60-2 trigger wheel help needed!

[3.7 V8]

 
   Hi Guys,
               Help needed as i need to find out how to set up the missing tooth
               figures on the car, i.e how do you know where to get the figures from!
               please bare with me as im new to all this!

                     regards danny

[rob@vems.co.uk]

Which engine are you using?

[3.7 V8]

   Hi Rob,
              Im using the Audi A8 3.7 with fidanza alloy flywheel and a 60-2
               trigger wheel fitted to the crank pulley and im using a vr sensor.
   
               The trouble is im finding it hard to find the info on how to
                work out the stuff about how to set up the missing teeth info.

               The loom is VEMS all connected into the audi loom by hilly,
                most of the config has been put onto the vems unit i.e
                basic maps and so on but as my trigger setup is slighty different
                and my fuel injector setup these could not be entered!

                The motor is just about ready to try and start apart from the exhaust
                 so im really trying to better my knowledge on the VEMS system
                 and trying to find out a bit more about this stuff before atempting
                 to conect the whole lot up! 

               Its really the trigger system that confuses me most and how to work
               out the fuel settings, im using bosch 250cc  injectors!

               cheers danny

[rob@vems.co.uk]

Do you know what the 60-2 trigger wheel was off?  The reason I ask is because a lot of these are already sorted and I should be able to just drop the trigger settings into a text file easily enough.

Fuel (From http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide)

req_fuel = 6.49 * (D / N / I)

D engine displacement (cc)
N number of injectors (eg. 4 for a 4 cyl port injection)
I injector flowrate (cc/min)

= 6.49 * (3700 / 8 / 250)
= 6.49 * (462.5 / 250)
= 6.49 * 1.85
= 12.0

[3.7 V8]

  Cheers for the injector settings Rob that has helped me a great deal

    As for the trigger wheel its a custom 034 motorsport joby fitted.
     It has been machined to get rid of any runout, and the vr sensor
      was from edis. will try and get a pic of it!

           cheers danny

[hilly]

Danny

Your injectors are 225cc/min units so the reqfuel should actually be 13.3

I thought we had been through the crank sensor position stuff.
You want tooth 0 (ie the first one after the gap) in line with the sensor at about 50° BTDC (40° - 60°), this will give plenty of scope to fine tune once the engine is running, this is working a treat with mine.

Now as your trigger wheel has been fitted to the crank pulley and that can only go on in one position on the crank you will have to move the VR sensor to get the correct location.
Alternatively, take the trigger wheel off the pulley, fit the sensor onto the Viscous fan mount using the bracket you made and then adjust the trigger wheel position on the pulley.

Easy peasy

Hilly

[3.7 V8]

      Sorry about the pic its not the best as its a tad difficult to photograph,

       The picture shows tdc marked by the bright green line, i have also marked the direction of rotation
        the teeth work out as 7 teeth the first been just under the vr sensor followed by six more
        then there is the 2 missing teeth and the final on just before the tdc mark.

        Hope this helps explain it a bit more!  Yes Andy i know you have been through this with me
         its keeping it in my head thats the trouble as you have already seen with my injector
         sizes that i gave to rob! 

          some would say thick as a brick , i like to think that my heads already full of knowledge
           so packing a bit more more in these days is a bit harder

            cheers danny

[hilly]

Danny

I'll break down the numbers a bit more for you.

As this is a 60-2 trigger, each tooth is at 6° (360°/60).
Now you want the the first trigger tooth to be at about 50° BTDC, to make the numbers easier lets change that to 48 as that divides by 6.

As 48° is 8 teeth, you want the VR sensor to be pointing at 8th tooth anti-clockwise from the gap when the engine is at TDC.

Looking at your picture it doesn't like it is miles out, though I don't think it is spot on, hard to tell.
If it is 7, maybe 6 then you will probabbly get away with it if you reduce the trigger ref angle to suit.

Does that help ?
Hilly

[3.7 V8]

   Ah i see now  

                       Yes Andy you are right following by what you are saying
              anti-clockwise from the 2 missing teeth there is in fact 6 teeth
               the last one been under the sensor! so its not all bad then.

                 Is this info easy to upload onto the vems and is there much to put in!

                      regards danny

[hilly]

                 Is this info easy to upload onto the vems and is there much to put in!

                      regards danny

Yeap and yeap there is loads of it.

Have you got MegaTune installed on your laptop yet ?

You really should take a bit of time out and search the Wiki to understand why you are entering certain values where.
It not only does it help you understand the whole tuning fundamentals and hence tune the car better, but when you have a problem it is easier to figure out how to sort it.

The config I sent you loaded into your VEMS is basically there, I left out the stuff that either I didn't know (due to unknowns with your hardware) or anything that may damage your engine if you blindly just fired it up without checking it.

The Wiki is a bit of a pain, but the info is there, it just take a bit of digging.

Hilly

[hilly]

Oh, and one more thing Danny

The gap between the sensor and the trigger wheel looks a bit on the large size, you really want it to be about 1mm (ish)

Hilly

[3.7 V8]

  Cheers again Andy,  have now reset it to about 1mm

      cheers danny