I was wondering if the ECU has to be replaced to tune an Rx7. I've have always been looking at getting a PFC, but with only intake and exhaust I'm wondering if it's really neccesary. Any tips for more mild tuning solutions?

 

Yes, it has to be replaced to be tuned. Other ECU's such as the M2 and etc. are just flashed stock ECU's. The PFC can run off of preset maps for mild mods, if you're looking for plug and play.

 

Tuning is simply the adjustment/reprogramming how much fuel and ignition advance is used based on rpm, boost, and a few other things.

The stock ECU can't be tuned. There are modified stock ECUs out there that make an overall adjustment of the stock computer outputs - these are called piggyback ecus. It's good for slight increases over stock boost and power levels, but still they are crude and have the same annoyances of the stock ECU (3k hesitation, for one thing).

A programmable ECU is the way to go. PFC obviously is most popular, but Wolf, Microtech, etc are other options. If you expect in the near future to go fully programmable, either buy it now or save your money.

It seems kinda silly to me to not spend the extra few hundred bucks to ge tthe PFC instead of a piggyback. So either keep your boost regulated at 10psi and use the stock ECU, or get a PFC now. The PFC base map is safe to run until you pay for a proper tuning or turn up the boost.

Personally, with just 2 mods I'd save the money and watch the boost. If it's at 10psi and never goes above 11psi, you don't need to do anything at all. All you need is a manual boost controller on the wastegate and you should have no trouble keeping it there.

Dave

 

+2

 

I would get the power fc re mapped as soon as. The base map is pretty poor imho.

Scott

 

Actually, the PowerFC has a damn good base map out of the box. It's good for many common bolt-ons and about 12psi, YMMV.

If you're totally happy with the car the way it is now, and you're not experiencing boost spikes, stay with the stock ECU. If you're having spiking, look into a simple boost controller to even out the spikes and stay at 10psi.

If you're wanting a little more out of the car, get a chipped stock ECU, like Pettit or M2. They're pretty reasonably priced used, and they plug right in.

If you think you might have other plans down the road, get a PowerFC. For me, it's one of the best mods I've done - car runs fantastic, no 3,000 RPM hesitation, and I know I have all I need for anything I want to do to the car. They're selling for $650-700ish with commander, which is a LOT of power for the money.

But, in general, there's not an intermediate step - it's either keep or ditch the stock ECU. Simple computers like the Super-AFC and E-manage simply don't work worth a crap on the FD, don't waste your money.

Dale

 

Is the pettit chip 700$ if you ship them your own ECU? Also, where can I find the PFC for 650$. That sounds like an awesome deal.

Thanks for all the help

 

erm... have you ever looked at the ignition split..........

 

I agree, the inconsistencies in the timing of the base map should be corrected, but there's nothing there that puts the motor at risk or makes the car drive crappily.

 

In the for sale section. Usually someone has one for sale. Just keep your eyes open.