4A-GZE conversion

[dave w]

has anyone run a toyota 4A-GZE (89 MR2, 1.6l 4 cylinder supercharged) on a GM ecm? I'm looking for a MAF based option if one is available.

I do not have personal experience with a supercharged Toyota.

One possible option for an OBD1 GM computer (with MAF) would be 16183247, which was mostly used for the 94 - 95 Buick V6 supercharged vehicles. Additional information is linked here: http://www.gearhead-efi.com/Fuel-Inj...47-16197428-5b

Another possibility (without MAF) would be to install a 2 bar MAP Sensor on OBD1 computer (16197427) so the 0v ~ 5v MAP Sensor will be "Tricked" into providing a voltage with boost.

dave w

[ericjon262]

I'm trying to stay away from speed density at the moment, I'd also be worried about cam and crank sensor matching as the 4A doesn't use either. a crank trigger is easy enough to add though. cam sensor would be a bit of a PITA to add...

[1project2many]

Why not use speed density? There are some v8 MAF applications which could be converted to 4 cyl use with some effort.

$58 from Syclone / turbo Sunbird would likely do the job with speed density. It's working on my 22RTE. The 22RTE and 22RE supply a crank signal through the distributor. How does the 4A ecu get an rpm signal?

[ericjon262]

Why not use speed density? There are some v8 MAF applications which could be converted to 4 cyl use with some effort.

$58 from Syclone / turbo Sunbird would likely do the job with speed density. It's working on my 22RTE. The 22RTE and 22RE supply a crank signal through the distributor. How does the 4A ecu get an rpm signal?

not sure yet where the crank signal comes from, I assume the distributor, but not 100% sure. Typically MAF will respond better to slight modifications than SD once a tune is created. it's a buddies car, and the stock ECU's aren't tuneable, there's some kind of hack job piggyback thing on it now, and it would be nice to delete all of that and have an ECM control it strait up.

what real benefit would he see going SD? just more accurate fueling/spark control?

[dave w]

not sure yet where the crank signal comes from, I assume the distributor, but not 100% sure. Typically MAF will respond better to slight modifications than SD once a tune is created. it's a buddies car, and the stock ECU's aren't tuneable, there's some kind of hack job piggyback thing on it now, and it would be nice to delete all of that and have an ECM control it strait up.

what real benefit would he see going SD? just more accurate fueling/spark control?

It comes down to one simple fact, the more you know about tuning an EFI system, more performance you can achieve. Anything and everything else is 100% hear-say information! Do some homework, leave everyone else looking at your tail lights!

Case in point, MAF has be added to the 16197427 TBI PCM. Post # 12.

Edit with the link:http://www.gearhead-efi.com/Fuel-Inj...Information-0D


dave w

[1project2many]

what real benefit would he see going SD? just more accurate fueling/spark control?

In this case the primary benefit imo would be the reduced amount of time tuning the ecm. There is potential for performance benefits as well. With the Sunbird code you can reduce spark timing as pressure and temperature increase, there's potential to reduce boost if excessive knock is detected, and you can run low and high octane spark tables. Some of this can be accomplished through the V8 Camaro and Corvette MAF systems but you're forced to do more work before you even start the engine because you have to change the calibration so it will work with a four cylinder engine.

What's the expect horsepower level of this project?

[ericjon262]

hp level eventually is probably around 300-350 hp, nothing outrageous. turbo sunbird, that's a thought I hadn't had yet, do you know a ECM part number? is it just a 7730?

[ericjon262]

Some of this can be accomplished through the V8 Camaro and Corvette MAF systems but you're forced to do more work before you even start the engine because you have to change the calibration so it will work with a four cylinder engine.

I guess I should have asked this in the first post, did GM ever use a MAF based tune with a 4 banger? it sounds like you're saying I'd have to mod V8 Bin files to make it work.