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oldtuckunder

Trigger Wheel Mounting Vitesse

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13 hours ago, Nick Jones said:

Vitesse MS2.JPG

Nick

Hi Nick

Nice Map!

Could you explain what happens in rows 11 & 12, which (and remember I'm still an absolute novice) Row 12 is essentially throttle shut and Row 1 is WOT?  so lets say I'm running WOT at 5.5K (I'm assuming that my advance is set from top RH cell i.e. 34.0),  If I  lift I jump to bottom RH cell i.e. 32.0 (fine) my revs may have only dropped a tad, and then I gently open the throttle a bit, I'm running high revs, small throttle opening, highish vacuum, and my advance jumps to mid 40's on a probable lean mixture?

I think I understand the high advance orange/red cells if you are lifting from highish rpm's as no load and little danger, but don't understand the same settings as throttle is being opened.

As you see I have a lot to learn.

Alan

Alan

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Thanks, Roger!    I'll plot those out.      That's in inches of mercury, the configuration programme shows 0-100 no units, so presume that's % of max.

J.

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Hello Alan

                  Do not forget your map is 10 x 10 not 12 x 12!

John

          If I remember right you need to see what your max vacuum is and calibrate the sensor or scale to suit?

Then you can use 0 to 100% range

(I think old brain is going fast) just been going around in circles working out how much to skim off the head to get to 9.75(I like to be able to use foreign fuel when touring 97 not always available)

Your write is good its just me but resorted to Tinterweb and used cylinder calculator

Roger

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No probs!  How did you estimate chamber cross sectional area?  Graph paper, dirty thumb and count small squares?

Sure I had a vacuum guage once, if I can find it.

J

Edited by JohnD

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Not Sure if you have to calibrate it you have the MAP version?  There is nothing in the manual about having to calibrate the internal MAP sensor

 

5.1 MAP
For 3D MAP control, simply connect the MJLJ bulkhead connector to a suitable vacuum point on the engine.
A suitable vacuum point is one that gives a good representative indication of average manifold air pressure – take-off from a plenum chamber is best, and from the barrel of single choke on a multiple carburettor set-up is worst.
It is recommended that the vacuum installation minimises the chance of moisture entering the MJLJ unit and affecting the on-board MAP sensor. Techniques such as not mounting the MJLJ well below the vacuum take off point and having a “U-bend” between the takeoff point and the MJLJ can help.
Once you have connected the vacuum hose to the ECU start the engine. It should now be running with the MJLJ controlling the ignition advance in a 3D MAP mode.
Check the timing at idle with a strobe light. It should be the timing set in the map for the idle rpm and measured MAP. Blip the throttle, whilst checking the timing using the Advance gauge in the Configurator. It should be move according to the values set in the map – there will be low manifold pressure (indicated by small KPa values) when the throttle is closed and high manifold pressure (indicated by large KPa values) when the throttle is open.

MJMAP.jpg.5f65b7371a50bd49a671eba5747a27de.jpg

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37 minutes ago, oldtuckunder said:

Not Sure if you have to calibrate it you have the MAP version?  There is nothing in the manual about having to calibrate the internal MAP sensor

 

5.1 MAP
For 3D MAP control, simply connect the MJLJ bulkhead connector to a suitable vacuum point on the engine.
A suitable vacuum point is one that gives a good representative indication of average manifold air pressure – take-off from a plenum chamber is best, and from the barrel of single choke on a multiple carburettor set-up is worst.
It is recommended that the vacuum installation minimises the chance of moisture entering the MJLJ unit and affecting the on-board MAP sensor. Techniques such as not mounting the MJLJ well below the vacuum take off point and having a “U-bend” between the takeoff point and the MJLJ can help.
Once you have connected the vacuum hose to the ECU start the engine. It should now be running with the MJLJ controlling the ignition advance in a 3D MAP mode.
Check the timing at idle with a strobe light. It should be the timing set in the map for the idle rpm and measured MAP. Blip the throttle, whilst checking the timing using the Advance gauge in the Configurator. It should be move according to the values set in the map – there will be low manifold pressure (indicated by small KPa values) when the throttle is closed and high manifold pressure (indicated by large KPa values) when the throttle is open.

MJMAP.jpg.5f65b7371a50bd49a671eba5747a27de.jpg

Hello Alan and John

                                   If you set it as the MJL instructions.

Configuring Normally Aspirated or Forced Induction

Check the 'Normally Aspirated' box if that matches your engine type. This setting will scale the load axis for the runtime and logging views to 103KPa maximum.

Otherwise, leave the box clear if your engine is turbocharged or supercharged. This will set the maximum scale to 255 KPa (approximately 21 PSI of boost)

 

I do not think you will ever get to the minimum of the map!

They say 103KPA which is 30in mercury and the WSM chart shows 20in mercury = 68 KPA

I think you edit it in RPM and load bins then you can alter it to reflect what you get?(I think?) ask Nick

This one of the maps I used on Spitty

This site will do KPA to ins

http://www.kylesconverter.com/pressure/kilopascals-to-inches-of-mercury

Screenshot_1.png

Edited by rogerguzzi

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there will be low manifold pressure (indicated by small KPa values) when the throttle is closed and high manifold pressure (indicated by large KPa values) when the throttle is open.

this is confusing.   Manifold pressure will be LOWEST withe the hrottle closed.   "Vacuum" - difference between manifold and atmosphere - will be highest behind a closed throttle.    Unless the throttle plate blocks the orifice to the line, which it won't.

j

 

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2 hours ago, JohnD said:

No probs!  How did you estimate chamber cross sectional area?  Graph paper, dirty thumb and count small squares?

Sure I had a vacuum guage once, if I can find it.

J

Hello John

                   I just measured length and width 74mm x 45mm(average) added them 119 divide x 2 = 60 approx 

Which with 0.020"(0.5mm) gives 1.4cc

74mm dia gives  2.15cc

a bit crude but probably close enough?

Biggest chamber is 42.4cc + gasket (74mm x 0.7mm = 3cc)  45.4

Cylinder is 378.36cc + 45.4 = 423.76 / 45.4 = 9.333 to 1

So skim 2cc off = 0.028(.7mm) = 421.76 / 43.4 = 9.717 to 1

I think?

Roger

ps I think I will have 0.030" skimmed off I can always open the chambers a touch if necessary? they are within 0.3cc at the moment so will do final balancing when valve seats have been cut to the 3 angle

Edited by rogerguzzi

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5 hours ago, oldtuckunder said:

think I understand the high advance orange/red cells if you are lifting from highish rpm's as no load and little danger, but don't understand the same settings as throttle is being opened.

Hello Alan

                   Vacuum drops so ignition is retarded

Roger

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34 minutes ago, rogerguzzi said:

                   Vacuum drops so ignition is retarded

Yes but if you look at 70% at 5.5K the advance is still 40 deg, which if I was lifting would be fine, but going back under load that's a lot of advance

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3 hours ago, JohnD said:

there will be low manifold pressure (indicated by small KPa values) when the throttle is closed and high manifold pressure (indicated by large KPa values) when the throttle is open.

this is confusing.   Manifold pressure will be LOWEST withe the hrottle closed.   "Vacuum" - difference between manifold and atmosphere - will be highest behind a closed throttle.    Unless the throttle plate blocks the orifice to the line, which it won't.

j

 

Hello John

                    I think it is the other way around!

Low vacuum with open throttle high vacuum low throttle

This may explain it?

http://www.fastfieros.com/tech/map_sensors_and_how_they_work.htm

Roger

ps and the scale is reversed on MJL

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Maybe I'm being pedantic, and it's in the use of words.   

 MAP, "Manifold Absolute Pressure", uses the word "Absolute" so should give the pressure relative to zero.  That's what "Absolute Pressure means, just as "Absolute temperature" is relative to absolute zero, -273.15C.    If a true vacuum is Zero pressure, then the more closed the throttle, the lower that will be

I think what is being measured is "Vacuum"or Relative pressure, below atmospheric.     With a wde open throttle this will be low, not much difference from atmospheric, and with a closed throttle it will be high, as the enghine sucks air against resistance.

John

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Not positive for MJL but for MS the standard sensor used is an absolute one with a 0 - 250kPa range, measuring from absolute zero (or somewhere near it) so 0kPa is 0, atmospheric at sea level is around 100 kPa and if you have forced induction you can go up to 1.5 Bar of boost before you need to upgrade to the 400kPa sensor.

You rarely see less than 25kPa in my experience and that's on the over-run at reasonably high rpm.  Idle typically in the 40 - 70 range dependent on how wild your cam is.

Nick

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1 hour ago, Nick Jones said:

Not positive for MJL but for MS the standard sensor used is an absolute one with a 0 - 250kPa range, measuring from absolute zero (or somewhere near it) so 0kPa is 0, atmospheric at sea level is around 100 kPa and if you have forced induction you can go up to 1.5 Bar of boost before you need to upgrade to the 400kPa sensor.

You rarely see less than 25kPa in my experience and that's on the over-run at reasonably high rpm.  Idle typically in the 40 - 70 range dependent on how wild your cam is.

Nick

Hello All

               I use one of these on Microsquirt  PRT 03/04 I found the 2.5 to coarse a calibration they are all 0 to 5v so it is more sensitive.

MAP sensor.pdf

 

Roger

 

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2 hours ago, Alfredo said:

Keep in mind that vacuum is a negative pressure... 

Only relative to another pressure, usually atmospheric.

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Hello John

                    Welcome to the electronic world were most things do not make sense(its all smoke and mirrors!)

But when you get your head around it it seems to work! (back to smoke and mirrors) if someone asks how it works use some big words and waffle on a bit until they glaze over then you are off the hook!

Roger

ps how old are the grandchildren? they would understand if 10 or above!

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5ab18d0008195_Advancecurves.thumb.jpg.c897c3d30e82f055bef0825b6086e395.jpg

I've plotted Centrifugal (top) and vacuum advance curves, from the workshop manual and from GT's book, which doesn't give any vacuum numbers.

But his curves, and he includes several standard as well as this "typical racing curve", which are all quite different from the WSM one, all much, much  higher.

And the WSM is a range, indicated by thre upright lines.

 

The WSM vacuum curve is difficult to translate, into practice as as well as a chart when it says 3.8 - 6.2 in of mercury - "must start to advance".  I have presumed from zero towards the 8 degrees for the next step.

All degrees in crank angle.

 

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They are 4 and 3.    As apprentices a bit too junior as yet, but No.1 does enjoy "Papa's car", and No.2 likes to hammer in nails!

John

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10 hours ago, JohnD said:

5ab18d0008195_Advancecurves.thumb.jpg.c897c3d30e82f055bef0825b6086e395.jpg

I've plotted Centrifugal (top) and vacuum advance curves, from the workshop manual and from GT's book, which doesn't give any vacuum numbers.

But his curves, and he includes several standard as well as this "typical racing curve", which are all quite different from the WSM one, all much, much  higher.

And the WSM is a range, indicated by thre upright lines.

 

The WSM vacuum curve is difficult to translate, into practice as as well as a chart when it says 3.8 - 6.2 in of mercury - "must start to advance".  I have presumed from zero towards the 8 degrees for the next step.

All degrees in crank angle.

 

Hello John

                   Just create 2 maps one high end of WSM and one racing curve but suspect you wil need a RR session to find the best one!

Then you can just switch on the fly if you want (look out F1)

Plus you can make lots of maps and just save them and once you have one you think is near just keep trying the others as second map

It is different for me I just want a drive able car and good MPG at cruising 

Roger

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On ‎20‎/‎03‎/‎2018 at 11:46 AM, oldtuckunder said:

Hi Nick

Nice Map!

Could you explain what happens in rows 11 & 12, which (and remember I'm still an absolute novice) Row 12 is essentially throttle shut and Row 1 is WOT?  so lets say I'm running WOT at 5.5K (I'm assuming that my advance is set from top RH cell i.e. 34.0),  If I  lift I jump to bottom RH cell i.e. 32.0 (fine) my revs may have only dropped a tad, and then I gently open the throttle a bit, I'm running high revs, small throttle opening, highish vacuum, and my advance jumps to mid 40's on a probable lean mixture?

I think I understand the high advance orange/red cells if you are lifting from highish rpm's as no load and little danger, but don't understand the same settings as throttle is being opened.

As you see I have a lot to learn.

Alan

Alan

Row 1 (top) is full throttle.  Row 12 is throttle shut.  IIRC the step between 11 and 12 was to address popping and banging on the over-run.  I think the reality with the "red zone", especially at the upper reaches of the rpm range is that it either never goes there at all or spends almost no time there.  Certainly that map (or one very like it) worked well for many thousands of miles and was only changed because the engine changed.

Something else that shows a bit (I think there was a later variant which shows it more strongly or it may be the current map as the new engine is much fussier at idle) is the anti-stall - which is additional advance in the top left corner intended to help pick the revs up if it tries to die.

Nick

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Nick's map Vitesse MS2.JPG

Sorry, guys still confused.

Nick, about your map above, you reply to Alan that top line is Wide Open Throttle.    But that row is labelled "100" for 'CalcMAP kPa' .   WOT delivers minimal vacuum and max absolute pressure, and I'd expect max advance under max load and max revs, which the map does, so WOT bottom line???

 

Roger's map uss the same vertical scale as in my version of Megajolt, 10-100, no units.   But here with low load (ie closed throttle) advance is highest in that row.    Shurely shome mishtake?  Certainly mine, but grateful for exposition.

Screenshot_1.png

 

Here's what I've done 

Excel file, Revs vs. vacuum

 
Revs 
                   
kPa - 
0 900 1000 1500 2000 2500 3200 4000 4500 5200 6000
68 22 32 34 36 37 38 49 51 52 52 52
58 18 28 34 36 37 38 49 51 52 52 52
49 14 24 30 32 33 34 45 47 48 48 48
41 14 24 26 28 29 30 41 43 44 44 44
37 8 18 26 28 29 30 41 43 44 44 44
29 8 18 20 22 23 24 35 37 38 38 38
21 0 10 20 22 23 24 35 37 38 38 38
13 0 10 12 14 15 16 27 29 30 30 30
0 0 10 12 14 15 16 27 29 30 30 30

 

WOT on the bottom line, with least vacuum.    The numbers are the sum of the centrifugal advance (as GT's chart) plus the vacuum advance from the WSM.

As you can see it goes up to more than plus FIFTY!  Ooerr, missus!    Again shome mishtake.  I recall, I think, that GT advocates locking the vacuum advance and relying on the centrifugal only, so what he illustrates is TOTAL advance.  I'll try again, starting with the  WSM numbers.

Meanwhile Excel is your friend, and here is the above, excessive map in 3D.  Pretty, innit?

image.png.eed67686b51c19773126a54def158c8f.png

 

John

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image.png.4de461b32cdb92a0a1e01df5b882fe64.png

        RPM                            
Vacuum Ins/Hg kPa   900 1000 1500 1650 2000 2400 2500 3000 3200 3500 3600 4000 4200 4800 5000
WSM  0   0 2 3 7.5 9 10 11 11 12 12.5 13 14 15 15 17 17
  3.8 13 0 2 3 7.5 9 10 11 11 12 12.5 13 14 15 15 17 17
  6.2 21 0 2 3 7.5 9 10 11 11 12 12.5 13 14 15 15 17 17
  8.6 29 8 10 11 15.5 17 18 19 19 20 20.5 21 22 23 23 25 25
  11 37 8 10 11 15.5 17 18 19 19 20 20.5 21 22 23 23 25 25
  12.2 41 14 16 17 21.5 23 24 25 25 26 26.5 27 28 29 29 31 31
  14.6 49 14 16 17 21.5 23 24 25 25 26 26.5 27 28 29 29 31 31
  17 58 18 20 21 25.5 27 28 29 29 30 30.5 31 32 33 33 35 35
  20 68 22 24 25 29.5 31 32 33 33 34 34.5 35 36 37 37 39

39

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Above is the map and the numbers, if I take the WSM figures for centrifugal advance and vacuum advance, take a mean for the latter's min and max, and add them.

 

Still looks pretty, but still goes to nearly 40 degrees advance.

And I'm now puzzled by my own magnificence figures.  Max advance when vacuum max - its merely addition, but I'd expect max vacuum when throttle closed and no load.  I'm missing something - help me here, please?

JOhn

PS can't use that width of map in Megajolt - the grid is only 10x10.  I'll do a version with that.

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