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Holy A9M conversion!!!!

3K views 39 replies 16 participants last post by  stangin it 
#1 ·
I finally got to yanking the old stock computer out of my 95 cobra and putting in an A9M from a fox. OMFG is all I can say, it unlocked a TON of performance. Where before it wouldn't accelerate good at low rpms it owns now. I couldn't even get the car sideways with the old comp but now it performs just like my old 91GT(this is with a stock exhaust and gears btw)! I highly recommend this swap if you've got the stock comp, makes tuning a breeze. I didn't want a tweecer because I didn't want to hook my car up to a computer every time I want to tune it. Plus I got the old style PIH module and an A9M box for less than a tweecer costs. Exhaust and gears are next and I should be seeing some 12 sec passes this spring :D

Much thanks goes out to Sillycobras for the great deal and all the help installing this sucker!
 
#27 ·
soon as I get the money my next mod is the Tweecer...
 
#28 ·
You have to run aftermarket ignition with the PIH. If not your car will never make it past 4000 rpms. Trust me I know from experience. My splice for my msd came loose and the car wouldn't start. So I re-connected the stock ignition and everytime I hit 4000 rpms the car would just quit, lost all spark. It ran fine until 4000 rpms though.

john
 
#29 ·
Can someone explain to me why you think you must have an aftermarket ignition?? think about it.. the A9L is controlling the same thing, there is still a TFI dizzy and coil. Nothing changed from the fox's to the SN95 as far as ignition goes... I ran my PIH on stock ignition and it never broke up or missed... and if you go to Pro M's site they mention nothing about needing an MSD...
 
#30 ·
I'm telling you that you need an aftermarket ignition. I was told by Pro-M. They told me the stock ingnition can't handle the old style computers. I also had to get a mass air calibrated for 24lbs injectors too. Because 94-95 cobras come with mass air meters calibrated for 19lbs injectors even though they have 24lbs injectors.
My car ran 12.96@106.16 on pep boy ultra Z's with: PIH, MSD, ProM-77, underdrive pulleys, o/r h-pipe, flowmaster catback, and 3.73's. It wouldn't have ran that with the crappy J4J1 computer!

john
 
#31 ·
I have a Tweecer. I just bought it about a month ago. Before, I had a stock Cobra computer and I am pushing 400rwhp and 10 psi. All I did was turn the distributor, use my BTM and adjustable fuel pressure regulator on the dyno and I walked away with great driveability and 400rwhp. The car idles and drives like stock and nobody even knows I have a blower.

With the Tweecer, I was able to adjust my MAF curve, eliminate the spark retard between shifts, adjust my fans, etc. I haven't really done anything major with it yet since the car drove well before it and I got the Tweecer for $440. You can find these thigns used.

If I look at a A9L bin file and J4J1 bin file, I can see that the J4J1 has more adjustability. I can also see that the A9L has a more agressive fuel and spark curve. I still think the Tweecer and stock Cobra computer is the best option. Now if you can find a PIH for a steal, I'd take that too. It all depends on the situation.

Henry
 
#32 ·
SSKiller said:
Can someone explain to me why you think you must have an aftermarket ignition?? think about it.. the A9L is controlling the same thing, there is still a TFI dizzy and coil. Nothing changed from the fox's to the SN95 as far as ignition goes... I ran my PIH on stock ignition and it never broke up or missed... and if you go to Pro M's site they mention nothing about needing an MSD...
Was not going to get into this, but you have said it twice now, and it is just wrong: the SN95 has a completely different method of spark control, not to mention the hardware is different. The EEC computes dwell, where the Fox did it at the distributor. You put a Fox EEC in a SN95, you get insufficent dwell and weak spark. Look under Scalars in Tweecer. Do you see spark_ignition_type? What do you suppose that does?

I knew when I screwed up and forgot to plug in the spark box after diddling the engine: all would run fine until I'd get on it, and it was like hitting a rev limiter at 4-4.5k. Normal driving I'd never notice it was not hooked up.

The instructions for the PIH state the need for aftermarket ignition.

Bob
 
#33 ·
Hmmm... I wasn't trying to say you guys were wrong, sorry if I came across like that. Maybe the newer PIH kits are different or something, I had the really, really old PIH where I had to change all the pins in the EEC Harness.. a real PITA. And nowhere did it tell me I had to have an MSD.. maybe thats why my car ran like crap on the PIH... I did not know that you had to have it for the A9L.

I still learn something every day...
 
#35 · (Edited)
SSKiller said:
Bob, can you elaborate more on the "spark ignition type" scalar? What is it telling the EEC? My J4J1 is set to 1.00000..
The scalar is a switch. "1" is supposedly to set EEC controlled dwell ignition, and "0" for distributor (Fox) controlled dwell. This is from guys who know a lot more about the EEC strategies than me. I suppose you could change it to "0" and see what happens, like get spark blowout.

So at least for a SN95, you could use the Fox setup, not that I know why you'd want to. I was surprised how well the stock ignition handled a blower: no spark blowout. The A9L strategy has no spark_ignition_type scalar, or no one has found it yet. Probably because there was no other version of ignition when they designed that EEC. A shame, because it would be an easy switch to run the SN95 ignition properly with a PIH/A9L. :D

Bob
 
#36 ·
HPLouis said:
I have a Tweecer. I just bought it about a month ago. Before, I had a stock Cobra computer and I am pushing 400rwhp and 10 psi. All I did was turn the distributor, use my BTM and adjustable fuel pressure regulator on the dyno and I walked away with great driveability and 400rwhp. The car idles and drives like stock and nobody even knows I have a blower.

With the Tweecer, I was able to adjust my MAF curve, eliminate the spark retard between shifts, adjust my fans, etc. I haven't really done anything major with it yet since the car drove well before it and I got the Tweecer for $440. You can find these thigns used.

If I look at a A9L bin file and J4J1 bin file, I can see that the J4J1 has more adjustability. I can also see that the A9L has a more agressive fuel and spark curve. I still think the Tweecer and stock Cobra computer is the best option. Now if you can find a PIH for a steal, I'd take that too. It all depends on the situation.

Henry
Did you notice any difference when you installed the Tweecer? Is this the base version or RT. I am guessing based on price that it is the RT.
What is your combo with the blower. I am putting an S trim on soon. It is a stock cobra at this point.
 
#39 ·
stangin it said:
Did you need to get a 87-93 MAF to work with this computer??? Im thinking about geting the PIH kit but i dont wanna have to get another MAF i just bought a pro-m 80mm.
MAF curves are close enough, I ran with a Pro-M calibrated (for 30's) stock MAF with wing removed and 30's with no Tweecer on the A3M, ran fine. Also ran fine with stock 94 MAF and 19's.

The J4J1 and recal'd MAF/30's was a total dog, dunno why. It ran smoothly enough, just no guts. I suspect the load based programming was really whacked by the miscalculated load, where the A3M was not nearly so far off. The J4J1 and A3M/PIH were closer with the stock MAF/19's, but the A3M was distinctly sharper and more eager.

Bob
 
#40 ·
robtmc said:
MAF curves are close enough, I ran with a Pro-M calibrated (for 30's) stock MAF with wing removed and 30's with no Tweecer on the A3M, ran fine. Also ran fine with stock 94 MAF and 19's.

The J4J1 and recal'd MAF/30's was a total dog, dunno why. It ran smoothly enough, just no guts. I suspect the load based programming was really whacked by the miscalculated load, where the A3M was not nearly so far off. The J4J1 and A3M/PIH were closer with the stock MAF/19's, but the A3M was distinctly sharper and more eager.

Bob
Thanks
 
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