Can anyone tell me the difference in performance between these three computers? Will there be any appreciable difference in street performance on a basically stock 93 cobra motor when using any of the three? Ford must have used the X3Z on the 93 for a reason. I'm converting a stock GT motor to a cobra motor using the cobra intake, TB, MAF, 24lb injectors and cam. Any and all help appreciated! I currently have an A9P, not the A9L.
A9L vs A9P vs X3Z
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An A9P is an EEC-IV out of an automatic 5.0. The A9L is the EEC-IV out of a 5 speed 5.0, and the X3Z is from the cobra.efimav said:
The X3Z "internally" sets the injectors to read as 24# injectors (meaning the mass-air is really just calibrated for stock 19# injectors, its the computer that converts the reading of the mass-air to 24# readings.) Also, the X3Z has an altered timing curve for speeds over 100mph (not sure of the reason) and im not sure if it has a speed limiter built in or not. but im leaning towards no.
The A9P is what i'm using for my mass-air conversion. I have ZERO problems running it with a 5 speed car, and from what i hear, it runs even better then the A9L, due to not messing with the timing any on shifts.
The A9L, is the computer everyone always uses when coverting from speed density to mass-air, although, like i said, the A9P is just as good (if not better.)
Hope that helps out some.
i will be converting from speed-density to mass-air.
a buddy has a computer that he took out of his 91gt, when he swapped to a 5-speed. what would the chances be that it is a a9p?? i would like to get the computer, BUT i am unsure of the type of computer and how well the automatic computer would work in my 5-speed.
a buddy has a computer that he took out of his 91gt, when he swapped to a 5-speed. what would the chances be that it is a a9p?? i would like to get the computer, BUT i am unsure of the type of computer and how well the automatic computer would work in my 5-speed.
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I don't know about the X3Z missing the rev-limiter, but that's interesting. About the A9L and the A9P, I've heard that the A9P (automatic 5.0) computer has a hotter spark advance curve to make up for the lack luster performance of the automatic equipped Mustangs. So, if anything, the A9P would be the one to run on any car. Additionally, I didn't think that the timing was retarded on shifts until EEC-V came out; EEC-IV computers are all exempt from this retardedness! 
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WOT Stang, you've got that backwards. I just did a bin dump of both the A9L and A9P to make sure and the A9P is definately the less agressively tuned of the 2.
While the A9L is richer than the A9P, the A9L has much more agressive timing curves than the A9P at part throttle. WOT is just about the same. Neither of them have shift timing retard, that's on later EEC's. Also, the A9P yanks fuel out earlier at redline.
If you like I can post the comparisions. Some people ***** when I put tons of data in a post but screw 'em if you'd like to see it.
While the A9L is richer than the A9P, the A9L has much more agressive timing curves than the A9P at part throttle. WOT is just about the same. Neither of them have shift timing retard, that's on later EEC's. Also, the A9P yanks fuel out earlier at redline.
If you like I can post the comparisions. Some people ***** when I put tons of data in a post but screw 'em if you'd like to see it.
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Yup, the A9L would make it less likely to ping. WOT isn't much timing difference but it is slightly richer. The EEC-IV determines WOT at a TPS voltage of 3.71 volts. Part throttle is anything less than that.
This can be confusing to a newbie. Just think of these as dots on a graph and you're connecting the dots. The EEC will extrapolate the difference between the 2 points. i.e. If point 2 is 5 and point 4 is 7 then point 3 would be 6. The left colume is RPM and right is timing including dist. advance.
This is the A9P WOT timing table:
WOT_ADVANCE_VS_RPM # WOT spark Advance vs RPM
( 16383.8, 26 ) ( 5000, 26 ) ( 3500, 22 )
( 2600, 23 ) ( 2250, 22 ) ( 1600, 18 )
( 0, 18 ) ( 0, 18 )
This is the A9L
WOT_ADVANCE_VS_RPM # WOT spark Advance vs RPM
( 16383.8, 26 ) ( 5000, 26 ) ( 3500, 22 )
( 2600, 22.5 ) ( 2150, 21.5 ) ( 1800, 18.5 )
( 1000, 8 ) ( 0, 8 ) ( 0, 8 )
OK, here's part throttle, it's a little more complicated, it's based off of load vs RPM, upper left corner is low load/low RPM. Lower right is high load high RPM. Now that I look at them closer, at low load the A9L would be snappier, at high load the A9P. This is PART THROTTLE ONLY.
Here's the A9P
BASE_SPARK_TABLE # Base Spark Table (Deg BTDC)(RPM vs Load)
28 28 28 30 30 30 30 30 30 30
28 28 28 30 30 30 30 30 30 30
28 28 33 36 36 37 38 38 38 38
25 26 30 33 35 36 38 40 39 39
15 15 22 28 29 30 33 34 34 35
10 10 11 14 19 20 27 29 29 29
7 7 8 12 15 19 22 25 26 26
Here's the A9L
BASE_SPARK_TABLE # Base Spark Table (Deg BTDC)(Load vs RPM)
28 28 28 31 33 34 34 34 34 34
28 28 28 31 33 34 34 34 28 28
28 28 33 36 36 37 38 38 28 28
25 26 28 29 32 32 38 40 28 28
20 21 25 28 31 32 33 34 28 28
15 15 16 16 18 20 23 27 27 27
8 10 10 11 13 15 21 21 21 21
8 8 9 10 12 14 18 21 21 21
Neither of these is optimum timing for performance and a custom chip sure does help.
This can be confusing to a newbie. Just think of these as dots on a graph and you're connecting the dots. The EEC will extrapolate the difference between the 2 points. i.e. If point 2 is 5 and point 4 is 7 then point 3 would be 6. The left colume is RPM and right is timing including dist. advance.
This is the A9P WOT timing table:
WOT_ADVANCE_VS_RPM # WOT spark Advance vs RPM
( 16383.8, 26 ) ( 5000, 26 ) ( 3500, 22 )
( 2600, 23 ) ( 2250, 22 ) ( 1600, 18 )
( 0, 18 ) ( 0, 18 )
This is the A9L
WOT_ADVANCE_VS_RPM # WOT spark Advance vs RPM
( 16383.8, 26 ) ( 5000, 26 ) ( 3500, 22 )
( 2600, 22.5 ) ( 2150, 21.5 ) ( 1800, 18.5 )
( 1000, 8 ) ( 0, 8 ) ( 0, 8 )
OK, here's part throttle, it's a little more complicated, it's based off of load vs RPM, upper left corner is low load/low RPM. Lower right is high load high RPM. Now that I look at them closer, at low load the A9L would be snappier, at high load the A9P. This is PART THROTTLE ONLY.
Here's the A9P
BASE_SPARK_TABLE # Base Spark Table (Deg BTDC)(RPM vs Load)
28 28 28 30 30 30 30 30 30 30
28 28 28 30 30 30 30 30 30 30
28 28 33 36 36 37 38 38 38 38
25 26 30 33 35 36 38 40 39 39
15 15 22 28 29 30 33 34 34 35
10 10 11 14 19 20 27 29 29 29
7 7 8 12 15 19 22 25 26 26
Here's the A9L
BASE_SPARK_TABLE # Base Spark Table (Deg BTDC)(Load vs RPM)
28 28 28 31 33 34 34 34 34 34
28 28 28 31 33 34 34 34 28 28
28 28 33 36 36 37 38 38 28 28
25 26 28 29 32 32 38 40 28 28
20 21 25 28 31 32 33 34 28 28
15 15 16 16 18 20 23 27 27 27
8 10 10 11 13 15 21 21 21 21
8 8 9 10 12 14 18 21 21 21
Neither of these is optimum timing for performance and a custom chip sure does help.
so what if i ran the A9P and a custom burnt chip? that should help solve the potential problem for pinging right?
it doesnt look like the difference in timing at WOT is all that different. Basically like a .5 degree in timing. Right? and part throttle wouldnt really affect pinging since pining usually occurs at WOT. Correct?
So if you were me, and could get a smokin ass deal on a mass-air conversion, about $100 incl. computer (a9p), mass-air, and harness, would you pick it up?
then maybe down the road pick up a custom burnt chip to help with the timing and spark issues??
it doesnt look like the difference in timing at WOT is all that different. Basically like a .5 degree in timing. Right? and part throttle wouldnt really affect pinging since pining usually occurs at WOT. Correct?
So if you were me, and could get a smokin ass deal on a mass-air conversion, about $100 incl. computer (a9p), mass-air, and harness, would you pick it up?
then maybe down the road pick up a custom burnt chip to help with the timing and spark issues??
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Actually, there more I compare the less difference I see between the A9P and A9L. I'd get which one is the best deal.
I custom chip turned by someone who knows their stuff will go a long way towards driveability. I had a bad part throttle ping that I got rid of tuning with the EEC-Tuner.
The further you get from stock, the more a custom chip will improve things.
I custom chip turned by someone who knows their stuff will go a long way towards driveability. I had a bad part throttle ping that I got rid of tuning with the EEC-Tuner.
The further you get from stock, the more a custom chip will improve things.
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I've got all the Cobra goodies in mine, including the X3Z computer and I love it. Can you tell the difference when driving? I haven't been able to, other than to say that the car hauls a$$ with everything I have done. Maybe on a dyno, you could get specific numbers, but I stayed with the X3Z so I could have all the OEM stuff matched. It runs fantastic!
As far as I know, they all still have the fuel cut-off at 6250 RPM, so the only way around it is a custom chip. I have heard of some guys getting the retard out of the X3Z with a chip as well, but I haven't noticed it yet in mine. There used to be a product for the Cobra's called the "finisher" that tied in to the VSS so the retard would go away. Haven't seen these in years though!
As far as I know, they all still have the fuel cut-off at 6250 RPM, so the only way around it is a custom chip. I have heard of some guys getting the retard out of the X3Z with a chip as well, but I haven't noticed it yet in mine. There used to be a product for the Cobra's called the "finisher" that tied in to the VSS so the retard would go away. Haven't seen these in years though!
Thanks for all of the input. jrgoffin, that is the route I was considering because it was designed to work together. I just wasn't sure if it was really necessary to switch computers. It sounds like I need the X3Z for the stock cobra MAF to work correctly (sound right WOT?). My combination will actually be the cobra intake, tb, maf, cam, computer and a set of 2bbl cleveland heads on a 302. What do you think?
shaker, I was thinking that running all of the cobra components would work. The 2V heads will likely not flow any better than a cheap set of aluminum heads or worked GT40s. I was basically thinking of all stock cobra parts except the heads. The 4V heads basically give you a boss 302. Most will never know the difference between the 2V and 4V. I'm doing it more for novelty than performance. How many EFI boss powered mavericks have you seen?
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Didn't realize that you were running this in a Mav... I guess I should've looked a bit closer, no?! Yep, converting to the 351C head's just plugging some holes in the block/head interface, right? What about intake? Are you going to build a custom manifold or do you know of an EFI manifold to fit 351C heads? The X3Z computer will work just fine on this setup. Just make sure you've got the 24 lb/hr injectors and the larger mass air meter. I think the intake might be tricky. Didn't B&O or some company named like that make a carb intake for the Clevor?
Yes, the head mods are relatively simple. Block off the coolant passage on the block face and drill a new passage on the intake face. BA used to make the street boss intake though I think they are no longer in business. The boss with the EFI is a nice combination of new and old. You can purchase or make spacers to adapt the windsor intake to the cleveland heads. I believe it is pricemotorsport.com that carries a complete line of ford adaptor plates for different applications. I have one of their adaptor sets, though I didn't pay full price! thanks for the interest
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you mention a custom chip, I’m running a 331 stroker with an A9P. Do you know what chip would be best?
As much as we enjoy celebrating a 20yr anniversary....
You are probably better using the info you found using the search function along with the info about you application to create your own thread.
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