In the photos you see a clear top
on the combo Airnoids.
This is a dual purpose thing that
keeps dirt out of the workings
and allows you to monitor
plunger wear, if any.
More on plunger wear later.
This photo shows the T bar
and a space between it and
the lock nut.

This is similar to your valve to rocker arm lash and is set at .020. The
.020 ensures that the plunger is seated properly. If the plunger wears in
the lash will decrease and you simply reset the clearance and race on.
All Text and images on this website are copyrighted by David Koehler 2000 and beyond
All sales are final. Items and services provided by Koehler Injection are intended for off road use only.
No responsibility whatsoever will be accepted by Koehler Injection for any damage, injury or loss resulting from their use.
Nitrous Master.
Postal Money Order
Combo-flo adjustment
A Review of Combo-Flo  Air Operated Solenoids
Pressure Capacity
The nitrous Airnoids are rated at 1250 psi maximum so naturally I tried them
at 1350 psi.

They opened and closed repeatedly with no drama. Granted, there is no
sound reason to be at 1250 psi since the nitrous is in a supercritical phase (a
bad thing) beyond 1060 psi but the Airnoids can handle it as advertised.

The fuel Airnoids are rated at a maximum of 90 psi which is way beyond any
system requirements that I have worked on, seen or heard of so life is good
and they can be used with low or high pressure fuel systems including EFI.
Naturally I ran them at 100 psi. No problems whatsoever, thus proving that
they are correctly rated.
Flow Capacity & Results
Flow capacity is pretty impressive. The nitrous side far exceeds what we
normally use via the electrical solenoids and the fuel side meets and exceeds
what it was intended to replace.
CF400 Silver 2630
CF450 Gold 2970
CF NS500 (monster) 4750
.116 Electric Solenoid 1620
Nitrous
Lbs/hr
Fuel
Lbs/hr
CF400 Silver 602
CF450 Gold 789
CF FS600 (red) 596
CF NS500 (monster) 1127
.157 Electric Solenoid 559
Nitrous Results were obtained at 900 lbs w bottle topped off each test. Fuel
Results were obtained @ 8lbs of pressure with .740 specific gravity test fluid.
Progressive Use
At the moment the Airnoids will not function with a progressive controller.
In the previous article on the Racing Instrumentation PROgressive box I
used a rotating door analogy to show what the flow is doing during the
pulse phase. The flow and corresponding pressure never actually falls
back to zero. The same thing happens here with the co2. While the little
electric Actuator handles the pulsing just fine, the actual flow of co2 does
not have enough time to dump to the atmosphere allowing the plunger
return spring to do its job. The system will pulse 1 to 1 times before it
goes into a float mode so there is not enough pulsing spikes for our
purposes. There may be some hope. A couple of ideas are being tested to
allow the pulsing to be utilized. Stay tuned.
You may create a link to this article.

You may not
copy / paste it to another site without permission.
machine shop engine industrial balancing, fuel injection  flow tesing urbana IL
Urbana IL, USA 
217 531 1770  
M-F  9 - 5 CST
Click to call
Many Photos may be enlarged
by clicking on them.
Postal Money Order
Nitrous Oxide
Cart Total
Combo-Flo 500 plate air operted solenoid
By David Koehler
copyright 11-30-05