[Vwdiesel] ECO -- VW ----( Hagars ECO -- Bunny Bondo )
Val Christian
val at swamps.roc.ny.us
Fri Apr 15 19:32:01 EDT 2005
>
>
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> Rob,
>
> I've been thinking about this & what I would try is a straight runner for each cylinder with a sliding pipe arrangement (like a telescope) to vary length.
> VW uses curved runner to fit in engine compartment & cast for ease of manufacture.
>
>
> Val,
>
> Please expalin about transducer & sweeping. Also, what is Q?
Transducer is something like a speaker which doubles as a
microphone, and can provide an impulse or a continuous wave,
and the response of the "cavity" can then be measured.
All as one sentence. Wow.
Q is the selectivity of the system at a certain frequency.
High Q results in a very narrow, precise frequency. Like
a flute. Low Q is a broader selectivity, with less spectral
restriction.
The ducting will be low Q, but the metal ducting in headers
is likely high Q.
I don't have allot of experience doing this stuff with engines.
But I have done allot of acoustics and wave propagation work.
So I guess you could say I know something about some of the
theory, but less about the practice.
> Yup, my 91 N/A is a Jetta (Gina). I find power to be adequate. LOL I can pretty much maintain 70 mph except on steep grades, but never need to gear down. Top speed amazes me though. Over 100 mph with some left before I shut her down. Hard to beleive from such a tiny diesel. I also drive an 81 1.6 N/A pick up, which wouldn't do 80 off a cliff. Big difference in power, not sure why. Both motors are fresh, tested injectors, hillbilly tuned over period of years. Mechanic friend says the hyrdraulic motors had different cam profiles, which would explain alot. I've not measured though.
Interesting, My 91 Jetta is governer limited at about 83 mph.
It'll overshoot on acceleration, but comes back to 82 or 83.
Power down the road, and on interstate grades is absolutely
fine. But acceleration is below agressive-SUV-impatient-driver
thresholds. On 2 lane roads I get allot of impatient people.
Val
>
> Bob
>
>
> **********
>
> Bob,
>
> I have a little, uh, reconstruction, of a detoriorated duct from the
> inlet to the aircleaner box. When that's done, I'll have dimensional
> measurements, and if I get carried away, I can slap a transducer on
> the inlet and sweep it, to see if the measurement matches the
> dimensional predictions.
>
> Inlet tuning is great for something like a generator, which is run at
> a constant RPM. If one wants a wide RPM range benefit, then it's
> necessary to tune the cavity for a lower Q, which means less
> "efficiency" but over a broader range.
>
> Now if we could tune the cavity with a variable displacement device,
> and adjust timing of the cam and pump parametrically, and real-time,
> then we could probably beat Hagar's Bunny.
>
> On your 91 NA, which is what I've driven for years, how do you find
> the total power capability? Mine is a Jetta, and all my previous diesels
> were Rabbits. They had plenty of excess power. The Jetta, doesn't
> live up to the first part of it's name. At cruise, it's OK, except
> when in mountainous territory, it's kinda like flying a glider. That
> is, it's an exercise in kinetic and potential energy management.
> That's not a problem by my way of thinking, except that there are allot
> of thirsty horse SUVs which would like to run me over, just to get ahead.
> The TDI doesn't have that problem, and with similar mileage. So I
> suppose that's an improvement. But the complexity is higher, and when
> the beast gets older, that's a headache.
>
> Consider the relative complexity of adapting a TDI to a stationary
> genset, vs. a NA. In the end, onceseveral problems get solved, the
> TDI might indeed be a better powerplant for that application.
> For example, my guess is that the cruise computer, tweaked, would be
> adequate for genset frequency regulation. But getting there could be
> a problem.
>
> A turbo will cut the noise, and that's real attractive.
>
> As for reliability, in the 80's I had personal experience with a handful
> of turbo'd aircraft engines. Yes, the parameters are different. For
> example, they are regularily run at 100% power (takeoff), and then spend
> the bulk of their life at 65 to 75% power. And due to liability concerns
> (read liability insurance) and certification costs, replacement parts are
> killers. Pre-sticker shocked on replacement turbos, I bought a car a
> couple of years earlier than I really needed to, just to avoid the ECO.
> Additionally, while I don't recall anyone on this group bashing the ECO,
> I do remember some bad press back when it was introduced.
>
> One final turbo observation...I notice that even the ground maintenance
> diesel powerplants are getting turbos these days. 25 and 35 hp engines.
> Small, and from what I am told by the friendly sales folks, the
> early reports are 4000 hours plus on turbos and engines. I have a
> Ford 1510 25 hp class tractor, which is a 3 cyl NA, and reports from a
> nearby city are that one of the landscape outfits there had 8000+ hours
> on three tractors with no major engine problems. When I last talked
> with them, the other parts of the tractors were starting to fail.
> (I can identify with that, because I have a transmission differential
> lock problem which will need attention. I baby the thing.)
>
> Back to radiometrics, and paying for the next car...
>
> Val
>
>
>
>
>
> >
> >
> >
> > True, wave tuning is to a certain frequency, with diminished effects on either
> side. A turbo eliminates wave tuning completely. I believe what VW tried to do
> was get some torque higher up in RPM range by use of tuned runners. I currently
> am driving 91 N/A, and am sometimes amazed at the power available above 3k RPM.
> > I am very curious as to the results of your calculations when you get to it.
> Please keep us informed.
> > For whatever it is worth to you, I shun turbos for the same reasons as you,
> and am very happy getting 49MPG US at 70 - 75 MPH. IMO you called that one right
> on.
> >
> > Bob
> >
> > ******
> >
> > The problem is that the tuning is limited to a certain frequency, which
> > means a certain RPM. In the case of my 91 NA, I believe that the
> > tuned system is for about 50 MPH. I haven't measured and done the
> calculations
> > yet. But after the rebuild, I will. Because I want to quiet the system
> > for operation at 70 to 75 MPH, which is more the norm on the highway
> > at commute time.
> >
> > Putting a turbo inline can simplistically be considered the introduction
> > of a DC injection point in a tuned circuit, which changes the impedance
> > of that circuit.
> >
> > Of course, its possible to put multiple resonances into a system.
> >
> > "Yep, 78 miles to the gallon in this puppy at 48 MPH, and 73 at 63 MPH.
> > At 55 MPH, it's down to 30 MPG."
> >
> > In 91, I bought one of the last NA diesels VW sold, because I didn't
> > want the added complexity of a turbo, and the attendant reduction in
> > reliability. I called that one wrong.
> >
> > -Val
> > _______________________________________________
>
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> <HTML><BODY><DIV style='font-family: "Verdana"; font-size: 10pt;'><DIV>Rob,</DIV>
> <DIV> </DIV>
> <DIV>I've been thinking about this & what I would try is a straight runner for each cylinder with a sliding pipe arrangement (like a telescope) to vary length. </DIV>
> <DIV>VW uses curved runner to fit in engine compartment & cast for ease of manufacture. </DIV>
> <DIV> </DIV>
> <DIV> </DIV>
> <DIV>Val,</DIV>
> <DIV> </DIV>
> <DIV>Please expalin about transducer & sweeping. Also, what is Q?</DIV>
> <DIV>Yup, my 91 N/A is a Jetta (Gina). I find power to be adequate. LOL I can pretty much maintain 70 mph except on steep grades, but never need to gear down. Top speed amazes me though. Over 100 mph with some left before I shut her down. Hard to beleive from such a tiny diesel. I also drive an 81 1.6 N/A pick up, which wouldn't do 80 off a cliff. Big difference in power, not sure why. Both motors are fresh, tested injectors, hillbilly tuned over period of years. Mechanic friend says the hyrdraulic motors had different cam profiles, which would explain alot. I've not measured though. </DIV>
> <DIV> </DIV>
> <DIV>Bob</DIV>
> <DIV> </DIV>
> <DIV> </DIV>
> <DIV>**********</DIV>
> <DIV> </DIV>
> <DIV>Bob,<BR><BR>I have a little, uh, reconstruction, of a detoriorated duct f
rom the<BR>inlet to the aircleaner box. When that's done, I'll have dimens
ional<BR>measurements, and if I get carried away, I can slap a transducer on <BR
>the inlet and sweep it, to see if the measurement matches the <BR>dimensional p
redictions.<BR><BR>Inlet tuning is great for something like a generator, which i
s run at<BR>a constant RPM. If one wants a wide RPM range benefit, then it
's <BR>necessary to tune the cavity for a lower Q, which means less <BR>"efficie
ncy" but over a broader range. <BR><BR>Now if we could tune the cavity wit
h a variable displacement device,<BR>and adjust timing of the cam and pump param
etrically, and real-time,<BR>then we could probably beat Hagar's Bunny.<BR><BR>O
n your 91 NA, which is what I've driven for years, how do you find <BR>the total
power capability? Mine is a Jetta, and all my previous diesels<BR>were Ra
bbits. They had plenty of excess power. The Jetta, doesn't<BR>live u
p to the first part of it's name. At cruise, it's OK, except<BR>when in mo
untainous territory, it's kinda like flying a glider. That<BR>is, it's an
exercise in kinetic and potential energy management.<BR>That's not a problem by
my way of thinking, except that there are allot <BR>of thirsty horse SUVs which
would like to run me over, just to get ahead.<BR>The TDI doesn't have that probl
em, and with similar mileage. So I <BR>suppose that's an improvement. 
; But the complexity is higher, and when <BR>the beast gets older, that's a head
ache.<BR><BR>Consider the relative complexity of adapting a TDI to a stationary
<BR>genset, vs. a NA. In the end, onceseveral problems get solved, the <BR
>TDI might indeed be a better powerplant for that application.<BR>For example, m
y guess is that the cruise computer, tweaked, would be<BR>adequate for genset fr
equency regulation. But getting there could be<BR>a problem.<BR><BR>A turb
o will cut the noise, and that's real attractive.<BR><BR>As for reliability, in
the 80's I had personal experience with a handful <BR>of turbo'd aircraft engine
s. Yes, the parameters are different. For<BR>example, they are regul
arily run at 100% power (takeoff), and then spend <BR>the bulk of their life at
65 to 75% power. And due to liability concerns <BR>(read liability insuran
ce) and certification costs, replacement parts are<BR>killers. Pre-sticker
shocked on replacement turbos, I bought a car a <BR>couple of years earlier tha
n I really needed to, just to avoid the ECO.<BR>Additionally, while I don't reca
ll anyone on this group bashing the ECO, <BR>I do remember some bad press back w
hen it was introduced.<BR><BR>One final turbo observation...I notice that even t
he ground maintenance<BR>diesel powerplants are getting turbos these days.
25 and 35 hp engines.<BR>Small, and from what I am told by the friendly sales f
olks, the <BR>early reports are 4000 hours plus on turbos and engines. I h
ave a <BR>Ford 1510 25 hp class tractor, which is a 3 cyl NA, and reports from a
<BR>nearby city are that one of the landscape outfits there had 8000+ hours<BR>
on three tractors with no major engine problems. When I last talked<BR>wit
h them, the other parts of the tractors were starting to fail.<BR>(I can identif
y with that, because I have a transmission differential <BR>lock problem which w
ill need attention. I baby the thing.)<BR><BR>Back to radiometrics, and pa
ying for the next car...<BR><BR>Val<BR><BR><BR><BR><BR><BR>> <BR>> <BR>> <BR>> True, wave tuning is to a certain frequency, with diminished effects on either <BR>side. A turbo eliminates wave tuning completely. I believe what VW tried to do <BR>was get some torque higher up in RPM range by use of tuned runners. I currently <BR>am driving 91 N/A, and am sometimes amazed at the power available above 3k RPM. <BR>> I am very curious as to the results of your calculations when you get to it. <BR>Please keep us informed. <BR>> For whatever it is worth to you, I shun turbos for the same reasons as you, <BR>and am very happy getting 49MPG US at 70 - 75 MPH. IMO you called that one right <BR>on.<BR>> <BR>> Bob<BR>> <BR>> ******<BR>> <BR>> The problem is that the tuning is limited to a certain frequency, which<BR>> means a certain RPM. In the case of my 91 NA, I believe that the <BR>> tuned system is for about 50 M
PH. I haven't measured and done the <BR>calculations<BR>> yet. But after the rebuild, I will. Because I want to quiet the system<BR>> for operation at 70 to 75 MPH, which is more the norm on the highway<BR>> at commute time.<BR>> <BR>> Putting a turbo inline can simplistically be considered the introduction<BR>> of a DC injection point in a tuned circuit, which changes the impedance <BR>> of that circuit.<BR>> <BR>> Of course, its possible to put multiple resonances into a system. <BR>> <BR>> "Yep, 78 miles to the gallon in this puppy at 48 MPH, and 73 at 63 MPH.<BR>> At 55 MPH, it's down to 30 MPG."<BR>> <BR>> In 91, I bought one of the last NA diesels VW sold, because I didn't <BR>> want the added complexity of a turbo, and the attendant reduction in <BR>> reliability. I called that one wrong.<BR>> <BR>> -Val<BR>> _______________________________________________<BR></DIV></DIV></BODY></HTML>
>
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