pre-programmed curves on 123 ignition - help please?

[Gfhug]

No, not seeking better mpg, it’s an E Type after all. Just feel the mpg has dropped since fitting the 123, hence my question to Malcolm. Set to curve 0 and will try 2.
My overhauled dizzie worked well but took the chance of buying a 123 from a friend. Plan to experiment a little but if others e.g. Malcolm, have found a good compromise then may as well benefit from their experiences.

Thanks to all for your input

Geoff

[mgcjag]

There is only one way to check mpg any where acurate and that is to start with a tank full till you can see it in the filler tube.....then drive........when you refill to the exact same point you can calculate mpg.....a 50 mile run isnt going to tell you much.......you need to look at local stop start driving.......motorway cruseing...and a 50/50 mix of both to get and meaningfull information....Steve

[Gfhug]

Totally agree Steve

[John ball]

Ok, so having read all four pages again and seen the comments, that the only way forward is to either go back to an original distributor OR buy the fully programmable version. I have the fully programmable version, but would like to know exactly what degrees at what Revs I should imput into my iPad. Based on 10 BTDC STATIC.
But also as importantly, I just do not understand how to programme the MAP points as I don’t understand what they all mean on the numbers. Is it to do with how high you live, altitude? So, what are the recommended numbers all the way up on both charts. I would like to base this on 3.8 engine, although as many of you will know from previous posts, my car is an XK120 3.4 with two HD8’s, UE needles, very slightly higher lift cams.
I just want to try the base line curves and pressures for the 3.8 E. I have tried so many curves that I have lost the plot in my brain.

[mgcjag]

Hi John...Have you just fitted the 123 and cant get your car running....or is it up and going but you want improvements..........this is from the E type Jaguar service manual..3.8 electrical section...all the curve details you need for the factor 3.8 setup....Steve.....Edit..this was your post from last year....it was discussed in detail..did you not get your car running as required.....you didnt give us a final update
http://forum.etypeuk.com/viewtopic.php? ... 3d87c5f3a7

[John ball]

Hi Steve, sorry I am not being very clear in my post. I do have the car running and also have that page from my manual. What I was trying to get at, is that I don’t understand on the programming of the 123 what are the MAP graphs and how to program them from the picture of the page you have posted. On the 123 MAP program there are various numbers that I do not understand. They seem to be about pressure but I can’t see how they relate to engine speed, vacuum etc. Do you know what curve or line I should imput on the MAP section of the 123 Bluetooth. I do understand the ignition curves of advance and have been trying various curves.

It is interesting reading a lot of these previous posts about the 123, that there are a lot of people confused, stating different answers and pointing out that the 123 does not produce the correct Jaguar ignition parameters. I am fairly appalled by the lack of support and knowledge from the manufacturer.

There is another Dutch company that makes a similar distributor called CSI. I have one of theirs in my Healey.
It is easier to program. Now I see they have just started to make a fully adjustable version for iPads and computers. I am tempted to contact them to see if their Jaguar knowledge is better than 123 people.
I believe the CSI team were a breakaway from 123 ??

[mgcjag]

Hi John...it might help if you posted photos of your maps and highlighted what numbers you dont understand...If your car is up and running...then whats wrong with the maps your useing?......The standard (non 123) distributor has two types of advance..mechanical controled by spinning weights and dependant on revs....the more revs the more advance.....Vacume....the distributor base plate is moved by a vacume unit to advance...vacume is not related to revs but by engine load....so for the 123 tune you have 2 maps one for mechanical and one for vacume...hope this helps.....Steve

[Tom W]

The numbers for the vacuum curve are on the left hand side of the workshop manual photo. You need to convert from inches of mercury to KPa for the pressure values. The corresponding values for advance in the workshop manual are distributor degrees, so they’ll need doubling to get the values for crankshaft degrees.

You shouldn’t have any initial (static) advance added by how the distributor is fitted in the car. This is all added in the app for the 123. I.e if you want 10 degrees at idle, the app should say 10 degrees at idle, and the timing should measure at 10 degrees at idle when checked with a timing light.

[John ball]

Tom, now I am confused about your statement about static setting. The instructions say to set the static at 10 BTDC. The screen advance degrees are crankshaft degrees. Therefore for example you program 0 degrees at the beginning and if you want a max of 30 degree, you input 20 degrees as the max. As far as the vacuum is concerned, I am going to do the maths and work out the inches to kpa’s and see how it compares with my MAP curve.

[John ball]

2F4FB2D8-4244-4F41-B227-8454F213CF75.png (178.84 KiB) Viewed 4569 times

This is the standard non adjusted vacuum curve. Not sure if photo has come out ?

[John ball]

Steve and Tom, sorry to be so stupid, but you can see the standard unmodified chart above.

How do I convert the inches and degrees from the Jaguar page manual on to this 123 screen. I cannot work it out - Help !! Sorry !

[mgcjag]

Hi John....if you look back at your previous thread that you posted that i linked you to above....you will see the photo of the two 123 maps that a friend is useing that i posted...look at the (converted)vacume figuers.....its for a S1 4.2....now look at your service manual...the 3.8 and 4.2 distributors both have the same figures for the distributor vacume advance.....Steve

[Tom W]

Tom, now I am confused about your statement about static setting. The instructions say to set the static at 10 BTDC. The screen advance degrees are crankshaft degrees. Therefore for example you program 0 degrees at the beginning and if you want a max of 30 degree, you input 20 degrees as the max. As far as the vacuum is concerned, I am going to do the maths and work out the inches to kpa’s and see how it compares with my MAP curve.

You can do it either way. The instructions I found are a bit vague, and only mention static point, not a specific value for the static point. If you use TDC, then the values in the app match what’s actually measured at the crank. If you use 10 degrees static, then you have to add 10 degrees to the values in the app to get what the value at the crank actually is. The end result should be the same, it’s just how the curve is represented in the app that’s different.

[John ball]

Steve & Tom, yes I understand that there are two ways of inputting the ignition advance graph, either by setting engine at TDC or at 10 BTDC then editing graph to match and follow. But I still don’t understand how you get the inches from the manual to Kpa’s in the MAP graph.

I cannot see from example shown how he has calculated the numbers from the manual ?

What does it all mean ? Numbers below:-

0 kpa @ 0 degrees
30 @ 20 degrees
50 @ 20 degrees
60 @ 10 degrees
75 @ 5 degrees
87 @ 0 degrees

[christopher storey]

John : the first thing to note is that these are not pressures, but depression, so that if 123 are working on pressure , then there is no advance until the "pressure" falls below atmospheric - let us say 29.92 inches = 1013 hPa = 101 kpa ( multiply by 3.4 to convert inches to kpa)

so converting the table - and taking the midpoint of the advance ranges given( remember these are in dist degrees so have to be multiplied X2 to get crank degrees ) . Note that the table you set out above is easier to understand if you read it a X degrees at y "pressure"

no advance before 4.5 ins = 15.3 kpa depression = 85.7 "pressure" = 0 degs crank advance
at 6ins = 20.4 kpa = 80.6 kpa = 2 crank degs extra advance
at 7.5ins =25.5 kpa = 75.5 kpa = 4 " " " "
at 9 ins = 30.6kpa = 70.4 kpa = 8 crank degs
at 13ins = 44.2 kpa = 56.8 kpa = 14 crank degs
at 20 ins = 68 kpa = 33 kpa = 16 crank degs

( apologies for the tabulation )

I hope this helps - if i can answer any further question I will try and do so

[Tom W]

Christopher typed his reply as I’ve been writing this, so apologies for duplication. KPa is an absolute measurement. Atmospheric pressure at sea level is about 101KPa. Figures below that represent vacuum, i.e below atmospheric pressure.

The figures you list show no change until 87KPa adding a maximum of 20 additional degrees by the time the absolute pressure drops to 50KPa. Below 30KPa, the additional vacuum advance is removed.

I presume the inches of mercury in the workshop manual is showing vacuum measured relative to atmospheric pressure.

[John ball]

Based on the Jaguar manual on post 65 and my un edited MAP curve on post 70.

Hello Chris and Tom,

These are the figures from your post with my new edited MAP graph.

Please can you tell me if I have entered the figures correctly.

Does it make any difference if I am starting at 10 BTDC on an ignition curve, or should I be using TDC
as a start point ?

Note the numbers are not capable of decimal points, so I have rounded up or down.

I really apologise for my total lack of knowledge about Vacuum etc.

[christopher storey]

John : your curve looks pretty well to reflect the figures I put in my converted table from the workshop manual . There would be no harm in using the top figure of the range in each case which would give you a maximum of 18 degrees extra advance. ( I used the midpoint figures from the manual ) . The vacuum advance is completely independent of ( and additional to ) the mechanical ( centrifugal ) advance so it makes no difference to the vacuum advance where you start or finish with the mechanical advance

The re-worked figures using the top of the range rather than the midpoint are

no advance before 4.5 ins = 15.3 kpa depression = 85.7 "pressure" = 0 degs crank advance
at 6ins = 20.4 kpa = 80.6 kpa = 2 crank degs extra advance
at 7.5ins =25.5 kpa = 75.5 kpa = 6 " " " "
at 9 ins = 30.6kpa = 70.4 kpa = 11 crank degs
at 13ins = 44.2 kpa = 56.8 kpa = 17 crank degs
at 20 ins = 68 kpa = 33 kpa = 18 crank degs

[abowie]

I contacted 123ignition.nl and asked if they could send me the curves for all the settings, and they said they didn't have them - bit hard to believe?

Precisely.

[John ball]

Andrew, like you I am pretty disappointed by the responses from 123 in Holland. On my Healey 100 I have distributor make by CSI. They are a breakaway team from 123 in Holland who produce a similar item and now have launched a fully programmable system like the 123 Bluetooth. I have the old simple version of the CSI that works well.

Chris & Tom, thank you for the MAP numbers and agreeing my graph looks ok. But does this really add
18 degrees which could be on top of for example 30 degrees mechanical advance at 3000 RPM or is this again something I have misunderstood ? I still don’t really understand all the different vacuum numbers, is this solely to do with suck from the engine or also to do with altitude where the car is driven ? Sorry if I sound so dumb, but maybe with your technical knowledge you are also teaching others who read this, which is a good lesson for all. At what stage of driving would the vacuum produce 18 degrees ?

It is strange that so many people say the 123 has transformed their cars, but if they are not modifying the MAP from the standard set position as my post picture number 70, then they are not getting full performance OR does the vacuum graph not matter too much. Many people run without vacuum- racers in particular.