60 HP With a Muffler & Intake?

[SS Crew]

I talked to Lyndon at Wester's Garage about some changes and he told me he has a remote location in So Cal. He gave me the number and I called them up. The guy told me of a muffler called an Aero Turbine muffler combined with an AFE intake netted 60 horsepower on an 8.1! That's right 60 hp. I find that hard to believe.

 

I checked out Aero-Turbine on their website and it shows a jet engine looking muffler that claims to reduce backpressure. In fact, it says it works like an expansion chamber creating a vacuum. It all sounds good, but isn't too little backpressure bad for low end? The sound clips sound kind of flatulant.

 

I was wondering if anyone on the boards has any experience with this muffler.

 

SS

 

Aero Turbine

[snoman]

I talked to Lyndon at Wester's Garage about some changes and he told me he has a remote location in So Cal. He gave me the number and I called them up. The guy told me of a muffler called an Aero Turbine muffler combined with an AFE intake netted 60 horsepower on an 8.1! That's right 60 hp. I find that hard to believe.

 

I checked out Aero-Turbine on their website and it shows a jet engine looking muffler that claims to reduce backpressure. In fact, it says it works like an expansion chamber creating a vacuum. It all sounds good, but isn't too little backpressure bad for low end? The sound clips sound kind of flatulant.

 

I was wondering if anyone on the boards has any experience with this muffler.

 

SS

 

Aero Turbine

 

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I do not know about the 60 HP but the 8.1 as shipped is far from its potential. I have little doubt that with the proper combination of parts and tune that another 50 to 75 HP may be had. The problem is you need to make all the changes in a "tuned" manor or the results may vary. A custom tune a a large single free flow exhaust or 3.5 inches or better would be a good starting point and I would not go to true duals without a properly tuned crossover pipe if you are looking for maximum gains in power and MPG.

[SS Crew]

It seems that the "expansion chamber" effect would severly kill any low end without any back pressure. In a way it would be like a vacuum. To me that seems bad for low end torque. Unless this would be like a supercharger effect from the back end. (Kinda like sticking a vacuum up your butt to chug that beer faster).

[mudbug660]

http://www.aero-turbine.com/seehear/seehear.cgi?search=y

I don't know about this. The dyno charts are kinda iffy. I mean the hemi chart doesn't show anything until 3500 rpm. Why's that? The 8.1 liter in gmc and chevy trucks don't make any hp or torque until they reach a little over 2000 rpm did ya'll know that. It seem this muffler solves that though. And it must suck for anybody who has that engine because at around 3950 rpm the hp and torque drops to 0. what a bummer. go ahead and get a throttle body spacer when you pick this one up, it's right up there with it. It might actually do some good at a certain rpm but with them altering the dyn o sheets and leaving out info I don't trust it. Mr. says run away, run away!

[snoman]

It seems that the "expansion chamber" effect would severly kill any low end without any back pressure.  In a way it would be like a vacuum.  To me that seems bad for low end torque. Unless this would be like a supercharger effect from the back end.  (Kinda like sticking a vacuum up your butt to chug that beer faster). 

 

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Aproperly size exhaust system with a properly sized and place cross over will minimize the loss of low speed responce and enhance the sound as well. Beleive it or not, some of the exhaust tuning and balancing is not only air pressure but also sonic pressure as well.

[99Silver6.0]

60 at the flywheel maybe!!

[Haulin' 8.1]

What the heck is an AFE intake? Back in my day an intake was a manifold, I hope this isn't some silly air filter.

 

Vernon

[99Silver6.0]

What the heck is an AFE intake?  Back in my day an intake was a manifold, I hope this isn't some silly air filter.

 

Vernon

 

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Advanced Flow Engineering. Its not an intake manifold. Just an intake kit. Tube and filter.

[cedjunior]

Back Pressure = bad

Velocity = good.

 

I'm having a hard time understanding why and when the word backpressure became associated with low end perfromance. The problem with having an exhaust set up that isn't restricted enough is you lose velocity. The wider the diameter of the exhaust tubing the slower the exhaust will pass through it. If you have exhaust pipes that are too narrow, you can't move enough exhaust out no matter how fast its going, too wide and it will move slow. Also the faster the ehaust in the system the more it helps scavenging, which is what helps to produce low end torque. If that muffler does infact create a vacuum, then it would greatly increase the scavenging effect.

[SS Crew]

Back Pressure = bad

Velocity = good. 

 

I'm having a hard time understanding why and when the word backpressure became associated with low end perfromance.  The problem with having an exhaust set up that isn't restricted enough is you lose velocity.  The wider the diameter of the exhaust tubing the slower the exhaust will pass through it.  If you have exhaust pipes that are too narrow, you can't move enough exhaust out no matter how fast its going, too wide and it will move slow.  Also the faster the ehaust in the system the more it helps scavenging, which is what helps to produce low end torque.  If that muffler does infact create a vacuum, then it would greatly increase the scavenging effect.

 

<{POST_SNAPBACK}>

 

 

But if you use headers that have too large of primary tubes, you lose low end, but pick up top end. Thus too little back pressure will take away some low end, but you should pick it up on the top end. Right?????

[cedjunior]

Back Pressure = bad

Velocity = good. 

 

I'm having a hard time understanding why and when the word backpressure became associated with low end perfromance.  The problem with having an exhaust set up that isn't restricted enough is you lose velocity.  The wider the diameter of the exhaust tubing the slower the exhaust will pass through it.  If you have exhaust pipes that are too narrow, you can't move enough exhaust out no matter how fast its going, too wide and it will move slow.  Also the faster the ehaust in the system the more it helps scavenging, which is what helps to produce low end torque.  If that muffler does infact create a vacuum, then it would greatly increase the scavenging effect.

 

<{POST_SNAPBACK}>

 

 

But if you use headers that have too large of primary tubes, you lose low end, but pick up top end. Thus too little back pressure will take away some low end, but you should pick it up on the top end. Right?????

 

<{POST_SNAPBACK}>

 

 

 

 

But its not back pressure you're losing, its velocity. If the primaries are too big then the exhaust gas will loose velocity and also lose some of the scavenging effect. Here is how the scavening effect works. You have en exhaust pulse come out of an ehaust port on a cylinder head and enters the primary tube. Just after that another exhaust pulse from the next cylider down comes out of the exhaust port and goes into its own primary header tube. When the first ehaust pulse enters the header collector, it creates a pull on the exhaust pulse still coming down the next primary tube headed to the collector. The higher the velocity of the exhaust gasses as they enter the collector the better the scavenging effect will be.

 

And the reason why you gain some top end power with larger diameter exhaust tubing (whether its header primaries or a cat back exhaust) is because at such a high RPM having oversized exhaust is actually a good thing because you're moving so much air in and then out of the engine.

 

Here is a good way to understand what I'm talking about, hold your hand in front of your face and blow on it like you're blowing out candles on a birthday cake, with your lips clenched up so there is just a small hole. Then blow on your hand with your mouth open wide like you're taking a big bite of food. You can feel that the air comes out faster when the opening is smaller.

[SS Crew]

I think I've got it now, thanks cedjunior.

SS

[snoman]

Back Pressure = bad

Velocity = good. 

 

I'm having a hard time understanding why and when the word backpressure became associated with low end perfromance.  The problem with having an exhaust set up that isn't restricted enough is you lose velocity.  The wider the diameter of the exhaust tubing the slower the exhaust will pass through it.  If you have exhaust pipes that are too narrow, you can't move enough exhaust out no matter how fast its going, too wide and it will move slow.  Also the faster the ehaust in the system the more it helps scavenging, which is what helps to produce low end torque.  If that muffler does infact create a vacuum, then it would greatly increase the scavenging effect.

 

<{POST_SNAPBACK}>

 

 

But if you use headers that have too large of primary tubes, you lose low end, but pick up top end. Thus too little back pressure will take away some low end, but you should pick it up on the top end. Right?????

 

<{POST_SNAPBACK}>

 

 

 

 

But its not back pressure you're losing, its velocity. If the primaries are too big then the exhaust gas will loose velocity and also lose some of the scavenging effect. Here is how the scavening effect works. You have en exhaust pulse come out of an ehaust port on a cylinder head and enters the primary tube. Just after that another exhaust pulse from the next cylider down comes out of the exhaust port and goes into its own primary header tube. When the first ehaust pulse enters the header collector, it creates a pull on the exhaust pulse still coming down the next primary tube headed to the collector. The higher the velocity of the exhaust gasses as they enter the collector the better the scavenging effect will be.

 

And the reason why you gain some top end power with larger diameter exhaust tubing (whether its header primaries or a cat back exhaust) is because at such a high RPM having oversized exhaust is actually a good thing because you're moving so much air in and then out of the engine.

 

Here is a good way to understand what I'm talking about, hold your hand in front of your face and blow on it like you're blowing out candles on a birthday cake, with your lips clenched up so there is just a small hole. Then blow on your hand with your mouth open wide like you're taking a big bite of food. You can feel that the air comes out faster when the opening is smaller.

 

<{POST_SNAPBACK}>

 

 

 

 

 

You are halfway right here. First you do not want large tube header in a street truck unless you have a very radical cam because stock cam will never use large tubes to yeild any gain at all and may result in a loss everywhere, especailly at the bottom end. Second, when tuning headers for certain RPMS you factor in engine size, tube diameter and tube length. It is the velocity of the gas moving down the header pipe together with the timing of the reflected sonic shock wave when the sound wave hits the collector and reflects back (sound travels faster than the gas and play a big roll in the tuning of headers together with tube size) that helps create a partial vacum at the exhaust point at the right time to help scavange gas from cylinder. The problem here though is that with a closed loop system it may also draw for extra unburn fuel into pipe from fresh charge causing O2 sensor to see mixture as being richer than it is cause it to lean it out and reduce power output and throttle responce. What worked with engine 30 years ago with carbs does not work the same way on a closed loop system and big pipes with high flow do not always equal more power but some backyard mechs seem to think so. YOu "tune/tweak closed loop engine a lot different than a open system if you want it to really do its best overall.

[SS Crew]

So.....getting back to my original question - does having a muffler that lowers backpressure so much that it actually sucks (velocity?) bad for low end torque?

[cedjunior]

Back Pressure = bad

Velocity = good. 

 

I'm having a hard time understanding why and when the word backpressure became associated with low end perfromance.  The problem with having an exhaust set up that isn't restricted enough is you lose velocity.  The wider the diameter of the exhaust tubing the slower the exhaust will pass through it.  If you have exhaust pipes that are too narrow, you can't move enough exhaust out no matter how fast its going, too wide and it will move slow.  Also the faster the ehaust in the system the more it helps scavenging, which is what helps to produce low end torque.  If that muffler does infact create a vacuum, then it would greatly increase the scavenging effect.

 

<{POST_SNAPBACK}>

 

 

But if you use headers that have too large of primary tubes, you lose low end, but pick up top end. Thus too little back pressure will take away some low end, but you should pick it up on the top end. Right?????

 

<{POST_SNAPBACK}>

 

 

 

 

 

 

But its not back pressure you're losing, its velocity. If the primaries are too big then the exhaust gas will loose velocity and also lose some of the scavenging effect. Here is how the scavening effect works. You have en exhaust pulse come out of an ehaust port on a cylinder head and enters the primary tube. Just after that another exhaust pulse from the next cylider down comes out of the exhaust port and goes into its own primary header tube. When the first ehaust pulse enters the header collector, it creates a pull on the exhaust pulse still coming down the next primary tube headed to the collector. The higher the velocity of the exhaust gasses as they enter the collector the better the scavenging effect will be.

 

And the reason why you gain some top end power with larger diameter exhaust tubing (whether its header primaries or a cat back exhaust) is because at such a high RPM having oversized exhaust is actually a good thing because you're moving so much air in and then out of the engine.

 

Here is a good way to understand what I'm talking about, hold your hand in front of your face and blow on it like you're blowing out candles on a birthday cake, with your lips clenched up so there is just a small hole. Then blow on your hand with your mouth open wide like you're taking a big bite of food. You can feel that the air comes out faster when the opening is smaller.

 

<{POST_SNAPBACK}>

 

 

 

 

 

You are halfway right here. First you do not want large tube header in a street truck unless you have a very radical cam because stock cam will never use large tubes to yeild any gain at all and may result in a loss everywhere, especailly at the bottom end. Second, when tuning headers for certain RPMS you factor in engine size, tube diameter and tube length. It is the velocity of the gas moving down the header pipe together with the timing of the reflected sonic shock wave when the sound wave hits the collector and reflects back (sound travels faster than the gas and play a big roll in the tuning of headers together with tube size) that helps create a partial vacum at the exhaust point at the right time to help scavange gas from cylinder. The problem here though is that with a closed loop system it may also draw for extra unburn fuel into pipe from fresh charge causing O2 sensor to see mixture as being richer than it is cause it to lean it out and reduce power output and throttle responce. What worked with engine 30 years ago with carbs does not work the same way on a closed loop system and big pipes with high flow do not always equal more power but some backyard mechs seem to think so. YOu "tune/tweak closed loop engine a lot different than a open system if you want it to really do its best overall.

 

<{POST_SNAPBACK}>

 

 

 

 

You like that sound stuff huh???? Sound is a wave that travels through a medium, not with it, in this case exhaust gas (and a limited amount through the metal that the exhaust system is made of, but thats not relevant). I'm not sure how a wave traveling through gas can cause a vacuum effect. Take 2 pipes, join then at a larger pipe making a y shape. Blow air into one of the smaller pipes and you'll also feel air being sucked into the other smaller pipe. Thats scavenging, no sound waves needed.

 

Anyway, I understand that LARGE primary tube headers are for higher RPMS, not the 4-6000 rpms that late model trucks produce, they would never move enough air in and out to utilize large primary headers unless the engine is blown or turboed. I wasnt even alive 3o years ago, so I wouldn't even know what works on those engines, but thanks.

 

And to answer SS's question, in my opinion that muffler might not create any added HP or Torque, but if its free flowing with out restriction it wont hurt anything either.