Caged and Uncaged Governors, a Mystery to most it seems. - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Caged and Uncaged Governors, a Mystery to most it seems. by Giles@PerformanceDiesel on 05 Dec, 2009 07:36
• Hi Guys
  
  Thought i would describe the function and purpose of what most guys are calling "Uncaged" and "Caged" governors.
  the real names for these governors is, uncaged is a Variable speed governor and caged is a Min/Max governor
  the main diference is when you have a variable speed governor the governor spring is always working against the flyweights to
  keep the rpm steady at the throttle position you set with your foot pedal.
  the min/max governor works differently in the fact that it only comes into play to govern your idle when you're not touching the
  pedal and to limit the Max rpm of your motor set by the max travel screw
  if you use a variable speed (uncaged) governor in a car/van then if you have a steady state throttle and you go up a hill the rpm
  will drop due to the load on the engine this will in effect let the flyweights retract therefore increasing the amount of fuel delivered
  by the pump. this will try and increase your rpm back to where your throttle is set. when you go down hill it's the opposite effect
  the flyweights will flyout therefore decreasing the amount of fuel injected. now some might say this sounds really good why not use
  this with all our pumps? well it has the feeling you are not in control of the car/van when driving since the pump is always trying to keep
  the rpm steady.this is a unnatural feeling tomost as the car seems to have a mind of its own.
  this why we use a min/max governor so that we have the control with of the rpm/engine all the time it feels much more natural. so this type of governor only comes into play at idle and max rpm hence the name min/max governor. now sometimes a manufacturerwill add in a 2nd spring or intermediate gov spring as we have in the VW pumps.
  hope this clears things up for everybody
  Giles
• #1 by MJF on 05 Dec, 2009 07:44
• Quote

  ow some might say this sounds really good why not use this with all our pumps? well it has the feeling you are not in control of the car/van when driving since the pump is always trying to keep the rpm steady.this is a unnatural feeling tomost as the car seems to have a mind of its own.

  
  I will kind of disagree with this. My pumps have had uncager governors and I love the pedal feel of it. It´s like cruise control built in your toe.
• #2 by truckinwagen on 05 Dec, 2009 09:39
• most diesels are governed so that it will try to keep a steady RPM.
  
  I have worked on some that will start blowing black smoke at half throttle when a big load is added.
  
  I like it too( never driven a VW with this kind of governor, but a bunch of trucks)
  
  it is different, and will throw you if you expect it to act like a gasser, but after getting used to it, I really like it.
• #3 by blackdogvan on 05 Dec, 2009 09:57
• Can you easily change pumps from caged to uncaged?
• #4 by rabbitman on 05 Dec, 2009 10:14
• I like it how it is, min/max. If I had it uncaged nobody else would be able to drive it, that would be fine with me except that sometimes people have to drive it (bugs me ) and they'd probably not notice the pyro or black smoke and ruin the engine. I hate thinkin' about it.
• #5 by RabbitJockey on 05 Dec, 2009 12:19
• thanks for the info giles
• #6 by MJF on 05 Dec, 2009 12:38
• Quote from: rabbitman on 05 Dec, 2009 10:14

  I like it how it is, min/max. If I had it uncaged nobody else would be able to drive it
  

  
  My uncaged pumps have been super-easy to drive. Muuuuch more driveable than stock pump.
• #7 by vanbcguy on 05 Dec, 2009 12:40
• So if I understand everything correctly:
  
  - Idle spring provides the 'Min' side of things
  - Main spring provides the 'Max' side of things
  - On VW the Intermediate spring provides a limited 'Variable' governor
• #8 by Giles@PerformanceDiesel on 05 Dec, 2009 14:20
• yes bassically you have it.
  most times there are numerous springs for idle and automatic starting fuel duties and one max governor spring for top end.
  the intermediate spring is for partial load governing to give a little bit of fuel increase for hills. if you have felt sometimes your
  vw will increase speed all on it's own with part throttle that's that spring doing it's work
  
  either setup will do the job intended. just depends on what the application is and how you prefer the pump to handle your vehicle.
  
  all big trucks have variable speed governors to assist the driver with loads so that he doesn't have to step on the throttle for every
  little load change.
  cars are much lighter and drivers are used to stepping on the load pedal to go up hills.
  
  Giles
• #9 by 87octane on 06 Dec, 2009 11:15
• Can someone please summarize which factory pumps have caged govs and which factory pumps have uncaged?
• #10 by vanbcguy on 06 Dec, 2009 11:44
• If we're talking about VW, they all have caged governors unless they were intended for industrial applications.
• #11 by Rabbit on Roids on 06 Dec, 2009 11:46
• how bout cummins pumps, do they have open spring governors?
• #12 by truckinwagen on 06 Dec, 2009 12:45
• the cummins pump I have is uncaged
• #13 by RabbitJockey on 06 Dec, 2009 19:20
• yeah i think they're all uncaged, and u can just change out the whole spring for a higher rev limit
• #14 by truckinwagen on 06 Dec, 2009 19:26
• yeah, there are lots of un-caged springs available in the aftermarket for the cummins pumps, although none of them are high enough RPM for our engines(4200RPM is the highest I have been able to find) and they cost like $100.
  
  I would wager that with a fish scale one could go to a hardware store and find a spring that would allow for whatever RPM limit you want for a dollar or two instead.