Every performance thread that pops up on the 2IS seems to get very bogged down about ECU talk. Alot of people on the forum are being mislead into thinking that nothing can be done about ECU tuning on the 2IS. Lets talk it out. Keep it on topic and facts only. If you state something have the facts to back it up. This thread is here to prevent "new" tuners from being caught up in jungle of tuning myths.

 

I'll jump start this by asking a question ( I know the awnser for) but others need to know.

What is cann-bus and how does it effect ECU tuning on the 2IS?

 

CAN - Control Area Network.

It's just a communication bus that links the many different computers together. It allows the Engine ECU to talk to the Transmission ECU etc....

You can also upgrade the software of any of these ECUs via the CAN bus if the system allows you to and you have the equipment. OBDII data can be read from the CAN bus. This includes timing, coolant temp., fuel trims etc...

AFAIK - only Tom's in Japan has the equipment to gain access to the 2nd Gen IS ECU to perform any type of modifications to the OEM engine strategy.

This in no way prevents any type of piggyback system to be installed. However, during closed loop operation, the vehicle will correct the Air/Fuel ratio and negate the piggybacks “tune”. Some piggybacks can tweak the O2 sensor inputs to the ECU so that it believes that the A/F ratio is at the factory setting. Then the “tune” can be maintained. This is a coming issue with most fuel injected vehicles.

 

Gaugster - Are you stating that NO piggyback system can be installed in our cars?

 

He stated the exact opposite actually.

He went on to add that a normal one like an SAFC or something won't make changes that actually last, because the factory ECU will tune them back out via closed loop feedback.

And he mentioned that you could design a piggyback that worked on both ends with a WBO2 to constantly retune. Gernby has done exactly that in fact with a home-built unit.

Gains won't be huge, I believe I've seen gains in the 7-10 hp range mentioned for such tuning on the 2IS so far, but they're gains.

The problem is, that's the only ecu altering you can do. You can't touch timing, base fuel maps, remove limiters, etc...

TOMs can do most/all that stuff on JDM ECUs, but nothing to be done on US ones. (and likely won't be out of fear of DMCA lawsuits)

Running a complete standalone isn't an option either... there's the complications both of the direct injectors and the fact there are so -many- different ECUs that all need to talk to each other

 

This being said, means that a Fuel Controller (ex. Haltec FX-10 ) "piggy-backed into the Port-injectors only could control fuel 100% of the time. Allowing the stock ECU to control the Direct-injectors as normal. You could use the FX-10 in closed loop mode and with alittle tuning could have a very wide A/F ratio band. Being able to support Nitrous, Supercharger, & Turbo most likly up to @ 10lbs of boost with stock port injectors. This setup does not interupt any can-bus network and as long as you Ref. off of the stock O2 sensors it will have the same correction in tadom with the direct-injectors.
What do you think? Possable problems?
(BTW I am NOT saying this motor will support any type of boost just that it can be tuned to.)

 

The stock ECU won't notice the port injectors aren't listening to it anymore and won't notice they're firing when it doesn't want em to?

I know normally with a standalone you can just fake the "everything is normal" signal to the stock ECU if you're replacing its fueling job entirely, but you're not doing that here.

(and with 12:1 compression I really don't think it's lack of fuel that's the big limiter anyway for boost)

 

What type of feed back can an injector give? The injector driver grounds the injector to fire it. Depending on load will determine how long it holds it to ground. (ie duty cycle). It doesn't matter if theirs a load on the driver or does it? The only way it would be able to monitor this is via milliamp feedback.
From my experience the ECU never knows the injectors are not wired to it. If you get the right tune the injectors should maintain the correct fuel trims and would never be picked up by the ECU. If your monitoring the same O2 in closed loop it will have the same correction at the same time as the DI's.

I'll just say this about BOOST. (then i'll leave it alone, and stay on topic) If or when I boost my 2IS I'll have three boost settings. I will replace the head gaskets with custom stronger, leave the compression the same, and replace custom head studs. #1 setting will be 6 psi max 93 oct. #2 will be 10 psi max 100 oct. #3 will be what ever boost I can get out of C16 race fuel. With head studs and stronger gaskets I see no reasons why this high compression motor can't be boost friendly. Lets just say you pick up 10 whp for every 1 lbs of boost. If the 2IS puts down 280 whp stock and you can get 15 lbs out of C16 race gas you should be able to lay down @ 430 WHP on the stock 2IS motor.

 

The ECU knows the duty cycle on the injectors (at least the ECUs I've read OBD data from have, and have shown lower DCs when larger injectors are used suggesting it's not just assuming DC based on the signal it sends, but I guess that could be adjusting from O2 feedback) so it knows something about what they're doing, but I suppose it might still be possible to fool it. Then again I'm used to cars with 1 or 2 ECUs tops, this is a much more complex system, so somebody would probably have to look at what the communication is really saying

TOMs in japan reprograms the ECU there to advance timing for 100 octane and only manages 5.8 lbs of boost doing it... I suppose the HG and stud changes might let the engine handle an extra 4.2 lbs, I dunno...you'd think if it took that little to almost double the boost though that TOMs would offer the option, especially with them already getting over 10k for their kit

C16 is leaded though isn't it? that creates other issues of course...

 

Well, if we're going to get serious about boost and engine management, what size pistons do these motors have? Seems the easiest (relatively speaking) option would be to install some dished aftermarket pistons in the motor to lower the compression a little bit, which would allow to use a piggyback that only does O2 skewing to dump more fuel under boost. Perfect example is the older gen (pre-2000) Honda Civics that use Suzuki Vitara pistons because the compression is lower and they are forged (IIRC on the forged).

If you can lower the compression, you can "reliably" use a piggyback engine management system, with colder plugs (to help retard the spark) and be able to run a low boost setup with different injectors.

Does anyone make different cams for these motors? I know a couple companies (not just Crower) who do custom grinds and it seems to me that with a donor cam to give a little more lift, some lower comp pistons, and bigger injectors, boost wouldn't be too hard to figure out.

Like was mentioned in the infamous Frank Turbo Thread, the AEM F/IC is a decent piggyback (kind of, lots of folks have had firmware issues), and the PCS-XFC works on the same O2 skewing concept. I don't know enough about the ECUs in this car (yet) to say whether or not a standalone OBD-2B, well, standalone like the AEM EMS will work or not, but it stands to reason that it could as long as a you either wired it in or got Boomslang (www.boomslang.com) to make a harness for it.

Just my .02. I'm learning about this engine as I go along here.

 

As far as I know changing pistons would require someone to forge custom pistons. Ditto changing the cams.

Last I heard there's no aftermarket spark plugs either (standard plugs don't fit due to the direct injection) but the last thread I saw on that was a while back so maybe there's something now.

I imagine you could find some kinda larger port injectors maybe for the 350 at least, dunno the specs on em.

But honestly if you're talking changing engine internals with custom parts you're starting to get into serious money.

 

It's cheaper and easier to buy an IS-F. Here are the issues - no matter what, you won't be able to change many of the necessary parameters on this ECM. I have a very good friend who does this for a living with Audi and Porsche ECMs. He's been working on a Toyota based project for the last two years and has not been able to get into the ECM. He's really good at it too.

So, you're going to have to go piggyback. No one manufactures an ECM with 12 injector drivers that are independently addressable AND half are port half are DI capable.

Playing with the port injectors has some promise for additional fueling but only because they are not used at WOT in the stock configuration. I've often thought it would be worthwhile to figure out how to allow a passthrough signal that would be taken over by a secondary signal (e.g. when NOS is sprayed or boost & WOT are concurrent) but I've never really felt it was worth the time to figure out the details.

Modifying the hard parts to make lower compression is a losing game. The piston crowns have a patented shape which works with the DI programming to create a stratified charge effect. Changing the dome of the piston will mean lots of trial an error unless you can get someone with intimate knowledge of how the piston dome needs to be shaped to help with your project. Unfortunately, that guy is an engineer at Lexus in Japan. Best of luck with that one.

Finally, this is an aluminum block with thin iron sleeves. It would make a lot of sense to hydrostatically test the bores before doing anything else to determine what the maximum allowable cylinder pressure is before the bores go into permanent deformation from being over-pressurized. That will tell you more about what can and can't be done with this engine than anything else (assuming you have an obscene budget for testing and development - if you don't, you're way ahead to just buy the IS-F.)

 

Changed the title. It just makes it easier to incorp both in the conversation.

 

I agree 100%

Everyone only sees the tip of the iceberg. There is much more than what we know of. The climate control system, body ecu, gateway ecu, smart entry system, and many more systems communicate to each other. Removing or attempting to disable one of these systems creates a big issue for the entire network to function properly (if any at all).

Since the OEM ecu doesn't use the port injectors during WOT, there is a possibility of using them during boost or nitrous. This would mean that the piggyback controller would be activating (and metering) these injectors then. But during the other times when the OEM ecu is in command of these injectors the piggyback controller should be deactivated and keep itself out of the equation. There is'nt one piggyback ecu that I can name that has that capability. The Greddy emanage ultimate is the closest but it needs an active injector command to sync its metering. Since it can't sync (as it can't read the CAN control from the OEM ecu to the DI controller) this piggyback controller won't be able to function to our advantage. It does have the capability of manipulating the timing control to our advantage. However, since no one has ever tried this, we can assume the OEM ecu could detect the timing being out of sync (by the ignition confirmation signal from the ignition coils) and the logic in the ecu may take action against it. It could also manipulate the MAF meter output to the OEM ecu but this could make air temperature and pressure changes inaccurate and very away from OEM drivability.

The OEM ecu is based on mass air A/F control. Speed density systems are designed differently and use tables for A/F controls vs MAF and throttle angle. Most OEM turbo cars are setup with Mass air. Tuner turbo cars are generally setup with speed density. They use speed density for better tuning but the compromise is usually the drivability. OEM manufacturers work very hard in regards to drivability where everyone spends 99% of their time when they drive their vehicle. That 1% of the time when the dyno sees the car is the WOT powerband. You don't need an elaborate ecu to deliver that. A '70s carburator can give a similar power curve as long as the A/F is tuned to it.

 

[quote=lobuxracer;3813640]It's cheaper and easier to buy an IS-F. [quote]
It may be. But thats not what its about. If I owned a IS-F I would be in the same boat. I'm a true tuner " everything must change no matter what the cost " I try to turn every car I own into a complete money pit.

I agree with everything else stated. AEM has a new pass through injector driver. The only problem would be no driver signal at WOT. Could you piggy off of the DI injectors for Signal?