Evil_F

I cant find what the 5.0's stock timing curve is. Anyone know? (and I dont mean what the stock timing is set at)

Evil_F

bump

vristang

Need more info...

EFI or Carb?

If EFI, what computer?

The computer uses different timing advance for wot and CL.

Why are you asking? This may help others provide a better response to your question.

jason

Evil_F

Any of the curves for the 5.0 HO EFI motors is what I would like. Though any curves would be helpfull. I am trying to compair my curve used on my after market dizzy to the stock curve used by the OEM EFI on my 86' GT.

Chitown racer

What timing curve are you referring too. I'm assuming you mean the open loopWOT spark advance curve as the closed loop part throttle spark iscalculatedusing a table based on engineload and RPM and is not what you would consider a linear curve. Anyhow the WOT throttle timimg curves dont vary all that much between the all the different ECU's ford used in the foxbody stangs. The big differences are between the ECU's for Auto transmission and the strictly manual trans ECU's. The following are examples ofthe different WOT timing curves ford used in its Foxbody SD and MAF ECU's. Their are a more, but for the most part they arevery close to one of the curves below.

A9L -87-93 5.0Mustang / Manual Trans
RPM Advance
5000 26
3500 22
2600 22.5
2150 21.5
1800 18.5
1000 8
0 8

A9M - 87-93 5.0 Mustang / Auto Trans
RPM Advance
5000 30.25
3500 26.75
2600 26.75
2150 25.75
1800 22.25
1000 10.25
0 10.25

X3Z - 1993 Cobra / Manual Trans
RPM Advance
5000 25
3500 22
2600 22.5
2150 21.5
1800 18.5
1000 8
0 8

Just about all 86-87 Speed Density ECU's
RPM Advance
5000 26
3500 22
2600 22.5
2150 21.5
1800 18.5
1000 8
0 8

Evil_F

TY for the info. I got to reading at what some others had and they were saying like 35*. So I thought my total of 28* may be a little low. It isnt low, but it may be a little early @ 3000 RPMs. I plan on getting a timing kit for my dizzy'. But was wondering what stock was to give me a better idea of things.

Joel5.0

28° is too low......regarding the EFI spark tables, you have to keep in mind one little detail.....you have to add the initial 10° setting the tables use as the "base" for the additions....hence 26°@5000 rpms is really 36° @5000rpms........BTW, having it set to max the curve @3000 in a carbed setup, is nothing out of the ordinary.

vristang

You have not stated what computer you are using.
I will just post general info...

There is no 'ignition curve'
In reallity the ignition timing tables will make the timing changes based on ACT/ECT/BP



A 3-way Comparison of Ford EEC-IV Computers: A9L, A9P, X3Z
WOT Spark Advance vs. RPM – FN131
[size=2pt]A9L
RPM_____0____0____1,000___1,800___2,150___2,600___ 3,500___5,000___16,384
Degrees___8____8_____8______18.5____21.5____22.5__ ___22______25_____25
A9P
RPM______0____0____0______1,600___2,250____2,600__ _3,500___5,000___16,384
Degrees___18____18____18_____18______22______23___ ___22______26______26
X3Z
RPM_____0____0____1,000___1,800___2,150___2,600___ 3,500___5,000___16,384
Degrees___8____8_____8______18.5____21.5____22.5__ ___22______25_____25[/size]

In FN131 (WOT vs. RPM), notice that the A9P does add 10* of advance at lower WOT rpm's. If proper gearing is being selected by the driver, then a manual t5 Mustang should not see WOT below 1,600 rpm. For this reason using an A9P in a t5 Mustang will provide minimal performance gain due to ignition timing advance.
Most likely Ford used the extra 10* of advance in the A9P to help ‘off the line’ performance in the automatic Mustang. Using an A9L in an automatic equipped Mustang would sacrifice this added timing. This is why an A9L is not recommended for AOD equipped Mustangs.
Below are a couple more WOT Ignition Timing tables. The influence of these tables will be less significant than FN131, as the following tables are ‘Adders’ to Total Ignition Timing.
As ‘Adders’ the following values are added to the WOT table, to arrive at Total Ignition Timing. For example, in an A9L at WOT, ECT at 246F, and 5,000rpm the total timing will be (25* - 4*) 21*.
Also, it should be noted that the computer assumes the distributor is always set at the stock 10* ignition advance setting. For example, advancing the distributor from the factory 10* of advance to 14* will add an additional 4* to the total timing.
Using the same example from above, this will return the total timing to 25* (making up for the 4* of retard from FN134 at an ECT of 246F).

WOT Spark Advance vs. ECT – FN134
[size=2pt]A9L
ECT_____-256____86____120___200___236___246___254
Degrees____3_____3______0_____0____-2_____-4____-4
A9P
ECT_____-256____86____120___200___236___246___254
Degrees____3_____3______0_____0____-2_____-4____-4
X3Z
ECT_____-256____86____120___210___236___244___254
Degrees____3_____3______2_____0____-2_____-4____-4[/size]

WOT Spark Advance vs. ACT – FN135
[size=2pt]A9L
ACT_____-256____-256____-256___-256___150___240___254
Degrees____0______0_______0______0_____0_____-6____-6
A9P
ACT_____-256____-256____-256___-256___150___240___254
Degrees____0______0_______0______0_____0_____-6____-6
X3Z
ACT_____-256____-256____-256___-256___160___240___254
Degrees____0______0_______0______0_____0_____-6____-6[/size]

WOT Spark Advance vs. BP – FN133
A9L
[size=2pt]BP_______0____23.5____26.5___27.75___31.875
Degrees__12_____4_______4______0______0
A9P
BP_______0____23.5____26.5___27.75___31.875
Degrees__12_____4_______4______0______0
X3Z
BP_______0____23.5____26.5___27.75___31.875
Degrees__12_____6_______5______0______0[/size]

Now some of the Part Throttle Ignition Timing Tables

Spark Table Base – FN901
The computer always assumes the base ignition timing to be set at 10* of advance.
Thus, this Table includes the factory 10* of the base timing set at the distributor. For example, an A9L with 14* set at the distributor will see 25* at 75% load and 4,000rpm (21* in the table, plus 4* over the initial of 10* = 25*). Likewise, an A9L with 10* set at the distributor will see 21* at the same load/rpm.





Part Throttle Spark Adder – FN1133

Chitown racer

First of all, to clarify NO you dont add the 10 degrees of initial timing to any ofthe WOTTiming figures I listed. Those figures include the 10 degrees inital timing. Take the A9M ECU for instance, do you really think Ford would have used 36.75 degrees of timing@ 2600 RPM on a stock 5.0? I could go into the reasons why they wouldnt but that would take more time then I'm willing to commit to this reply

Secondly, nice post on the part throttle tables vristang. I didnt feel it was necessary to get into all that cuz I was pretty sure, as like most people, he was more concerned about WOT performance than anything else. I also neglected to post the WOT Adder tables as they really dont effect the WOT timing under normal conditions, but as usual your abit more thorough than I.

vristang

I would never post anything that detailed if I couldn't just 'cut and paste' it.

I do love 'cut and paste' though



I'm still not sure what the question was though...
If it wasn't answered let us know,
jason