I see a consistent theme... the Power FC. There are newer ECU's that maintain twin functionality with WAY more resolution than the PFC. It's been around almost as long as the stock ECU.

 

The PFC maintains all of the stock drive-ability and allows the tuner to focus on making power. Yes, you can still tune the cruise and idle a bit but there is a lot to take for granted. Here are some examples:

1) Idle timing and mixture are accounted for. Idle timing drops to -5 deg leading and -15 trailing. I had no idea. I've never had to deal with this before. The PFC just idled smooth out of the box.

2) Off throttle rev-down is taken care of for you. In my Adaptronic I spent weeks figuring out where I could cut fuel, where I had to turn it back on, where to add fuel, etc. All to allow the car to rev down from a closed throttle downshift without backfiring or staling out.

3) Electric load compensation has to be set up on the Adaptronic. I'm still working this out. This has to be set for the engine cooling fan, the headlights, the A/C and the P/S. The PFC just "learns" this when you first set it up.

You can see a lot of this happening in my tuning thread. I've been spending gobs of time on drive-ability issues. (link)

The PFC has all of the stock ECU's drive-ability and allows you to take things to the next level. It's a good next step after the stock ECU has reached its limits.

 

There were a handful of factory tuned stock ECU's that were used in the Mazda factory and factory backed FD race prepped cars that ran 13psi.
I cannot comment on the drivability but was told by one of the race team members that the car drove like a factory car with it. Just with more HP.
When one of the race cars came up for sale a co worker at the time commented that the ECU alone was probably worth as much as the car it came with.

The car in question was the red car with stock white wheels Peter Farrell drove. (One of them)
That ECU is probably still out there and with today's tech could probably have the map copied and flashed on any factory ECU.

So what the OP is saying is actually a reality. The thing is...it would take some inside info to find out where it went. But I understand there were maybe half a dozen of them done for the race series. I doubt even Mazda can tell you were the map for the race ECU's went to even try to duplicate it. Which they wouldn't in their right minds.

I was told the car had about 300hp with that ECU but again I can not verify.

Also the cars built in 91 and possibly into 92 had a stock ECU that put out 11.5 psi. But as soon as motors started showing up broken they lowered the boost to 10 psi.

I had one of those 11.5 psi factory ECU's and it was never determined if that was causing the motor failures. I believe they kept failing but Mazda left the boost at 10 psi.
Is actually not 10 for both turbos but you know what I mean.

There is some history for you.

On another note. The factory ECU is an 8bit and the PFC I believe is a 16bit.
I've driven and owned a car with a PFC. I worked well on a stock twin turbo car.

 

Its a real pity no one has cracked the 99 spec ECU and sells a plugin tuner like they do for EVO's and Nissan's and most other JDM tuner cars.

 

As with most things, the effort of doing it doesn't outweigh the benefit of doing it. Too many easier, simpler solutions that operate just as well.

 

re-amemiya
http://www.re-amemiya.co.jp/commodit...d3228&scd=5346

 

I am running with 3inch FGK catback, twin k&n apollo air intake and changed piping to the intercooler to stainless on stock s8 ecu haven't had any issues. I am going to put a downpipe on soon guess I could let you know in a month or two. I can't tell you what's going on it the engine

 

I would recommend getting a wideband before the next mod.

 

I understand that the 16 bit ECU is an obvious inprovement. But in addition to my experience being similar to Adam's, there are other advantages for the PFC. I was also able to simplify and delete emissions without worrying about CEL's or Limp. Others are also able to delete the OMP with it. Given no one has any warranty concerns on these cars, I just don't see any stock ECU on any FD in the U.S. being the best choice.

 

Given no one has any warranty concerns on these cars, I just don't see any stock ECU on any FD in the U.S. being the best choice.

It depends on your priorities. If reliability is one priority I would beg to differ with you.

Don't take my word for it though, talk to engineers that design ECUs- they cannot dedicate the time/money to duplicating the factory closed loop knock control for instance.

I wonder if instead of audible knock if they could go the more expensive route and monitor combustion pressures and run a reliable closed loop knock control off that.

 

If it's legitimate, there's one for sale down here. Story I seem to recall, Mazda engineer was flown back and forth to do the development....I understand, there were a few grenades in the process!

 

Using your example, if reliability is a priority and you're concerned about knock why not add an AI system with the PFC? They've also come along way since the 8 bit days...even the early 16 bit days. Cheaper, more effective and come with other benefits too.

 

You cant adjust anything with a stock ecu. It doesn't matter what version. A stock ecu limits what you modify. A pfc opens up a whole new world. If we all wanted engines that were close to stock, a stock ecu would be perfect. That just wont work for most of us.

 

in california we don't have warranty concerns, but we do have to be able to smog the car, which means full emissions, and vacuum rack. the previous owner did lots of horrible things to the car. it was either get the 99 ECU running, or find a whole US spec vacuum rack/wiring harness...

99 ECU was easier, and it does actually run way better.

 

The stock ECU is 80's technology and has all but no memory. PFC is not a bad add on if you want to stay under 400 HP. Had mine for about six years with twins, non seq twins and a single set up. Big reliable power calls for at least a Microtech.

Stock turbo's suck IMO


LMAO........ "warranty concerns" Its a Rx7 the "X" is for experimental .

 

has anyone tried using a stock jdm ecu with their fd? the jdm rx7 doesnt have the precat like its usdm counterpart. so a stock downpipe is already "open". wouldnt that play a big role in the stock tune?

i dont know what this guy should od about his ecu issue other than swap out all the wiring to an earlier year so he can use a pfc or something else. not really sure if that is an option although i cant see why it wouldnt be possible.

 

There are a few options for the JDM 99-02 cars:

Re-Amemiya REDOM chipped standard ECU
Knightsports chipped standard ECU (not sure if still available new)
PowerFC
Greddy E-Manage Ultimate

 

What did you end up doing Jobro ?

I'm currently in the same situation an want to keep the stock ecu on my S8.

 

This statement is not true. All Adaptronic ECUs, including the FD PNP, support closed loop ignition control. It will use the OEM knock sensor and pull timing based on a preset knock limit. Generally once you knock its game over on stock seals/pump gas however.

 

There are many flexible ECUs that can be made to perform far better than stock and the PFC while retaining stock smog controls and functionality, you just need to understand how to set them up. They aren't 13B specific out of the box.

-David Guy