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Engine Specific Info and Questions => IDI Engine => Topic started by: RabbitJockey on August 22, 2011, 04:58:23 pm
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has anyone else ever stuck a 1.5 yellow dotter on their 1.6? i just stuck one on my car this weekend, it seems to run a bit smoother and it has a more broad power band, like after 3k it really tugs, i haven't increased fueling yet either. just wondering what everyone elses experiences with them were. as far as timing yellow dot pumps are supposed to be set to 1.1-1.2 i believe, and i don't have a gauge so mine is set to where it drove best ;D
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has anyone else ever stuck a 1.5 yellow dotter on their 1.6? i just stuck one on my car this weekend, it seems to run a bit smoother and it has a more broad power band, like after 3k it really tugs, i haven't increased fueling yet either. just wondering what everyone elses experiences with them were. as far as timing yellow dot pumps are supposed to be set to 1.1-1.2 i believe, and i don't have a gauge so mine is set to where it drove best ;D
you set timing based on injectors.. so i would say that its the advanced timing giving you more power..
the YELLOW DOT pumps were coupled with 180bar injectors.. thats why they had such a high timing spec, from the high break pressures.
if you have 135, or 155bar injectors, timed to 1.2mm, then yea, the timing is way advanced, and thats where you gained power from..
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have u ever tried one?
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no, never personally used one, but i know the differences between a yellow dot pump and a normal pump. there almost identical inside.. im not even sure if there are any internal differences..
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i thought they have a very different timing curve and governor. it feels that way, like it pulls better and is more willing to rev up higher. but at the same time, my old pump could have just been worn out, and i time with my ear and my ass so i don't have any real numbers to compare. this pump is def better tho. i bought it off ebay a while ago just for the better 1.5 governor and springs, then my pump started leaking so i figured i'd try this one out.
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The 1.5 did have the fastest advance spring of all the VE vw pump IIRC. I have no clue what it has for a pump head. AND if you think EPA this is probably the farthest from EPA regulations as any pump out there.
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The 1.5 did have the fastest advance spring of all the VE vw pump IIRC. I have no clue what it has for a pump head. AND if you think EPA this is probably the farthest from EPA regulations as any pump out there.
that was another thought i had, it was the highest revving pump with least concern over emissions. nothing i have posted is scientific, i just wondered if anyone else has had similar results in a more accurate manner, as in they actually used a timing gauge and had a known good pump before hand
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hagar had lots of good things to say about the yellow dot pumps. He was always looking for mileage but the fun thing with diesels is often something that gives you more power also results in better mileage... :)
I BELIEVE he said they had more advance, but I'm basing that on distant recollection.
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the housings are the same, but yes, i just checked, the advance spring is indeed softer. the roller cages and all the rest of the advance mechanism is the same tho.. so i would bet that they have more advance sooner.. but the same total timing advance..
they had the same pump top as a regular ol' n/a pump. well every one ive seen did..
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where is this info about 180 bar injectors coming from? i've seen it mentioned before but never anything solid, and i've never seen it in any books or parts supplier listings.
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where is this info about 180 bar injectors coming from? i've seen it mentioned before but never anything solid, and i've never seen it in any books or parts supplier listings.
dont even remember where i read it, but the earliest 1.5s with the yellow dot pumps, should have had 180 bar injectors.. and that was the reason for the high timing spec..
make sense?
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where is this info about 180 bar injectors coming from? i've seen it mentioned before but never anything solid, and i've never seen it in any books or parts supplier listings.
dont even remember where i read it, but the earliest 1.5s with the yellow dot pumps, should have had 180 bar injectors.. and that was the reason for the high timing spec..
make sense?
Although it would make sense at least for a standard pump, I think you simply misread a poorly printed 130 asbeing 180, or at least the PO of the quote you've read ;D
Note it was not ther earliest pumps, but actually only occured during 1980 on some of the 107A pumps.
Several Bosch manuals refer to the yellow dot pump from this period and make the setting 1.1 to 1.2 operational limits with resetting to 1.15
The figures Hagar played with for internal pump pressures are of I believe a 107A pump. If it's a yellow dot I don't know, but the [corrected by me ] graph clearly shows a faster internal pressure to rpm rise than any other figures presented by punters, or indeed by the SAE graph of averages.
This steeper graph is easily obtained by the use of a stiffer spring at the vane pump relief valve, but alas doesn't explain why the pump needed to be advanced more. Advance spring may have been stiffer, but someone [oops who?] just posted otherwise. ;D
All references to injector pressure from the same books refer to 120 to 142 bar ranges for the break pressures. More research needed I think
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the mystery of the yellow dot pump continues... its nice to clear up some of the fact from fiction here
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ive seen more than one place refer to the early 1.5L engines having 180 bar injectors..
im not crazy.. ive read it a few different times..
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ive seen more than one place refer to the early 1.5L engines having 180 bar injectors..
im not crazy.. ive read it a few different times..
Is it as factory or possibly someone's experiment?
IIRC only Google result that I get is here :o
I'll retry ;D
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Mark, Do you have any idea the differences in spring resistance that control the advance? The color scheme is known with the green spring being the softest but does it give the most advance?
I may play around with my pump as I have both a red and silver colored spring. I have a gauge on my IP so I can see if they make any difference in initial pressure and total pressure along with speed at which they get from here to there.
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no, it was a standard for the yellow dot pumps, im pretty sure..
1.15mm would be right on par with a 180bar injector, for a timing spec..
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no, it was a standard for the yellow dot pumps, im pretty sure..
1.15mm would be right on par with a 180bar injector, for a timing spec..
If you take a standard TD pump that normally operates at 155 bar for 1mm, I'd totally agree that 1.15 would get you back on a similar advance.
However that negates the point of a yellow dot being different.
My questions include are all 107 A pumps 'yellow dot' ?
The 107A was what Hagar thought was the holy grail, and internal pressures increased faster than 1.6 pumps. So why would a 107A pump need to be advanced more than a usual pump? ... Unless the advance spring was stiffer, which gents here are saying does not seem to be the case.
This means that the higher revving 1.5 engine would advance quicker and soon run out of advance....Alas I'm not a pump expert, but having the pumps available for testing would answer all the questions, especially coupled with a strobe for dynamic advance readings. Unfortunately, Quantums[Dashers] never had the 107A pump.
( Interestingly, going back the other way ie dropping break pressures dramatically, reduces gauge readings dramatically, {to say 0.5 @125bar} which is where I operate, and makes sense, as at lower pressures, the diesel becomes incompressible [1% @100bar I believe])
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( Interestingly, going back the other way ie dropping break pressures dramatically, reduces gauge readings dramatically, {to say 0.5 @125bar} which is where I operate, and makes sense, as at lower pressures, the diesel becomes incompressible [1% @100bar I believe])
can u explain all this more, i wish i had more time tonight to sit and search old threads, but wasn't there one that discussed more what pumps had what spring? but a stronger spring with a faster increasing internal pressure would make sense, how ever what would the real advantage be, and even then what is the purpose of the initial advanced timing.
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( Interestingly, going back the other way ie dropping break pressures dramatically, reduces gauge readings dramatically, {to say 0.5 @125bar} which is where I operate, and makes sense, as at lower pressures, the diesel becomes incompressible [1% @100bar I believe])
can u explain all this more, i wish i had more time tonight to sit and search old threads, but wasn't there one that discussed more what pumps had what spring? but a stronger spring with a faster increasing internal pressure would make sense, how ever what would the real advantage be, and even then what is the purpose of the initial advanced timing.
If you are referring to the cold start advance, then that is because of the design defect in IDI's where better starting is not achieved at best operating timing. So the temporary 'over advance' is required.
The break pressure thing of the injectors is perhaps clarified by a suggestion that if I made my injectors open at say 90bar, then gauge timing may be as little as 0, or 0.01mm, due to the diesel acting like an incompressible solid, and there being almost no delay to injector opening :o
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( Interestingly, going back the other way ie dropping break pressures dramatically, reduces gauge readings dramatically, {to say 0.5 @125bar} which is where I operate, and makes sense, as at lower pressures, the diesel becomes incompressible [1% @100bar I believe])
can u explain all this more, i wish i had more time tonight to sit and search old threads, but wasn't there one that discussed more what pumps had what spring? but a stronger spring with a faster increasing internal pressure would make sense, how ever what would the real advantage be, and even then what is the purpose of the initial advanced timing.
If you are referring to the cold start advance, then that is because of the design defect in IDI's where better starting is not achieved at best operating timing. So the temporary 'over advance' is required.
The break pressure thing of the injectors is perhaps clarified by a suggestion that if I made my injectors open at say 90bar, then gauge timing may be as little as 0, or 0.01mm, due to the diesel acting like an incompressible solid, and there being almost no delay to injector opening :o
atomization would probably really suck @ 90 bar tho..
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( Interestingly, going back the other way ie dropping break pressures dramatically, reduces gauge readings dramatically, {to say 0.5 @125bar} which is where I operate, and makes sense, as at lower pressures, the diesel becomes incompressible [1% @100bar I believe])
can u explain all this more, i wish i had more time tonight to sit and search old threads, but wasn't there one that discussed more what pumps had what spring? but a stronger spring with a faster increasing internal pressure would make sense, how ever what would the real advantage be, and even then what is the purpose of the initial advanced timing.
If you are referring to the cold start advance, then that is because of the design defect in IDI's where better starting is not achieved at best operating timing. So the temporary 'over advance' is required.
The break pressure thing of the injectors is perhaps clarified by a suggestion that if I made my injectors open at say 90bar, then gauge timing may be as little as 0, or 0.01mm, due to the diesel acting like an incompressible solid, and there being almost no delay to injector opening :o
atomization would probably really suck @ 90 bar tho..
Maybe, but perhaps new nozzles would help. However it must be noted that the larger droplets would penetrate further into the swirl, and are torn apart by the swirl and the flame front. Ricardo certainly thought so and he specialised in this 'Comet V design that we use today. A slower burn may be beneficial.
I'm not saying that 90bar is sufficient, but my best mileage straight after my rering last year had the injectors down to 125 bar
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ok thats interesting, now is it due to the better burn from the larger droplets, or is it because the engine doesn't have to create as high of a pressure to inject the fuel?
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It might be related to the slower burn of the larger swirling drops. Think of burning a piece of paper from the edge a little at a time versus throwing a match on a pile of shredded paper. One consumes faster but the total energy derived is from the same piece of fuel.
When it comes to atomizing in the diesel I think bigger drops burn slower and thus better consumption to power the net effect. You don't get the fast release of energy as the pistion comes to TDC, it doesn't take away from the piston travelling up the stroke but tends to add downward force to the stroke as the burn completes.
I may have this confused with adding propane or some other additive that slows burn down in the form of micro seconds. Correct if I am wrong please.
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the large droplet thing makes sense, not that it has anything to do with a yellow dot pump, but a larger drop would help keep more fuel burned outside of the swirl chamber. the only thing keeping idis from being far superior to a tdi is that there is soooo much heat energy wasted in the swirl chamber and absorbed into the head.
honestly tho i wonder how a modernized idi would compare to a new tdi. like a 2.0 computer controlled 16v idi with a vnt turbo... would it compare haha. its funny cause red rotors was actually working on a project to have a completely electronically controlled idi. which actually would be pretty easy. use a tdi block(for the crank positions sensor) with aaz pistons and rods, aaz head, you would need 1 bmw injector for the injector sensor thats on one of the tdi injectors, and then bolt on the tdi pump, possibly modefied, with all the sensors and crap, and then u'd need a custom burned chip, and woot woot u could compare an aaz to a 96-04 tdi fairly. wonder what ever happened with red rotors project
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where does the burn actually happen? the combustion chamber, or swirl chamber?
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Let's think this out. The intake valve is open and air is coming in through the valve opening. Once the valve is closed the piston rises in the cylinder until just before it reaches the peak of the cycle and squirt goes the injector. Into the air that was moving in the swirl chamber but how far down into that chamber is the end of the injector? A fair piece don't you think. The fuel is under how many PSI? So I doubt much is fired up in the swirl chamber itself. I go for combustion occurs in the cylinder. With just a peek of it entering the chamber.
Just my 2 cents less a penny.
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Head cutaway partway down. http://www.vwdiesel.net/forum/index.php?topic=20109.0
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Is there a yellow dot painted somewhere on said pump? I'd like to know where to look for it if I run across one.
where does the burn actually happen? the combustion chamber, or swirl chamber?
From the cutaway it looks like all the fuel needs to come through the pre-chamber to get to the cylinder. Maybe the bigger droplets don't get torn apart and fully burn until they swirl thru the orifice and into the cyl, resulting in more combustion in the cyl. itself. Just guessing.
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yellow dot pumps have a bunch of yellow paint all over the advance mechanism cover and also their part number ends in 107a
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I'm not saying that 90bar is sufficient, but my best mileage straight after my rering last year had the injectors down to 125 bar
Is this for diesel only?
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I'm not saying that 90bar is sufficient, but my best mileage straight after my rering last year had the injectors down to 125 bar
Is this for diesel only?
gassers dont run that high of a fuel pressure, so, yea, its a diesel only thing.. (1350psi)
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Yep, yellow paint on the front timing cover,.. but not all 107As are yellow dots,.. that just means it's a 1.5 pump.
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I'm not saying that 90bar is sufficient, but my best mileage straight after my rering last year had the injectors down to 125 bar
Is this for diesel only?
gassers dont run that high of a fuel pressure, so, yea, its a diesel only thing.. (1350psi)
Thanks man I know little about disel/gassers, the reason I ask is that in GB is in use VVO(legal up to 2000 lit?) or bio/same oil?
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sorry, i couldnt make sense of that post.. usually i can, but not this one..
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I'm not saying that 90bar is sufficient, but my best mileage straight after my rering last year had the injectors down to 125 bar
Is this for diesel only?
gassers dont run that high of a fuel pressure, so, yea, its a diesel only thing.. (1350psi)
Thanks man I know little about disel/gassers, the reason I ask is that in GB is in use VVO(legal up to 2000 lit?) or bio/same oil?
WVO? 2500 litres per year allowed now in UK.
Generaly need to run higher injector pressures. However, I stick 10 % clean cannola into the tank once a month or so, with no issues.
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Hi Mark!
Do you use 10 % clean cannola because of ULSD,our engine is made for D2.
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Hi Mark!
Do you use 10 % clean cannola because of ULSD,our engine is made for D2.
I do it partly to see how performance is affected, and partly because its 25% cheaper than ULSD when on offer and because it seems to run fine and smell good. ;D
I used to run pure, and run it from the headlight washer tank in the engine compartment, as it conveniently was about 1 ft away from the injection pump.
I used to get similar performance, and mileage.
Maybe I'd get better results running pure now I've rebuilt [reringed] the engine.
Doesn't our Euro diesel contain 5% bio? I have some WVO, but I really need to filter it.
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Hi Mark!
Do you use 10 % clean cannola because of ULSD,our engine is made for D2.
Doesn't our Euro diesel contain 5% bio? I have some WVO, but I really need to filter it.
Yup min 5%,but I don`t like WVO even VO is cheaper,I prefer 2t oil by advice from hagar the great or same alse oil.
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Hi Mark!
Do you use 10 % clean cannola because of ULSD,our engine is made for D2.
Doesn't our Euro diesel contain 5% bio? I have some WVO, but I really need to filter it.
Yup min 5%,but I don`t like WVO even VO is cheaper,I prefer 2t oil by advice from hagar the great or same alse oil.
I'm guessing, but WVO from a vegetarian restaurant would be easier to use, wouldn't it?...
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I'm guessing, but WVO from a vegetarian restaurant would be easier to use, wouldn't it?...
Ha,ha could be but here vegetarian restaurant is rare.
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here is the video of my car doing 0-60, this with stock everything, and my pump timed to 1.13.
http://www.youtube.com/watch?v=dQ23ceaRk-s (http://www.youtube.com/watch?v=dQ23ceaRk-s)
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yellow dot pumps have a bunch of yellow paint all over the advance mechanism cover and also their part number ends in 107a
Who would use yellow paint to mark a pump? I hope not Bosch! Shouldn't it be something more permanent like a part number stamped into the housing?
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yeah it was bosch, a lot of pumps have the yellow stuff on them just on adjustment screws and such