MAF to SD by splicing

[Blue89rs]

Has anyone successfully done a MAF to SD conversion? I used electrical schematics to build a jumper cable adapter to go from an 89 to 91 ecm. Seems like everyone talks about it, but has anyone done it?

The one I did cranks, sparks, but no start. It throws a VATs code, but that's about it. Everything else seems to work, but no fuel??? The fuel injector wiring is different between the two, but not enough to cause concern. Can anyone offer suggestions as to something to watch out for, like the VATs module? I'm going to post the "conversion" later to see if someone can catch any mistakes.

[Blue89rs]

Aight! I did it. I made a harness that converted my car to MAP, and it works. I just had to program the VATS out of it, but it runs fine (so far)

Thanks for the help.....

[Ace_holio]

Aight! I did it. I made a harness that converted my car to MAP, and it works. I just had to program the VATS out of it, but it runs fine (so far)

Thanks for the help.....


really?!?! same power? fuel economy? hows it run/sound....305 or 350? is map that much better then maf that i need to be concerned? did you swap computers?

[Blue89rs]

Wow, I finally got attention!

Sounds WAY burlier. Its a 3.1, but the ecm's are the same between the V6 and V8 engines.

This system is better for me. I need the flexibility that MAP offers over MAF. I'm intending to do a custom dual throttle body intake, and explore forced induction some day. Both of which are hard to do with a MAF system.

I used a 92 ECM and spliced together an adapter harness and added the MAP sensor. This enables me to run on the MAF or the MAP at my leisure, I just plug the old computer back in and its back to stock!

I still need to do the knock sensor, but its programmed to give me tons of gas WOT so I'm not worried about pinging. The fuel economy seems to SUCK, but thats because of the EPROM i have.

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[89vert]

MAF is better then MAP to a point for hp,

MAP offers better driveability,
MAF offer better wide open throttle performance,
up to 255 g/sec air flow, which is about 400hp, you can add extra fuel through PE and AE, and get power above 400hp
after that you'll have to go to MAP but aftermarket would be like DFI would be better

[Blue89rs]

I thought about this for a long while.

A 255g/sec MAF will measure up to 440cfm if the density of air is 1.222kg/m^3. More cfm if its warmer outside.

A 2.8L at 5000RPM will draw 245cfm
A 5.7L at 5000RPM will draw 498cfm
A 3.25 (what I have) at 7000 will draw 398cfm

So I guess I could have used a properly tuned MAF system. But if i boost it at 6psi, the 3.25L would draw 568cfm. So I would eventualy have to go MAP anyway because I would be over the amount a stock MAF sensor can read.

Plus now I can run an open intake system (or dual tb's!) to get my volumetric efficiency up. :D


How do boosted FI SBC's manage thier fuel? Boost controlled FPR?

[89vert]

I thought about this for a long while.

A 255g/sec MAF will measure up to 440cfm if the density of air is 1.222kg/m^3. More cfm if its warmer outside.

A 2.8L at 5000RPM will draw 245cfm
A 5.7L at 5000RPM will draw 498cfm
A 3.25 (what I have) at 7000 will draw 398cfm

So I guess I could have used a properly tuned MAF system. But if i boost it at 6psi, the 3.25L would draw 568cfm. So I would eventualy have to go MAP anyway because I would be over the amount a stock MAF sensor can read.

Plus now I can run an open intake system (or dual tb's!) to get my volumetric efficiency up.* :D


How do boosted FI SBC's manage thier fuel? Boost controlled FPR?




your numbers might be right given that the engine is 100% efficeint
which is impossible

did you account for revolutions per second/2 for intake and power stroke,
I could crunch the numbers but I don't feel like doing that right now, I'd haver to get a pen and what not :D

MAF is a far better system for power, is just 3rd gens MAF source code is limiting, if they would have stuck with MAF when they went to a 32k bin it would have been better,

LT1's and LS1's use MAF for a reason,

I belive by using a ECM from a turbo sonoma you can effectviely tune boost

[Blue89rs]

Yup, I divided by two. And I did assume 100% efficiency.

How much airflow would a stock 3rd gen ECM and MAF read?

[89vert]

Yup, I divided by two. And I did assume 100% efficiency.

How much airflow would a stock 3rd gen ECM and MAF read?


255 grm/sec

they say it'll support 350hp with out adding extra fuel in PE,

there is a guy on TGO that runs low 11's with his MAF setup