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Re: pse
You'l find a number of threads on this - do a search and you'll find opinions every way you can imagine. Supposedly (according to Porsche) the PSE does not add any HP - only affects sound quality. For about 2x the price I went with the Tubi (according to Tubi & Champion worth up to 30 hp), and I love the sound and the noticeable difference in performance. I did the full exhaust with headers, but kept the factory cats - consistent with the power claim configuration, and no fault codes to worry about. (Changing cats will sometimes cause faults to appear.) The Tubi saves about 30 lbs of weight, has a great sound all the time with no stinkin' switches 
and is unobtrusive when cruising.
and is unobtrusive when cruising.
Re: pse
Quote:
RoadRacer said:
You'l find a number of threads on this - do a search and you'll find opinions every way you can imagine. Supposedly (according to Porsche) the PSE does not add any HP - only affects sound quality. For about 2x the price I went with the Tubi (according to Tubi & Champion worth up to 30 hp), and I love the sound and the noticeable difference in performance. I did the full exhaust with headers, but kept the factory cats - consistent with the power claim configuration, and no fault codes to worry about. (Changing cats will sometimes cause faults to appear.) The Tubi saves about 30 lbs of weight, has a great sound all the time with no stinkin' switches
Porsche does not claim any HP for the PSE because they only publish actual engine HP ( not at the driven wheel )
In by-pass mode, the exhaust goes only thru ~ 1/3 of the muffler , so there should definitely be some power gains .
I like the PSE precisely because it HAS the "stinking" switch. I like it quiet occasionally . Lol
Mufflers are pretty much straight forward affairs.If the Tubi's weigh 30 lbs. less, it can only mean they use cheap tubing instead of pipe and paper thin sheetmetal gauges in their construction .
But the main reason I prefer the PSE is the SOUND. Not the few extra HP. And I believe that a 30 HP claim for just mufflers is B.S.
You would not get that much if you deleted them alltogether .
Jul 14, 2006 1:40:47 PM
- Alex_997TT
- Rennteam Master
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- Loc: Reading , United Kingdom
- Posts: 3320, Gallery
- Registered on: Nov 20, 2005
- Reply to: jcs
Re: pse
Quote:
jcs said:
Porsche does not claim any HP for the PSE because they only publish actual engine HP ( not at the driven wheel )
In by-pass mode, the exhaust goes only thru ~ 1/3 of the muffler , so there should definitely be some power gains .
I love this site, learn something new every day! Thanks jcs!
Re: pse
Quote:
jcs said:
Mufflers are pretty much straight forward affairs.If the Tubi's weigh 30 lbs. less, it can only mean they use cheap tubing instead of pipe and paper thin sheetmetal gauges in their construction .
Sorry, but you're quite wrong on that assessment... the Tubi is mandrel-bent stainless (100%, and polished no less) with material thickness and build quality that rivals, if not exceeds the best you'll find anywhere. The weight savings is by design difference, and typical of what can be found when replacing a factory exhaust with a quality aftermarket system.
Quote:
jcs said:
But the main reason I prefer the PSE is the SOUND. Not the few extra HP. And I believe that a 30 HP claim for just mufflers is B.S.
You would not get that much if you deleted them alltogether .
I think you missed a couple of points - first, the increased HP claim is for a full system - mufflers AND manifolds, not just the mufflers. Take a look at the system on Champion Motorsports' website, and compare the Tubi manifolds with the factory versions. If the factory manifolds were designed for optimum power, why would any race team replace them with aftermarket? I'm not swearing by the 30hp claim - but I could feel a noticeable difference in performance after the exhaust install, so if it's 30hp or 3hp I'm not concerned. A LOT of engineering and flow analysis goes into the design of ANY exhaust system - Porsche, Tubi, AWE, Fabspeed, or any other, and anyone will tell you that just deleting the mufflers or the exhaust system altogether will not result in power gains.
The bottom line - to each his own. I'm not criticizing you for your choice of PSE, nor am I criticizing the PSE system either. You don't have to like my choice of a Tubi, but it was my preference as the PSE was yours. I simply stated what my decision was based on - a simple comparison of the two.
Re: pse
Quote:
fritz said:Quote:
jcs said:
Porsche does not claim any HP for the PSE because they only publish actual engine HP ( not at the driven wheel )
So you're saying that power at the rear wheels is increased, though it isn't at the flywheel?
Let's say a normally aspirated engine generates a total of X hp ( at the flywheel )
Some of those hp are required to overcome friction in the drivetrain, the transmission etc. and to draw in the combustion air ( thru filter etc.) and expel the burnt gases out thru the exhaust system .
If the resistance thru an exhaust system (freer flow mufflers, 100 cell "racing" vs. 300 cell catalytic converters etc.) is reduced, it requires less energy from the engine .
So,up to a point, if you reduce the energy required to "operate" the engine, you gain it at the driven wheel.
Re: pse
Quote:
fritz said:Quote:
jcs said:
Porsche does not claim any HP for the PSE because they only publish actual engine HP ( not at the driven wheel )
So you're saying that power at the rear wheels is increased, though it isn't at the flywheel?
No, that is not what he said. Porsche does not measure HP at the wheel. Consequently they make no claims of increases HP for PSE versus stock mufflers. In reality, there "COULD" be some HP gain due to reduced back pressure(again Porsche makes no such claim) but even "IF" there is a gain, it would probably not more than a couple of HP, max.
Re: pse
Quote:
RoadRacer said:
Sorry, but you're quite wrong on that assessment... the Tubi is mandrel-bent stainless (100%, and polished no less) with material thickness and build quality that rivals, if not exceeds the best you'll find anywhere. The weight savings is by design difference, and typical of what can be found when replacing a factory exhaust with a quality aftermarket system.
[
I think you missed a couple of points - first, the increased HP claim is for a full system - mufflers AND manifolds, not just the mufflers. Take a look at the system on Champion Motorsports' website, and compare the Tubi manifolds with the factory versions. If the factory manifolds were designed for optimum power, why would any race team replace them with aftermarket? I'm not swearing by the 30hp claim - but I could feel a noticeable difference in performance after the exhaust install, so if it's 30hp or 3hp I'm not concerned. A LOT of engineering and flow analysis goes into the design of ANY exhaust system - Porsche, Tubi, AWE, Fabspeed, or any other, and anyone will tell you that just deleting the mufflers or the exhaust system altogether will not result in power gains.
The bottom line - to each his own. I'm not criticizing you for your choice of PSE, nor am I criticizing the PSE system either. You don't have to like my choice of a Tubi, but it was my preference as the PSE was yours. I simply stated what my decision was based on - a simple comparison of the two.
First , I'm happy you like your Tubi's.
As to the weight: St. stl. is st.stl.
The only way to save meaningful weight is by using thinner wall tubing and lighter gauge sheetmetal .
As to the engineering: You are quite right . It takes a lot of it to match the right resistance to a particular normally aspirated engine (it affects not only HP but Torque as well ).
So why do you put your faith in someone who welds mufflers in his garage , or the Fabspeed "expert" who sells them from his driveway ?
As to the HP claims, well that's all been discussed before . If it makes you happy to believe outlandish claims of 40 HP or more for an exhaust system or 30 plus HP from a K&N air filter intake ,or 12 HP from Fabspeeds rubber hose intake ... what can I say .
Just do yourself a favor. Go to the Europipe site and take a look at their system and ask youself this question:
Why would someone buy the Europipe exhaust system headers, 100 cel racing cats and mufflers for close to $ 5000 when they claim only 16 HP gain from it ?
By contrast , Fabspeed and other American aftermarket guys claim 12 and 14 HP just for their headers alone and almost three times that for their systems.
Is it that the Europeans are that stupid, and we that good ? Or maybe the Europeans use different dynos? or maybe they publish ( let me be kind ) LESS OPTIMISTIC RESULTS ?
But thank you for not criticizing my decision to go with the Porsche PSE's.( I am not doing it for the HP, but because they sound the way I think a Porsche should . Lol)
Enjoy your car .
Re: pse
I appreciate the well-wishes, and wish you the same enjoyment of your car. I bought the Tubi over the PSE based on sound as well, after listening to both side-by-side. it's as subjective a decision as any, and as I stated, whether I got 30hp or not is not a concern. And yes, it does feel faster, but shame on me for not running before-and-after test runs. Point is, I don't regret the decision I made and neither should you.
As far as the weight savings, you're right - stainless steel is stainless steel. But 40lbs of stainless steel is still heavier than 25lbs of stainless steel, right? I found the cutaway pic below of a 997 muffler, and it's probably easy to see where some of the weight comes from. Sorry, I couldn't find a cutaway of a Tubi to compare, and I don't plan to carve up one of mine as an example - I still like them! I didn't buy it from someone in a trenchcoat on a street corner, and don't recommend that anyone else do that either. Whatever anyone buys, make sure you're happy with the quality and the sound, and that you deal with a reputable dealer - 'nuff said.
One last thing to ponder... if Porsche claims 355hp at the flywheel of a 3.8L S engine, assumingly it is with the standard, factory, non-PSE exhaust, and is a result of engine dyno runs. Why could they not install a PSE on the same engine, do another series of dyno runs, and thereby state whether or not additional flywheel horsepower is produced by the PSE? Maybe they did, and the fact is the PSE doesn't produce any change in hp or torque. Again, not a criticism by any means, but if I can get additional hp for my $$ I'll take it.
As far as the weight savings, you're right - stainless steel is stainless steel. But 40lbs of stainless steel is still heavier than 25lbs of stainless steel, right? I found the cutaway pic below of a 997 muffler, and it's probably easy to see where some of the weight comes from. Sorry, I couldn't find a cutaway of a Tubi to compare, and I don't plan to carve up one of mine as an example - I still like them! I didn't buy it from someone in a trenchcoat on a street corner, and don't recommend that anyone else do that either. Whatever anyone buys, make sure you're happy with the quality and the sound, and that you deal with a reputable dealer - 'nuff said.
One last thing to ponder... if Porsche claims 355hp at the flywheel of a 3.8L S engine, assumingly it is with the standard, factory, non-PSE exhaust, and is a result of engine dyno runs. Why could they not install a PSE on the same engine, do another series of dyno runs, and thereby state whether or not additional flywheel horsepower is produced by the PSE? Maybe they did, and the fact is the PSE doesn't produce any change in hp or torque. Again, not a criticism by any means, but if I can get additional hp for my $$ I'll take it.
Re: pse
Quote:
gota911 said:Quote:
fritz said:Quote:
jcs said:
Porsche does not claim any HP for the PSE because they only publish actual engine HP ( not at the driven wheel )
So you're saying that power at the rear wheels is increased, though it isn't at the flywheel?
No, that is not what he said. Porsche does not measure HP at the wheel. Consequently they make no claims of increases HP for PSE versus stock mufflers. In reality, there "COULD" be some HP gain due to reduced back pressure(again Porsche makes no such claim) but even "IF" there is a gain, it would probably not more than a couple of HP, max.
Thats it. I'm telling everyone that my car now makes 359hp
Goes along with Porsche Hp pricing (15K for ~X51 - 30 hp more, therefore for 2K I should be getting 4 Hp more..... ) 
Re: pse
Quote:
RoadRacer said:
One last thing to ponder... if Porsche claims 355hp at the flywheel of a 3.8L S engine, assumingly it is with the standard, factory, non-PSE exhaust, and is a result of engine dyno runs. Why could they not install a PSE on the same engine, do another series of dyno runs, and thereby state whether or not additional flywheel horsepower is produced by the PSE? Maybe they did, and the fact is the PSE doesn't produce any change in hp or torque. Again, not a criticism by any means, but if I can get additional hp for my $$ I'll take it.
Your mufflers have nothing to do with HP at the flywheel .
The only way you can get more ENGINE HP from a normally aspirated engine is by either putting in hotter burning fuel, or increasing the size of the combustion chamber , or by first compressing the air (via turbocharger, supercharger, compressor or whatever else you wish to call it ) thereby allowing more air to be shoved into the combustion chamber , which allows more fuel to be added, which will give you a bigger bang .
And as far as I know, no muffler on earth will put more air into the combustion chamber .
As I stated before, Porsche publishes the HP produced by the engine at the flywheel. Not what's left over to drive the wheels after you deduct the HP needed for the transmission, intake , exhaust etc.
I really believe the more aggressive exhaust sound can give people the illusion of more power . I doubt the average driver can feel the difference of a 3 or 5% power increase by the seat of their pants. I sure can't .
Re: pse
Quote:
jcs said:
Your mufflers have nothing to do with HP at the flywheel.
Sorry, you have a misunderstanding of how an internal combustion engine works if you believe that.
Quote:
jcs said:
The only way you can get more ENGINE HP from a normally aspirated engine is by either putting in hotter burning fuel, or increasing the size of the combustion chamber , or by first compressing the air (via turbocharger, supercharger, compressor or whatever else you wish to call it ) thereby allowing more air to be shoved into the combustion chamber , which allows more fuel to be added, which will give you a bigger bang .
And as far as I know, no muffler on earth will put more air into the combustion chamber .
The problem is, if you ram more air/fuel into the combustion chamber without an improved process to exhaust the spent mixture out of the chamber, you reach a point where the engine can't "exhale" fast enough in order to "inhale" more air/fuel faster or in greater quantities.
The point of an efficiently designed exhaust system is to create a scavenging effecct that helps draw the exhaust gases out of the combustion chamber when the exhaust valves open.
The design of an exhaust system absolutely affects how much horsepower and torque the engine creates at the flywheel.
Re: pse
Quote:
RoadRacer said:
Sorry, you have a misunderstanding of how an internal combustion engine works if you believe that.
The problem is, if you ram more air/fuel into the combustion chamber without an improved process to exhaust the spent mixture out of the chamber, you reach a point where the engine can't "exhale" fast enough in order to "inhale" more air/fuel faster or in greater quantities.
The point of an efficiently designed exhaust system is to create a scavenging effecct that helps draw the exhaust gases out of the combustion chamber when the exhaust valves open.
The design of an exhaust system absolutely affects how much horsepower and torque the engine creates at the flywheel.
I was under the impression that the exhaust gases were pushed out of the combustion chamber by the piston in the up-stroke . Not sucked out via a scavenging effect by the exhaust pipes and the mufflers.
I'm curious : If you were to add a supercharger to your Tubi equipped car, would you also have to add a SUPERTUBI exhaust sytem ? Or would your regular Tubis be OK to "scavenge" out all those additional combustion gases ? Lol
Re: pse
LOL at this thread...thanks. 
now my .02
If Porsche dynoed the PSE, I'm sure (if it bypasses 2/3rds of the muffler like jcs stated) it produces more hp and torque somewhere on the curve...may not be at peak which they publish.
Most (if not all) of these increased hp claims are not at the peak but are at some other point on the curve. This is allot easier to believe than a 30 peak hp gain. There may be a difference in feel at say, 4000 rpm from torque with the Tubi compared to the stock system which does not necessarily mean better 1/4 mile E.T.'s...but it might.
BTW...I love my PSE.
now my .02
If Porsche dynoed the PSE, I'm sure (if it bypasses 2/3rds of the muffler like jcs stated) it produces more hp and torque somewhere on the curve...may not be at peak which they publish.
Most (if not all) of these increased hp claims are not at the peak but are at some other point on the curve. This is allot easier to believe than a 30 peak hp gain. There may be a difference in feel at say, 4000 rpm from torque with the Tubi compared to the stock system which does not necessarily mean better 1/4 mile E.T.'s...but it might.
BTW...I love my PSE.
Re: pse
Here's where you'll add horsepower to the 997,--use racing fuel. what octane are you buying each time you stop for gasoline? For every octane drop that you must buy in your area you are robbing horsepower. The knocksensors in conjunction with the Variocam system essentially de-tune the engines so they don't detonate and destroy themselves. They adjust and optimise themselves to the fuels. Dynos are so subjective. It's tough to run a test fairly.
I actually prefer the PSE design. There are several excellent design features in there. First, notice the accordian design in one of the tubes (on the right). That absorbes some harmonic vibration that would otherwise be passed onto the other components. Ultimately the Tubi may vibrate itself to the point that metal fatigue will set in and the tube will crack. The standoff mounts for the PSE are in several axis,--not the single of the Tubi. One WILL fail before the other,--and it won't be the Porsche.
Which formulation of SS is the Tubi made? Which for the PSE? (What I'm getting at here is which is made of better materials and would be more resistant to burn through, cracking, and/or corrosion?) How many miles of testing have been completed on the Tubi for the 997 application? How many for the Porsche?
Having been a Porsche customer into 4 decades, I absolutely am amazed at the number of their customers who continue to take off first rate parts only to put on other parts thinking they are buying better. There are dozens of aftermarket companies who have gotten rich off this behavior.
I'm extremely pleased with my PSE equiped 911, I like the ability to turn it on or off because I have a cabriolet. There are times that I want just to quietly cruise and with the push of a botton I can have that. Other times I lust after the sport sounds and feeling. I like the choice. I found that I generally would run with the PSE on until I came up on a sleepy little town and the last thing I wanted to do was arrive in a chorus of "hey, listen to me." We have enough noise pollution in the world today and people are entitled to some relief at their homes and in their villages. On the track we can do something else!
Dan
Happy with OEM
I actually prefer the PSE design. There are several excellent design features in there. First, notice the accordian design in one of the tubes (on the right). That absorbes some harmonic vibration that would otherwise be passed onto the other components. Ultimately the Tubi may vibrate itself to the point that metal fatigue will set in and the tube will crack. The standoff mounts for the PSE are in several axis,--not the single of the Tubi. One WILL fail before the other,--and it won't be the Porsche.
Which formulation of SS is the Tubi made? Which for the PSE? (What I'm getting at here is which is made of better materials and would be more resistant to burn through, cracking, and/or corrosion?) How many miles of testing have been completed on the Tubi for the 997 application? How many for the Porsche?
Having been a Porsche customer into 4 decades, I absolutely am amazed at the number of their customers who continue to take off first rate parts only to put on other parts thinking they are buying better. There are dozens of aftermarket companies who have gotten rich off this behavior.
I'm extremely pleased with my PSE equiped 911, I like the ability to turn it on or off because I have a cabriolet. There are times that I want just to quietly cruise and with the push of a botton I can have that. Other times I lust after the sport sounds and feeling. I like the choice. I found that I generally would run with the PSE on until I came up on a sleepy little town and the last thing I wanted to do was arrive in a chorus of "hey, listen to me." We have enough noise pollution in the world today and people are entitled to some relief at their homes and in their villages. On the track we can do something else!
Dan
Happy with OEM
Re: pse
Noise pollution? Oh...Dan! It's a symphony unlike any other. I've actually had people tell me to let them know when I was leaving so they could come outside just to hear me drive off. Take a neighborhood poll and you may be surprised.
And why not "hey, listen to me." to go with the "hey, look at me" color? Stunning car you have.
And why not "hey, listen to me." to go with the "hey, look at me" color? Stunning car you have.
Re: pse
Quote:
GA997S said:
Noise pollution? Oh...Dan! It's a symphony unlike any other. I've actually had people tell me to let them know when I was leaving so they could come outside just to hear me drive off. Take a neighborhood poll and you may be surprised.
And why not "hey, listen to me." to go with the "hey, look at me" color? Stunning car you have.
Subtle. Isn't the color subtle? Like my PSE...
;-)
D
Re: pse
Quote:
jcs said:
As I stated before, Porsche publishes the HP produced by the engine at the flywheel. Not what's left over to drive the wheels after you deduct the HP needed for the transmission, intake , exhaust etc.
jcs, to put it bluntly, you are out of your depth here in terms of your understanding of the operation of auto power trains.
It is correct to say that transmission losses have to be deducted from engine torque / power output measured at the flywheel to arrive at the torque available at the driving wheels.
This does not apply to losses / gains arising from modifications to induction or exhaust systems, because both these systems are "upstream" of the flywheel in the process of turning the calorific energy in fuel into torque.
Re: pse
Quote:
fritz said:Quote:
jcs said:
As I stated before, Porsche publishes the HP produced by the engine at the flywheel. Not what's left over to drive the wheels after you deduct the HP needed for the transmission, intake , exhaust etc.
jcs, to put it bluntly, you are out of your depth here in terms of your understanding of the operation of auto power trains.
It is correct to say that transmission losses have to be deducted from engine torque / power output measured at the flywheel to arrive at the torque available at the driving wheels.
This does not apply to losses / gains arising from modifications to induction or exhaust systems, because both these systems are "upstream" of the flywheel in the process of turning the calorific energy in fuel into torque.
You are absolutely correct .
I should have chosen my wording more carefully.
How about this : " The power available at the driven wheel = energy produced by the piston( at the power stroke), minus all mechanical losses due to piston friction, connecting rods ,drivetrain, transmission etc. AND the power required for the induction and exhaust systems "
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