HOWTO: Falcon Spark Cut

[Roland@pcmtec]

We developed a spark cut limiter for the Falcon. After extensive testing and advice from professional calibrators we have decided that there is no safe way to implement a spark cut limiter without also cutting fuel to some extent or using advanced spark recovery methods. Most aftermarket manufacturers highly discourage a pure spark cut due to the uncontrolled deflagration it can cause in the exhaust (and if you are unluckly the intake) manifold. You can listen to a fantastic explanation by Scott Hilzinger from Haltech here on this. For example an SR20 may last a few few seconds before throwing a rocker arm if an ignition cut is used. Scott on Spark Cut

After testing we have decided not to release the full spark cut build due to the reasons above.

For those of you who want a "pop and bang" limiter you can achieve this using the principles discussed here and an aggressive spark retard of -60 degrees. Note this can cause pre ignition, lifter pump up and general destruction of the exhaust system/valve train. Use with caution

This can be achieved via aggressive spark retard to the point of misfire. This does also also ensures you retain all of the built in OEM safety features and "round robin" cycling of cylinders with all the pops and bangs you want

For the latter we have set the limiter at 6350rpm

ID  Name  Value
auF0133  RPM Limit Fuel Cut  6350
auF0144  RPM Limit  6000 (use this for individual cylinder cutting, or set it to 6350 for a hard cut that will simply toggle all cylinder on and off. 

auF12796  The amount of time that RPM limit is allowed to be exceeded 1 sec  (this avoid hitting the limiter on gear changes which can occur occasionally). For race cars, set this to 0 otherwise you could experience a large overshoot in rpm.

auF11698  The amount of RPM that the engine RPM is allowed to exceed the engine RPM Limit for time specified in auF12796  250 (set this much lower, eg 50 rpm)

ID    Name    Value
auF12516    Minimum torque ratio below which torque reduction via spark are not possible.    0

This is how far the rpm can fall before rpm is no longer limited, a smaller value means it will recover faster, a larger value means a slower recovery time.

auF12773  Hysteresis for in gear RPM limiting.  100
auF12290  Hysteresis for neutral REV limiting.  100

auF16586    Spark Min Clip    -60    -15        Minimum allowed spark angle

Set Engine Speed Limit to 0 in auF0262

Disable ETC engine speed limiting.

Set your BLK/MBT table to something like this (eg -60 deg at 6320 with a hard cut at 6350) will mean you a essentially a misfire (with spark still) at 6320rpm giving a window of "spark cut" of 30rpm.

You can then combine this with rolling anti lag as described here for more of the same.

For more information on the Falcon torque reduction system please read the follow thread which goes into it in lots of detail here

For those engineers out there here are the PID gains for the limiter.

ID    Name    Value
auF1689    Proportional gain for powertrain protection over n    0.2

ID    Name
auF2155    Initial I term for n limiting control (increments over time)

[Mrdriftstar]

Hi team is there a price to add spark cut to the software? 

[Roland@pcmtec]

4 minutes ago, Mrdriftstar said:

Hi team is there a price to add spark cut to the software? 

Simply be a workshop customer who has an actual workshop who understands the risks.

[Mrdriftstar]

I’ve got one car workshop and own a mechanical and auto electrician business or you looking for full car workshop. I’ve got a few spare motors 😂

[Roland@pcmtec]

On 7/31/2024 at 5:19 PM, Mrdriftstar said:

I’ve got one car workshop and own a mechanical and auto electrician business or you looking for full car workshop. I’ve got a few spare motors 😂

Simply follow the guide above. You don't need the spark cut itself to get the result you are after. We can turn it on if you want though.

[yoda598]

we took our drag car out for testing last night, the custom os spark cut worked well. 9psi flat at 2800rpm on the stally. Unfortunately, there is an issue. Spark cut didn't disengage until 10-20kph. so, the car would launch well, but then continue to buck on the spark cut until it got past that speed. 

[Mrdriftstar]

On 8/2/2024 at 3:23 PM, Roland@pcmtec said:

Simply follow the guide above. You don't need the spark cut itself to get the result you are after. We can turn it on if you want though.

Yes please that would be great if you could. Cheers 

[Roland@pcmtec]

On 8/8/2024 at 8:00 AM, Mrdriftstar said:

Yes please that would be great if you could. Cheers 

At this stage we are not releasing it until we can do more testing. We don't have an ETA on that.

[Mrdriftstar]

7 minutes ago, Roland@pcmtec said:

At this stage we are not releasing it until we can do more testing. We don't have an ETA on that.

Oooh bro we doing we’re not ohhh we might ohh na we not now 🤦🏾‍♂️

[Puffwagon]

 

[Mrdriftstar]

😂😂😂😂😂well done 👏👏👏