WHICH FORD PROCESSOR IS BEST????

SRT said:

I have been looking for parts for my mass air conversion, and all I need now is the computer. I am running a five speed. Some people say the A9L is the best then some say the A9P, which is for an automatic is best because of aggressive timing down low. ANYONE know what the best would be THANKS

oh ya searched the threads and could not come up with anything?? I would definatley think this would have been asked before??

Click to expand...

I think the general consensus is the A9L is best. I knew there were slight differences between the A9P and A9L, but I didn't know the A9L had more agressive timing.

Personally I'd go with a A9L, but if you can get a good price on a A9P, that would be fine too.

Jeff

The A9L reportedly does have a more aggressive curving (I'd still like to see some graphs/tables on this, as I bet it's slight over the A9L).

I agree with Jeff - I'd just get which ever you can - both are proven to work very well in 5 spd cars.

Good luck.

I too would buy the first one I come across.

JT-
Graphs would be nice to put the timing discussion to rest.
Maybe I have something to do after work now...

I do have a page on my site which compares many settings in these 2 ecu's along with the X3Z.
I would post a link but can't get there from work.

jason

I have one I am not going to use on my new combo. A9L that is. PM if you are interested.

WOT Spark Advance Comparison of A9L / A9P / X3Z


Here is how the WOT Spark Tables differ between X3Z, A9L, and A9P.

X3Z & 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


The A9P does add 10* of advance at lower WOT rpm's, but a manual t5 Mustang should not see WOT below 1,600 rpm.
For this reason using a A9P in a t5 Mustang will provide very little performance gain due to timing advance.

There are some differences in Timing Advance based on ACT and ECT, but they are pretty minor.

Jason, as always, very nice info!

FYI:

The A9P you can run in an auto or 5 speed. The A9L you can only run in a 5 speed car.

The last FYI is misinformation! Both will work in either auto or manual trans.
I ran both to see if there was any noticable difference and both performed well, the a9p seemed smoother at low rpm though.

My A9P works well with my 5 speed.

They both can run both ways. The L in an auto is less common and unless the processor was free, I'm not sure why one would do it.

So the A9P adds 10* of timing up to 1600 rpm's . I have the A9p as my car used to be an auto . Will this have any effect when I hook up my NX?

SPEEDYLIFSAVR said:

So the A9P adds 10* of timing up to 1600 rpm's . I have the A9p as my car used to be an auto . Will this have any effect when I hook up my NX?

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Only if you hit WOT under 1,600rpm.

If the car is a 5sp, I doubt this is a concern.

If you take the standard precautions for nitrous, I doubt you will have any issues.
Keep in mind I am no expert with N2O.



There are some other timing differences, but I haven't had a chance to format them out. Maybe tonight.

jason

Jason, please don't go out of your way (as you often do ) but if you ever come across any timing tables for the U4MO (94-95 GT Auto puter), please send them my way.
I have T4MO (5spd) info already but now am thinking the U4 probably adds a ton of timing down low (and if it does, that answers a LOT of questions I had).

A little bit has been added...

A 3-way Comparison of Ford EEC-IV Computers: A9L, A9P, X3Z

WOT Spark Advance vs. RPM – FN131
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

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, but help to illustrate the minimal difference between the A9L/A9P/X3Z computers.
Keep in mind that…
The following tables are ‘Adders’ and are summed with the above 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, the computer assumes that 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. BP – FN133
A9L
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


WOT Spark Advance vs. ECT – FN134
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


WOT Spark Advance vs. ACT – FN135
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




Now some of the Part Throttle Ignition Timing Tables

Part Throttle Spark Adder – FN1133







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.

HISSIN50 said:

Jason, please don't go out of your way (as you often do ) but if you ever come across any timing tables for the U4MO (94-95 GT Auto puter), please send them my way.
I have T4MO (5spd) info already but now am thinking the U4 probably adds a ton of timing down low (and if it does, that answers a LOT of questions I had).

Click to expand...

I put it on my list, as I am interested in seeing this myself...

But I need a break


jason

Will a A9L or A9P run my 93 gt 5spd or should i go with the A3M that is in it? The computer in my car is bad I believe.