Any series 4 ecu will run either s4 AFM. IT is just that one afm is more sensitive than the other; or, one afm can read more volume than the other.

Supposedly, the n338 convertible ecu will run a turbo engine the same as a n332/3 turbo ecu, it is mapped for boost whereas the NA ecu's are mapped only to atmospheric and no farther.

For instance, you could take an t2 ecu, and put an NA afm on it, and even though you're mapped (in the ecu) for x amount of airflow, you won't have that much fuel delivery and you'll still blow your **** up, because the airflow meter can not report proper high end air flow to that computer.

 

Interesting, I assumed they had different voltage outputs at the same ammount of air flow?

I thought it was the S5's that had the "interchangeable" AFM's.

Oh well ya learn something new everyday.

So why would they release the USA vert with an AFM that would give worse resolution (higher spring tension)? Or is the vert AFM still an N/A one with a normal low spring tension?

If it is then I guess you could just put in a TII AFM in place of the N/A one....?

Why Don't more people do this when turbocharging their N/A cars? Seems like an easy way out.

 

I havent done enough research to be exactly sure what the voltage differences are. I believe the voltages are the same, but since the spring tension is different. The voltages may vary as well. Afm's are a very hard thing to measure, they are very nonlinear so without extensive testing and equipment you are left guessing.

The s5s had 2 different afms just like the s4's.

All verts in the US are NA. So, they get teh standard NA setup, save the computer. For some reason, mazda felt the need to change that.

You still have a wiring harness that is not the same, and a lot of other differences. So you still wind up needing to change everything out...afm, boost sensor, wiring harness, engine w/injectors, etc.

How so? This ONLY applies to vert ecu's, and not many people know about it. Hell, I don't know 100% that it is true, but everything I have heard points to that. But just because you have the ecu doesnt mean that the rest of the swap is any easier. You still need all those other parts...everything NA is different.

 

***1200 down to 500 depending on temperature, that I imagine will be easy for me to adjust tomorrow when I have more time. Funny thing is my 3k start-up is gone, probably due to some of the stuff removed like the ACV?****

The missing 3000 on startup....maybe the water temp switch at the bottom of the radiator is off? Or the neutral switch is not connected up right?

The idle b/t 500/1200 is an odd ball. I wonder what the idle does with the initial set coupler installed???? Act different? The 1200 figure caught my eye. I have noticed that if I gently raise my idle with my accelerator pedal, that as I slowly increase the rpms around 1000/1100 rpm, the ECU will advance the timing at that point, and what happens next when it does that, the rpms increase to about 1300.

The reason I know about this is that I had a bac that evidently was dirty, and it would on occasion stick open a touch. Just enought to hit that magic point where the ECU advances the timing which in turn kicked the rpms up a couple of hundred. Soooooo...possibly that might be a slight problem your having.

Another thought was maybe you have your oil injectors airbleed connected to a source of vacuum when it should not be connected to a source of vacuum?? Just a thought.

Or in the same vein.....if the fuel injector airbleed nipple is connected to a source of vacuum when it should not be connected to a source of vacuum, will cause a irregular idle.

Getting a good idle without the benefit of a screw on the bac would seem to be difficult without messing with the throttle stop screw on the throttle body.

I don't know what type afr gauge you have, but a rx without a airpump and acv WILL read rich at idle. Using a wideband you will see rich like 13.0 on a normal car that does not have a acv/airpump. The same car if you put a airpump/acv on it will see 14.7 or so without changing the rich/lean variable resistor. That's normal for obvious reasons. So what I'm saying, is that your car has no airpump/acv, so I would expect you to see rich at idle. That is as normal as it gets. If you try to turn the variable resistor til you see a leaner figure....you will mess up your idle. It will be too lean and do the little poof, poof thing like its missing. So don't aim for anything other than rich at idle. Its as normal as can be.

I don't see your idle problem being a afm/pressure sensor issue....but you do need to get a turbo ecu and boost/pressure sensor to make things Korrect! for boosting.

Just rambling, pay no heed.

 

Apparently I have an oddball ECU (the N388), The 88 vert. is the only one that reportedly used a universal ECU. That is likely because in Japan they were only available as a turbo and being the first production year of a model manufacturers sometimes do whatever they can to get a car to market ASAP. I bet the second year of the RX-8 has a lot of little changes. Some other things to note as Kevin said in another post and I discovered myself, is that the verts have multiple trans mounting points, and a crossmember came shaped right for my turbo downpipe. As for other years and models they are supposed to be noninterchangable for NA and TII. Other things I have noticed is a slew of unused plugs on my harness even though mine is loaded with factory features, I even have the electric fan connector but have no electric fan, I think that may be there for automatic trans. cars though.

 

I will have to clean my BAC valve and see
That could be it I just used a vacuum diagram off of the forums that showed how to hook things up after the rats nest removal.

I don't know why but both my NA and TII bac valves have no adjustment and the FSM shows it as an adjustment point....... weird.

Thanks for the input