Engine Management Systems - Which one?

[shaggy]

Hey guys I have a 2003 Caldina GT-4 ST246W and was wondering what engine management systems were out there for this vehicle. I'm not trying to achieve big HP just a better more responsive drive. I don't intend on upgrading the turbo, exhaust or things like that unless failure of these items insist. I would like to have the flexibility to increase the boost to 14psi when required for a little extra punch here and there.

So let me know what system you would recommend be it stand alone or biggy back as they both have there pro's and con's. And preferably ones that you know support the ST246W.

Cheers

Shaggy

[Shifty]

Hi mate

Honestly your first port of call should be the exhaust. It will be cheaper, easier, and give a much larger gain than an ECU... and ECU is more about capitalising on existing modifications rather than giving an improvement on an otherwise standard car.

It is unlikely that you will find a 'plug in' option for such an uncommon car here in QLD, so you will either need to go piggyback (unichip, e-manage, etc) or full stand-alone (Adaptronic, Haltech, etc). You mentioned something about an auto in another thread, this is an important point as a lot of ECUs are unlikely to support an electronically controlled auto gearbox.

If so your best option is a piggyback/interceptor as this runs the standard ECU and just intercepts/modifies fuelling etc so all your standard gear runs as normal... or possibly a standalone ECU spliced in to just control fuel and ignition and the factory ECU otherwise left in control. I don't know much about the complexity of the latter. The best option is full standalone but if you want to run an auto then one of these two options will likely need to be taken.

As far as extra boost goes you will probably find that you're running 10-12psi from the factory... speaking generally an increase to 14psi on an otherwise standard car will only create more heat due to the restriction of the factory exhaust etc... and any performance gains will be minimal and certainly a trade-off as far as long-term reliability goes.

[Slasher]

I'm not qualified on the particular setup, but after the exhaust, a standard fuel controller / afc and/or adjustable fuel pressure regulator could help with tuning the fuel curve on a dyno. There wouldn't seem to be just cause for the complication or price of a standalone or advanced piggyback with a stock turbo. Probably won't pick up a lot power either way. Efficiency is a great thing to shoot for, IMO.

Curious if the DIY Jaycar fuel controller is recommended on here; I haven't read any reviews or heard of anyone using one in the states.

[shaggy]

Thanks shifty thats good advice for all.

I have looked into the exhaust system already and according to the compliance mechanic(who at one stage has owned one of these) it already has a reasonably good dump pipe setup with basically an external waste gate pipe molded into it. But I will check it out more closely when I've got time. As for the rest of the system I will have it looked at to see if any gains can be made.

I know I wouldn't be seeing huge gains from an EMS with the stock parts. But I was just hoping to trim the fat so to speak and make it more economical and a more responsive. They are naturally a little rich to help preserve there engines and can benefit from a tune without hurting the internals.

This car has a few were'd things like the exhaust manifold and rear turbo housing are all in one. The boost level spikes to 16psi for a second or two and then drops to a constant 9psi this is supposed to give a little more initial push in the lower rpm. So I have a lot to learn about this car and appreciate all the info I can get.

Cheers

[shaggy]

I'm not qualified on the particular setup, but after the exhaust, a standard fuel controller / afc and/or adjustable fuel pressure regulator could help with tuning the fuel curve on a dyno. There wouldn't seem to be just cause for the complication or price of a standalone or advanced piggyback with a stock turbo. Probably won't pick up a lot power either way. Efficiency is a great thing to shoot for, IMO.

Curious if the DIY Jaycar fuel controller is recommended on here; I haven't read any reviews or heard of anyone using one in the states.

Thanks Slasher that sounds like a option to look into. Would this work with two levels of boost? Say 10psi for daily and 14psi for a bit extra when needed or does it have to be tuned to the one boost level?

Cheers

[MWP]

I know I wouldn't be seeing huge gains from an EMS with the stock parts. But I was just hoping to trim the fat so to speak and make it more economical and a more responsive. They are naturally a little rich to help preserve there engines and can benefit from a tune without hurting the internals.

What do you mean by "responsive" exactly?
An ECU will only make the car feel more responsive if the current one has a really bad tune... which the factory ECU wont do.

You also wont squeeze out much more fuel economy than your getting from the factory ECU either.
Installing a standalone ECU will probably do the opposite.

Leaning out on boost to get that AFR back to a reasonable level can be done with a piggyback ECU. This also wont effect the economy, and other features of the factory ECU.
Something like an Apexi AFC will do the job.

Would this work with two levels of boost? Say 10psi for daily and 14psi for a bit extra when needed or does it have to be tuned to the one boost level?

Your factory ECU will handle 14psi of boost without any extra tuning.
All you need is a boost controller and possibly a fuel cut defender.

[shaggy]

What do you mean by "responsive" exactly?
An ECU will only make the car feel more responsive if the current one has a really bad tune... which the factory ECU wont do.

There's always economical gains to be made some where in the rev range with turbo charged cars as they are always tuned a little richer to preserve engine life. And as far as responsiveness goes things like ignition timing and electronic valve controllers can be adjusted to reduce turbo lag and increase acceleration via the stand alone ECU. A factory tune is good and reliable but can always be better.

I will be looking into AFC's a little more as an option. Can you recommend any brands and/or models?

Cheers.

[MWP]

There's always economical gains to be made some where in the rev range with turbo charged cars as they are always tuned a little richer to preserve engine life. And as far as responsiveness goes things like ignition timing and electronic valve controllers can be adjusted to reduce turbo lag and increase acceleration via the stand alone ECU. A factory tune is good and reliable but can always be better.

Yes they run rich on boost, but reducing the AFR's from around 10:1 to around 12:1 will give very very small economy increases with normal everyday driving.

Think about it... how often do you spend on boost?
The most gains youll get for fuel economy will be from your right foot, not engine tuning.
If your driving for fuel economy you shouldnt be on boost.

As for ignition timing, the factory ECU will already be close to the optimal settings for that.
There are no "electronic valve controllers"? No 3S-GTE engine got VVTI or similar.

Okay, yes, the factory ECU maps can be improved on for economy, but are you going to spend over (probably far over) $5000 to get those probably very small gains?

I will be looking into AFC's a little more as an option. Can you recommend any brands and/or models?

Ask the person/shop that will be doing the dyno tuning for you.
Making sure they are familiar with the AFC is often more important than the features of the AFC itself.

[shaggy]

Think about it... how often do you spend on boost?
The most gains youll get for fuel economy will be from your right foot, not engine tuning.
If your driving for fuel economy you shouldnt be on boost.

So very true.

But do you think when you are on boost that there is fuel to be saved and performance to be gained? If so than I think its worth looking into.

[MWP]

But do you think when you are on boost that there is fuel to be saved and performance to be gained? If so than I think its worth looking into.

Performance to be gained, yes... hence the suggestion of a piggyback fuel computer.
As for fuel to be saved, youll spend far more on that piggyback unit and dyno tuning than youll spend on that extra bit of fuel that youll save.

[Norbie]

What he said.

The best engine management system for a stock or near-stock engine is the factory engine management system. Believe it or not Toyota are pretty good at tuning their own engines, and any tiny efficiency gains you might find won't come close to making the effort and expense of this project worthwhile.

Do you know just how many hours you need to spend on the dyno to get an aftermarket ECU even close to the factory ECU for reliable cold start performance, part-throttle drivability, and yes even fuel economy? Hint: LOTS.

I should also add that your ECU is in closed-loop mode most of the time (ie ignoring the fuel maps) and this is where most of the fuel efficiency comes from in a modern ECU.

[shaggy]

Thanks everyone for your opinions they have been very helpful.

I have bee talking to some tuners and suppliers of ECU's which has been very helpful to. I've decide to start with collecting all the info I can first which means putting the car on a dyno and seeing what the base tune is then I can research products that will suit.

I will post a dyno sheet when I get this done. It maybe a few weeks as its hard to find time whilst working.

Cheers

[Shifty]

Will be very interesting to see a dyno sheet for a stock Caldina!

[The Witzl]

seriously - WHY BOTHER???

The stock ecu will be as good as it gets for fuel economy on a stock motor.
I would spend your money on a good electronic boost controller and exhaust system. You will have much more fun doing these things.

With a stock engine - you will ALMOST NEVER achieve the economy, driveability, response, cold starting, idle control, etc etc if you go to an aftermarket ECU.

Toyota spends MONTHS tuning their ECUs.... by comparison, you would spend about 5 hours on a dyno tuning an aftermarket ECU.

I know which i would chose for a stock, or near stock engine.

[shaggy]

Thanks all. I have learnt that it is not necessary for an ECU at this stage of tune.

I wasn't just trying to achieve better fuel economy but better performance during wide open throttle as well. I asked this question with my modified cars in mind as I have generally achieved better fuel economy for those conditions when re-tuning them they all had stand alone ECU's.

I will be checking plugs and oxygen sensor before it gets dyno'd to make sure we get accurate figures. As these can upset the performance of the engine.

Thanks once again for all the help. And I think the result is no ECU of any sort required just yet! Dyno to come soon.