Common tuning FAQ

[foxdie]

Hi all

This thread has been created to address commonly asked questions in relation to tuning EC5A (Galant VR-4) and EC5W (Legnum) cars. The questions answered here are aimed at those asking if something is possible, or to tuners starting out with little experience.

There are some questions that, when asked, you may receive a cold shoulder to. This is because, although not apparent to yourself, the answer is never simple nor practical. This is just a forewarning to expect a bad response to some questions but not to take it personally

1. If I send you my cars ROM, can you set it to run at such-and-such boost?

There are 2 reasons this is a poor question;

1. As our cars don't have a MAP sensor, engine performance calculations are done based on a perceived Load, this is a calculation the ECU does based on a number of factors such as how much air is passing by the MAF sensor, what temperature etc. It is not directly related to manifold pressure (aka "boost" and "vacuum").
2. Every car differs, even before it's left the factory they could differ slightly due to tolerances in manufacturing process, and once it's left the factory it's a free-for-all on how the car changes, factors such as servicing, how the car is treated etc all cause differences.

In short, it's impossible to tune a car to run at a specific amount of boost, and close to impossible to get it to run close to that figure without mapping it in person.

There is a similar question that often comes in that has both the above answered factored into it and some more;

2. Can you send me a ROM that gives me an extra 40 HP?

Asking for pre-tuned images for use on your (or anothers) car is a very bad idea. It's unreliable, often dangerous, but always downright lazy. Asking for a previously-tuned image so you can learn from it isn't so widely frowned upon, but it's still encroaching on something that someone else has invested time in preparing.

Also, there's no such thing as a ROM that gives you an extra "something" HP, as stated earlier, every car is different and requires it's own unique map to make the most of it and handle it's subtle differences that can often result in vast differences.

Here is a theoretical example; 3 identical cars all leave the factory supposedly tuned to 260 HP could meet up 5 years later and put on a dyno;

• Car 1 makes 230 HP because it's been serviced poorly
• Car 2 makes 250 HP due to natural wear/tear/age
• Car 3 makes 265 HP because its fuel pump is failing causing the car to run leaner than intended

If I was to create a generic ROM image that ups the target load (ie. loosely how much extra boost to apply) by an additional 15%, it could have the following effects on the above cars;

• Car 1 makes 240 HP because gains were harder to achieve due to poor servicing
• Car 2 responds well and makes a respectable 280 HP
• Car 3 briefly makes 290 HP before excessive knock causes the engine to die

In addition to this, asking for gains such as +40 HP is a pipe dream unless you have sufficient backing in your wallet for supporting mods. Lets say you're tuning a manual or a facelift auto, you're already starting with 280 HP (well, 276 HP for the pedantic), if you want +40 HP on top of that (320 HP) you've already exceeded what the fuel pump can deliver, and you're also close to the usable limit of our TD03 turbos.

Some people claim you don't need to upgrade the fuel pump before you ready the limit of the turbos, however that's if the fuel pump and pressure regulator are in perfect working order, which after 10-15 years is highly unlikely. If you're gonna ask for 320 HP out of a VR-4, it's highly recommended you invest in good supporting mods; Fuel pump, fuel pressure regulator, intercooler, exhaust system and performance air filter. You also need to start thinking about cooling if you plan on running 320 HP for extended periods (such as on track days). Once and only when you've done that, you will definitely need the ECU tuning to suit the modifications.

Here's a nice example of that last point about reflashing after the modifications have been done, using the stock fuelling table after installing my fuelling modifications (Walbro GSS342 255 LPH fuel pump and a Sytec Fuel Pressure Regulator) I actually LOST power because the car was running significantly richer (AFRs of around 7-8 under WOT). I've had to set those matching entries in the fuelling table to around 12.5-13 just to bring the fuelling up to a safe 10.5-11.0 (and still I feel there's still power to be had by leaning it out to 11.5). I feel my "tune" is circa 320 HP, an upcoming dyno day will confirm that, however if my ROM was to be flashed onto a car without those fuelling mods, I'd be very surprised if it didn't go bang.

3. Can you lean out my cruise for better economy?

As of March 2012, not by a reflash, the ECU is set to match 0.5V from the lambda sensor but as of yet the location of this value in the ROM is undetermined. And if / when it does become possible the benefits won't be safely usable.

Stock narrowband oxygen / lambda sensors output a voltage signal between 0-1V with the stoichiometric air-fuel mixture of 14.7:1 being around 0.5V, there is very little room to change this because the change can often be very sharp (here is a very optimistic narrowband graph), if you were to aim for 14.9:1 the voltage would be around 0.2V, not leaving much room between potentially running much leaner.

It's fairly well adopted that a cruise AFR of around 15.2:1 is beneficial to fuel economy on 8G VR-4s, the only safe way to achieve this is to use either a wideband kit (such as the Innovate LC-1 or MTX-L), or a fuelling computer, that has a programmable narrowband emulation.

That said, economy benefits can be had by advancing timing a few degrees (no more) around the cruise areas.

4. What ECU do I have? Can it be reflashed?

The following is correct as of March 2012;

7201 - Silver metal casing with green connectors - Commonly found on Pre-facelifts - Requires EcuFlash to edit ROM, requires a Tactrix OpenPort 1.3U or 2.0 cable to reflash the ECU, requires MMCFlash USB Module #1 to do the flashing

H8/539 - Black plastic casing with black connectors - Fairly rare and straddled the Pre-facelift and Facelift switch - Requires EcuFlash to edit ROM, requires a Tactrix OpenPort 1.3U or 2.0 cable to reflash the ECU, requires MMCFlash USB Module #1 to do the flashing

7202 - Black plastic casing with black connectors - Commonly found on early Facelifts - Requires EcuFlash to edit ROM and flash, requires a Tactrix OpenPort 2.0 cable to reflash the ECU

7203 - Black plastic casing with black connectors - Commonly found on late Facelifts - Requires EcuFlash to edit ROM and flash, requires a Tactrix OpenPort 2.0 cable to reflash the ECU

Links:

• EcuFlash
• MMCFlash USB Module #1
• OpenPort 1.3U Cable
• OpenPort 2.0 Cable

5. Can my ECU use another ROM and/or have mods / switchable maps?

Again, as of March 2012;

7201 - This ECU can only run ROM images specifically built for the 7201, basic tuning can be done such as raising the boost / fuel cut threshold, adjusting fuelling / timing and boost control

All others (the H8/539, 7202 and 7203) - These ECUs can all interchange ROM images, and in addition to the above basic tuning they also support Kenneths ECU mods.

Kenneth has released 2 ROMs that add additional features:

• v1.x that adds switchable anti-lag / launch control / flat shifting / CEL-on-knock - link
• v2.x that adds 8 switchable maps and CEL-on-knock, with 8 unique Fuel / Ignition Timing / Boost Control tables that are interchangeable with the switchable maps - link

6. Can I swap ECUs?

Yes, but only if you flash the correct ROM image and follow this truth table;

• All VR-4 engine ECUs are compatible with manual VR-4s, regardless of what VR-4 it came from
• Engine ECUs from automatic cars with TCL are compatible with all VR-4s
• Engine ECUs from automatic cars without TCL may have problems if put into an automatic car with TCL
• Engine ECUs from manual cars may have problems if put into an automatic car (either with or without TCL)

I say "may have problems" because it's unclear given so many different PCB revisions if the pins for TCL or auto ECU communication are connected internally to the processor.

More questions will appear here later, watch this space