Difference between A9L and A9P Mass air computers?

NoSlow5.0 · 12-17-2001, 06:19 PM

What is the difference if any and wich one would be the better of the two for a swap on a 5-spd car? Thanks

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DRASTiK · 12-17-2001, 06:56 PM

Well, technically speaking, the A9P will have more aggressive timing and fuel curves than the A9L, but it's not really a big enough difference to matter. Either one will be fine. I have an A9P in my 5 speed, but that's just because when my first one died, that's all I could find at a decent price.

byrnech · 12-18-2001, 03:37 AM

Myself and D&R Stang have recently had this conversation. I had always heard it was the A9L that was better in terms of fuel and spark. Either way the A9L is made for the T5, so get that one if you can.

fiveohpatrol · 12-18-2001, 01:00 PM

The A9L has a thing called a dashpot that reads your vehicle speed sensor and keeps your RPM's up when you slow to a stop. If it didn't do this, then the engine would die on a quick stop.

The A9P is also all i could find when i did my mass air conversion It wouldn't stay running when i came to a stop so I had to run an extra wire to the VSS and it was fine after that.

good luck

NoSlow5.0 · 12-20-2001, 02:46 PM

Thank you guys for answering that. Jonathan

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Unit 5302 · 12-22-2001, 03:54 AM

The A9L is the hot "known" computer. The A9P is supposedly more aggressive with fuel and timing curves. It is built for the automatics which aren't trying to spare the T-5.

The A9L is proven, and the A9P not so much. Running either computer should not cause problems.

As far as keeping your engine idle up to avoid stalling, putting your car in neutral for an auto and doing a quick stop will kill your car then? Not that I've noticed. My 87GT has no problems with dropping to idle speed 800rpms with the clutch depressed and not stalling. I don't know though, I am SD while those computers are all for MAF cars.

12-17-2001, 06:19 PM	#1
NoSlow5.0 YOU HAVE NO MARBLES!!!!!! Join Date: Aug 2000 Location: Jonesboro,Georgia,USA (Providence, Ri) Posts: 868	Difference between A9L and A9P Mass air computers? What is the difference if any and wich one would be the better of the two for a swap on a 5-spd car? Thanks Light Em Up!!! __________________ My 87 GT....Marbles....The one and only O.G.!!! AIM: Marbles87Fox Light Em Up!!!

12-17-2001, 06:56 PM	#2
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	Well, technically speaking, the A9P will have more aggressive timing and fuel curves than the A9L, but it's not really a big enough difference to matter. Either one will be fine. I have an A9P in my 5 speed, but that's just because when my first one died, that's all I could find at a decent price. __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

12-18-2001, 03:37 AM	#3
byrnech Registered Member Join Date: Jun 2001 Location: Anderson, TX. Posts: 166	Myself and D&R Stang have recently had this conversation. I had always heard it was the A9L that was better in terms of fuel and spark. Either way the A9L is made for the T5, so get that one if you can. __________________ 331 10:1, AFR 185's, TFS-R intake

12-18-2001, 01:00 PM	#4
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	The A9L has a thing called a dashpot that reads your vehicle speed sensor and keeps your RPM's up when you slow to a stop. If it didn't do this, then the engine would die on a quick stop. The A9P is also all i could find when i did my mass air conversion It wouldn't stay running when i came to a stop so I had to run an extra wire to the VSS and it was fine after that. good luck __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

12-20-2001, 02:46 PM	#5
NoSlow5.0 YOU HAVE NO MARBLES!!!!!! Join Date: Aug 2000 Location: Jonesboro,Georgia,USA (Providence, Ri) Posts: 868	Thank you guys for answering that. Jonathan Light Em Up!!! __________________ My 87 GT....Marbles....The one and only O.G.!!! AIM: Marbles87Fox Light Em Up!!!

12-22-2001, 03:54 AM	#6
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	The A9L is the hot "known" computer. The A9P is supposedly more aggressive with fuel and timing curves. It is built for the automatics which aren't trying to spare the T-5. The A9L is proven, and the A9P not so much. Running either computer should not cause problems. As far as keeping your engine idle up to avoid stalling, putting your car in neutral for an auto and doing a quick stop will kill your car then? Not that I've noticed. My 87GT has no problems with dropping to idle speed 800rpms with the clutch depressed and not stalling. I don't know though, I am SD while those computers are all for MAF cars.