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IP control collar doubt
by
gigaz2
on 18 Aug, 2008 16:49
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I was studying how VE pumps work and just realized something, but not sure so here it goes:
with a 2mm lift cam (1.6TD), the control collar only needs to move 1mm to be able to control 0 to 100% (spill port uncovered to spill port fully covered)
with all being equal, with a 3mm lift cam, we would need 1.5mm travel in order to achieve the same result right?
other doubt.. are the 9mm(1.6 IDI) and 10mm(1Z TDI) spill ports equal?
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#1
by
jimfoo
on 18 Aug, 2008 17:32
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The port on my AAZ 9mm head and my 10mm TDI(prothe)head are different. The AAZ one had a thin slit for the top half while the 10mm one was open the same width the whole way up.
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#2
by
gigaz2
on 18 Aug, 2008 17:34
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ok, I went to look at the pumps I have sitting in the shelve, the 1.6 and 1.9 IDI spill ports are different.
the 1.9 one seems "fatter" so the control collar travel should be the same or less than the 1.6 one
anybody has a pic showing the spill port on a 10mm tdi plunger? (mine is in the car right now
)
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#3
by
gigaz2
on 20 Aug, 2008 17:51
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I had another go at looking at the spill ports:
1.6 "front"
1.6 "back"
1.9 "front"
1.9 "back"
and unrelated, but the difference on the springs between 1.6 and 1.9 (both 9mm)
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#4
by
gigaz2
on 20 Aug, 2008 18:48
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yes, that explains the different springs, when possible I'll measure them by applying weight and measuring difference in size.
also noticed the shim on the 1.6 ones.
but that pic is unrelated, I'm trying to figure out the different spill port configurations and their relationship to the control collar movement.
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#5
by
gigaz2
on 21 Aug, 2008 01:56
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good idea, its basically the same thing, but I won't need to chase down specifi weights, nor balance them on a tiny spring while measuring length.
on the spill ports: somebody should have a 10mm tdi plunger laying around.. taking a pic won't take long
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#6
by
gigaz2
on 23 Aug, 2008 10:09
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thanks a lot!
that left me puzzled, I expected something different, a longer spill port for instance.
instead it only seems that the port sits closer to the ridge then the other two.
I got an SB pump yesterday, going to put it in the car for the time being, so I end up with a working car and 3 pumps to compare/play
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#7
by
Tintin
on 23 Aug, 2008 21:41
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Never forget that diesel injection is not only the amount of fuel injected, there is missing parameter, it's the injection time.
It's not how far the spill port is covered, but for how long time is covered.
Even at idle the spill port is fully covered........
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#8
by
gigaz2
on 24 Aug, 2008 02:25
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yes, I understand that its not quantity we are adjusting with the VE pump, its duration really.
we extend duration of injection to increase quantity in the VE.
In the Rotodiesel system, the duration isn't increased, there is a valve before the plunger that throttles the ammount of fuel there.