DSL-1, rpm, tachometer etc settings

[doonboggle]

Thanks once again to Vincent, I have now been able to 'grasp' the process of establishing the rpm reading for my rabbit as associated with it's present tires.  Some of you may recall that I recently installed a gasser tachometer using a (USED) signal converter from Dakota called the DSL-1, that converts the 'W' signal from the alternator to a usable signal for the 4 cylinder 1.6L diesel engine.

Now, having determined that the readings that are being given to me are 'off-base' ... caused by the existing unchanged settings when purchased ... I want to calibrate it for more accurate readings.  Dakota puts out a guide, but here again, at least in my case, it is not that well written. 

So let me ask a question or 2 for those who may have adjusted one in the past.  I've sent 2 inquiries to Dakota, and they have yet to respond.  Hopefully I can    get a response from forum members.

First off it says to reset everything for ratio settings by putting switch #3 as 'ON', and #4 'OFF'. 
it says nothing about #1 & 2. 
Any idea how those should be set?

Next, at the beginning, it says that an independent source of determining the (in this case alternator I presume) rpm for that source is required, under the category of 'required calibration ratio'.
But it never says what to do with that information. 
Before I go out and buy a mobile battery tach. stick, would like to know it's purpose.
I presume is it for reference as to what the dash tach should read ... which will only be idle in the garage.
Is this a must???  To buy this mobile tach. that is.

Then it goes into 2 more calibration methods:  engine off ... engine running ... wherein you use the on-board switches and buttons.
In addition to all of the above ... which one should I consider?
Sure wish the guide was written in better construction.

[gldgti]

i think the calibration ratio its looking for is surely just the number of alternator pole pulses per engine revolution (or the inverse).

You should be able to work that out by the number of poles and the "gear ratio" of the crank pulley to alt pulley.

any help?

[rodpaslow]

I have the same setup - after work tonight I can tell you what #1 and #2 are set to.  I also have a digital tach that I used to set mine up - You don't have a location with your user, I'd be willing to send you mine if your willing to wait a bit and then return it to me. (I'm in Canada - I'm assuming your in US).  My personal feeling is you need a tach even to get it close.  I'm a bit anal when it comes to settings with the car, and with the DSL you can get it exact.  I'll get back to you later today with what 1 & 2 are.

[bajacalal]

To calibrate it, I think you could just start by running it as is then determining what your actual RPM is based on your gear ratios, tire size and vehicle speed- say 50 mph... There are formulas to caculate this, google it and gear ratio information at http://www.brokevw.com/020ratios.html. You can even verify your speed with a GPS to be exact. Then compare your calculated RPM to your measured RPM and determine the % difference, then adjust your tach accordingly at idle. Repeat the process once or twice and you can probably get your tach really close to the actual speed.

[TPW]

http://www.dakotadigital.com/pdf/dsl-1c.pdf  1:0ff 2:On 3:off 4: On  I'm getting one set up on my 5 cylinder, so I phoned them today, and the tech rep was a great help.

[Vincent Waldon]

To calibrate it, I think you could just start by running it as is then determining what your actual RPM is based on your gear ratios, tire size and vehicle speed

Yup... and the universe has officially looped back on itself:

http://www.vwdiesel.net/forum/index.php?topic=27256.0

 

[doonboggle]

Thanks rod for the offer. 
But rather than go thru that process ... and I appreciate the thought ... I ordered a mobile tach last nite off the internet. 
Heck, was not that costly, and shipping was even free.  17.00 and change.

So hopefully when it arrives I'll be able to determine the rpms of the alternator and go from there....... I HOPE !

I have the same setup - after work tonight I can tell you what #1 and #2 are set to.  I also have a digital tach that I used to set mine up - You don't have a location with your user, I'd be willing to send you mine if your willing to wait a bit and then return it to me. (I'm in Canada - I'm assuming your in US).  My personal feeling is you need a tach even to get it close.  I'm a bit anal when it comes to settings with the car, and with the DSL you can get it exact.  I'll get back to you later today with what 1 & 2 are.

[doonboggle]

I dabbled around today with the readings from the scirocca calculator and came up with the following table with list.  
Do these seem more appropriate for the 1.6L engine than what I originally posted a few days ago?

TACHOMETER TEST RESULTS 10/19/10
GEAR          40                50                  55                  60
   CAL   ACTUAL   CAL   ACTUAL   CAL   ACTUAL   CAL   ACTUAL
3   2979   3100          3724   4000          2254   2400           --   --
4   2101   2100          2627   2800          2889   3100         3152   3500
5   1639   1600          2049   2100            --   --             2459   2700

3rd gear:   
40   actual high by approx. 100
50   actual high by approx. 275
55   actual high by approx. 150
60   not tested

4th gear      
40   actual on mark
50   actual high by approx. 50
55   actual high by approx. 200
60   actual high by approx. 350

5th gear      
40   actual low by approx. 50
50   actual high by approx. 50
55   not tested
60   actual high by approx. 250

I've also got an inexpensive laser tach on it's way to verify.
TIA

To calibrate it, I think you could just start by running it as is then determining what your actual RPM is based on your gear ratios, tire size and vehicle speed

Yup... and the universe has officially looped back on itself:

http://www.vwdiesel.net/forum/index.php?topic=27256.0

 

[rodpaslow]

Sorry for the delay, but mine are set like TPW listed, 1 off,2 on, 3 off and 4 on when it's running.  I'm not rough with my car so it sure is nice to have one working. 

If you have a tranny with .75 fifth I could tell you what the rpm would be at 120kph (75 mph).  Mine's right at 3000 rpm (with 96 final drive of 3.67 I think)