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Engine Specific Info and Questions => IDI Engine => Topic started by: Rabbit on Roids on November 20, 2009, 08:06:36 am
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ok, so i have had some thoughts about why my car runs SO MUCH BETTER when i run my own blend of fuel through it. is it possible that running a thicker fuel through the injection pump will make it harder for the fuel to leave the pump and builds more than normal pressure in the pump and advances it? because i have a couple gallons of mixed up motor oil, trans fluid, 2 cycle oil, and white gas that i have been running in there because i cant afford real diesel. anyways, my car really scoots when it burns this stuff. hit boost, start burning out. its dumb. i used to love how my car had so much traction when it was gutless. now first and second are about useless with a heavy foot. i just want to figure out why it runs like a raped ape with this fuel and not on regular diesel.. i know there cant be that much more heat in the fuel i made..
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What's your injector break setting?? 155 Bar?
You're theorizing a timing increase internal to the pump, not lifting the pintle sooner do to increased system pressure?
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yea, just got stock 155's in it.
never thought that maybe the injector was opening sooner, but why would it open sooner with thicker fuel?you would think it would take a little bit longer since the fuel is thicker. i bet anything its just that the fuel is working harder to get out of the pump, and in turn is making the internal pump pressure rise, witch is advancing the dynamic timing. there again tho. nothing set in stone. might just be a big ol pipe dream.. i want one of the veterans to chime in and either agree with, or destroy my theory. either way would be fine, i just want a reason why my car has so much more power on the other fuel...
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Build a pressure gauge for the pump and check it out and let us know
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that would mean i would have to reseal the pump to get an accurate reading. and that would mean i have to take it off. and i dont have a timing gauge. im not taking this engine back apart till i have a dial indicator. ive never had it run this good and i really want to know what my timing is at before i pull it apart again. i know its time for a timing belt soon tho, so it will have to happen sooner or later. and how do i get a pressure reading off the pump? theres no obvious plugs to take out, or any holes to tap and drill. where would you hook up a gauge?
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To get the pressure you gotta get your reading from between the pump and out bolt.
I built an adapter out of a bolt drilled lengthwise and through the middle, a spare inlet and outlet banjo and two nuts of the right size. I'll snap a pic of it when I get to work.
EDIT: Due to my stupid 'puter, I can't get pics off the camera ( >:() so I edited this to be slightly more discriptive.
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I'm no veteran, but wouldn't the energy contained in the fuel, being different than diesel have an effect on performance due to flame travel speed in the cylinder/head and other issues similar to this, be more the issue than fuel viscosity?
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Motor oil trans fluid and gas are much higher BTU value fuels then desulferized diesel. I burn all these in a waste oil heater and when the heater is at the same setting the heat output is very different. So different that the flue pipe can double in temperature. Also the addition of gas changes the flame front temperature and ignition temp. Do you have an exhaust temp gauge?
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DUDE, RABBITONROIDS! you just have to give us a formula for this stuff you are running iot has been said more than once on this forum already, that your fuel gives wicked gnarly power and has excellent lubrication. So how bout' it??? let us in on your little secret. Or better yet patent the formula and sell it to racers etc. for a mint you always talk about how you don't have money well here is your chance at something incredibe. Hell, I know that I'd buy the stuff from ya.
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Ok I took the camera with my pics home so here you go,
The whitish looking end of the bolt goes into the IP outlet.
(http://i249.photobucket.com/albums/gg218/rabbitdude82/Nathan001.jpg)
(http://i249.photobucket.com/albums/gg218/rabbitdude82/Nathan002.jpg)
(http://i249.photobucket.com/albums/gg218/rabbitdude82/Nathan003.jpg)
Of course then you gotta put a gauge on the other end of the hose, use a good gauge or it'll bounce all over and be hard to read. I forgot the specs too. ::) I think it's 40something @ 1000rpm (crank) and 70something @ 2000rpm.
I don't think there's a way to adjust the 2000 without also changing the 1000rpm reading.
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Keep an eye out at the breakers, many of the bosch pumps on a variety of diesels have a spacer pillar on one of the banjos. This is to inprove the pipe routing. It has a male and female thread, and is about 1" long and hexagonal. Drilling this is a cinch to glue a bit of brass pipe to fit a pressure guage to so you get the inernal pressure and the outlet banjo is doing what it should. Google "hagar" and "smileage" for lots of photo's. But take the pressure settings given there for the pump internal pressures with a pinch of salt though, as my injector nozzles went blue from overheating. But your mileage may vary. 8)
The Bosch spec for a 1984 turbodiesel is 2.5 to 3.2 bar at 1000rpm engine. 4.7 to 5.2 bar at 3000 rpm engine and 6.5 to 7.1 bar at 4500 rpm. This is what I set my I set my two SB turbodiesels to. But who knows? ???
Here is the Bosch page in all its glory, http://www.vwdiesel.net/forum/index.php?topic=19692.0 (http://www.vwdiesel.net/forum/index.php?topic=19692.0)
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The short answer is YES. Fuel viscosity has a significant effect on the dynamic advance system just as you suggested. If, however, it has that effect from an alternative fuel, that means that your pump is significantly out of adjustment for pump diesel and the same gains can be had using pump fuel and having the pump adjusted properly.
i know it needs to be adjusted. i built the fuel pump, turned up the smoke screw, and have been driving it. never adjusted anything else really tho. dont really know how to.
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Motor oil trans fluid and gas are much higher BTU value fuels then desulferized diesel. I burn all these in a waste oil heater and when the heater is at the same setting the heat output is very different. So different that the flue pipe can double in temperature. Also the addition of gas changes the flame front temperature and ignition temp. Do you have an exhaust temp gauge?
no sir, i am too broke to afford anything fancy. ive been running it hard for almost 2 years now tho, never burnt anything down.
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DUDE, RABBITONROIDS! you just have to give us a formula for this stuff you are running iot has been said more than once on this forum already, that your fuel gives wicked gnarly power and has excellent lubrication. So how bout' it??? let us in on your little secret. Or better yet patent the formula and sell it to racers etc. for a mint you always talk about how you don't have money well here is your chance at something incredibe. Hell, I know that I'd buy the stuff from ya.
i dont know my exact formula tho. and who is gonna buy racing diesel? like 20 people on the face of the planet? im sure this stuff isnt safe for anything besides a VW diesel.
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another thing, my car has more power with the cold start lever pushed in. you would think it to be the other way around right?
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another thing, my car has more power with the cold start lever pushed in. you would think it to be the other way around right?
That actually really means there's something goofy in your pump. The cold start just gives a little 2 degree nudge to the timing piston - as soon as the pump is spinning much faster than idle its own internal pressure should be pushing the timing piston a lot further than 2 degrees. If you're noticing higher RPM differences between the cold start in and cold start out then you probably have next to no internal pump pressure. Your higher viscosity fuel would definitely help build more pressure in your pump giving you more dynamic advance, but adjusting the pump internal pressure (and fixing whatever is causing your low pressure) would probably REALLY surprise you... :)
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when i got my '81 a few weeks ago, It had 1/4 tank of 4 year old diesel. So i pulled the fuel lines and hooked it up to a 4 liter jug of 2 liters 15w-40 diesel oil, 1 liter 2 stroke oil (ashless), and 1 liter of good 'ol ATF. I have driven it on normal diesel since and i think the seat of the pants experience was more on the "special fuel" lol. However i could be having the same problems as RoR.. The car has 410k kms and i have no idea of pump condition.
As stated though that combination of fuels probably yields another what 5-15,000 BTU's ??
Is it really cheaper to buy all those things? or do you just have MASS AMOUNTS of the stuff lying around? lmao
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I've noticed quieter idle, and a 1-2 MPH gain on a 50 MPH grade burning heated Vegoil, and attributed it to timing, but like the OP, took no pump measurement.
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DUDE, RABBITONROIDS! you just have to give us a formula for this stuff you are running iot has been said more than once on this forum already, that your fuel gives wicked gnarly power and has excellent lubrication. So how bout' it??? let us in on your little secret. Or better yet patent the formula and sell it to racers etc. for a mint you always talk about how you don't have money well here is your chance at something incredibe. Hell, I know that I'd buy the stuff from ya.
i dont know my exact formula tho. and who is gonna buy racing diesel? like 20 people on the face of the planet? im sure this stuff isnt safe for anything besides a VW diesel.
I do the same thing with waiste products. I have never had a TD other than a Mercedes Wagon. Sometimes I feel it helps over pump fuel, and other times not so good. I keep all my stale gasoline and mix that in too. I have even burned waist aviation engine, and transmission oils, which is thin enough to go 100% in the summer. Bottom line is if you filter it enough and it burns why not use it. In the past I have always based my mix on milege vs performance though.
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I've noticed quieter idle, and a 1-2 MPH gain on a 50 MPH grade burning heated Vegoil, and attributed it to timing, but like the OP, took no pump measurement.
i will NEVER!ever run vegi oil in my diesel. not even if its set up right. ive heard too many horror stories about people coking their engines to death. diesels dont like to overdose either.
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another thing, my car has more power with the cold start lever pushed in. you would think it to be the other way around right?
That actually really means there's something goofy in your pump. The cold start just gives a little 2 degree nudge to the timing piston - as soon as the pump is spinning much faster than idle its own internal pressure should be pushing the timing piston a lot further than 2 degrees. If you're noticing higher RPM differences between the cold start in and cold start out then you probably have next to no internal pump pressure. Your higher viscosity fuel would definitely help build more pressure in your pump giving you more dynamic advance, but adjusting the pump internal pressure (and fixing whatever is causing your low pressure) would probably REALLY surprise you... :)
well, i did have to put a different body on the pump, i forgot about that. and when i did it, i never messed with the pressure regulator and i never swapped in the one from my TD pump, witch i still have. would it be worth while to install the old one? or should i just dive in head first and finally figure out how to tune my pump? ive never done anything besides set the idle screw, and max out the fuel screw. never even messed with the LDA cause i like how it feels like a hit when you get to 10 psi and it kicks in. my pump is probably more out of adjustment than any of you have ever seen. i knew nothing about fuel pumps when i built this one, just how to take them apart and put them back together and still have them work.
and as for the CS lever, im not for positive if it has more power throughout the power band, but i know it has a little more low end with the knob pushed in. i base that finding on the ability to burn out with the knob in or out. i can squeal 2nd with the knob out, but with the knob in, it fries the tires off again in 2nd, and squeals 3rd. maybe its just me tho. and it is quite possible that my pimp has no internal pressure. but it does leak like a bastard, so that tells me there must be some sort of pressure in there.
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When I put new bushings in my IP I used all the old pump guts but I also used a different body. That screwed my internal pressure up bad! It's supposed to be like 43psi at 2000rpm (crank) but mine was at about 55psi @ idle :o.
I didn't know it was that bad for a few weeks but I did notice it had to crank way too much before it started, then once it started and the internal pressure came up it would clatter real bad so I put lots of washers under the timing piston to try and quite it down some.
Anyways I think you should at least check your pressure, as long as it leaks adjusting it won't really cut it, since you'll rev it high and the pressure will make it leak faster thus not advancing enough. ;D
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When I put new bushings in my IP I used all the old pump guts but I also used a different body. That screwed my internal pressure up bad! It's supposed to be like 43psi at 2000rpm (crank) but mine was at about 55psi @ idle :o.
I didn't know it was that bad for a few weeks but I did notice it had to crank way too much before it started, then once it started and the internal pressure came up it would clatter real bad so I put lots of washers under the timing piston to try and quite it down some.
Anyways I think you should at least check your pressure, as long as it leaks adjusting it won't really cut it, since you'll rev it high and the pressure will make it leak faster thus not advancing enough. ;D
What causes low internal pump pressure? I think i have this issue as well.
What are you saying about the loud clatter and adding washers to something?
Mine sometimes sounds like loose alluminum pans or like sheet metal is loose banging around in there but i just attributed that to 1 stage injectors...
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I thought I had bad bearings..... well they were bad, but I heard the same sound as the other guy like pans clattering, or maybe a monkey wrench banging around inside of my engine. Time for a pump and injector rebuild I suppose, on top of having to rebuild the engine.
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well, that crappy n/a pump isnt gonna do what you want it to bolted onto a fire breathing monster. thats like bolting on a rochester 1 bbl to a blown alcohol burning big block race engine. its not the best match. of course it will run, but not to its full potential.
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I thought there was a FAQ post about internal pressure, but it might have been on the other side. Either way, here's the gist of it:
On the sprocket end of the pump there's a pressure regulator. It's round with two flat sides and a depression in the center. The center is the "adjustment" - if you press it down somehow (there's a Bosch tool for this, or you can use a hammer and a punch) you increase the pressure. To reduce the pressure you have to remove the regulator from the pump and press it back the other way. It's INCREDIBLY sensitive - it's not something you should adjust without some way of measuring the result. We're talking fractions of a mm making big jumps in pressure.
There's two parts to the pressure regulation system - the regulator itself and the OUT bolt on the fuel return side of the pump. It's got a small orifice in it and between the regulator and the out bolt the pressure inside the pump increases as RPM increases, pushing on the timing piston and advancing the timing. If you don't have a proper OUT bolt (say you just stuck any old banjo bolt in there) then you have no restriction on the outlet side of your pump and next to no internal pressure. The car will run but there will be next to no advance.
To check the pressure you need to measure what's going on inside the pump. This is kinda tricky since there aren't really any provisions for it from the factory. Some people drill a hole in the end of their OUT bolt and tap it for a gauge, the best method I've seen is using the little "pedestal" thingy on top of NA pumps. It's large enough to drill/tap, comes off the pump and then you've got a nice reusable measuring "instrument". The important thing though is that the OUT bolt still has to be in place and you have to be measuring on the PUMP side of the OUT bolt.
BTW, the NA pump can shoot out just as much fuel as the TD pump can... It's big difference is it can't HOLD OFF fueling until the turbo spins up like a TD pump, so you're going to leave great big smoke clouds... If you want to think about it like carbs, the TD is more like a vacuum secondary carb while the NA pump is more like a double pumper. Both can deliver the same amount of fuel, the TD pump just lets you hold it off for a bit to prevent overfueling.
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I'll tell yeah, anything that improves power on my 1.6na I'd definitely take!
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I'll tell yeah, anything that improves power on my 1.6na I'd definitely take!
snail? :) nos?
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For your reading pleasure :D http://www.vwdieselparts.com/forum/viewtopic.php?t=5936 (http://www.vwdieselparts.com/forum/viewtopic.php?t=5936)
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wow, kinda makes me hopeful. i thought my car went alright already. its for sure the fastest diesel in town, hands down. and its the only diesel car in town.
so when i take and crank up the internal pressure in my pump to where its supposed to be, i should have wuite a bit more power, and probably a few more pounds of boost right? this would probably explain why it seems like my car has more power on some days than others.
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Gonna lower the pressure on my Volvo this weekend. Gave that pin a smack already, and have had remorse every since.
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No kidding, and I do this for a living too. But.. I have milked a couple of past Rabbits into running smoother, while reducing white smoke. At the end of the day internal pressure problems usually indicate a worn pump. As far as measuring pressure while adjusting, it is difficult to calibrate a hammer blow to a punch. Just need to modify a socket to git that valve out and get out the ole hammer, and punch and go the other way. Wonder why Bosch didn't put a screw there instead of that pin.
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Wonder why Bosch didn't put a screw there instead of that pin.
My guess... same reason the fuel screw has a steel collar welded to it... "if you have to ask, don't touch". ;-)
There *is* a Bosch-specific tool that attaches to the top of the pump and allows you to gradually increase the internal pressure upwards... unfortunately it remains a one-way adjustment however.
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Yeah, I know but I must touch it. Got lots of part to put on the Caddy this week end. Im gonna outright molest the pump on it (http://i1000.photobucket.com/albums/af125/verdigo59/Picture.jpg)
(http://i1000.photobucket.com/albums/af125/verdigo59/Picture002.jpg)
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hi rabbit,
I run a two tank system on my 1.6. one has diesel and the other has a mixture of 4/5 used motor oil, 1/5 kerosene or diesel, one ounce acetone per 5 gal fuel, one ounce seafoam per 5 gal to prevent carbonization, and filter it down to one micron. I start it up and get it up to temp on the diesel, then switch over to the used oil by turning two 3 way valves in the cockpit. the oil is routed through a flatplate fuel heater that I got off ebay for about 74 bucks. If I don't wait for the engine to get up to temp, it doesn't run worth a *** on the oil. I suppose it is somehow related to the thickness of the fuel as well since the flatplate heater thins it out alot. Might be worth a try for you. BTW. when I switch it over on the highway, speed increases when the mixture hits the engine even though i don't change the accelerator position. It sounds a lot quieter too. I switch back to diesel before I shut it down too. I've ran about 6k on this mixture so far with zero problems. I only need to buy a tank of diesel about every 3 thousand miles ;D