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Engine Specific Info and Questions => IDI Engine => Topic started by: R.O.R-2.0 on October 10, 2011, 10:35:27 am
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ok, so im going to add an LDA to my car finally..
im aware the n/a fuel pump body has a fuel limiter pin. and its in the way to install an LDA..
ive drilled the outer boss enough to push the pin out of the way before, and then put a little epoxy around the base of the pin, and that worked.
but more or less, what im wondering about, is if it would be easier to just stuff my pump with rags or paper towels, and take the dremel to it with an abrasive wheel, and just cut the end off the pin. but i dont want to get a bunch of metal in my pump, and it seems almost impossible to cut the pin in half on the car, and not contaminate the inside of the pump horribly..
im kinda leaning towards just pushing the pin half way out again. i know it worked for me once..
more or less just looking for other peoples ideas, or points of view? i know its been done both ways, but im thinking that the pin is usually CUT when the pump is just an empty housing..
i have a complete pump im working with, still mounted to the engine.
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Push the pin out and cut it on the outside
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you still have to drill, or machine the peening off the outside of the boss it sits in..
and i would still have to epoxy around the outside of the pin. it would be easier to push it out and not cut it. after you push it out of the way, cutting it off is a whole extra, unnecessary step.. i dont care that its sticking out. i just dont like it that i have to put epoxy around the pin to keep it from leaking there.
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I do not know if it's the same on your IP, but I knocked out my pin from the inside, without drilling anything. Then cut it on the outside without it leaking.
But if it is not in the way, there's no reason to cut it.. :)
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EVERYONE that i have tapped out, has leaked, and i have had to seal it over with something.
its done and over with tho, just took the dremel to the outside peening, and tapped the pin out from the inside. and it doesnt leak. i know it doesnt.. because the epoxy is still drying.. time to play with the idle/smoke screw settings again..
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i thought that the LDA interfered with N/A injector lines?
cause, AFAIK.. i just bolted an unmodified LDA to my n/a pump, and it CLEARED the n/a lines by about a 1/4" of the rubber isolator clamps.
ive never checked my timing, but the car starts GOOD, and having extremely retarded timing would be one reason that the LDA clears, correct?
i just thought it was kinda weird.. i got my LDA all bolted on, throttle lever, and springs back on, AND THEN I NOTICE that there are still a pair of TD lines in the rain tray, and there are still a set of n/a lines still hooked up in the car, and clearing the LDA.. it was just one of those ?? ??? moments..
anyways, the pump fired up on the first try, and fairly easy i might add.. i had to thread the smoke screw in about 1.5 turns to bring the idle up close to where i wanted it, then fine tuned the idle with the idle screw, maybe 1/4 of a turn..
took it out for a test drive, and immediately i could tell the difference, less smoke, and more power. i have the fuel screw in probably 1 full turn less than the n/a pump top, and its quicker, and makes more boost sooner in the RPM range. you can really feel the LDA kick up the fuel around 10psi.. and +3psi boost up top. WITH LESS FUEL SCREW!!!
dunno why i waited soo long to add the LDA top to the n/a body.. its not like ive never done it before! guess i just didnt wanna mess with a good thing. but this time, it paid off to do the work.
oh, BTW.. dunno if anyone cares, but i took the governor, out bolt, and fuel screw out of the n/a pump top, and used them in the LDA top. it actually worked out very well. made setting up the pump easy since everything was dead nuts on the last top. had to adjust it very little, and the pump is NOT maxed out, as the n/a pump was turned up as far as it would go without getting some throttle hang. i used the out bolt from the n/a top, primarily because the regulator is calibrated to it, and im not sure how exact the out bolts are, and if there are any variations..
if any of you are still running an n/a pump, and have a spare useable LDA laying around, then do yourself a favor, and install it already. its easier than i remember to knock the limiter pin out of the way, and you might get lucky like me, and not have to install your TD lines. not like its hard or takes very long anyways tho.
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I'm thinking the limiter pin doesn't need removed.
The LDA lever contacts a different point on the accel lever,
so they don't interfere with each other.
The pin basically stops the accel lever from hitting the spinning governor, the LDA should stop it before that.
I haven't tried this yet.
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I'm thinking the limiter pin doesn't need removed.
The LDA lever contacts a different point on the accel lever,
so they don't interfere with each other.
The pin basically stops the accel lever from hitting the spinning governor, the LDA should stop it before that.
I haven't tried this yet.
you wont get the full potential of the LDA with the pin still in the pump..
it limits the fueling capabilities, the pin IN FRONT of this one is the one that keeps everything from hitting the governor..
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Yea, the LDA effectively replaces the function of the fixed pin with a moveable stop. At low boost, the fueling is limited to the same position as the fixed pin, then moves with increasing boost to a point higher up in the fuel map.
Chris
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I don't have numbers from the na pump I was working with recently to build one good pump for my car.
But after looking it over I took a dremel to the inside and grinded that pin off flush and didn't touch it as it seemed solid when I initially tried to smack it.
But another thing is I had to break my pump down completely because that governor assembly was one piece on the na pump! So instead of putting it in its notch and all of that with a turbo top to make it easy I had no choice as the sizes of the bushing were drastically different :(
Also found that the sizes of the fuel screw and some other stuff were not the same like the delivery valves. Since I had it tore down I took the turbo governor stuff and then the plunger, delivery valves and distribution head onto my new pump and left the other bits that could alone.
I am glad I did it I guess, resealed everything and the na pump had good mainshaft bushings. No leaks and the car works, although I don't know how to tune it right and I am not getting the best mileage that I have with the car, only about 42mpg now. The highest I have ever seen my t3 turbo boost it is around 10 when I am on it and now when I stomp on the gas, it leaves a grey colored small smokescreen, when before it had the same power but just let out little puffs of black inbetween shifts or climbing a nasty hill.
Anyway just wanted to post that, because you could get into a big mess like I did one day. Luckily I had 3 pumps laying around :)
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i have LOTS of pumps laying around.. that wouldnt have been a problem.
but uh, the TD pump i tore apart for the LDA, was worn out too, and i re-cased the TD pump into a n/a body with the pin removed..
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you can really feel the LDA kick up the fuel around 10psi.. and +3psi boost up top. WITH LESS FUEL SCREW!!!
More powah, Less Fuel! SCORE!
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you can really feel the LDA kick up the fuel around 10psi.. and +3psi boost up top. WITH LESS FUEL SCREW!!!
More powah, Less Fuel! SCORE!
yea dude, it really helps out.. its like adding +3 turns to the fuel screw when boost comes on..
and i dont hardly make smoke now off boost.. its HARD to make it smoke. you used to be able to just pedal it and get copious clouds at will.. now it just blows a little gray, and then takes off..
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I don't think that pin limits fuel,
It's possible the LDA arm stops the lever's full swing at around the same area.
Having the injection pump increase fuel as boost increases makes it seem like it has more power, because your foot moves less.
I think the NA pump can still be turned up to the point where the RPMs hang when you mash it, that's all the fuel it needs, and that's with the pin.
I'll have to try putting an LDA top on an NA bottom without removing the pin and see what happens.
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The pin does limit fuel on boost. Off boost, the LDA arm sits at the same location as the pin and there's no difference. On boost, the arm moves, allowing additional fueling and effectively extending the available fuel map.
It's been so long since I've been into one of those pumps, but as I recall, through a monkey-motion series of levers,the LDA allows the control collar to slide lower on the plunger and to cover the control port for a greater duration. Fuel screw only changes the position of the fuel map and the LDA extends the fuel map, to the best of my memory.
Chris
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basically, when the pump is off boost, its capable of about the same fueling as the n/a pump.
but when the boost picks up, it moves the LDA stop, and kicks up the fuel. i imagine that the LDA adds the equivalent of 3-4 turns on the fuel screw.. it moves quite a bit, i tested mine with some pressure, and it makes the stop lever move a considerable amount.
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The pin does limit fuel on boost. Off boost, the LDA arm sits at the same location as the pin and there's no difference. On boost, the arm moves, allowing additional fueling and effectively extending the available fuel map.
It's been so long since I've been into one of those pumps, but as I recall, through a monkey-motion series of levers,the LDA allows the control collar to slide lower on the plunger and to cover the control port for a greater duration. Fuel screw only changes the position of the fuel map and the LDA extends the fuel map, to the best of my memory.
Chris
The LDA arm can't sit at the same position as the pin off boost,..
The pin is what the lever hits when it's floored.
That would be like saying the LDA arm holds the lever in the same position off boost as an NA pump does when it's floored.
When you went to put the lid on; the lever would be floored to the pin, instead it sits at rest and the LDA slides in next to it
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That's exactly what I'm saying. Remove the boost hose to LDA, run around at WOT and it acts just like a NA pump, because the LDA arm is at the same location as the pin would be in a NA pump (limiting travel of the control collar lever). Now, while at WOT and full boost, reinstall that boost hose and you have a wider fuel map as the LDA arm responds to the boost signal (as the LDA arm moves and allows the control collar lever additional movement).
I don't follow the last statement. The lever won't be against the stop pin when you install the pump cover unless you're also holding the throttle arm against the max-speed stop. If you don't remove the fixed pin and install the LDA, the pin and LDA arm will sit side-by-side and not interfere with one another but the fixed stop pin will not allow the control collar lever the additional movement under boost.
Anyone have comparison photos?
Chris
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The pump is capable of pushing out just as much fuel NA or TD.
The LDA arm doesn't limit the control collar lever to the same place.
With the LDA in place the lever won't move as far without boost
The LDA limits fuel off boost, so off boost you won't get much smoke with the boost line disconnected,.. but you will with an NA pump.
Yet you say it acts just like an NA pump.
Pretty obvious the LDA arm is keeping the lever from moving off boost, but you say it's sitting in the same place as the pin in the NA pump,..
the one that allows smoke off boost.
If the lever was able to move all the way to the pin off boost,.. there would be smoke just like an NA pump.
There is no extra movement provided by the LDA arm, there is no extra fuel provided by it or extra travel of the lever. It simply limits fuel off boost.
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The pump is capable of pushing out just as much fuel NA or TD.
The LDA arm doesn't limit the control collar lever to the same place.
With the LDA in place the lever won't move as far without boost
The LDA limits fuel off boost, so off boost you won't get much smoke with the boost line disconnected,.. but you will with an NA pump.
Yet you say it acts just like an NA pump.
Pretty obvious the LDA arm is keeping the lever from moving off boost, but you say it's sitting in the same place as the pin in the NA pump,..
the one that allows smoke off boost.
If the lever was able to move all the way to the pin off boost,.. there would be smoke just like an NA pump.
There is no extra movement provided by the LDA arm, there is no extra fuel provided by it or extra travel of the lever. It simply limits fuel off boost.
my experiences are quite contradicting to your statements..
an n/a pump, and a TD pump not connected to boost, supply the EXACT SAME fueling.. take an LDA head off, mark the lever movement. then mark where the stop pin is.. the stop pin is farther back than the LDA lever.
i have LESS fueling than with the n/a pump top.. yet more boost. how does that work out if the n/a and LDA fueling are the same? less fuel but more boost? and no smoke on the bottom end?
the LDA allows n/a fueling while off boost. then when you hit the boost, thats when the LDA really helps out. particularly over 10 psi boost..
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I kinda agree with R.O.R. there...
Like I said, it's been a long time since I did this mod and I'm going off memory but as I observed from comparing things side-by-side, operating the LDA & watching the arm move relative to the stop pin position, it was clear to me that the LDA allows a wider fuel map, extending available fueling beyond what's allowed by the fixed pin, only on boost.
It really would help to have photos of an LDA pump top next to an NA body to see where the LDA arm limits fuel off boost compared to the fixed pin, then to see the upper limit with the LDA pin pushed down in it's travel as if at max boost.
Chris
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I kinda agree with R.O.R. there...
Like I said, it's been a long time since I did this mod and I'm going off memory but as I observed from comparing things side-by-side, operating the LDA & watching the arm move relative to the stop pin position, it was clear to me that the LDA allows a wider fuel map, extending available fueling beyond what's allowed by the fixed pin, only on boost.
It really would help to have photos of an LDA pump top next to an NA body to see where the LDA arm limits fuel off boost compared to the fixed pin, then to see the upper limit with the LDA pin pushed down in it's travel as if at max boost.
Chris
damn it, knew i should have taken pics.. too bad the car is all bolted together. i would almost consider taking the TD pump top off just to prove a point or 12..
anyways, i played with the LDA and n/a pump tops. eye-balled the hell out of both. but even with the naked eye, the LDA allows more travel than the n/a pump limiter pin allows..
anyways, the LDA adds what i would say is like 3-4 turns more fuel screw when the LDA is actuated to 100%
idk how many PSI it takes to fully actuate the LDA, but it DOES allow more fueling, i know that for sure.. my car sounds different on boost now. it seems to growl more out the pipe when boost sets in..
i used to think the same thing.. LDA and N/A pumps had identical fueling, just the TD limits the off boost fueling.. but thats wrong..
they have the same fuel curve when the LDA is not hooked to boost.. but when you hook up the LDA, it supplys MUCH MORE fuel..
this is a good test, someone take and install a LDA on a n/a pump, with the limiter pin still in the pump.. then knock the limiter pin out of the way.. after that is done, you will be able to use the full travel of the LDA arm, and will prolly say "HOLY S#!T" when you floor it for the first time..
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So if you floor a pump with an LDA (not connected to boost) there will be just as much smoke as an NA pump?
When you eyeballed the LDA arm,.. did you put it under boost and see where it sat?
That's the only way I can think of that would give any idea of real LDA arm travel.
The max fuel a pump can put out is to the point where the RPMs hang.
An NA pump can do that.
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If it's set-up right, there shouldn't be much smoke at all, floored & off-boost. I can usually only see my NA Rabbit smoking in the headlights of a car behind me, but almost nothing during daylight. With a turbo and no enrichment (either LDA with no boost reference or NA pump), you should see even less smoke since there will be boost present at full throttle, same as Ecodiesel.
I never really understood the hanging throttle thing (but I've never turned my pumps up that high either). Seems like the only way the throttle could hang is if the mods performed are creating a mechanical issue where the pump can't return the control collar to idle on its own. As long as the control collar returns, there's no way the pump head can get excess fuel beyond what the throttle input dictates. Governor mods effect the balance between collar return spring and governor... fuel screw effects the pivot point of the control lever... LDA arm effects the stroke of the control lever. The first two options effect ratios and mechanical advantages designed into the pump, the LDA swap preserves design features and only increases control collar travel.
Increasing fuel on an NA pump still gives a linear fuel curve, regardless of conditions. An LDA pump gives a linear fuel curve as well, to handle off-boost conditions but adds fuel as needed as boost and load increase (boost increase extends the available fuel 'window', load increase via additional throttle input makes use of this additional 'window').
Chris
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So if you floor a pump with an LDA (not connected to boost) there will be just as much smoke as an NA pump?
When you eyeballed the LDA arm,.. did you put it under boost and see where it sat?
That's the only way I can think of that would give any idea of real LDA arm travel.
The max fuel a pump can put out is to the point where the RPMs hang.
An NA pump can do that.
yes, i used my air compressor, and made the LDA work the full range of its travel..
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I removed the LDA cover and cycled the diaphragm with my finger... same result.
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I removed the LDA cover and cycled the diaphragm with my finger... same result.
yup..
either way, the lda off boost is about the same as the limiter pin, positioning wise..