ppritchard

What is the advantage to Tune a daily driver? Seems like the factory ECU map takes care of all the variables.
So if the plugs/wires and filters are good -- what would the Tune actually address?

Just wondering out loud.

Thanks for any insight.

RENESISFD

iTrader: (13)

Depends on who you talk to.

Most people agree if the car is almost completely stock (stock boost, aftermarket down pipe and maybe a cat back) the stock ECU is fine.

On the other hand, the stock ecu runs rich and can carbon up a motor. If you have AI that can help eliminate that problem.

It all depends what you want to do with your car. With an aftermarket ECU you have room to "grow" You can add mods and tune the car for those mods and basically have the same reliability as a stock ecu car. You just have more power. I practically daily drive my car, I have a PFC and do not have problems.

BTW, You can not tune the stock ecu.



John

arghx

iTrader: (3)

I don't see how the stock ECU is going to carbon up a motor any more than a different ECU with a tune, all other things held equal.

Turbo8

iTrader: (17)

It's hard to beat the OEM ECU for driveablitly and environmental changes. Of course, as is common knowledge on this forum, too many mods can mean too lean conditions.

RENESISFD

iTrader: (13)

Arghx...I was always under the impression the stock ecu ran rich during crusing. And sime people get better mpg with a properly tuned ecu.

IMHO... If you can mod an fd with an intake, dp, and catback. And control boost. While not running lean, the stock ecu is rich.


John

Supernaut

iTrader: (83)

I like the PFC over the stock ECU because the transition to the secondary turbo seems smoother to me with the PFC.

DaleClark

iTrader: (55)

The big downside to the stock ECU, as we all know, is it's only good for stock or near-stock cars. The farther you modify the car the greater the chance you'll be running leaner than you'd like. If you can keep your boost around 10psi you're in pretty good shape but that can be a tricky proposition.

I've found a car with a PowerFC and a car with a stock ECU generally drives pretty much the same for putting around town. The PowerFC has the advantage that it removes the 3000 RPM cold startup and also completely does away with the 3000 RPM hesitation.

The PowerFC also has the headroom to handle most any modification you want to do to the car. Even the stock map it comes with is quite good and only needs some minor adjustment with the commander to iron a few things out.

Fuel economy wise they really get right about the same. In theory you can lean out your cruise mixture with the PowerFC to get better highway fuel economy if you have the time to work on that.

Dale

gracer7-rx7

iTrader: (16)

You don't actually "Tune" a car running a stock ECU.

At the last tuning day, a guy showed up with a stock car and stock ecu wanting to get "tuned". Apparently people don't understand what it means to "Tune" a car. It is based on the fact that you are running a tune-able ECU - which means Power FC, Haltech, MOtec etc in the RX7 world. If you have a tune-able ECU and a tuner that actually knows what they are doing (most don't), that tuner can adjust your ignition timing and fuel delivery to provide more power by optimizing the fuel and ignition maps to the air flow needs of your motor.

Supernaut

iTrader: (83)

You can reflash a stock ECU though no?

DaleClark

iTrader: (55)

Not really. You can CHIP a stock ECU, this is what Pettit, M2, and various Japanese tuners do. They pull out the stock ECU, remove the stock ROM with the programming for the ECU, put on a daughterboard with a new ROM, and there ya go.

The US shops basically had a few different ROMs that they would use, just a standard map. In Japan they do the same thing but they would also do custom chip tuning on a dyno.

Our ECU is VERY old school and is not flashable like modern ECU's are.

Dale

arghx

iTrader: (3)

The problem with the FD is that it is an expensive and low-volume platform.

On a EG chassis 92-95 Civic, which came out the same year as the FD, you can't "reflash" the ECU in stock form. But with the hardware available now you can cheaply send in a regular ECU off your grandma's old Civic EX to become reprogrammable, and use free software to tune it. That's actually an oversimplification of the ECU options available for a 92-95 Civic. These "chipped" Civic computers are in many ways as powerful and more reliable than most standalones for most applications. Some of these computers are heavily modified; for example, a Civic never came with a turbo but you can have a Civic ECU modified so that it can control boost.

It's the same way with a Mustang or Camaro of that era, and even the 2nd gen FC Rx-7 has a similar system.

I guess this comes down to preference. The stock ECU has more sophisticated gear-based logic for the sequential turbo system, but we have no way of reprogramming it. A Power FC or other computer lets you adjust the transition.

The stock ECU control logic is divided into control "zones" that are outlined in the service highlights manual. Under some conditions it runs at a stoichiometric AFR of 14.7:1. Under other conditions it runs richer than that and uses the air pump to lean the mixture out. At idle the ECU is designed to run as lean as possible without misfire; it has a closed loop system to do this. But here's the deal... it's designed for mostly stock components. Most of the stock emissions systems need to be installed, and you really shouldn't have porting because that changes the engine vacuum. You can't just install a Power FC and run it as lean as you want to whenever. Any rotary engine prior to the Rx-8 Renesis engine needs to run rich under certain low load conditions or it will misfire; this is due to the internal exhaust gas recirculation that is inherent in the configuration of the exhaust ports.

It is conceivable that you can get better gas mileage with a properly tuned aftermarket computer, but better compared to what? Better gas mileage compared to a stock computer operating on a stock car? Maybe. If you lean it out under certain conditions yes... stock ECU cruising on the highway at 14.7:1 and PFC cruising at 15.5:1 , then probably it would be better. But an aftermarket computer typically varies significantly with the weather (compared to a stock ECU that must meet emissions standards), and usually uses more fuel at idle and tip-in.

The hesitation issues with the stock ECU is unfortunate and there's not much you can do about it. There are ways around the accelerated warmup system.