The engine measures boost via a Mitsubishi concept of Ecuload, with a value between 0 – 200.  By default the Ecuload logging only goes up to 160, despite the ecu being able to see up to 200 ecuload.  How much boost is this? The following table is a rough guide (credit Merlin, Evo X tuning guide):

Boost vs EcuLoad

So the Rcolt Ecu can only see up to 200 load (about 17-18 psi depending on mods).  This means any map in the rcolt ecu that goes past 200 load will not be used by the ecu, instead it will use the 200 load column (fuel, ignition, mivec etc).  As ecuload is also a measure of the amount of air the engine is receiving, it also means as you go over the 200 load figure to say 220 load, the ecu is seeing and fuelling only to 200 load worth of air. This will cause the ecu to run leaner than the targeted AFR ration in the fuel maps, potentially catastrophically leaner depending on your boost level and richness of target AFR.

Another negative of the 200 ecuload limit is that the boost control system starts to not function properly as you approach and exceed 200 load. You might dangerously overboosting at 250 ecuload, but as the ecu only sees 200 load, it does not react to the overboost condition, potentially causing problems.

Fueling

With 400 load patch applied, the ECU will be more able to hit the target AFR ratio. A highly tuned Rcolt’s fuel map without 400 load patch might have a number of seemingly very rich AFR ratios in its fuel map like the example below:

With 400 load patch this over fueling compensation is not needed, and you can target closer to what you actually want to hit.  Example below:

Boost Control

With 400 load patch applied we can turn back on the factory ECU’s reactive boost. This is both a safety mechanism to stop over boost, but also a way to achieve faster spool when the ecu is not hitting the target boost you are wanting.

Turning on Reactive boost with 3 port boost solenoid

The following shows the configuration to set up reactive boost on a 3 port boost solenoid system:

WGDC and Boost Target Engine Load

The two WGDC tables define the wastegate duty cycle values for 1^st and 2^nd gear, and then 3^rd thru to 5^th gear.  With reactive boost, these tables set the initial wastegate duty cycle (WGDC). The ecu then compares the current ecuload figure against the equivalent Boost Target Engine Load table value (again 2 maps for the gears) plus the ‘Boost Offset’ value.

For example. We are in 2^nd gear, at 4,000 rpms and full throttle.  The WGDC map 1 (for 1^st and 2^nd gear) sets WGDC to 43.5%:

Lets say the car hits 160 ecuload.  The ecu then gets the corresponding value from Boost Target Engine Load #1:

In this case, 140.  It then adds this to the Boost offset value, to arrive at the final target load we are wanting to hit.  With a boost offset of 75, it means the ecu wants to hit 140 + 75 = 215 ecuload, much more than our current 160 ecuload.  The ecu will then modify the WGDC being used based on the reactive boost tables mentioned earlier (Reactive Solenoid Max Total upward WGDC correction tables etc).  So WGDC is increased, and the car’s boost & ecu load starts to raise. It continues to try and hit the target, adding (or subtracting) constantly during operation.  With this example we would see the car start to spool up faster than it would have otherwise.

The other benefit is over boost protection.  Lets say we are hitting 250 load, but the target ecu load + boost offset = 215.  WGDC would be reduced to try and rein in boost until it hit the target, providing a safety need. This safety net is particularly useful on the track, or on the dyno when a slower ramp up rate is being used.

Logging

To load an ecu with the 400 load patch you need to apply the MUT 2 Byte Ecuload patch.  This is done by changing the first two values in the MUT table to :

Then use your regular logging method (Tactrix or Evoscan, see turbocolt.com on how to set this up), with MUT 2 Byte Load logging enabled.

Other Random Notes

Launch Control

Example:

1^st & 2^nd Gear Throttle Limiter

Stock ecu limits throttle in 1^st and 2^nd gear, making 1^st gear easier to launch, but inhibiting 2^nd gear acceleration. This can be turned off by changing the table from stock settings to 100%:

Disabling Cat Warmup

The negative timing, and the leaner fuel serve to help the cat reach operating temperature faster. Set to 0, and 14.7 to achieve a smoother cold driving experience.

Disabling Immobiliser

Setting bit.03 to 0x0 disables the immobilizer check before starting:

Disabling 2^nd O2 Sensor

As above but set bit.01 to 0x0

Pops and Bangs

See turbocolt.com on how to set this up.  People want it, but its all a bit silly (and not as effective as modern pops and bangs or burble tunes).

Logging

See turbocolt.com for guide on Evoscan or Tactrix Logging. Also check out the bit about 200 load logging, to ensure you are capturing the newly patched 400 ecuload limit

Example Changes to Non 400 load tuned ROM:

Fuel Maps:

No longer need to target super rich AFR’s to try and compensate for ECU getting fueling wrong. Assuming injectors & MAF is dialed in nicely can set the fuel map to hit what you actually want to hit:

High Octane Fuel Map, before, unpatched:

After, patched:

Spark Maps:

Build up the ignition more progressively. Log knocksum and adjust ignition maps appropriately.

Tuned Hi Octane Spark Map 1, Mivec Max – map before:

Tuned map, after (note if tracking probably want to take more timing out):

Note – that is just an example, often timing ends up lower than this. To find the right timing, a combination of knocksum & traditional dyno tuning techniques should be combined. On boost, any regular repeatable knocksum value should be reduced to zero by decreasing timing until it does not occur anymore.

The above map will be used when MIVEC advance hits its maximum value.  The other hi octane maps are for MIVEC at minimum, or at target and should be adjusted similarly.

Comparing Changes in the Base to what you had before

Load up both srf files in Ecuflash, go file->compare Roms. This will highlight all maps with a change.

Summary of changes made – 400 load, timing map changes (log knocksum to see if safe), stationary launch enabled, cat warmup stuff removed (smoother cold driving), dual boost maps back on (wgdc 1 and 2), reactive boost back on (faster spool, overboost protection), more mivec (trial it maybe you like the old map), modified wastegate/boost maps for faster spool (will need tweaking, could be too much or too little – change both WGDC maps AND boost target load maps), Mut 2 byte load mod (enables proper ecuload logging).

The post Mitsubishi Colt Ralliart 400 Load Patch – AUDM JDM Rcolt Z27AG appeared first on Turbo Colt.

Boost vs EcuLoad

For colts, I’ve found 160 load to equate to around 13-15psi.  But most of us are running higher? How can we reliably tune the car when ECU Load stops reporting load past 14psi? The answer is 2 byte load.

Colt Ralliart 2 Byte Load

Evoscan (and Tactrix SD card) logging can handle something called 2 byte load but to do that some changes are needed to your MUT table, and also your logging configuration. Before we get into that, some more background.
ECU Load is only 1 byte load. To log it, only one MUT request is required.  It maxes out at 159.375.  2 Byte load requires two MUT requests, one after the other, to retrieve the ECU’s internal master load value, which peaks at 200 load.  The two requests for 2 byte load can cause some rare strange results but more on that later.  For the most part, it is reliable and enables you to log up to 17-19 psi.  This sounds good but how does this impact on tuning?

Impact of tuning with only 1 byte load

If you tune a Colt Ralliart with only 1 byte load, maxing out at 159.375, then your ignition maps at 160 load, will end up being tuned to what doesn’t cause knock at your maximum boost.  Peak power might be the same, but when your car is actually producing 160 load, its ignition will be set as though it was producing 200 load and be too retarded, resulting in less power at that point.  It’s tricky to explain but a few graphs might help:

ECU Load 1 Byte tuning session:

ECULoad Logging

Based on this, a tuner would look to reduce timing at 160 load, rpms 3500 through to 6000.  They should also reduce timing in 180-260 load range based on this data.  Lets check out the 2 byte load version of the same logging session:

ECU Load 2 Byte version of same tuning session:

Based on this, a tuner would look to reduce timing at 200 load, rpms 4000-6000 (note the reduced range to before).  As with above, other cells would be adjusted too.  The key take away is that the tuner using 160 load max would be seeing a very different picture of when the car was knocking to the tuner using 2 byte load.

The different picture would result in a different, and inferior tune.   Peak power would be the same, but power at less boost than peak would be compromised.

OK so it’s important – how do I log it?

You’ll need to do two things. First you’ll need to modify your MUT table and then flash the changed ROM to your car’s ECU.

Colt Ralliart 2 Byte Load For AUDM and most JDM rcolts:

Set MUT00 to 0x804E90 and MUT01 to 0x804E91:

Save the changes then flash this onto your car.  Now you need to modify your logging setup.  If you’re using Evoscan check the option :

Then when in Live Logging, ensure the Load dropdown is changed to Load MUT 2 Byte Load:

Tactrix SD Card loggers need to edit their logcfg.txt to include the following two lines:

paramname=Load2Byte1Raw
paramid=0x00
scalingrpn=x,256,*
isvisible=0

paramname=Load2Byte2Raw
paramid=0x01
isvisible=0

paramname=LoadMUT2Byte
scalingrpn=Load2Byte1Raw,Load2Byte2Raw,+,0.3125,*

So that’s Colt Ralliart 2 Byte Load. Give it a crack and let me know how it goes. Hopefully this helps you, or your tuner, get your rcolt tuned as best as it can be.

Oh one more thing – in the Evoscan log used above you might have noticed there’s a data point past 200 load – 240 load @ 5500rpms. What’s that about?

As the 2 byte method needs to make two memory requests, it is possible that in the time between the two requests that the memory location gets over written.  So we have half of 1 byte of information read, then both bytes are changed, then we read the 2nd byte.  The result is an erroneous ECU load result, that should be ignored.

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