Diesel Pulse Adapter Info Thread

[theman53]

I took it as "for this HP time it to____ with the timing light"

Also, in the pics above I do not see a timing spec for the timing light, just the mm gauge style, so they are kind of irrelevant to this thread.

If it were as simple as "time it to ___ with the timing light", why would VW change the spec for the next decade or more?

I don't understand you question. I was commenting on the picture. I can separate this into another thread if you want as it doesn't make sense at all to me.

[libbydiesel]

VW changed the way the timing spec was expressed, but not the spec for start of injection.  The differences in the plunger lift spec are directly related to injector break pressure, camplate profile and plunger diameter but all result in the same 10° BTDC for start of injection.  I believe that VW has consistently given a lower than optimal timing spec in order to reduce NOx emissions.    

[ORCoaster]

 I believe that VW has consistently given a lower than optimal timing spec in order to reduce NOx emissions.    

How dare they!  Going for clean air over performance and or engine life.  Dirty buggers.

[Toby]

I was also told many years ago by someone at VW that they were also quieter at the "US" spec and because Americans did not like clattery diesels our diesel Rabbits were slower than those of the rest of the world. They claimed that when they set the timing at the "European" timing spec people complained because of the noise. This would have been around 1980, IIRC.

[ORCoaster]

Yes as far as I know the "Clatter" of the diesel of the day back in the early development and use of them had Americans flat out refusing to even consider them.  Now look at the Pick up truck on the street today.  Sure used more for pulling and doing work most of the time.  But plenty on the road.  Diesels now are ubber quiet compared to mine but my mileage beats theirs hands down.  Largely due to the additional half a ton of safety gear on their cars. 

[92EcoDiesel Jetta]

The piezo adapter fires at the start of injection.  The micro-expansion of the metal line is what charges the crystal pickup and it fires it's pulse when the line starts to relax which is at the actual start of injection which precisely coincides with needle lift.  Yes, the piezo pickup DOES detect needle lift very accurately.
................................

I am revisiting this and trying to find reference that the piezo outputs a pulse when the line relaxes (as opposed to when the line expands). Can you provide a source of that info?

Per http://en.wikipedia.org/wiki/Piezoelectricity there is a simulation that shows voltage rise as the piezo crystal is compressed, not when it is relaxed.

[ORCoaster]

Regarding the timing for performance versus NO reductions.  Does anyone have a reference on the number of degrees difference that would be?  I thought the 1.6 L was best at 12 BTDC.  Libby says so I think.  Just wondering as the use of the pulse adapter makes changing the IP timing a lot easier now.  All that stick it in and dial work is a thing of the past.  For me, pull a glow plug and time away. 

[libbydiesel]

12° BTDC using my pulse adapter and strobe has consistently yielded the best results for me.  I would encourage everyone to arrive at their own conclusions, tho, as no further 'proof' will be offered by me.  YMMV and it has been proven to cause cancer in California.

[ORCoaster]

What was really interesting to me was how the actual timing in degrees was varied from the dial indicator.  I had my pump mechanically dialed in at  88 to 95 mm at different times and this equated to about 15 to 20 degrees BTDC.  So Now I am back to 15 and see what I get for mileage around town. 

It is quieter but I am looking for MPG so we will see. 

[libbydiesel]

You seem to have a different experience from mine.  I have checked several, and with spec injectors and a properly functioning pump timed to stock timing with the dial indicator I have not seen a pulse timing over 13°BTDC and more typical is to see 9-12°.  At 15° it is obviously too clattery and 20° would be advanced enough to make it hard to start.  Are you sure your cold start knob wasn't pulled?

[92EcoDiesel Jetta]

OK, Twas sunny and very nice in the driveway today so I pulled out the optical and the pulse adapters and the timing light.  Also dug out the timing dial gauge and all the needed sockets to do a multitude of timing setups.

I started with my base setting of 85 on the dial gauge just to test out the process.  That being set the timing to the desired dial mm number, Spin engine by hand and recheck setting.  Then pull the dial off and set it up to run and take two measurements.  One with the Pulse adapter located about 3/4 of an inch above the injector nut and the other with the Optical (Lumy) adapter.  I worked up the scale to 110 mm and then picked up the 70 and 80 measures on the bottom.  Once I had all the readings I wanted I rest the timing to 88 as per label on the strut. 

The base setting I had 85 mm was giving me 33 mpg in the stop and go city traffic on my short 3 mile jaunts to work.  Temps in the 40s generally during that time.  And ran the car for 450 miles between last fillup.  I added an extra five gallons to the tank some time in March. 

So the results are charted below and I just have to wonder why my pump does not get down to the 12 degree mark that I was expecting at the lower settings.  Or at the base setting for that matter.  Perhaps my internal IP pressure is too high, and I am running some advance at idle al the time?   I have read that one might need to run the idle at 1000 RPM doing this sort of thing but I kept mine in the 840-870 RPM range.  On the chart the red line is the Pulse adapter and the left axis is the scale, on the right is the Optical readings per mm setting.  I threw in the linear trend line to see how well it lined up and to allow others to perhaps get to the numbers one would expect to be here.  I am not sure why there is that stairstep effect going with the optical readings.  Maybe I was not aligned with the pointer dead on.

Just the same a lot of time to make all the adjustments and double check all the process. 

Open for discussion on what we can learn here. 

OrCoaster, please clarify the units of the vertical and horizontal scales and what they represent.

[ORCoaster]

I tried for a bit to put text on those vertical axis and will do again.  I thought in the thread I discussed the pulse adapter needed BTDC readings so that is the left side.  That crazy Lumy thing a ma gig that goes in the glow hole reads the actual fire of the piston stroke so it is ATDC readings.

I will see if I can edit it proper and reload.  Kind of like a map without a North arrow or a scale isn't it.  I should be coaled for that.  

Thanks for asking.  Like I need more homework.  DAS

Best to bump it forward but I did correct on initial page.  

[92EcoDiesel Jetta]

I have more home work for ya. Horizontal scale need decimal points. Numbers on blue line need ATDC label.

[ORCoaster]

MOAR Betta?  Or do I have to go back to my desk and do MOAR to it?

Kind of been that way at work this week.  Second time ever in my 35 yr career that I have been ordered to do a job because someone else did not.  Only in the govt.

[jimfoo]

The limiting factor of the max rpm for the pulse adapter can not be the lines! If it were, a Tiny Tach would be useless as it would only measure to 1500 RPM. The most likely limiting factor is the timing light itself, which must have time to produce the high voltage the tube needs, and the less likely, but still possible pulse adapter itself, being the limiting factor. Tiny Tach says their unit will measure up to 19990 RPM, so lines can't be a factor at our RPM range.