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HOWTO: Torque by gear for high power S550s


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Problem: You have a 3.0L whipple and street tyres that won't hook in most situations

Solution: Torque limiting in lower gears.

Note: This is a complex task and requires a solid understanding of the Ford torque model to set up. This guide is a work in progress.

Using the PCMTEC Multi tune you can set up multiple maps. In this example you can set the following tables to limit torque in different tune slots. Tune 1 can be a "snow/valet" mode, tune 2 could be more power, tune 3 could be full torque at all times.

To do this add the following tables (auF63130 through auF63137, and auF63150 through auF63152) to each tune slot. Note that this requires your torque calculations and tables are correct. It also requires that the WOT = WOP switch is disabled and the car is tuned like an ecoboost. The tables that are used work up to gear 6 as they are a hangover from the 6 speed and calibrated out by ford (eg set to 2000 nM) by default.

The following tables are required to allow the torque by gear limiting to work in a AUTOMATIC

Firstly the "engine type" is determined via 

auF74454

image.png.a9f2f5fa276183cbed6081b8aff1ecd4.png

If set to 0, the maximum torque per gear is hard coded as 10000 nM

If you set this entire table to 1 the following table should now be active. You can then set the torque limit per gear in table auF63135. This goes up to gear 6. If you set auF74454 to 2 it will use auF63135 instead, if you set it to 3 or any number other than 3 it will use auF63137

image.png.1375454a8981c5d348c17e59814cce57.png

These tables are typically used in the ecoboost and not an NA mustang however they should allow you to limit torque in gear.

There are several other tables that also use this input, if this does not work I would set all of the following tables to be the same.

image.png.fa22ce0da9167a13622609b0f58f4c62.png

To disable the throttle going wide open when WOP=WOT you will need to set the following out of range:

ID    Name    Value    Stock    Units    Description
auF28212    ETC Pedal Ramp 1 Pecent    200    83        ETC Pedal Ramp 1. % where WOP=WOT.
auF28213    ETC Pedal Ramp 2 Percent    200    90        ETC Pedal Ramp 2. % where WOP=WOT.

If left at 80 the torque limiting will only work until the pedal reaches the value in auF28212

auF62990 and auF62997 will need their torque values updated to suit what the engine is making, otherwise even at WOT when no gear torque limiting is requested will mean that the throttle will float. These will need to be calibrated correctly like an ecoboost along with all of the other torque maps to ensure you actually get full torque when no limits are in place. This also will mean the cars drives nicely as your torque model matches what the engine is actually making.

auF50735 needs to be set to 1.

MANUAL

In a MANUAL you can set the following tables for torque limiting. Note that these are not mapped or available in every single calibration, if this is the case you need to use the AUTOMATIC method above.

auF74489 through auF74496

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This guide is a work is progress. More information to come later. If anyone would like to contribute to testing this and what is involved with the torque model to make it work nicely please let us know.

A video of someone demonstrating this working.

 

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A good example of this is the GT500. If you look at any FHJJ2 calibration you can see that auF74454 is set to 1 (eg engine type == 1) which I believe means "supercharged".

They then limit first gear to 700nM of torque which can be seen here auF63151, auF63152,auF63150

image.png.e8f509aee447a6a3bca8d317acc39788.png

and also here in auF63135,auF63136,auF63137

image.png.547e4352ea43a0ffdb78825263e351b7.png

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Been using this over 10 years and it works perfectly.

As you have alluded to, the HDFX needs to have been extended out to suit your highest power figure without turning the factory power load settings into imaginary figures, but so long as you do, it works pretty well.

This parameter has always interested me, I would appreciate your thoughts on what it actually does:

ID    Name    Value
auF57831    pedal position threshold to declare WOP=WOT.    100

I assumed it would cause a pedal follower type arrangement at 100% pedal, but in testing, load control always takes precedence and it will only go WOT if load allows anyway, making it kind of defunct. Or dos it override the calculated airflow-optimum blade position to some extent at 100% pedal? 

 

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