your posts. since he still as the stock y pipe, and he is going to larger pipes afterwards, with no restriction, he is cancelling out the scavanging effect of the exaust and the expansion of the exhaust gases...that's how he's losing low end torque. Now if he totally redid his exhaust with headers and used the correct tubing and an x pipe, the result of the lack of a muffler would be different. As you stated "this effect can be accomplished by merely using the correct size of pipe" is true, but he isn't using the correct size of tubing and thus loosing any venturi effect and losing low end torque
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RE: more power with muffler or no muffler?
ORIGINAL: spaz_22
the reason why he's losing low end power is becuase of the piping he's using as stated in one of your posts. since he still as the stock y pipe, and he is going to larger pipes afterwards, with no restriction, he is cancelling out the scavanging effect of the exaust and the expansion of the exhaust gases...that's how he's losing low end torque. Now if he totally redid his exhaust with headers and used the correct tubing and an x pipe, the result of the lack of a muffler would be different. As you stated "this effect can be accomplished by merely using the correct size of pipe" is true, but he isn't using the correct size of tubing and thus loosing any venturi effect and losing low end torque
the reason why he's losing low end power is becuase of the piping he's using as stated in one of your posts. since he still as the stock y pipe, and he is going to larger pipes afterwards, with no restriction, he is cancelling out the scavanging effect of the exaust and the expansion of the exhaust gases...that's how he's losing low end torque. Now if he totally redid his exhaust with headers and used the correct tubing and an x pipe, the result of the lack of a muffler would be different. As you stated "this effect can be accomplished by merely using the correct size of pipe" is true, but he isn't using the correct size of tubing and thus loosing any venturi effect and losing low end torque
Record Breaker
Joined: Oct 2004
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From: Gaylord, MI
RE: more power with muffler or no muffler?
ORIGINAL: mopowar
In what way does backpressure help a stock motor?
ORIGINAL: Bouncer88
Stock engines need all the backpressure they came with, only time you can really make any power by getting rid of backpressure is when it is on a heavily modded engine, race car, or an engine that has forced induction.
ORIGINAL: mopowar
How so?
ORIGINAL: spaz_22
your losing low end torque with no muffler
your losing low end torque with no muffler
I ran straight pipes from the cat back and I didn't notice the power loss until I added a Magnaflow cat back exhaust.
Get a real exhaust. Its bad for all motors to run straight out of the headers or w/no backpressure. If you don't believe me to bad, I have more experience then you'll ever have.
Record Breaker
Joined: Feb 2006
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From: Richmond, Va
RE: more power with muffler or no muffler?
ORIGINAL: Socha_62
These motors along with pretty much all other recent motors are designed and programed to run with backpresure. With no backpresure your more or less confusing the PCM and your going to burn up your exhaust valves.
I ran straight pipes from the cat back and I didn't notice the power loss until I added a Magnaflow cat back exhaust.
Get a real exhaust. Its bad for all motors to run straight out of the headers or w/no backpressure. If you don't believe me to bad, I have more experience then you'll ever have.
ORIGINAL: mopowar
In what way does backpressure help a stock motor?
ORIGINAL: Bouncer88
Stock engines need all the backpressure they came with, only time you can really make any power by getting rid of backpressure is when it is on a heavily modded engine, race car, or an engine that has forced induction.
ORIGINAL: mopowar
How so?
ORIGINAL: spaz_22
your losing low end torque with no muffler
your losing low end torque with no muffler
I ran straight pipes from the cat back and I didn't notice the power loss until I added a Magnaflow cat back exhaust.
Get a real exhaust. Its bad for all motors to run straight out of the headers or w/no backpressure. If you don't believe me to bad, I have more experience then you'll ever have.
Spazz brings up a good point that I keep missing. If you intend to use the factory Y, none of this applies. He istotally correct in saying that opening things up on both sides of the factoryY will cancel out the scavenging effects.
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Registered User
Joined: Aug 2007
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RE: more power with muffler or no muffler?
ORIGINAL: mopowar
That's what I was talking about when I said it was all about the tune. PCM will compensate for less backpressure. It will compensate even better/faster flashed. This is where the myth that opening up the exhaust causes torque loss comes from. On a carberated vehicle, you cannot just throw a big exhaust on there without adjusting the fuel mixture. People did that and lost torque. "These motors" have showed big gains (33ft/lbs low to mid range) from going from 1 5/8" primaries to 1 3/4" primaries alone. Albeit while being bolted up to a real exhaust.
Spazz brings up a good point that I keep missing. If you intend to use the factory Y, none of this applies. He istotally correct in saying that opening things up on both sides of the factoryY will cancel out the scavenging effects.
ORIGINAL: Socha_62
These motors along with pretty much all other recent motors are designed and programed to run with backpresure. With no backpresure your more or less confusing the PCM and your going to burn up your exhaust valves.
I ran straight pipes from the cat back and I didn't notice the power loss until I added a Magnaflow cat back exhaust.
Get a real exhaust. Its bad for all motors to run straight out of the headers or w/no backpressure. If you don't believe me to bad, I have more experience then you'll ever have.
ORIGINAL: mopowar
In what way does backpressure help a stock motor?
ORIGINAL: Bouncer88
Stock engines need all the backpressure they came with, only time you can really make any power by getting rid of backpressure is when it is on a heavily modded engine, race car, or an engine that has forced induction.
ORIGINAL: mopowar
How so?
ORIGINAL: spaz_22
your losing low end torque with no muffler
your losing low end torque with no muffler
I ran straight pipes from the cat back and I didn't notice the power loss until I added a Magnaflow cat back exhaust.
Get a real exhaust. Its bad for all motors to run straight out of the headers or w/no backpressure. If you don't believe me to bad, I have more experience then you'll ever have.
Spazz brings up a good point that I keep missing. If you intend to use the factory Y, none of this applies. He istotally correct in saying that opening things up on both sides of the factoryY will cancel out the scavenging effects.