Torpedo style AFMs

[MazKid]

Just a thought(whether it's good or bad I'm sure someone will let me know).

The Protege's BP(as well as the EGT, E-LX-E, Tracer LTS, etc) uses flapper-door AFMs. The Miata's BP uses the torpedo style AFM.

Now then, noticing side-effects of flapper door AFMs I've been thinking of switching to the other type as it has no moving parts to "flap" in the way of the air flow...as odd as it sounds my RX-7 AFM causes hesitation around corners and after hard manuvers that result in the flapper door bouncing back and forth creating rich/lean conditions for split seconds. The other style AFM won't do this.

Now then, if I look at the wiring diagrams on both cars, is this a possible thing to do? Having not properly researched I know that the torpedo style has a different plug...I figure I could make a connector mid-way on the AFM wiring so that it's swappable whenever I want.

Any ideas or am I just not making any kind of sense?

[naprotejay]

the signals are completely different between the VAF(vane air flow) and the MAF(mass air flow) the ecu is different as well. so, even with a change of the connector it won't work

[D323]

correct... it has also been thought of swapping to the miata ECU, but they have ditsy less ignition and other small things that you would have to mod into your system.

In theory its a good idea though.

edit:

I wonder if anyone has checked the JE50 MAF's that come on K series v6's.

[Speedyj]

Use some MAF to VAF converter and it will work.

[mike_moss]

I love the JE50 AFM...those torpedo style meters with an nice cone filter on them make SWEET sounds at partial throttle.

I'm missing hearing that just thinking about it.

[MazKid]

So wait, NAprotejay says that I'd have to not only change the connector but the ECU and the wire harness to that as well as switch to a coil-pack from the Miata.

But don't '97-'98 Protege ESs use the torpedo style AFMs with the same ECU as the BG and a disty?

Yeah, I was thinking JE50 also.

So what exactly is a MAF to VAF converter?

[D323]

converts MAF signals into useable VAF for the ECU.

[bmikedaman]

So wait, NAprotejay says that I'd have to not only change the connector but the ECU and the wire harness to that as well as switch to a coil-pack from the Miata.

But don't '97-'98 Protege ESs use the torpedo style AFMs with the same ECU as the BG and a disty?

Yeah, I was thinking JE50 also.

So what exactly is a MAF to VAF converter?

97-98 ESs would also be OBD2, much like the 96 Escort GT, there are a large number of differences, second o2 sensor for starters. I doubt they even use the same plugs on the ECU, even if they did, its probably more trouble than its worth. Your best bets are go miata and DIS cuz its better anyways, or get a vaf/maf converter, or heck, even a map to VAF converter and go speed density. I believe there are some programmable ones out there, but you're getting into "might as well go megasquirt" territory. If I had a VAFC and a MAF I'd give a go at hacking it to work, at least on the original VAFC you could get funky with the selections

[D323]

97-98 ESs would also be OBD2, much like the 96 Escort GT, there are a large number of differences, second o2 sensor for starters. I doubt they even use the same plugs on the ECU, even if they did, its probably more trouble than its worth. Your best bets are go miata and DIS cuz its better anyways, or get a vaf/maf converter, or heck, even a map to VAF converter and go speed density. I believe there are some programmable ones out there, but you're getting into "might as well go megasquirt" territory. If I had a VAFC and a MAF I'd give a go at hacking it to work, at least on the original VAFC you could get funky with the selections

Heck before you spend the 180 + S&H for the CS MAF conversionor the 250 for the Apexi SAFC, I would just go the MSnS route and be done. MAP sensor is better than either and with the MS you can tune better while you're there.

[bmikedaman]

Heck before you spend the 180 + S&H for the CS MAF conversionor the 250 for the Apexi SAFC, I would just go the MSnS route and be done. MAP sensor is better than either and with the MS you can tune better while you're there.

While I agree its least restrictive and easy to use, a MAP based system is not ideal from a standpoint of tuning and safety. Speed Density type systems don't actually measure the volume of air directly unlike MAF/VAF systems. They infer the volume based on known parameters for the engine. The problem is if any of those parameters change drastically the tune can go right out the window. You can throw any bolt on you want at a VAF equiped escort without much worry, throw all the bolt ons at a Civic and its going to be running WAY lean. But yeah, if you're going to jump through a bunch of hoops you should start thinking about standalones.

[Silentbob343]

I was about to type in MAF vs. MAP because I knew it would happen.

[D323]

true, but if you use a wideband o2 with the Map sensor, you can tell how accurate the MAP sensor is by the EGT's of the motor.

But I understand what your saying.

[MazKid]

Oh. I was thinking there was some magical junkyard solution to get a JE-50 to work.

I thought that the VAF and MAF, if using the same metering voltage, could just be wired differently to work.

Hell, what am I doing, I'm at work with wiring diagrams near by. Time to check it out.

[integrat610]

correct... it has also been thought of swapping to the miata ECU, but they have ditsy less ignition and other small things that you would have to mod into your system.

In theory its a good idea though.

CS sells a PRM intake for the Protege BP AFAIK.

edit:

I wonder if anyone has checked the JE50 MAF's that come on K series v6's.

I got lost a little bit back there...the CS kit will change flapper door to hot wire?

[mike_moss]

I got lost a little bit back there...the CS kit will change flapper door to hot wire?

No, it's just an intake kit.