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XF - EST TIMING MAPS

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Does anyone have any detail on the shape of the advance map in the EST ignition? - like how much centrifugal and how much vacuum?

I gather from past threads that the 3.3 (and maybe manual) versions have less RPM advance.

 

It'd be good to track down some more detail on that though.

 

But in particular I'm wondering about the temperature component.

 

I've seen one report that it advances at lower temperatures. Is that a flat across-the-board advance in addition to whatever the RPM and vacuum?

I'm thinking in terms of suitability to gas.

 

For example, if the cold advance happens to advance more in the lower areas of the map, it could work really well as a poor-man's regraph and dual timing setup.

- Replace the temp sensor with a switch and on petrol, have the EST to think it is hot, and for LPG tell the EST that the engine is cold.

 

http://www.xfalcon.com/forums/index.php?/topic/20318-est-timing-maps/

http://www.xfalcon.com/forums/index.php?/topic/2516-help-dizzy-stuff/

http://www.xfalcon.com/forums/index.php?/topic/32106-throttle-position-sensor/

http://www.xfalcon.com/forums/index.php?/topic/14010-curious-about-idle-behaviour/

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I've set up a microcontroller board to interface the EST module (4.1 Auto) to my PC, and have started calculating some timing maps from it.

This is the basic one.

It doesn't include the 10 degrees of base timing, so that is in addition to what is in this table, ie it advances up to 48 degrees BTDC at 3000RPM, 50kPa.

 

EDIT: this table is wrong. See fixed one below.

 

Temp: 100.0;  AC Off; Throttle Open;
Advance above base timing
MAP(kPA)                        RPM
       500   800  1000  1500  2000  2500  3000  3500  4000
100   0.3   0.1   0.3   0.0   3.7  10.9  14.0  15.2  15.0
  90   0.7   0.5   5.6   8.7  15.5  16.4  15.0  15.0  15.2
  80  15.4  15.3  15.5  15.1  23.1  23.0  20.5  18.3  18.2
  70  15.4  15.2  15.5  15.5  27.8  29.9  28.2  26.7  26.8
  60  15.5  15.3  15.5  15.4  28.5  33.8  33.7  33.8  33.7
  50  15.5  15.3  15.5  16.5  31.7  36.6  37.6  37.8  37.7
  40  15.4  15.3  15.5  18.3  30.6  34.8  37.5  37.5  37.6
  30  15.5  15.3  15.5  18.3  30.6  34.8  37.6  37.5  37.7
  20   0.3   0.2   0.4   8.1  23.9  34.7  37.6  37.7  37.7
  10   0.3   0.1   0.3   8.0  23.9  34.8  37.6  37.5  37.5

 

Changing temperature seems only to affect the idle, returning to 15 degrees at all pressures under 80kPa when below 1500rpm and under 70 C.

AC seems only to have an affect in the cold running mode, and then advancing it up even more at idle RPM low pressure.

 

I'm still having troubles with the EST module detecting sensor faults - mainly with the throttle position. It looks like it identifies infeasible TPS, MAP and RPM combinations, and logs a fault, either with TPS or with MAP.

 

When MAP fault is logged, it ignores the MAP sensor, and gives a basic curve that advances up to 33 degrees.

I haven't yet worked out what effect the TPS has on the timing.

 

Anyone have any hints on what are sensible manifold pressures for throttle closed across the range of RPM? Does this table look right?

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Strange that engine temp does not affect the performance,as soon as mine got to operating temp it went backwards,but when under 1/4 or so it went so much better.Mine use to run a 3.3 man EST and only a 515-520 lth and 215-220 dur or so cam.

 

A electronic dizzy fixed all it's problems.

 

Good work so far and goodluck...

Slydog

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I made an error in the above, with the wrong scaling in the advance angle. My calculations had a spark every 180 degrees of crank angle, not every 120 degrees, as there is with a 6 cyl.
Here's a new table. This time the base timing of 10 degrees is also included.


Temp: 90.0;  Thottle Open; AC off

kPa                   RPM
       750 1000 1250 1500 1750 2000 2250 2500 3000 3500
100 |  10   10   10   10   10   13   15   17   20   20
  90 |  10   14   14   16   18   21   22   22   20   20
  85 |  16   19   19   19   20   24   24   23   21   20
  80 |  20   20   20   20   21   26   27   25   24   22
  70 |  20   20   20   20   24   29   30   30   29   28
  60 |  20   20   20   20   24   29   31   33   33   33
  50 |  20   20   21   21   26   31   33   34   35   35
  40 |  20   20   20   22   26   30   33   33   35   35
  30 |  20   20   20   22   27   30   32   33   35   35
  25 |  20   20   20   22   26   30   32   33   35   35
  24 |  10   10   11   15   21   26   31   33   35   35
  20 |  10   10   11   15   21   26   31   33   35   35


At 5000rpm, advance jumps to 38 degrees (rev limiting?)
The dwell varies with battery voltage, and is around 5ms

Now, the effect of the other sensors:


Throttle Position:
With the TPS closed (throttle closed), timing below 2000RPM is retarded to the same curve as for pressures below 25kPa. ie, at idle reverts to base timing.
A disconnected TPS flags an error, but otherwise operation is as normal.

 

Temperature
Idle timing varies between 60C and 80C
Below 60C, for <80kPa <1250RPM advance goes to 20 degrees regardless of TPS.
If the sensor is disconnected, an error is logged, and operates as per warm engine

 

Air Conditioner:
Advances low RPM. Specific amount varies with temperature.
If temp <=60 C, then for map < 70kpa, and <1300RPM set advance=40 degrees
As temp increases, pressure threshold and rpm threshold decreases
Above 80, for <=1000RPM, <60kPa, set 30 degrees advance

 

Start:
When starter engaged, reverts to base timing
around 50 crank degrees of dwell
250 34ms, 500 15ms, 750 10ms

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I was expecting more effect from the temp sensor too.

It seems mainly about defeating the idle retard that normally happens on closed throttle.

 

My understanding is that higher temperatures give faster combustion and hence do better with some retarding across the range.

 

The flatness of the map below 1700RPM surprises me.

I'm suspicious of how all the activity seems to happen just around 2000RPM, and I'm suspecting that it may have been tailored to suit the autos, which tend to sit around that rev range in normal running.

If I come across a manual EST somewhere local I can borrow, I'll be interested to see what differences there are.

Regardless, I'm looking to go to a custom timing map, either megasquirt or by replacing the microcontroller in the EST.

 

I've only got the 4.1 Auto module, so basically any of the others would be of interest to confirm just what the differences are.

My main interest at the moment would be to see what they do different in the manuals, though there is also some interest around in the differences for the 3.3 in terms of running on gas.

 

I don't know what the temperature issue was with that EST module. I can only speculate that it was the retarding for low RPM, or perhaps it was advancing it too much at that temp at higher RPM - though you'd probably hear the pinging if that were the case.

 

Anyhow, here's a plot of the advance curve

 

timing_est_41_auto.gif

 

If anyone should happen to want all the gory details of the data, here's a file with detailed data:
XF 4.1L Auto EST Timing Map Data

http://www.2pi.info/auto/timing_est_41_auto_scan.txt

 

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Thats a great bit of work there Mate, Really appreciate you going to that effort and putting up the Data, Will be really interesting to see what the 3.3 ecu timing map looks like.

 

This will make things very easy for the guys who want to setup a base map in megasquirt or any other ECU
I just made it a sticky

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Here's the map we used on Wes's XF.

http://home.exetel.c...rting SPARK.vex

You can load it into megatune or put it into your graphic program. If you look at the numbers the RPM is the horizontal scale, subtract the translation and multiply by the scale to get the actual timing.

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That stock map is pretty anemic! Plenty of torque to be gained by tweaking the spark there. That 2nd map looks a lot better.

Jason

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It seems that EST has some more tricks up its sleeve than I thought.

Doing some logs on the road I discovered that it is giving some extra advance when cold, as slydog thought.

 

Below 35C, it gives an extra 6 or 7 degrees of advance, but not all the time - which is why I didn't pick it up on the test rig.

 

It seems to only give the extra advance while the MAP and/or RPM is increasing - doesn't give it for constant parameters - also generally more likely above 60kPa. The effect tapers out until after around 50C where it follows the main map.

 

It may be some compromise between advancing up when cold for performance, but retarding back to heat the cat when it doesn't think its being loaded.

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thought this might be helpful withe making sense of in in the real world

 

kPa Vac
0 29.5
5 28.1
10 26.6
15 25.1
20 23.6
25 22.1
30 20.7
35 19.2
40 17.7
45 16.2
50 14.8
55 13.3
60 11.8
65 10.3
70 8.9
75 7.4
80 5.9
85 4.4
90 3.0
95 1.5
100 0.0

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When MAP fault is logged, it ignores the MAP sensor, and gives a basic curve that advances up to 33 degrees.

 

Do you have this curve? Will a disconnected (from the ECU) MAP sensor cause the fault?

 

At 5000rpm, advance jumps to 38 degrees (rev limiting?)
At all pressures?

 

I'm looking to go to a custom timing map…by replacing the microcontroller in the EST.
This would be good.

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MAP faults: Looking back on my notes, the simple answer is it uses the 60kPa curve.

 

After just running a test on one on the bench it's a bit more complicated, because it seems to only handle one fault mode at a time, and you can easily end up with a throttle position error instead, which gives a different curve.

 

I wouldn't recommend relying on the fault mode curve, and it'd only be the same as locking it to 60kPa anyhow.

 

At 5000rpm it goes to 38 deg at all pressures.

 

I've managed to get an EST running in the car with an Arduino microcontroller doing the timing.

I added a knob that I could manually advance/retard the timing map, and found it remarkably insensitive to it, so ended up shelving it for a while.

 

I'm about to shave the head and give it a cam, so will revisit it with the higher compression to see if fiddling the timing will make more of a difference then.

 

I have some more info on interfacing to the circuit that I'll see about posting up soon.

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I've just put my crossflow back together with 50 thou shaved off the C2 head and have been working to get the ignition advance right. I've modified the EST module and added a knob inside the car that will advance/retard the timing map.

 

What I'm finding though is it seems to make no real difference, at least running on gas. I can advance or retard 10 degrees from the standard map on 12 degrees base timing, and it has little noticeable effect on performance. I've had it out briefly to 25degrees either side under various loads, and still runs fine with not much power loss: but will start to feel a bit different in the engine note. Still not a ping to be heard.

It does affect the idle speed, with more advance giving faster idle, up to something like 45 degrees or more.

 

With the shaved head I should be running around 9.5:1 compression, and with that I would have at least expected it to ping and lose power when over-advanced. Also, with the talk of regraphed distributors, I would have expected significant effects from getting the timing right. Anyone know whether this is normal? Could there be anything wrong with the motor to cause it to be less sensitive to advance? Error in cam timing maybe? Any hard figures on hp loss with timing changes?

 

I also notice there's a moderate amount of unevenness on the hall sensor from the EST distributor. I estimate it results in around 5 degrees of variation in advance between the cylinders. I can program up a filter into the ignition to cancel that out, but if combustion isn't really that sensitive to timing anyhow, it's probably not worth it. Or maybe that variation is making it less noticeable when the timing is just right.

 

http://www.xfalcon.com/forums/index.php?/topic/26035-does-timing-really-matter/

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yes timing does mater you gotta make sure that all the engine geometry work together so every thing goes bang at the critical time that why it's called timing

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Is the EST doing anything else to the spark supply aswell..? Doe's it behave differently when colder and how much has been done to the engine.A close to stock engine benefit close to f*ck all when messing with em.I did find that changing to extractors with a 2.5" exhaust and a modified and raised Webber it felt better with a 3.3 EST and 10# of timing but still got smashed by almost every other car on the road...lol

 

The current engine reacts too timing changes alot more noticeably,take timing out it slows down and becomes less responsive crank it up and it's much snappier and wound up too much it will rattle a bit.

 

If we lived closer I'd donate my ute to the cause for a weekend cause the EST and stuff is all still in it but not used...

Good luck bro,I like where your heading with it.

 

Slydog

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