VWDiesel.net The IDI, TDI, and mTDI source.
Engine Specific Info and Questions => IDI Engine => Topic started by: darrenjlobb on March 29, 2010, 02:41:47 pm
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Hey guys....
Wanted to ask some questions regarding injectors.....
I currently run stock injectors, but with an 11mm head, and stock delivery valves...
What options are there in terms of upgrading the injectors? will higher flowing injectors, that break at the same pressure increase the ammount of fuel, or make no odds?
I assume raising the break pressure will shorten the injection period, and loose me flow...so i guess this isnt good, but lowering it will just make it longer, and drop the effectiveness of the atomization? so also not good?
Basically....what can i do to try and get some more from it regarding injectors...
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Stock nozzles with stock pressure will be fine. With idi´s, there is no need to fool with injectors.
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DI engines respond to replacement nozzles because they have very small orifice holes in the head after the nozzle. IDI injectors have no such restriction.
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So injectors are not a restriction in the idi engines.
Is the delivery valve a restriction and if so can it be modified to help any?
Ive read a bit on cummins mercedes etc engines and they see gains by altering the little plunger in the DV. Can any of that be applied to our pumps?
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Ant you stole my words :P
Basically, without changing injectors, is there any way to increase the total ammount of fuel that goes in in the same ammount of time WITHOUT changing the 11mm head or camplate..?
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Run 2 pumps ;D
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From what I've seen on here there's no real problem getting more than enough fuel for our little engines out of our stock pumps without modification. Most of the mods you see have to do with holding off fueling till boost comes on, adding more dynamic advance at higher RPMs, and raising the fuel cutoff RPM of the governor.
You can crank the max fuel screw in on just about any of our engines to the point where you're blowing a heavy black smoke screen out the back, but all you're doing at that point is wasting fuel!
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An injection pump is a positive displacement hydraulic device, more fuel can't be injected without increasing the pumping volume.
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From what I've seen on here there's no real problem getting more than enough fuel for our little engines out of our stock pumps without modification. Most of the mods you see have to do with holding off fueling till boost comes on, adding more dynamic advance at higher RPMs, and raising the fuel cutoff RPM of the governor.
You can crank the max fuel screw in on just about any of our engines to the point where you're blowing a heavy black smoke screen out the back, but all you're doing at that point is wasting fuel!
The max fuel screw only elongates when fuel is being injected it doesnt raise the quantity hence the reason we only end up with black smoke as the diesel is being injected past the point where it can be used.
The idea behind the delivery valve mod is that we get more fuel in in the same time.
This is one reason why people upgrade the heads to 10/11/12mm. More fuel in in the same time as a 9mm head.
OM617 can you explain a bit more?
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Any more info lads?
Could our stock delivery valves be a flow restriction?
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people on this side of the board dont really do it. talk to zukgod or burn_your_money or libbybapa, they would have some better answers. and i think one of them would have done the mod by now if it were worth while.
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Any more info lads?
Could our stock delivery valves be a flow restriction?
I believe zukgod did some cummins DL's and they did not help IIRC....probably have to read his old build thread....
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Cheers 53willys il take a look for it.