lda spring - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• lda spring by dieseltech on 20 Mar, 2005 20:48
• anybody ever try a lighter (easier to compress) spring under the lda diaphragm?
  if so how was it?
  i think i nam going to try it, but i am still waiting for other parts for the car.
  
  i just took the top off of another pump i had, came off of a 89 1.6na with altitude compensator. the spring in there is much softer. my thought is the turbo would posably spool faster once it has started to build pressure, because it would be adding more fuel sooner due to the softer spring. just a thought?
• #1 by dieseltech on 20 Mar, 2005 21:06
• i also notice that the lda pin for the td has a steeper ramp than the altitude compensator pin.  the td has 27 stamped on tne bottom the other has 67
  
  by the way how do you upload and post pics here?
  thanks
• #2 by jackbombay on 20 Mar, 2005 21:11
• Quote from: "dieseltech"

  by the way how do you upload and post pics here?
  thanks

  
  
    imageshack hosts pics for free, you can link them to any web site you want, works great for me.
• #3 by fspGTD on 20 Mar, 2005 23:07
• I am running an LDA spring from a 5-cylinder Audi 5000 TD on my 1.6lTD.  I found it to have more coils, and to be a softer (lower rate) spring than the original 1.6lTD LDA spring (which was found originally from an '84 Jetta 1.6lTD by the way.)
  
  Getting the fuel to come in a lower boost seems to reduce turbo lag a bit and extend the boosted power band a little downward, although it does make for a more smokey turbo spool-up.
• #4 by fspGTD on 20 Mar, 2005 23:44
• PS - pins of the VE pump altitude compensators I have looked at were not interchangeable with a LDA pin.  Was the one you looked at interchangeable?
  
  The main difference in the ones I've looked at were, there was a big metal bellows in the top of the housing, and since that contracted when atmospheric pressure increased, and expanded when atmospheric pressure decreased, it moved the pin down when max fueling needed to be restricted more, and up when max fueling could be increased.  This is the opposite of an LDA function where downward movement of the pin means allow more fuel.
  
  But maybe the atmospheric compensator you looked at was a different design?  The one I looked at was found in a VE pump but it wasn't from a VW (it was from a mitsubishi pickup truck, or some other mid-80's truck, I think.)  I do have it sitting in my garage, so can take another close look at it and pictures, etc if needbe.
  
  PS - Thanks for the info on the boost pin numbers.  I added that info into the thread where we are collecting that data for comparison, here:
  http://www.vwdiesel.net/phpBB/viewtopic.php?p=8179
  It is interesting to note that someone else has found a different boost pin number in an '86 Jetta.
• #5 by moosiah on 21 Mar, 2005 19:24
• Hi all .... So I  have one of those alt.comp ip's as well ....... I know your thinking another poor sucker.....:roll:......  So last night I was fiddeling around in the motor cave..I've got a poegeot lda pump,,, jedda 84 lda pump ,,,,and a quantum 83 pump all sitting on the bench ........  Yes jake the alt comp ip internals are the same as a turbo pump,,,,,(on a vw)  how ever the pin cone is longer as is the pin it's self ... I haven't measured it yet ,,,,,,,, this one looks externaly just like a regular lda ve pump....I believe that the 89 hyd na motors also come with piston jets??..:idea: . if so  it looks to me as though a tricky guy could build him self a td motor w a intake man and turbo setup....  I find the poegeot  pumps in the pican'pul yards now an' then ... got the last one for $20 ..... these are 2.3 turbo models.... w 10mm plungers :!: .. that and a old na pump w a vw bolt pattern for a case...... good to go!!!!  :twisted:
  ps the vacuam for the altitude compensation is controled by a electronic device on the VW ..and piped to the lda below the diaphram ; opposite of the turbo lda.... the vacuam is used to hold the pin down ,  air is bled in to regulate the vacuam and cut back the fuel..... :?
• #6 by leprechan on 21 Mar, 2005 19:46
• Quote

  .I believe that the 89 hyd na motors also come with piston jets??..Idea . if so it looks to me as though a tricky guy could build him self a td motor w a intake man and turbo setup.

  
  
  I have been told that all 1.6na don't have piston jets, but if you find out something different make sure you tell us all.  My car was manufactured 01/91(When ecodiesel production started), must be one of the last dreadful na models made.  Talk about luck huh?  Sorry for going a little off topic here, been stuck in the slow lane too long.
  
  Nick
• #7 by shakakan on 21 Mar, 2005 20:08
• I will be pulling the bottom off of my 91 NA this summer for a redneck rebuild.  I will let you know if there is any jets in it.  If there is, mine is gettin a turbo.  I somehow doubt that there is though.
• #8 by dieseltech on 21 Mar, 2005 20:36
• i have come across 2 that were na and had oil sprayers. they were automatic trans, one was a 91 and the other 92
• #9 by leprechan on 21 Mar, 2005 20:52
• Well now......That is good news.  Anyone else out there with na oil squirters?  Don't be afraid to say hi .   I may have to drop the pan when I get back from spring break next week.  It might be time to make a td shopping list.  Thx for the reply dieseltech.
  
  Nick
• #10 by dieseltech on 21 Mar, 2005 22:02
• 
  
  
  
  
  
  some of my work in progress. the same dial indicator i use to set the ip timing threads into the hole in top of the lda. that and a pressure guage and pressure regulator alows me to set how much fueling ant certain psi, helps me decide choice of spring and starwheel ajustment and preeload.
  i hate lots of smoke out the tail pipe for normal driving, but i do have an electric solinoid on a vacuume line going to the bottom side of the lda diaphragm. i flip a swithch and it pulles the diaphragm down with no boost and i can lug it and smoke out the "nice" people behind me. i also have a 2 stage custome boost cotroler for stock 10psi and power(22psi), i have plans that i drew up but sourcing the parts is hard unless you have "friends" that fix school busses, all the solinoids and hose and regulators are from various door and radiator shutter controlls on big school busses :lol:  whadda i know. it fell of the bus when i was driving behind it
• #11 by jackbombay on 21 Mar, 2005 22:14
• I see you got the imageshack account set up.
  
     Your smoke on demand set-up sounds like it could be fun for tailgaters.
• #12 by dieseltech on 21 Mar, 2005 22:53
• Quote from: "jackbombay"

  I see you got the imageshack account set up. .

  
  yup thanks for pointing me in the right direction
  
  
  
   .[/quote]  Your smoke on demand set-up sounds like it could be fun for tailgaters.[/quote]
  
  oooh yea. thats why i have it. the car in the pics is going to be my autocrosser
  
  its a 83 gtd. the head is on my bench awaiting the 3 angle valve job and a port (to a D port tdi manifold) and polish. i still have not decided what turbo to use but i am thinking  ecodiesel turbo, with my custom mitsubishi air to h2o intercooler.  i want as much powerband as possable for the track.
  the autoX events i go to are usually small, but they get a kick out of a diesel cleaning up the track. time will tell the winning combo, but it will be fun :lol: in my pocket rocket.
• #13 by fspGTD on 22 Mar, 2005 08:14
• That's a great idea to measure the displacement of the LDA device using a dial indicator set up like that, with a known amount of pressure... and really the threads are same as in the injection pump timing measurement hole?  Amazing, and you're the first I know to have thought of it.
  
  In the past I've measured LDA cone setup by installing it, running it a few days, and observing the "scratchings" made on the control cone from the feeler needle... but using the dial indicator seems more reliable and quicker.
  
  So another GTD autocrosser... sweet!    I also love making people say "wow! That's a diesel?  I never knew a diesel could go THAT FAST!"  Beware that a ported head and turbo swap would put you into pretty tough classing category under SCCA rules, which is what is used for the most competitive national level.  I'll bet you could do well with it and have plenty of fun with it locally, though.  Does your local club use SCCA classes or their own?
• #14 by dieseltech on 22 Mar, 2005 17:43
• Quote from: "fspGTD"

  That's a great idea to measure the displacement of the LDA device using a dial indicator set up like that, with a known amount of pressure... and really the threads are same as in the injection pump timing measurement hole?  Amazing, and you're the first I know to have thought of it.
  
  
  
  In the past I've measured LDA cone setup by installing it, running it a few days, and observing the "scratchings" made on the control cone from the feeler needle... but using the dial indicator seems more reliable and quicker.

  
  
  yup same threads, and i use a litthe grease around where the dial indicator fits into the pump adapter.  i measured the length of the ramp on the cone and compare it with the reading on the dial to make sure i am getting the full travel
  
  

  Quote

  So another GTD autocrosser... sweet!    I also love making people say "wow! That's a diesel?  I never knew a diesel could go THAT FAST!"  Beware that a ported head and turbo swap would put you into pretty tough classing category under SCCA rules, which is what is used for the most competitive national level.  I'll bet you could do well with it and have plenty of fun with it locally, though.  Does your local club use SCCA classes or their own?

  
  
  using a ecodiesel turbo is still stock, there are no other vw's at any of the events i go to, and i was realy not going to tell them what i did.  thats why i want smoke to a minimum. the rule class book also does not show a gtd as an option, so they said i would go under a turbo diesel, "G Stock" but if i put the intercooler on it will get me to a "prepared cless"  the reason why i have no thought of telling them what i did to the car is, last year when i raced my stock 91 peugeot 405 mi16 "H Stock"and cleaned up track, i got disqualified for cheating, but i never cheated. i won every event in my class and in the next class up fare and square. maybee they dont like french cars, well they banned that car from the track. sore loosers. it even had the stock exhaust and intake with paper filter and posi from the factory and original clutch with 80,000 miles on it.   so since i cant race the Peugeot, the old "rabbit" is going to be next to clean it up, but it will take time and experimentation with what combo of tires/pressure and shocks and springs. schirocco sway bar and springs are next.   oh yea, the first time i raced the peugeot, they laughed in my face and said "you wanna what withe the family 4 door" i told them "just wait n see"   well i took second place, with h rated tires, real junk.
   :lol:   the rabbit will be a harder challenge, it does not handle nearly as well as the peugeot.