[Vwdiesel] ECO -- VW ----( Hagars ECO -- Bunny Bondo )

slatersfb at aol.com slatersfb at aol.com
Thu Apr 14 11:28:35 EDT 2005

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.

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.


More information about the Vwdiesel mailing list