> =20 > Hi Marv, To be honest I have not even thought about DIE with a Turbo, so am = hesitant to make any pronouncements. But, hey! my opinion is worth what = you pay for it {:>). You will pay me by the word won't you? First, the DIE phenomena is unlike the "Organ Pipe" or "Helmhotz = Resonance" type theories, because it IS NOT DUE TO A RESONANCE = Phenomenon or the physics associate with it. All of these theories are = based on acoustical waves that result from a vibration (that is - a = repeating wave with a positive and negative pressure region associated = with the energy wave). There are some similarities like - they all are = based on the speed of sound of a wave of energy. However, the DIE = effect is based on finite-amplitude Waves which - while they are = disturbances of the air - have little else in common with the normal = acoustical wave (we normally thing of as "sound" ) in a pipe. A FAW for = one thing only has either a positive or a negative pressure zone = associate with it - not both a the typical "sound wave" does. Also, it = is tens of thousands of time more powerful than even a 120db sound wave. = I am a novice in my understanding of FAW, but that much I understand = (and perhaps a bit more {:>)) The DIE effect is a result of some careful timing considerations and the = very powerful finite-amplitude waves (FAW) generated (in any internal = combustion engine - but perhaps even more intense in the rotary). The = wave travels at the speed of sound (1100-1350 ft/sec depending on = manifold air temp) when it slams into the relatively stationary air = that has accumulated in the chamber by the normal inflow of air, the = kinetic energy of the wave is transformed into increased manifold = pressure right at the intake port. Normally, after a piston/rotor has = reached Bottom Dead Center and started back on the compression stroke, = the intake is still open - or perhaps just starting to close. The = increasing pressure inside the chamber caused by the decreasing volume = as the piston/rotor comes in on the compression stroke forces a = considerable amount (20%? - it depends on a great number of variables) = back out the closing, but still open port. This is called "reversion" = as I know you and many are aware of. However, the increased pressure = inside the chamber pushing out this air/fuel mixture is sudden slammed = by this high speed energy FAW wave that transforms its energy into = considerably more pressure in the intake near the port. This higher = pressure in the intake right next to the port then overcomes the = reversion pressure and probably even stuffs a bit more air/fuel mixture = into the chamber just before the port closes and goes on to the power = stroke. Now having said all of that, it is my estimate that the process will = continue even with a turbocharger - I can't see any reason why it = shouldn't PROVIDED the intakes of the two rotors are interconnected to = provide a path. But, In most turbo installations that is not = necessarily the case, IF NOT - NO DIE. But, if the interconnected path = does exist in the turbo installation, the effect probably still exists. = In fact, in the NA 13B the most powerful wave is created when the intake = opens and the residue exhaust gas (still left from the exhaust gas not = expelled) burst from the opening intake port. With a turbo charger, the = exhaust back pressure is higher than an NA engine. It seems reasonable = to speculate that even more exhaust gas may be retained by the rotor = cycle as it come to opening the intake port. If so it might follow that = the wave that exits the opening port just might be even more powerful, = but would follow the same physics. The air temp in the intake manifold = will likely be higher than with an NA due to the heat caused by the = turbo compressor, so that means the wave would travel a bit faster. So = the exact length that is right for an NA engine might be off a bit for a = turbo engine. However, that would just mean that the effect would = happen at a (slightly?) different rpm than for the NA engine.=20 I am, however, not certain that all of the design needs for turbo and = an DIE effect are compatible. For instance, what happens to the = structure of this FAW wave when it hits the intercooler?? Bet it doesn't = stay the same {:>). But remember this THE BASIC PERFORMANCE OF YOUR INDUCTION SYSTEM IS = STILL THE MOST IMPORTANT FACTOR. If it is not up to snuff, then DIE = effect does have much to enhance {:>). I know there are folks getting ready to cut tubing and would like to = know all the answers now. But to be truthfully, it really needs to be = looked at on an individual basis because of the different variables = involved. Lets see if I can offer any suggestions.=20 1. IF there is not a contiguous runner path from the intake port of one = rotor to the intake port of the second rotor in your intake design - = then forget DIE and press on. This might well be the case in a = turbocharger set up or even with a NA set up with Webber throttle body. = There must be a path for the wave to get from one intake port to the = intake of the other rotor=20 2. For the DIE effect there is a correlation between DIE RPM point and = runner length. BUT the length can be very heavily influence by other = variables. Selection of the DIE RPM point you want sort of sets the = basic environment that is fine tuned by other variables. So what rpm = point would you pick. Well, if you wanted the additional enhancement at = cruise, you would of course pick an higher rpm than if you wanted the = enhancement for take off and climb performance. The DIE effect is to primarily enhance torque, but as you know HP and = torque are related.=20 Without stepping off this tree limb, I would say don't cut your tubing = too short. You can always shorten it later. 3. Now this IS IMPORTANT, the actually tube length you might use is = only PART of the port to throttle body distance. Since I don't know = what configuration your manifold may have I don't know how much of your = port- port length will consist of tubing as compared to perhaps using = part of the stock lower manifold or creating your own manifold casting = etc. Just for your information the intake ports are approx 2.5" inside = block so you would need (at a minimum) subtract 2 (for each port) x 2.5" = =3D 5" from the port-port length because that is inside the block and = you couldn't change it if you wanted to {:>). Then you have to consider = the length inside your plenum (remember you have to connect the runners = from each port) that would have to be subtracted from the remaining = distance, then if you are using say the lower stock manifold or a after = market casting as part of your system, then the total path length it = provides (remember once for each port) would need to be considered = BEFORE you could decide on the tube runner length - EVEN if you already = knew your DIE rpm and the total port-port distant required. 4. So there, now you see why it somewhat difficult for me to give any = suggestion as to how long you should order your tubing. If you have a = stock NA (6 port) engine block you intend to use I would say keep the = individual runner length (port to throttle body which is 1/2 the = port-port distance) at least 30 inches (for the moment) that is a port = to port length of 60 inches. The DIE length for aircraft use will = undoubtedly be shorter and so your tube length (what ever part of the = total path length (60") that is) should not be any less than it takes to = ensure the port-TB length (1/2 Port-Port length) is 30". What ever you = use as a lower manifold (if not tubing) then will shorten the amount of = tubing you need, but if you created everything from block inlet to block = inlet out of tubing then I would say that you would be safe ordering at = least 30" of tubing for each 1/2 of the runner or the block to throttle = body distance for a total of 60". You would probably need to do this = both for the primary and secondary paths This will leave you a tubing = length that will probably still be excessive once you fine tune it (at = least you hope so) by cutting some of it down, but easier than trying to = add length. 4b. Another consideration is whether you are going to maintain the = primary and secondary runners separate. My analysis shows there are = some cases where this is probably wise to do and other cases where it = probably does not matter. Did I tell you I've spent months on working = this DIE analysis problem, while it is straight forward and is not = complex, its not necessarily simple due to the number of variables = involved. 5. If you are using a stock turbo block without the turbo the tube = length can be a bit shorter, but how much shorter just depends. Follow = same advice as for stock NA block. 6. If you have a none- stock block then it just becomes too difficult = to generalize without the specifics. Best answer is to wait for the presentation - because you just might = decide that what I have to show you is horse hocky {:>) or the bovine = equivalent {:>) Best Regards Ed Anderson eanderson@carolina.rr.com ------=_NextPart_000_0064_01C37DED.02FF1AE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

----- Original Message -----

From: "Marvin Kaye" <marv@lancaironline.net>

To: "Rotary motors in aircraft" = <flyrotary@lancaironline.net>

Sent: Thursday, September 18, 2003 = 12:39=20 AM

Subject: [FlyRotary] Re: Intake=20 questions

> >>> Also it turns = out there is=20 no one magic runner length for the DIE effect and
> the length = for this=20 effect depends not only on the rpm point you select for
> = this=20 effect to occur but also on your particular engine specifications - =
>=20 there that sounds mysterious enough, I think.<<<
> =
>=20
> Lots of really great information showing up as a result of this = thread... this
> has to be one of the longest running discussions = we've=20 enjoyed here. But
> that's not what I wanted to = say....
>=20
> Considering how the DIE works (could the Dynamic Intake Effect = possibly=20 have
> resulted in a worse acronym?) I'm really anxious to see = the=20 results with the
> turbo. It seems to me that in a NA = engine the=20 DIE is functioning in a low
> pressure system (at least until you = get to=20 WOT and the MAP equals the baro
> setting). I'm wondering = if the=20 positive pressure provided by the turbo's
> compressor is going = to change=20 how it works. If we were to liken the intake
> system to an = organ=20 pipe, as you lengthen the pipe its resonant frequency goes
> down = (and is=20 the same reason you need to tune the runner length for maximum
> = DIE at a=20 given RPM). At a fixed length that pipe will always sound the same =
> note when a volume of air causes the column of air in the pipe = to=20 resonate.
> If you increase the pressure, the pitch = (frequency) of=20 the note remains the
> same but the volume increases. Given = this=20 phenomenon, I wonder if the intake
> tubes set to the same length = as=20 those that are providing an actual DIE in a NA
> application (at = a given=20 RPM, of course) will show an increase in DIE with the
> positive = turbo=20 pressure, or if the runners will need to be shortened
> = (lengthened???)=20 to account for the DIE wave being slowed by the higher
> pressure = intake=20 charge opposing it? OR..., it could be that the DIE is
> = negligible=20 in the pressurized turboed system and the best results are to be =
> gained=20 by the shortest runner length possible to minimize friction losses on =
>=20 the incoming air stream. Lots to think about.........
> =
>=20 <Marv>
> = =20
> Hi Marv,

To be honest I have = not even=20 thought about DIE with a Turbo, so am hesitant to make any = pronouncements. =20 But, hey! my opinion is worth what you pay for it {:>). You will = pay me=20 by the word won't you?

First, the DIE phenomena is = unlike the "Organ=20 Pipe" or "Helmhotz Resonance" type theories, because it IS NOT DUE TO A=20 RESONANCE Phenomenon or the physics associate with it. All of these = theories are=20 based on acoustical waves that result from a vibration (that is - a = repeating=20 wave with a positive and negative pressure region associated with = the=20 energy wave). There are some similarities like - they all are = based on the=20 speed of sound of a wave of energy. However, the DIE effect = is based=20 on finite-amplitude Waves which - while they are disturbances of = the air -=20 have little else in common with the normal acoustical wave (we normally = thing of=20 as "sound" ) in a pipe. A FAW for one thing only has either a = positive or=20 a negative pressure zone associate with it - not both a the typical = "sound wave"=20 does. Also, it is tens of thousands of time more powerful than even = a 120db=20 sound wave. I am a novice in my understanding of FAW, but that much I = understand=20 (and perhaps a bit more {:>))

The DIE effect is a result of some = careful timing=20 considerations and the very powerful finite-amplitude waves (FAW) = generated (in=20 any internal combustion engine - but perhaps even more intense in the=20 rotary). The wave travels at the speed of sound (1100-1350 ft/sec=20 depending on manifold air temp) when it slams into the relatively=20 stationary air that has accumulated in the chamber by the normal = inflow of=20 air, the kinetic energy of the wave is transformed into increased = manifold=20 pressure right at the intake port. Normally, after a piston/rotor = has=20 reached Bottom Dead Center and started back on the compression stroke, = the=20 intake is still open - or perhaps just starting to close. = The=20 increasing pressure inside the chamber caused by the decreasing volume = as the=20 piston/rotor comes in on the compression stroke forces a considerable = amount=20 (20%? - it depends on a great number of variables) back out the closing, = but=20 still open port. This is called "reversion" as I know you and many = are=20 aware of. However, the increased pressure inside the chamber = pushing out=20 this air/fuel mixture is sudden slammed by this high speed energy = FAW wave=20 that transforms its energy into considerably more pressure in the intake = near=20 the port. This higher pressure in the intake right next to the = port then=20 overcomes the reversion pressure and probably even stuffs a bit more = air/fuel=20 mixture into the chamber just before the port closes and goes on to the = power=20 stroke.

Now having said all of that, it is my = estimate that=20 the process will continue even with a turbocharger - I can't see any = reason why=20 it shouldn't PROVIDED the intakes of the two = rotors are=20 interconnected to provide a path. But, In most turbo = installations that is not necessarily the case, IF = NOT=20 - NO DIE. But, if the interconnected path does exist in = the turbo=20 installation, the effect probably still exists. In fact, in the NA = 13B the=20 most powerful wave is created when the intake opens and the residue = exhaust gas=20 (still left from the exhaust gas not expelled) burst from the opening = intake=20 port. With a turbo charger, the exhaust back pressure is higher = than an NA=20 engine. It seems reasonable to speculate that even more exhaust = gas may be=20 retained by the rotor cycle as it come to opening the intake port. = If so=20 it might follow that the wave that exits the opening port just might be = even=20 more powerful, but would follow the same physics. The air temp in = the=20 intake manifold will likely be higher than with an NA due to the heat = caused by=20 the turbo compressor, so that means the wave would travel a bit = faster. So=20 the exact length that is right for an NA engine might be off a bit for a = turbo=20 engine. However, that would just mean that the effect would happen = at a=20 (slightly?) different rpm than for the NA engine.

I am, however, not = certain that all=20 of the design needs for turbo and an DIE effect are = compatible. =20 For instance, what happens to the structure of this FAW wave when it = hits the=20 intercooler?? Bet it doesn't stay the same {:>).

But remember this THE BASIC = PERFORMANCE OF=20 YOUR INDUCTION SYSTEM IS STILL THE MOST IMPORTANT FACTOR. If it is = not up=20 to snuff, then DIE effect does have much to enhance = {:>).

I know there are folks getting ready to = cut tubing=20 and would like to know all the answers now. But to be = truthfully, it=20 really needs to be looked at on an individual basis because of the = different=20 variables involved. Lets see if I can offer any=20 suggestions.

1. IF there is not a contiguous = runner path=20 from the intake port of one rotor to the intake port of the second rotor = in your=20 intake design - then forget DIE and press on. This might well be = the case=20 in a turbocharger set up or even with a NA set up with Webber throttle=20 body. There must be a path for the wave to get from one intake = port to the=20 intake of the other rotor

2. For the DIE effect there is a = correlation=20 between DIE RPM point and runner length. BUT the length can be = very=20 heavily influence by other variables. Selection of the DIE RPM = point you=20 want sort of sets the basic environment that is fine tuned by other=20 variables. So what rpm point would you pick. Well, if you = wanted the=20 additional enhancement at cruise, you would of course pick an higher rpm = than if=20 you wanted the enhancement for take off and climb = performance.

The DIE effect is to primarily enhance = torque, but=20 as you know HP and torque are related.

Without stepping off this=20 tree limb, I would say don't cut your tubing too short. You = can=20 always shorten it later.

3. Now this IS = IMPORTANT,=20 the actually tube length you might use is only PART of the port to = throttle body=20 distance. Since I don't know what configuration your manifold may = have I=20 don't know how much of your port- port length will consist of = tubing as compared to perhaps using part of the stock lower = manifold or=20 creating your own manifold casting etc. Just for your information = the=20 intake ports are approx 2.5" inside block so you would need (at a = minimum)=20 subtract 2 (for each port) x 2.5" =3D 5" from the port-port length = because that is=20 inside the block and you couldn't change it if you wanted to = {:>). Then=20 you have to consider the length inside your plenum (remember you have to = connect=20 the runners from each port) that would have to be subtracted from the = remaining=20 distance, then if you are using say the lower stock manifold or a after = market=20 casting as part of your system, then the total path length it provides = (remember=20 once for each port) would need to be considered BEFORE you could decide = on the=20 tube runner length - EVEN if you already knew your DIE rpm and the total = port-port distant required.

4. So there, now you see why it = somewhat=20 difficult for me to give any suggestion as to how long you should order = your=20 tubing. If you have a stock NA (6 port) engine block = you intend=20 to use I would say keep the individual runner length (port to = throttle=20 body which is 1/2 the port-port distance) at least 30 inches (for = the=20 moment) that is a port to port length of 60 inches. The DIE length = for=20 aircraft use will undoubtedly be shorter and so your tube length (what = ever part=20 of the total path length (60") that is) should not be any less than it = takes to=20 ensure the port-TB length (1/2 Port-Port length) is 30". What ever = you use=20 as a lower manifold (if not tubing) then will shorten the amount of = tubing you=20 need, but if you created everything from block inlet to block inlet out = of=20 tubing then I would say that you would be safe ordering at least 30" of = tubing=20 for each 1/2 of the runner or the block to throttle body distance for a = total of=20 60". You would probably need to do this both for the = primary and=20 secondary paths This will leave you a tubing length that will = probably=20 still be excessive once you fine tune it (at least you hope so) by = cutting some=20 of it down, but easier than trying to add length.

4b. Another consideration is = whether you are=20 going to maintain the primary and secondary runners separate. My = analysis=20 shows there are some cases where this is probably wise to do and other = cases=20 where it probably does not matter. Did I tell you I've spent = months on=20 working this DIE analysis problem, while it is straight forward and is = not=20 complex, its not necessarily simple due to the number of variables=20 involved.

5. If you are using a stock turbo = block=20 without the turbo the tube length can be a bit shorter, but how much = shorter=20 just depends. Follow same advice as for stock NA = block.

6. If you have a none- stock = block then it=20 just becomes too difficult to generalize without the = specifics.

Best answer is to wait for the = presentation -=20 because you just might decide that what I have to show you is horse = hocky=20 {:>) or the bovine equivalent {:>)

Best Regards

Ed Anderson

eanderson@carolina.rr.com

------=_NextPart_000_0064_01C37DED.02FF1AE0--