Another Mazdaspeed tuning guide

[EmPeEs6]

This is my(!) personal basic Mazdaspeed tuning strategy.
I've made the experience that this is a quite fast and stable way to achieve proper tuning results.
Please feel free to comment on the process...



Fuel:
The following considerations assume that you already have a "stable" fuel curve established.
Basically you can start with the OEM curve, increase the constant afr values for higher loads in each rpm row by 0.1 and interpolate down to load 1.0 afterwards. Repeat this procedure until you see a (reproducable) knocking with kr of max. 1-2 for your current boost configuration at the specific revs and take the last "pre-knock" value for that rpm row. As WOT fuel values you can take the load 2.0 values from the main table and decrease them for the maximum boost range by 0.1-0.2 ("safety method").
After all my (real) AFR values go from 12 at 3k to 11 at readline which seems to be a safe compromise - not too low/rich (which would result in a significant power loss), but also rich enough to protect the engine/cool the combustion down and suppress any (consistant) knocking, even if I chose a slightly different boost or ignition configuration.

Consider that it is simply impossible to find a perfect overall setup, because different driving conditions, temps/atm/weather, fuel quality etc. may have a huge influence on the behaviour of the engine so I strongly recommend to stay within a safe range and don't go to the very top most limit of afr/timing/boost just to get the maximum power out of the car, because this can only be achieved for very special conditions and will stress the engine to the max in all other cases!

Boost:
This is the main, leading map of the tune. I always start with a new boost curve and adjust my other maps accordingly.

You should be aware that the MPS engine (->rods) doesn't like too much boost at lower rpm, so it is recommended to keep boost down below 3k - my BNR starts to spool ~500 rpm later than the k04 and generates real high boost not before 3.6k, so I set my maximum boost (21.5 psi) from 4-5k, tapering down to 18 psi at redline. This drop in boost pressure is highly recommended if you drive the car over a long period of time with high speed/high boost (like on German highways). Otherwise the exhaust temperatures would rise too much (even with a pretty rich fuel mixture), which is as much a concern as the appearance of knocking because of high BATs.
To prevent the machine from overboosting in the low rpm regions, you could lower the appropriate boost and load limits (since a fuel cut is always better than a "blown" engine), lower target boost and starting wgdc values and reduce the throttle opening angle for high load values.
Theoretically it should also be possible to reduce the target boost per gear by populating the boost comp vs. gear tables with values lower than 1, but this didn't work for me.
If you do load tuning (or a mixture of load- and boost tuning), you can also use the load vs. gear table to reduce target boost for the higher gears (5th+6th), in order to protect the engine during long-lasting high speed runs at summer temps.

The maximum target boost value you can chose for each rpm mainly depends on your turbocharger and its efficiency range. My reworked k04 was able to produce 21 psi from 3k-5.2k without any problems, but above that I could only run 16-17 psi without producing just hot, useless air...

In principal, there are 3 ways to design the shape of the boost curve:
1.) "flat": choose the same (constant) boost values for all cells between 36% and 70% (which can be considered as starting point for WOT, which is always between 76-79%)
2.) "smooth": choose a value for WOT (tps 70,80...) and a significant lower one to start with at 36%, then just interpolate between 36% and 70%
3.) "steps": e.g.: 17 psi for 36 and 40%, 18 psi for 50 and 60% and 19 psi for 70 and 80% (WOT).
Remark: 36% seems to be a good starting point to modify the OEM boost curve in order to have an early response on acceleration pedal movements. Of course you should also interpolate between 28 (OEM) and 36% (beginning of custom boost values).

Concerning the boost limiter table, I simply used my max target boost values (per rpm) increased by 1.5 psi.

WGDC:
You should use the same sort of "shape" for the WGDC curve like you use for the desired boost curve!
If you use the "step"-variant you have to - in contrast to the boost curve - decrease the wgdc values down to the WOT area (70-80%) - here 1.5 psi more boost pressure may be "compensated" with ~5 less WGDC.
The WOT values for WGDC should be chosen at least 10-15% under the observed WGDC values for the desired boost (around 3500 rpm even 30% less -> boost spikes!) and slowly rising till the efficiency limit of the tc is reached (~5k for the k04), then there should be a sharp rise (if necessary) to ~70 (with Grimmspeed) or ~90 (stock ebcs) up to redline.
The aim is to keep WGDC as low as possible, but high enough so that target boost is achieved.

Throttle:
You probably will have to try out a lot of different throttle maps until you decide that the driving behaviour fits your personal requirements.
In any case you should increase the (maximum) factory values by at least 10% to reach the largest possible opening angle and set the tps values for the high rpm ranges to this value, too.
Again, the maximum tps value for each rpm row shouldn't be set much before the corresponding WOT load values are reached.
I suggest to try values like "OEM", 60, 70, 80, 88, 88, 88... at each row - from whatever starting load value you want.

Load:
Please notice that the desired load-, target load- and load vs. gear maps always have to be consistent since the ecu takes all 3 maps into account to determine the proper target load for a given rpm/tps situation.
When boost tuning, load tabels don't matter, otherwise you should use realistic load values which are slightly higher than the maximum reachable load values under ideal conditions (cold, dry weather) for the desired boost, so that the WGDC corrections the ecu has to made to reach the desired values will be as small as possible.

Torque:
It seems that you can use the factory torque map, although it won't harm to adjust the table according to your previously modified boost and load tables.

Ignition:
As a starting point you can use the OEM ignition map and increase the "WOT cells" for a rpm row step by step by 0.5-1 degree until knocking occurs during several 4th gear log runs.
Another possibility is to "design" a base WOT curve (which could rise by ~1.5° per 500 rpm) and interpolate down to the load 1.0 cells. This works fine for me. In addition I decreased the timing advance from the first WOT cell up to load max (which mostly isn't reached) by 1° per cell, to ensure that even under extraordinary high load conditions I won't run into any ignition problems.

Logging:
After changing a setting, you should always do several test runs - in case of "critical" changes start with short accelerations in 3rd gear and if everyhing is ok, increase the accelaration duration, then do the same for the 4th gear up to a wide rpm range (e.g. 2500-6500).
Ideally, you shouldn't have/see any knocks at all, but don't worry if there is some occasional knocking of ~1 during some very "hot runs" (high IATs) - if it's not persistent and just apears from time to time, this won't damage the engine.
Remark:
From all logs you made you should determine the lowest (i.e. for high IATs) maximum reachable load under WOT for each rpm.
A lot of tables depending on rpm and calculated engine load can be populated if you assume reasonable, equal values for the "WOT-cells" (cells reaching from the minimum WOT load from your logs up to 2.0) at each rpm and interpolate down to 1.0 or 1.5 load - for example.



To be continued............

[weakdog85]

very nice writeup. when talking about the boost target and WGDC, are the percentages you're refering to the Accelerator PP %?

[EmPeEs6]

Originally Posted by weakdog85 very nice writeup. when talking about the boost target and WGDC, are the percentages you're refering to the Accelerator PP %?

Thank's! The meaning of the % values is TPS (relative throttle position), which is of course also correlated with APP (accelerator pedal position).