Need help setting up 1st time ignition map table

Mad Professor · Post by **Mad Professor** » Sat Feb 18, 2006 2:23 pm

Hi All.

I need help settings up my 1st time ignition map table.

Before anyway say it yes I have read "Setting up an initial ignition timing table", But like anything when you 1st look into it, it is over my head.

I am in the middle of converting over from dizzy to EDIS, So I need to get a basic ignition map table sorted.

I mostly run Unleaded (RON95), and some times Super Unleaded (RON97).

I have most of my engine details in my sig below, but if you need any more info to help me out please just ask away.

Thanks for your time.

woh · Post by **woh** » Sat Feb 18, 2006 9:12 pm

A good place to start is with the advance curve of the distributor you have. I assume it is not electronic advance. You don't give a year of the car. You should be able to find the curves on the web (maybe) or one of the car clubs.
Most cars with mechanical distributor have very similar advance curves. There are usually three parts. Each has a start and stop to in the specification.

1. A fast increase in advance due to rpm
2. A slow increase in advance due to rpm
3. An increase in advance due to vacuum. (decrease in MAP relative to ambient)

These are added together to get the total advance. Attached is a spread sheet that attempt to create a table from these three parts. If you can't find any advance curves/data then start with the table in the spread sheet.

Mad Professor · Post by **Mad Professor** » Tue Feb 21, 2006 12:42 am

As of yet I have been unable to find any mechanical distributor advance curves for my engine.

I have contacted one of the guys who did the 205 Turbo Conversions.

Question: Do you have any data on the Mechanical Distributor Advance Curves for the 205 1.9 GTi and or 205 1.9 TT? Thanks...

Answer: Hi.. not as such, although they are pretty lousy! They all suffer with under advancing, which means if you set the ignition for best performance at over 3500 rpm, they pink like mad at 2000. We tend to use the Superchip Icon programmable piggy back with these, then setting the correct advance is a doddle. The Turbo Technics versions would probably be ok with the standard advance, as you don't want it to crank up so much anyway. TT supplied a retard capsule, which backs off about 8 degrees under load. Crude, but reasonably effective!

Mad Professor · Post by **Mad Professor** » Tue Feb 21, 2006 6:05 am

My Dizzy unit is a "Bosch 0 237 009 066", The vac unit on the dizzy does not seem to have a make and or model, all I can find on it is "065".

Mad Professor · Post by **Mad Professor** » Tue Feb 21, 2006 9:50 am

Well I e-mail'ed Bosch this morning, and I have just got a reply back with this.

Is this the data I need to help with making a new ignition map table?

woh · Post by **woh** » Wed Feb 22, 2006 8:25 pm

Mad Professor

The diagram gives a range of values or specs for the mechanical advance, the vacuum advance, and the static timing. Here is how I read it. Anyone else have a different interpretation?

Static timing is 9deg
Mechanical advance:
primary; starts at 600 rpm, stops at 1000 total of 10 deg
secondary; starts at 1000, stops at 2500 rpm total of 5 deg

Vaccumm advance:
starts at 150mbar (85kPa MAP), stops at 525mbar (47.5kPa MAP) total of 10deg.

I attached a spread sheet that adds up the various values and creates a ignition table for you. It is very similar to other cars. The difference is the max advance when all the different advance parameters add up. The max advance will be 9+10+5+10=34deg

Mad Professor · Post by **Mad Professor** » Fri Feb 24, 2006 4:33 am

Thanks.

I gave that map a try this morning, and it works much better then the other map, But still not quite right.

What do I need to do to the map for boost, as when I change the data in the excel file >100KPa the the data does not change?

This is what the map looks like atm:

Mad Professor · Post by **Mad Professor** » Fri Feb 24, 2006 5:02 am

From reading the other post.

Is this right?

220Kpa, -22, -17, -16, -15, 14, -12, -12, -12, -12, -12, -12, -12.
180Kpa, -10, -5, -4, -3, -2, 0, 0, 0, 0, 0, 0, 0.
140Kpa, 2, 7, 8, 9, 10, 12, 12, 12, 12, 12, 12, 12.

Peter Florance · Post by **Peter Florance** » Fri Feb 24, 2006 5:28 am

woh wrote:Mad Professor

The diagram gives a range of values or specs for the mechanical advance, the vacuum advance, and the static timing. Here is how I read it. Anyone else have a different interpretation?

Static timing is 9deg
Mechanical advance:
primary; starts at 600 rpm, stops at 1000 total of 10 deg
secondary; starts at 1000, stops at 2500 rpm total of 5 deg

Vaccumm advance:
starts at 150mbar (85kPa MAP), stops at 525mbar (47.5kPa MAP) total of 10deg.

I attached a spread sheet that adds up the various values and creates a ignition table for you. It is very similar to other cars. The difference is the max advance when all the different advance parameters add up. The max advance will be 9+10+5+10=34deg

I have similar data in my BMW Factory Book. It has the timing in terms of dist shaft angle, so I felt I had to double those #'s for crankshaft angle.
I think my centrifugal advance has about 20 degrees of crankshaft range and the vacuum advance is about 14 IIRC. There's also a retard port on the canister that has about 7-8 degrees range, but only certain years used both. I tried years ago and it didn't work well.

2.8L 8.2:1 was the original motor that my dist was made for.

That's a great tool, BTW!

woh · Post by **woh** » Fri Feb 24, 2006 9:21 am

Peter

Good catch. It's "distributor shaft speed" and "distributor shaft adjustment".

So those numbers should double in the spread sheet. That seems like a lot of advance though. That would give a max advance of 68 deg. That's too much.

Something is not right. I would expect the max to be less than 45deg. Are the numbers you see on your car in line with these? My old MG sees about 36deg max advance when all is added together. We need to confirm the raw data somehow.

Mad Professor
I would increas the advance at 50kPa during idle to about 15 and increase the 9deg values at 800rpm to about 20 to help stabilize the idle.

I can't help you with the boost values.

Peter Florance · Post by **Peter Florance** » Fri Feb 24, 2006 9:48 am

woh wrote:Peter

Good catch. It's "distributor shaft speed" and "distributor shaft adjustment".

So those numbers should double in the spread sheet. That seems like a lot of advance though. That would give a max advance of 68 deg. That's too much.

Something is not right. I would expect the max to be less than 45deg. Are the numbers you see on your car in line with these? My old MG sees about 36deg max advance when all is added together. We need to confirm the raw data somehow.

Mad Professor
I would increas the advance at 50kPa during idle to about 15 and increase the 9deg values at 800rpm to about 20 to help stabilize the idle.

I can't help you with the boost values.

I would probably use the middle of the tolerance window and say 8 and 4 degrees (dist) yielding 16 and 8 for 24 degrees of total cent advance relative to crankshaft. Then 10 degrees of vacuum yielding 20 degrees total relative to crankshaft. So 24 + 20 + 9 (are we sure of this static figure?) = 53 degrees. Still a little hot depending on the static timing.

Maybe it's a real low compression motor?

Mad Professor · Post by **Mad Professor** » Fri Feb 24, 2006 9:58 am

I have got a ECU map form another make of ECU, but the last time I tryied to post any data regarding it, I got a big slap around the face from the powers that be.

So this time I will not say any names or web links, and hope I don't get any more beatings.

This other ecu used Load Sites vs Speed Sites.
The speed sites is just RPm so thats easy, But I have talk to other peps about the load sites, and it seems this other ecu uses TPS, so it's TPS vs RPm witch seems very strange.

Anyway to the data.
Across left to right is speed sites:
0, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000.
going down from top to bottom is load sites:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.

20, 17, 0, 0, 0, 26, 34, 40, 44, 44, 44, 44, 44, 44.
17, 17, 20, 24, 28, 36, 43, 40, 44, 44, 44, 44, 44.
15, 15, 13, 22, 23, 28, 32, 37, 44, 44, 44, 44, 44.
12, 12, 11, 21, 23, 28, 28, 29, 31, 32, 33, 33, 33.
10, 10, 10, 20, 22, 26, 25, 30, 31, 31, 32, 32, 32.
08, 08, 10, 20, 22, 26, 25, 29, 30, 30, 29, 30, 30.
07, 07, 10, 20, 22, 26, 25, 25, 26, 26, 26, 26, 27.

And so on.

I know a screen shot would be helpful, but I don't want to end up, upsetting the powers that be.

woh · Post by **woh** » Fri Feb 24, 2006 10:22 am

Peter said

are we sure of this static figure?

No, not sure of any of it.
Also, if you read the text literally (distributor shaft speed) we should half the start and stop rpm (for crank rpm) for the centrifugal advance. To me it just does not come out correctly that way.

I've seen a general advance curve that maps typical engine advance. Most engines have roughly the same advance curve within some tolerance given the same gas. I'll look for that.

woh · Post by **woh** » Fri Feb 24, 2006 9:41 pm

I did not find the web page I was looking for, but this one seems to tell a similar story.
http://www.jcna.com/library/tech/tech0015.html

The graph is near the bottom of the web page. The graph shows a variety of advance curves for different distributors. All are mechanical advance. Vacuum advance would be added to this. My point is, that as a starting point any of these will work well on an engine but is not optimized. For additional details see the web page, and several links at the bottom of the web page.

Post by **jsmcortina** » Sat Feb 25, 2006 4:45 am

woh wrote: I've seen a general advance curve that maps typical engine advance. Most engines have roughly the same advance curve within some tolerance given the same gas. I'll look for that.

Lance's description in the Sticky already did that in Megasquirt terms and included boost. The default advance tables that come pre-loaded in Megasquirt are a good starting point too.

James

Peter Florance · Post by **Peter Florance** » Sat Feb 25, 2006 6:27 am

woh wrote:Peter said
are we sure of this static figure?
No, not sure of any of it.
Also, if you read the text literally (distributor shaft speed) we should half the start and stop rpm (for crank rpm) for the centrifugal advance. To me it just does not come out correctly that way.

I'm thinking it may be ok (and possible correct) to double the dist shaft speed based on some of the curves you've collected (nice work).

The cent advance on Proff's Bosch datasheet doesn't seem out of line when doubling the rpm and advance. But the vacuum advance seems really large. Unless possible the head is a really old design (I know nil about 205's) and/or burns really slow at light loads.

FWIW, my car with mech dist never had enough advance at full load as I tried to time it for max performance. It always pinged at light load (vacuum advance) first. It has about 14 degrees of vacuum advance (rated for US 87 octance fuel)

woh · Post by **woh** » Sat Feb 25, 2006 8:42 am

Mad Professor
Do you have any information on timing for your engine. For example is there a timing advance given for idle? I'll try to 'fix' the spread sheet with the new learnings and inputs from Peter

Do you know if the carburettor has port vacuum advance? This has the vaccumm taken just upstream of the throttle with a small hole. As the throttle opens, the throttle passes the hole and puts it downstream of the throttle.

Peter
I'm thinking the static timing is wrong as I've interpreted it.

In the later MG's there is a similar problem. If you set the timing for good performance at high rpm the timing is too retarded at low rpm resulting in poor throttle response. Increasing the static timing for better throttle response may cause detonation at higher rpm. This change was due to efforts to improve emissions. As you suggest, we may have that here.

Note; on the collection of curves, the max advance is normalized to 36deg. So the max may vary by engine, but 35-40 seems pretty common.

woh · Post by **woh** » Sat Feb 25, 2006 8:46 am

Peter/Lance

How do you put a picture in you post without a file?? I tried doing a copy paste, but it doesn't work.

OH, I did not create those curves, they come from Marcel Chichak web site above.

Peter Florance · Post by **Peter Florance** » Sat Feb 25, 2006 9:45 am

woh wrote:Peter/Lance

How do you put a picture in you post without a file?? I tried doing a copy paste, but it doesn't work.

OH, I did not create those curves, they come from Marcel Chichak web site above.

I just right clicked on the image and copy and pasted it's link:http://www.msefi.com/files/ign_mech_adv_134.jpg and then selected it (highlighted it) and clicked the Img button which surrounds it with the img and /img tags.

Mad Professor · Post by **Mad Professor** » Sun Mar 12, 2006 3:23 am

I will scan in some of the doc's regarding the timing for my engine later on today.