36-1 and config

[gunni]

I have a config that has Angular Width of Tooth as 12
And Angular width of missing tooth as 6

I´m using firmware 1.0.73
and am skeptical of these numbers.
http://www.vems.hu/manual/html/ch09.html#Detailed.Sensor.RPM.Config

Tells me dec is

dec = 255 / (2 * imaginary teeth)

Or 255 / 2 * 36 = 3.54 or ~ 3

Engine phase is

Engine phase = 2 * (dec * real teeth + dec * missing teeth)

Or

2 * ( 3 * 35 + 3 * 1 ) = 2 * (105 + 3 ) = 2 * (108) = 216

Then

Angular width is

Angular width of tooth = engine phase / ( imaginary teeth * 2 )

OR

216 / 36 * 2 = 216 / 74 = 2.981 ~ 3

Angular width of missing tooth is

Angular width of missing tooth = (missing teeth + 1) * dec

Or

(1+1) * 3 = 6

While in my config I have
Angular Width of tooth as 12 and missing as 6.
Which is wrong?

Could this cause some strange advance issues?
The original file I got from Rob has 3 and 6 ...........
I have not messed with those settings so could it have gotten messed up at one point?
The owner HAS uploaded a MSQ file and I actually uploaded the .msq to begin with and all subseqent files
are like this. So I have no real time for when that config went strange maybe from the beginning.
And it was hell to get this thing going as well.

I´d rather have users just upload .VEX files for fuel and timing from now on as that´s all that is supposed to be changed after running is up.

But. Should I not change it to 3 and 6?

In this file.
http://www.vems.co.uk/VEMSInstalls/VEMSFordRST.zip

Firmware 1.0.53
Angular width is 10 I´m assuming (360/36 = 10)
and missing is 6
Is there a different calculation in that firmware?
This file also has very similar TDC after the trigger settings as well as triggers tooth.
So I´m thinking it´s just the width of tooth and missing that have mysteriously changed.

Everybody agree?

[Denmark]

Hmm.

I have always used tooth with 10 degrees, and missing 20 degrees, becourse that is what it is, with a 36-1,


/Skassa

[rob@vems.co.uk]

You can put pretty much what you like in there, until filtering is enabled those figures seem to be ignored.
Once you enable filtering... who knows what happens, because I've never managed to get anything to work with filtering.

Rob

[gunni]

Damnit..

Ohh well thought I had the case cracked wide open

[gunni]

And  I have now.

By some amazing bizareness my timing light measures 4stroke correctly in 2stroke mode,
just tested it today on a 325i turbo I was doing but not VEMS this time.
Under normal base timing adjustment it didn´t even accelarate, and the timing map is a 100%
close enough map.

Timing was set at 90deg BTDC, after trying the 2stroke mode it came down to 72deg.
just like my VEMS 325i has it. and low and behold the car is now behaving EXACTLY as expected.

in 2stroke mode it counts half the rpm´s but strangely the timing advance is correct.

This means I´ll be going to the Focus after the weekend and fixing it´s timing as well. As it´s always been low on power.
It´s sitting at 77deg now but Rob´s Focus file assumes 65deg, so for this car it´s potentially of by 12deg which would explain why it is the way it is now.

[rob@vems.co.uk]

Always keep your advance on the timing light at zero and use the TDC after trigger value to tune what the ECU is actually doing.

[gunni]

Just to update.

today i visited the focus and re adjusted the base timing and it´s on 65deg just like the
VEMSFordRST.zip file has it.

So it´s safe to say that adjusting the base timing should always be done running the ecu ignition at 0deg
especially on wasted spark engines. Car idles ALOT better even though it was alright before,
to bad that the intake manifold is bad and peak torque is at 4500rpm and falls of right after that.
 
They are going alpha-n over winter so should be more lively next rally season

[GintsK]

Always keep your advance on the timing light at zero and use the TDC after trigger value to tune what the ECU is actually doing.

Rob, you are too conservative. I use this timing light with success.
http://www.iequus.com/product_info.php?product_id=5568&category_id=1_20
 Tachometer allows see what happens. If it reads double (wasted spark, dual outputs), it have 2-stroke mode.

Sometimes with wasted spark timing light reads real rpm on 4-stroke mode. Because it sense only higher voltage spikes for compression stroke.

I even use this device on primary circuit!

Agree - must be careful. Timing light can read wrong rpm (then zero adjustment is safe). And it can even read dwell period start point. But all kinds of misreading is easy to to recognize.

Gints