Stebro questions...

[SVXMAN2001]

For those who have or know about the stebro exhaust system (complete from exhaust manifold to muffler)...will this system be a good match for a NA engine with upgraded camshafts/valvetrain, injectors and the hydra EMS? Meaning will it be more of a hindrance to overall performance or will it allow a more efficient flow as opposed to the stock system? Thanks, Chris

[odepaj]

For those who have or know about the stebro exhaust system (complete from exhaust manifold to muffler)...will this system be a good match for a NA engine with upgraded camshafts/valvetrain, injectors and the hydra EMS? Meaning will it be more of a hindrance to overall performance or will it allow a more efficient flow as opposed to the stock system? Thanks, Chris

I dont think anybody has the front portion of the Stebro system yet as it is almost brand new?

The system is designed very well and the only flow hinderance I would guess at would be the rear muffler as it is similar to the stock muffler.

The piping connects to it at a straight-on 90* angle, which could easily be improved upon.



FYI: I have the cat-back portion of the Stebro.




Dustin

[Freeman]

Why pay so much for it though? You could get one custom built by one of the Tom's with almost the same performance gains!!

[Green1995SVX]

Why pay so much for it though? You could get one custom built by one of the Tom's with almost the same performance gains!!

The Stebro has such a buttery-smooth sound. I have yet to hear something custom that comes close. (as far as sound is concerned)

[TomsSVX]

Sound and performance are always mixed w/ the 3.3

the #1 thing if you want power from the exhaust is the headers a nice 30" equal length header will do more than any cat-back. In this case sound are performance are a compromise.

I sacrificed a little flow from my exhaust by using a flowmaster muffler for a little better sound.

Stebro is nice for sound.... but prob not the best solution for power

Tom

[odepaj]

The Stebro has such a buttery-smooth sound. I have yet to hear something custom that comes close. (as far as sound is concerned)

:) I fully agree.

To answer Freeman's question: I didn't purchase my Stebro seperately, it came with the car :D

YT: I agree, the Stebro deffinetly isn't the best thing for performance. But I wouldn't trade mine for the world :D (of course, its also not on my "performance oriented" car so everything is all good).




Dustin

[Myxalplyx]

For those who have or know about the stebro exhaust system (complete from exhaust manifold to muffler)...will this system be a good match for a NA engine with upgraded camshafts/valvetrain, injectors and the hydra EMS? Meaning will it be more of a hindrance to overall performance or will it allow a more efficient flow as opposed to the stock system? Thanks, Chris

Based on what was said above, it would be a hinderance to overall performance however it would allow a more efficient flow as opposed to the stock system. :D

[Freeman]

I wouldn't doubt that for a second it would be more sufficient than stock. The stock system can be much improved with new technology and through many experiments from other people. My argument was, why pay so much for a system when you can get one for cheaper with almost identical, if not better performance gains. Guess I got my answer. There is no comparison in sound when it comes to a stebro system. I imagine the sound is so distinct, that another stebro owner can note when someone else has a similar system!

Now if you wanted sound as well as gains in performance, it does not, in fact, have to be a sacrifice sound for performance situation. In a recent post, someone stated that they had an electronic cut out on their exhaust. This, I think, is a wonderful idea. You can keep everything sealed and quiet with great performance but at the flip of a switch, have an exhaust that announces that you are around, lol. I recently had one of these systems put in front of me, and my jaw dropped. If you want a world where sound and performance are there without sacrifice, check into the electric cut out..

[odepaj]

I wouldn't doubt that for a second it would be more sufficient than stock. The stock system can be much improved with new technology and through many experiments from other people. My argument was, why pay so much for a system when you can get one for cheaper with almost identical, if not better performance gains. Guess I got my answer. There is no comparison in sound when it comes to a stebro system. I imagine the sound is so distinct, that another stebro owner can note when someone else has a similar system!

Quoted for 100% truth.

Infact, even though the sound quality in my Stebro video is of very low quality; the first time I played it I had people running into my room telling me someone was outside starting my car! :lol:

I'll try and get a good recording of it sometime soon.



Dustin

[Freeman]

Quoted for 100% truth.

Infact, even though the sound quality in my Stebro video is of very low quality; the first time I played it I had people running into my room telling me someone was outside starting my car! :lol:

I'll try and get a good recording of it sometime soon.



Dustin

I hope you do. I admit, I enjoyed listening to it. In fact, I really haven't heard anything like it before. I was sitting at the counter with the laptop at my girlfriends place and turned the volume up.. She hated it..

[ridered777]

I'm with Dustin on this one.

My SVX also came with a Stebro. It's probably my favorite part of the car. I wouldn't give up for the world, I don't care if someone offered me MORE than what they cost new! The sound just feels like what the SVX SHOULD sound like...

[longassname]

Would clearance be any harder at 28 or 29 inches?


Sound and performance are always mixed w/ the 3.3

the #1 thing if you want power from the exhaust is the headers a nice 30" equal length header will do more than any cat-back. In this case sound are performance are a compromise.

I sacrificed a little flow from my exhaust by using a flowmaster muffler for a little better sound.

Stebro is nice for sound.... but prob not the best solution for power

Tom

[TomsSVX]

Would clearance be any harder at 28 or 29 inches?

No I wouldn't see why they would. It is harder to make them longer than 32 but to make them shorter would be relatively simple

Tom

[Mensaf]

Those ELHs cost about as much as a catback though, don't they? Or are you planning on offering those as bolt ons as well? That would be awesome.

[TomsSVX]

Those ELHs cost about as much as a catback though, don't they? Or are you planning on offering those as bolt ons as well? That would be awesome.

Bolt-in to what?? There is not a single part of the stock exhaust system I would put behind a set of ELH. Thats why I have not offered them as such

Tom

[RallyBob]

Another point worth mentioning is that the header lengths and diameters would be quite different depending on the application. For a standard engine w/automatic I'd use 1.5" primary diameters that were +/-36" long, with a manual tranny I'd knock about 2" off the primary lengths. If you have other mods such as mild bowl blending and mild cams, then I'd probably go with a stepped header (1.5" into 1.625") that was 31" long to correspond with the higher peak power rpms. I wouldn't step up to 1.625" all the way unless the vehicle had a manual trans and a few more mods...particularly higher compression and hotter cams. The only exception for me would be if you had either a supercharger or nitrous, then the larger 1.625" headers would make sense. Bigger than that, then you'd better have a bunch more cam, compression, and headwork, and be revving it up pretty high!

[oab_au]

Sound and performance are always mixed w/ the 3.3

the #1 thing if you want power from the exhaust is the headers a nice 30" equal length header will do more than any cat-back. In this case sound are performance are a compromise.

Tom

Would clearance be any harder at 28 or 29 inches?

Have you all tried working the length out?:cool:

30" will resonate at 9000 rpm.
28" will resonate at 9642 rpm.

Where do you expect to develop peak torque?
Are you really talking about a svx engine?:D

Harvey.

[TomsSVX]

Have you all tried working the length out?:cool:

30" will resonate at 9000 rpm.
28" will resonate at 9642 rpm.

Where do you expect to develop peak torque?
Are you really talking about a svx engine?:D

Harvey.

Yes, but remember I am also talking about an SVX and things still need to make their way under the car. That being said, the 30" length is a compromise between the length you may want, and what will fit. Also you might want to add the 6" of collector into that as well. Not everything can be numbers.

Tom

[oab_au]

Yes, but remember I am also talking about an SVX and things still need to make their way under the car. That being said, the 30" length is a compromise between the length you may want, and what will fit. Also you might want to add the 6" of collector into that as well. Not everything can be numbers.

Tom

Sure I know there are space problems, but if you can't fit the right tuned length in, why do it its not going to help.

It is better to just use a header with short branches to suit the No. of degrees, that will prevent the exhaust gas pressure from cause interference between cylinders. Then keep the down pipe the same overall length, that suits the rpm that you want the peak torque to occur.

Keeping the header branches short and compact, will help to maintain the sonic wave that the right tuned length will provide.

Harvey.

[longassname]

120*1700fps/7200rpm=28.33"

[oab_au]

120*1700fps/7200rpm=28.33"

Why 120*, that would bring the negative wave back at 115*BTDC. far too early. Needs to be around 55*/50* BTDC.

1700 fps is a bit high for our exhaust system, it won't get that hot.

7200 rpm Is this where your engine is going to make peak torque????

180* X 1500 fps / 5000 rpm = 54".

Harvey.

[longassname]

I think maybe you are calculating the end of the collector. I was talking about the begining. 7200 would be peak power; on a race car it's most common to tune to reinforce peak power rather than torque. I come up with 28" to 33" primary lengths with 14.5' to 16.5" collector lengths.




Why 120*, that would bring the negative wave back at 115*BTDC. far too early. Needs to be around 55*/50* BTDC.

1700 fps is a bit high for our exhaust system, it won't get that hot.

7200 rpm Is this where your engine is going to make peak torque????

180* X 1500 fps / 5000 rpm = 54".

Harvey.

[oab_au]

I think maybe you are calculating the end of the collector. I was talking about the begining. 7200 would be peak power; on a race car it's most common to tune to reinforce peak power rather than torque. I come up with 28" to 33" primary lengths with 14.5' to 16.5" collector lengths.

Mike I think we are talking about two different types of exhaust headers. Probably an Australian thing.:D

I took it that Tom was talking about his type of "equal length headers" Three tuned length pipes, into an expansion area.
Bob was on a "branched pipe collector" header, and I see you are on the same as Bob, OK.:)

I design an exhaust to suit the cams that the engine is going to run. Three tuned length pipes into an expansion area (chamber, large dia collector, etc) is the best, keeps all the energy to goes back to start the inlet wave.

If they can't be fitted, then a short branched header, with the branches just long enough to prevent the exhaust pressure plug from entering the cylinder next to it, that is on overlap.
Then doing the same tuned length measurement from the ex. valve to the expansion point, that brings the negative pressure pulse back to the combustion chamber, for the opening of the inlet valve.
Just a slightly long branches that it is now.The branching needs to be as compact as it can, so as not to lose too much of the sonic wave pressure..

The rpm that the pulse is returned, has to match the rpm that the inlet lobe center is set for. Maximum cylinder filling, gives Maximun torque. The rpm that torque is produced gives the 'peak power', not what is most common.:)

Harvey.

[RoughSilver92]

http://www.wallaceracing.com/header_length.php

using
4400 for engine speed (peak tq)
202.476 for displacement
55 for exhaust valve opening

Your Primary Tube Length is 55.92
Your Primary Tube Diameter is 1.06 inches
Your Collector Length is 27.96 inches
Your Collector Diameter is 2.02 inches .

I think this calculator is for a v8, though, since 1" primaries seem tiny. I need to find a more comprehensive calculator, or invest in a good book! Based on these lengths, though, where does the rest of the system go??

[RoughSilver92]

http://www.slowgt.com/Calc2.htm#Header

Better calculator using bore and stroke.
Stock engine using peak torque:
1.46" primaries @ 42.4"
2.78" collector @ 21.2"

Stock engine using peak hp:
1.62" primaries @ 34"
3.08" collector @ 17"

Still huge! I think for my simple purposes I'll stick with the stocker! Now I don't even know if porting it is worthwhile, since it's at about 1.5" already.

[oab_au]

http://www.slowgt.com/Calc2.htm#Header

Better calculator using bore and stroke.
Stock engine using peak torque:
1.46" primaries @ 42.4"
2.78" collector @ 21.2"

Stock engine using peak hp:
1.62" primaries @ 34"
3.08" collector @ 17"

Still huge! I think for my simple purposes I'll stick with the stocker! Now I don't even know if porting it is worthwhile, since it's at about 1.5" already.

Some good calculators on that site.
It would be very easy to work it out, IF it was so cut and dried.:)

I can work out the lengths on a bike engine and it is going to be very close. The system we have to have on a car, is not so easy. There are too many variables, every change in dia will produce a wave change, so the system has many different waves running up and down the pipes.

Then there is the temperature, that the exhaust gas will run at. This changes the speed of sound in the gas, to change the time of the negative pulse return. How many have pulled off the tin covers on the pipes and cats, that maintain the exhaust gas temp.

The system that we have, has been worked out on a computer to bring the negative pressure back to the cylinder at the right time. They then put the whole system on an engine dyno to see what the results are. The system is then trimmed to correct the difference, and get the maximum effect on the inlet opening.

So the length that we measure on the car now, down to the resonator, has been set to incorporate all the variables that the cats, temp, etc produce. While we stay with the same results that they have got, we can't go too far wrong.

Removing the front cats, replacing the resonator with a straight pipe, joining the two header pipes with a Y pipe, will alter the resonate system and down grade the power.

Harvey.

[RoughSilver92]

Wait, when you say "the system we have..." do you mean the stock manifold, or are you saying that you and others are designing a system and dyno testing it?

[oab_au]

Wait, when you say "the system we have..." do you mean the stock manifold, or are you saying that you and others are designing a system and dyno testing it?

Shock, horror,:eek: Yes the ones that Subaru designed to get this engine to produce the HP that it does.

They flow the exhaust gas away, with very little restriction, deliver a strong negative wave back to the inlet.

What more could do to improve them for the rpm range, that the cams are going to run at.

If the exhaust cam duration is increased more that about 15*, a new header that has branches slightly longer, would to needed. That doesn't mean 'the longer the better,:rolleyes:, as the extra volume of the header will absorb some of the returning negative pulse.



Harvey.

[TomsSVX]

A gain of .5 seconds in ET and a gain in excess of 6mp in trap speed with the only change being in my headers and exhaust system, I would think I was getting an increase??:confused: Who knew I was losing power:rolleyes:

tom

[oab_au]

A gain of .5 seconds in ET and a gain in excess of 6mp in trap speed with the only change being in my headers and exhaust system, I would think I was getting an increase??:confused: Who knew I was losing power:rolleyes:

tom

Not to mention all the other variables that go with 1/4 mile runs.:)

I guess you mean this version of yours.

http://www.subaru-svx.net/photos/files/TomsSVX/43683.JPG

A great job of plumbing, but they were too short to resonate at a engine speed that you could get the engine to rev at.
They do a good job of preventing the interference that the cams that you used, would develop.

If the three pipes were at the resonate length, and entered an expansion box, it would be fantastic, but it has to fit under the svx.:D

If the three pipes were kept short enough to prevent the interference, then run into the standard header pipe, it would fit under the car and it would still be able to use the std cats for emissions.

You would sell a lot more of this set up that you did of the
other.:)

Harvey.

[TomsSVX]

Not to mention all the other variables that go with 1/4 mile runs.:)

I guess you mean this version of yours.

http://www.subaru-svx.net/photos/files/TomsSVX/43683.JPG

A great job of plumbing, but they were too short to resonate at a engine speed that you could get the engine to rev at.
They do a good job of preventing the interference that the cams that you used, would develop.

If the three pipes were at the resonate length, and entered an expansion box, it would be fantastic, but it has to fit under the svx.:D

If the three pipes were kept short enough to prevent the interference, then run into the standard header pipe, it would fit under the car and it would still be able to use the std cats for emissions.

You would sell a lot more of this set up that you did of the
other.:)

Harvey.

The expansion event in this system did no happen until further back, 2.5" resonators followed the collectors the into the expansion event which was placed just behind the rear X-member. If I had measure the length I would imagine it was about 20" further back. OT might have pictures floating around of how it all came together.

Tom

[Freeman]

I want this......

[RoughSilver92]

Harvey, I'm not understanding the benefit of having the 3 pipes run into the expansion chamber without the use of a collector. And please don't get me wrong, I'm not questioning your knowledge. In fact I'm certain that you know more about the voodoo of engine tuning than I do, that's why I ask. But from what I have read from David Vizard, power is made in the collector. He even says that equal length primaries are not as important as a correctly tuned collector. Is the difference in the type of engine? Vizard generally writes about old V8's. As you explained in your camshaft thread, there are differences in what our engines like and what those like. Is this another one of those instances?

[RoughSilver92]

Ok, went back and reread everything. You did say an expansion chamber or a collector. But I still am curious if it would be beneficial to have a properly tuned collector on this engine or not.

[oab_au]

Ok, went back and reread everything. You did say an expansion chamber or a collector. But I still am curious if it would be beneficial to have a properly tuned collector on this engine or not.

You read quicker that I write.

Harvey.

[oab_au]

Harvey, I'm not understanding the benefit of having the 3 pipes run into the expansion chamber without the use of a collector. And please don't get me wrong, I'm not questioning your knowledge. In fact I'm certain that you know more about the voodoo of engine tuning than I do, that's why I ask. But from what I have read from David Vizard, power is made in the collector. He even says that equal length primaries are not as important as a correctly tuned collector. Is the difference in the type of engine? Vizard generally writes about old V8's. As you explained in your camshaft thread, there are differences in what our engines like and what those like. Is this another one of those instances?

That’s ok mate, I know that it runs across the accepted theory, but as you say, it is another one of those instances.
The older ‘low engine speed’ theory, is based on the inertia of the exhaust gas flowing down a pipe, to create a low pressure behind it. They used this pressure to start the flow of inlet gas into the cylinder, during the over lap period. There is the theory that the flow would suck the exhaust gas out of the next cylinder. That worked up to a engine speed that was low enough, and the overlap was long enough to do it, but as this gas flow only travels at about 300 ft/sec, it was too slow for engines that had to develop there torque at 6/7000 rpm. The main function that a V8 header has is that, when the long overlap is used, there is a huge amount of interference between cylinders, some only 90* apart, so the header branching had to be very long to prevent it.

To the present, the exhaust that we have is the modern high-speed type; it does not rely on the inertia and overlap to induct the inlet air. It uses the sound wave pressure that is developed in the engine pipes, from the exhaust valve down to the third cat. This wave travels at 1700 ft/sec, fast enough for the highest engine speeds. This is the difference that changes the way we design headers, because, they have different functions to do.

We have three cylinders (the other side will be the same) they exhaust 240* apart, there is no chance that one cylinder will push exhaust gas into another cylinder, so the branching is kept as short as possibly. The three cylinders then use the exhaust pipe, from the exhaust valve to the 3rd cat, as its own tuned length resonate system, returning all the negative pressure back to the cylinder that needs it, to induct its air. It works the same as Toms three pipe header, but only needs one pipe, to do it.

To answer your question “, I'm not understanding the benefit of having the 3 pipes run into the expansion chamber without the use of a collector”.
The three pipes have to serve the three cylinders, the same as the STD single pipe does. It’s the end of the pipe that makes it or breaks it. Each pipe has to enter the chamber separately to return its energy back to its cylinder, when the three pipes join into a ‘collector’ pipe, the wave will divide into three, sending one third of its pressure up the other two pipes. The original one third enters the expansion chamber to return a weaker negative wave back to the end of the three pipes, divide into three again. Leaving precious little to work the cylinder that started it.

The exhaust gas inertia and the sonic wave can’t be treated the same. Exhaust gas has mass, hence inertia. It can flow gas pressure past another pipe and draw a low pressure in it. The sonic wave will divide send the same pressure up both pipes.
That is why we keep the branching short and the whole header system as compact as possible to preserve the pressure returned to the cylinder.

Does this answer your next question?:D:lol:

Harvey.

[RoughSilver92]

Makes much more sense now, at least as much as I can comprehend. But I believe I get the just of it. Thanks:)

[longassname]

I think Tom was just limited by the collectors he could find for less than an arm and a leg. Those look like the hooker formed collectors which are 2.5"x10". They certainly do represent an expansion event and from what I've read the negative pressure wave is almost exclusively returned through the pipe it came from and barely enters the others at all which is obviously contrary to Harvey's understanding. I didn't study this in school or anything so I can't swear what I've read is right and Harvey's understanding is wrong--it's clear there is a dissagreement by our sources though.

If Tom were to take a sawzall to those collectors and replace the body of them and some of the tubing behind them with 16" of 3.5 tubing they would be an excellent match for a race car running the ECUtune 264 exhaust cams and shift maps or a manual transmission.

[sicksubie]

http://i149.photobucket.com/albums/s73/facagoalie/silver%20svx/IMG_6641.jpg

This is what is under my car now...

[intellibomb]

pics on car pics on car:pics: on car

[oab_au]

I think Tom was just limited by the collectors he could find for less than an arm and a leg. Those look like the hooker formed collectors which are 2.5"x10". They certainly do represent an expansion event and from what I've read the negative pressure wave is almost exclusively returned through the pipe it came from and barely enters the others at all which is obviously contrary to Harvey's understanding. I didn't study this in school or anything so I can't swear what I've read is right and Harvey's understanding is wrong--it's clear there is a dissagreement by our sources though.

If Tom were to take a sawzall to those collectors and replace the body of them and some of the tubing behind them with 16" of 3.5 tubing they would be an excellent match for a race car running the ECUtune 264 exhaust cams and shift maps or a manual transmission.

May be Tom would like to answer this first bit,:)but I thought it was more a case of cams and ignition advance.

Mike you are obviously reading the wrong magazines. You must have learned at school that "pressure acts in all directions equally". The sound wave meeting a junction of three pipes, will divide equally, to enter each pipe, with the same, one third of the orignal pressure.

When you dyno your 'race engine' with 264* exhaust cams, we will all see what you mean.:)

Harvey.

[longassname]

Harvey,

I did get A's in University Physics at the University of Miami back when i took the courses; however, what little I remember of what we studied about the effects of waves on gases only reminds me that I don't know enough to presume any such thing. The best I can do is hope the sources I have read give correct rule of thumbs and you are the only source I have read that claims that. Please feel free to provide the literature to explain otherwise to me.

If I remember correctly that .5 second improvement in et from putting on his headers was the low of a series of runs Tom did with the high being a full second improvement over before the headers. I feel confident the improvement he thinks he saw with his headers is genuine. Maybe some other design would give him even better improvment but I haven't seen any other source supporting your design suggestion other than you. His design is fairly close to what I would come up with using most online calculators or by going off the rules of thumb on wikipedia.

Maybe you are right and I'm certainly open to being convinced. Saying the same thing again like it is a given won't do it though. How about sending me a copy of what you are reading?


May be Tom would like to answer this first bit,:)but I thought it was more a case of cams and ignition advance.

Mike you are obviously reading the wrong magazines. You must have learned at school that "pressure acts in all directions equally". The sound wave meeting a junction of three pipes, will divide equally, to enter each pipe, with the same, one third of the orignal pressure.

When you dyno your 'race engine' with 264* exhaust cams, we will all see what you mean.:)

Harvey.

[TomsSVX]

May be Tom would like to answer this first bit,:)but I thought it was more a case of cams and ignition advance.

Mike you are obviously reading the wrong magazines. You must have learned at school that "pressure acts in all directions equally". The sound wave meeting a junction of three pipes, will divide equally, to enter each pipe, with the same, one third of the orignal pressure.

When you dyno your 'race engine' with 264* exhaust cams, we will all see what you mean.:)

Harvey.

Yes Harvey, the collectors I used were not the ones I would have like to use. I did buy them for roughly $75 a piece. The collectors I really would have liked to have were slip on formed collectors that cost roughly $275 a pop. Now considering the cost, which avenue would you have chosen?

Now along the lines of 1/4 times, I always take my times with a grain of salt. A .1 or .2 increase or decreasein ET w/ 2-3mph differences in trap speeds are more than likely driver error. But .5sec in ET and 6-7mph in trap speeds is not a mistake.

Tom

[oab_au]

Harvey,

I did get A's in University Physics at the University of Miami back when i took the courses; however, what little I remember of what we studied about the effects of waves on gases only reminds me that I don't know enough to presume any such thing. The best I can do is hope the sources I have read give correct rule of thumbs and you are the only source I have read that claims that. Please feel free to provide the literature to explain otherwise to me.

If I remember correctly that .5 second improvement in et from putting on his headers was the low of a series of runs Tom did with the high being a full second improvement over before the headers. I feel confident the improvement he thinks he saw with his headers is genuine. Maybe some other design would give him even better improvment but I haven't seen any other source supporting your design suggestion other than you. His design is fairly close to what I would come up with using most online calculators or by going off the rules of thumb on wikipedia.

Maybe you are right and I'm certainly open to being convinced. Saying the same thing again like it is a given won't do it though. How about sending me a copy of what you are reading?

OK Mike, I suppose I have been pushing this barrow for a while. I first wrote about the SVX exhaust design about 10 years ago on the Yahoo forum.
As you well know I have often been the lone voice for the technology.:)

As for the technical information that I use. I haven’t kept that a secret, the two main textbooks that I use are, THE HIGH-SPEED INTERNAL COMBUSTION ENGINE, by Harry Ricardo, for engine operating principals, and THE SCIENTIFIC DESIGN OF EXHAUST AND INLET SYSTEMS, by Philip H Smith, based on the experiments of John Morrison. Smith wrote this book, but Morrison did all the research work.

These will provide the basic technical facts for building on. The rest of my knowledge was gained from experiments carried out on Bike engines both 2 and 4 stroke. These are a lot cheaper to develop than a 6 or 8 cylinder engine; after all, it is the cylinder that you are trying to increase the Volumetric Efficiency on. Now days I use an Engine Simulation program to carry out experimental changes on, to save all the expensive, and time consuming work.:cool:

From what I can see, most of the ‘on line calculators’ are based on work for the domestic V8. Using long primary pipes (branches) to separate the cylinders exhaust gas from entering other cylinders. The SVX does not have this problem, so the exhaust system design can be directed to filling the cylinder, using the sonic wave technology.

Harvey.

[longassname]

I don't intend to run out and make any book purchases. If you could post the exerpt/exerpts that explains/explain that the negative pressure generated from the sound wave entering the expansion chamber is evenly split between the primary tubes we could make some progress though. The citation without the referenced material isn't very illuminating.

Actually the material I've read online along with the calculators says that they are calculating the length of the primary tubes and the length of the collectors so that the negative pressure generated from the soundwave leaving the primary tube returns to and continues through the ideal timespan at the same cylinder that it came out of and they ignor the other cylinders because the % of the negative pressure that enters the other primary tubes is negligable.

[oab_au]

I don't intend to run out and make any book purchases. If you could post the exerpt/exerpts that explains/explain that the negative pressure generated from the sound wave entering the expansion chamber is evenly split between the primary tubes we could make some progress though. The citation without the referenced material isn't very illuminating.

Actually the material I've read online along with the calculators says that they are calculating the length of the primary tubes and the length of the collectors so that the negative pressure generated from the soundwave leaving the primary tube returns to and continues through the ideal timespan at the same cylinder that it came out of and they ignor the other cylinders because the % of the negative pressure that enters the other primary tubes is negligable.

OK Mike, if you are not interested in learning, then I can't help you. I'll leave you with the 'bent iron technology'.

Cheers Harvey.

[longassname]

Who said I'm not interested in learning? Can't you post the passage? You're saying something contrary to what I've read--if that's what the books you have say then yes please post it so I and we all can learn.


OK Mike, if you are not interested in learning, then I can't help you. I'll leave you with the 'bent iron technology'.

Cheers Harvey.

[sicksubie]

I love these arguments between people who have done things and improved performance numbers on the SVX and people who havent. Sure there are theories out there about all kinds of internal combustion engines and the various processes involved. Until there are proven "hardware" items based on both theories, I will go with the people producing results...