[Vwdiesel] Propane injection testing - pros and cons - Long

[dieseltdi at earthlink.net]

Well now that the holidays are finally over and things have settled down a
bit,I finally have a chance to update you all on the two propane systems
that I have tested in my Jetta.  First of description of the two systems and
how they performed.

Import Power Online system - This system works similar to a NOx injection
system.  When a Hobbs switch senses boost of 10 lbs or so, it singles a
valve to open letting propane enter the manifold and giving a substantial
boost of power.  I found out by trial and error, that a gas pressure of
around 10 psi was sufficient to give a good boost of power without being
harsh and jerky.  Increase in power is very noticable and I smoked the tires
in 1st and 2nd gear on one occasion.  Main drawback is the 10 psi HObbs
switch.  I think that a lower pressure, say 5-7 lbs would be better for our
TDIs.  I also think that this system could be easily adapted to even a NA
diesel if the flow rates were kept VERY low and a simple throttle activated
switch was used.  In my case I drove the car 1585 miles with this system and
consumed 39 gallons of diesel/biodiesel and about 2 gallons of propane (I
used a small BBQ style tank for the gas supply).  This gives me a MPG of
40.6 mpg.  It should be noted that 700 miles of this amount was highway
driving at constant speed while the rest was in town.

Welsh Technologies Mizer dual fuel system -  This system is VERY different
from the IMport system.  It is engineered to supply a small amount of
propane to the engine at all running speeds.  There is a low flow for idle
and a running curcuit for speed.  The effect of this system is more subtle.
Because the propane is ALWAYS on there is an increase in power across the
board, you just don't realize it until you disconnect the system.  I did
have to make an adaption to get the system to work on the TDI.  It is
designed to have a throttle switch trigger the high speed curcuit on the
controler to increase the flow of propane.  Obviously we have no throttle so
I installed a 2 psi Hobbs switch as the trigger for high speed running.  If
you have a boost gauge on your car, you know that the TDI achieves 2 psi
very rapidly.  The results were for 1797 miles driven I consumed 44.7
gallons of diesel/biodiesel giving me a 40.2 mpg rating.  I firmly believe
that the slight difference in the two systems MPG was due to the large
amount of highway driving on the Import system.  I only had 325 highway
miles on the Welsh system.  I consumed more propane 3-4 gallons or so
because the system is on all of the time.  My current propane supply is a
10.3 gallon RV tank mounted in the trunk.  Unfortunately, I have recently
learned that this is an illegal mounting and I will be replacing the tank
with one specifically designed for the interior space of cars.  BTW the
Welsh system is touted as giving you a tax break during the year that you
install the system.  That is true as long as the sytem is permanently
installed and has an approved fuel tank.  These approved fuel tanks are $300
dollars!

So which system is best?  WEll that depends.  If you are looking for
something that will give you a noticible boost when you need it and is not
present at other times, then the Import system is best.  If however, you are
looking for a system that not only gives more power BUT lowers emissions at
the same time qualifying your car as a clean fuel car And you don't mind a
higher expense, then the Welsh technologies system is for you.  BTW for
those of you with pickups, the Welsh tech system can still qualify you for
the credit if you install an RV style tank in the bed of the pickup.  ONly
cars have to have the special tanks because it is necessary to make sure all
fumes are vented OUTSIDE the engine compartment.

Well there you have it.  The Mizer system will stay installed in my 98 Jetta
and the Other system with be put into my Caddy later on.  If you have any
questions feel free to ask.  hayden

-- Visit my homepage at http://home.earthlink.net/~dieseltdi
    2002 Jetta Wagon GLS TDI, Upsolute Powerbox
    98 Jetta TDI Wetterauer chipset, Dual Fuel Propane system
    98 Jetta TDI, Speed Tuning Chipset (daughter's car)
    87 Scirocco 16v (son's car, gas :^P)
    81 VW Rabbit Pickup (Caddy, Diesel of course, awaiting
    a TD engine transplant)
    And many, many water cooled and aircooled
    VW cars now departed or sold.