Boost by Gear with OEM Logic

[engineermike]

@Midwestracer if your tuner is worth his salt he can make this happen. If hobby tuners can do it why can’t professionals?

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[80FoxCoupe]

@Midwestracer if your tuner is worth his salt he can make this happen. If hobby tuners can do it why can’t professionals?

Because for a pro, the juice is not worth the squeeze.

 

[Midwestracer]

I don't currently have a tuner and would rather learn how to make the adjustments as needed for surface conditions, my car was dyno tuned by rpg from pervious owner

 

[mejohn50]

What all do I need to employ this and how will it work with my current tune will it overlay with it or will the engine need to be tuned for my setup first then play with this and my car to find the sweet spot

The short answer: someone willing to figure it out and set it up for your modifications needs to tune your car.

I worked on figuring this out off and on for about two years (I took many breaks from working on it). I shared just enough information in this thread that anyone who understands the logic should be able to figure out the rest and make it work. My intent was not a tutorial showing how to make it work, but more simply share the fact that this functionality exists in the OEM PCM logic and works if one is willing to spend the time and effort.

As @engineermike said, this is something that any professional tuner should be able to implement. Though I can understand why they won’t/don‘t. Imagine having to dial this in for every single car that wants it, and then giving the end user no ability to change it other than a tune revision. PCMTEC’s multitune solves at least part of that problem. It’d be easy to give an end user 2-3 different settings, including a full power setting, all changed with the cruise control buttons. But, you’d still need a tune revision for a tire change. Haha.

 

[mejohn50]

I don't currently have a tuner and would rather learn how to make the adjustments as needed for surface conditions, my car was dyno tuned by rpg from pervious owner

If your tune is able to be read out by HP Tuners or PCMTEC then it should be easy to get the initial set up done.

 

[Rolls]

Pay your tuner 3-4k with 30+ tune revisions and it they might consider it.

No ROI otherwise.

 

[Angrey]

What an incredible thread. This ought to be a sticky with giant flashing billboard lights for everyone.

To be able to achieve torque (or boost) by gear with the OE PCM is incredible. No need for mechanical external controllers. Extremely useful for everyone, but particularly for the PD guys who were forced to use some gimmick like smoothboost (bypass regulation) or expensive aftermarket stand alone to achieve this.

Massive jump in tuning capability. This is what REAL tuning looks like. Not pumping out a carbon copy with some name changes and tweaks.

There only exists one last feature of the external boost controller to be resolved and that's the ability to have multiple tunes, settings, etc. There may be times when you want the full sauce in each gear (for burnouts, for driftards, or just shits and giggles). But it's way better than having no control at all.

Hell, if this had been available 2 years ago, I could have went this route instead of dropping a fortune on a MOTEC. While the MOTEC does add another dimension with traction control integrated, just being able to dial in the output per gear would have been a huge improvement and covered 90% of the desired issue.

Great work guys, this is truly monumental.

In all honesty, why doesn't Ford employ this better? We'd probably see less videos of crowd strikes if they did.

 

[mejohn50]

What an incredible thread. This ought to be a sticky with giant flashing billboard lights for everyone.

To be able to achieve torque (or boost) by gear with the OE PCM is incredible. No need for mechanical external controllers. Extremely useful for everyone, but particularly for the PD guys who were forced to use some gimmick like smoothboost (bypass regulation) or expensive aftermarket stand alone to achieve this.

Massive jump in tuning capability. This is what REAL tuning looks like. Not pumping out a carbon copy with some name changes and tweaks.

There only exists one last feature of the external boost controller to be resolved and that's the ability to have multiple tunes, settings, etc. There may be times when you want the full sauce in each gear (for burnouts, for driftards, or just shits and giggles). But it's way better than having no control at all.

Hell, if this had been available 2 years ago, I could have went this route instead of dropping a fortune on a MOTEC. While the MOTEC does add another dimension with traction control integrated, just being able to dial in the output per gear would have been a huge improvement and covered 90% of the desired issue.

Great work guys, this is truly monumental.

In all honesty, why doesn't Ford employ this better? We'd probably see less videos of crowd strikes if they did.

Thanks. I am very happy with how this has been working, and I have plenty of room to dial it in more. I am still using some arbitrary torque values for testing purposes.

Those of us doing our own tuning are lucky we aren't limited to what the big name tuners want us to have. Don't get me wrong, they have thier place. These things are incredibly complex to tune and it's no real surprise people don't want to get into it. As I said above, I have been poking at this functionality off and on for two years. The Whipple OS didn't help because the intuitive way to do it is dead in thier OSes.

Thankfully, with PCMTEC's Custom OS, this can be setup to have multiple settings. I intend to set this up to give me 2-3 different curves: one for street tires that's really tame until 5th gear, one for drag radials on the street, and one with no limits in place for full power all the time.

 

[engineermike]

In all honesty, why doesn't Ford employ this better? We'd probably see less videos of crowd strikes if they did.

I believe they do this in both applications of the predator.

There is a yt video of the ram trx beating a raptor R from a dead stop repeatedly but the raptor R won from a roll. I checked the tune and it appears as though ford does use a similar strategy in 1st and 2nd gear in the raptor and 1st in the gt500 iirc.

 

[Angrey]

Some deeper examination to this, so it seems like this is being over written by the tune/PCM vs user pedal input.

How are you feathering that in? One approach would be just to limit the total output, another would be so that in that gear, the maximum throttle travel is "re scaled" such that zero is still zero, but the new 100% is rescaled to the restricted throttle travel.

The reason I ask is because WOT condition is the easier condition to contend with, it's part throttle and where the motor is compared to what you're asking.

In the first scenario, let's say the total throttle is limited (by arbitrary torque/load inputs) to be 70%. You mash on the gas to 50% of throttle, are you then getting 50% throttle angle or are you getting the scaled 35% (half of the new range established for that gear)?

By smoothing it and rescaling it I would imagine that part throttle manners and behavior would be better than just a wall/limit that it runs into.

I experience this condition sometimes merging onto the freeway in 3rd gear, I want to hold some rpm and gradually increase and so a reset of the total throttle range compared to the pedal travel probably makes for a more intuitive driver experience. Rather than 50% is 50% of the full range and 90% pedal is only 70% (using our example).

 

[mejohn50]

Some deeper examination to this, so it seems like this is being over written by the tune/PCM vs user pedal input.

How are you feathering that in? One approach would be just to limit the total output, another would be so that in that gear, the maximum throttle travel is "re scaled" such that zero is still zero, but the new 100% is rescaled to the restricted throttle travel.

The reason I ask is because WOT condition is the easier condition to contend with, it's part throttle and where the motor is compared to what you're asking.

In the first scenario, let's say the total throttle is limited (by arbitrary torque/load inputs) to be 70%. You mash on the gas to 50% of throttle, are you then getting 50% throttle angle or are you getting the scaled 35% (half of the new range established for that gear)?

By smoothing it and rescaling it I would imagine that part throttle manners and behavior would be better than just a wall/limit that it runs into.

I experience this condition sometimes merging onto the freeway in 3rd gear, I want to hold some rpm and gradually increase and so a reset of the total throttle range compared to the pedal travel probably makes for a more intuitive driver experience. Rather than 50% is 50% of the full range and 90% pedal is only 70% (using our example).

The way the PCM decides how far to open the throttle blade is based on a torque request. Through a series of events, it turns a throttle pedal input into a torque request then into an air mass value, which is turned into a throttle blade opening. I am only re-stating this so the rest of the post makes sense to anyone newly following along.

All this is doing is limiting the torque request value to whatever value I have commanded in this table.

If I am requesting 500 ft lbs of torque from the driver demand table, through the throttle pedal, in first gear, all this logic does is limit the actual torque request to 350 ft lbs in the case of this table configuration. That's it. It just puts a cap on the driver demand torque request value based on gear and RPM. Since a torque request gets turned into an air mass value, it limits the throttle blade opening to limit the torque produced by the engine.

I did nothing to the throttle pedal functionality. 100% is still 100% throttle, unless there is a torque limit based on the gear it's in and the RPM it's at.

In my opinion, the little I have driven it, it is seamless. I haven't experienced any adverse issues yet, but I have driven the car only about 100 miles with it setup like this.

 

[Angrey]

I guess I'm not being clear.

If the car is capable of say 750 ft-lbs, but the table is limiting it to 500 ft-lbs, what does the pedal position voltage and how the motor reacts handle that?

0 is 0. 100% would be 500 ft-lbs limited, but what happens at part throttle? Is 50% throttle 50% of the original 750 (375 ft-lbs) or is it commanding 50% of the new limited (250 ft-lbs).

You indicated it didn't seem wonky or out of place when driving, but I can see how addressing the overall pedal travel and feel of the torque would be affected if it's one vs the other.

In one scenario, the car behaves rather rowdy with partial throttle and then hits a "wall" where it stops, vs the other where the entire gear/pedal feel is re-"scaled" if you will to make it smoother.

 

[mejohn50]

I guess I'm not being clear.

If the car is capable of say 750 ft-lbs, but the table is limiting it to 500 ft-lbs, what does the pedal position voltage and how the motor reacts handle that?

0 is 0. 100% would be 500 ft-lbs limited, but what happens at part throttle? Is 50% throttle 50% of the original 750 (375 ft-lbs) or is it commanding 50% of the new limited (250 ft-lbs).

You indicated it didn't seem wonky or out of place when driving, but I can see how addressing the overall pedal travel and feel of the torque would be affected if it's one vs the other.

In one scenario, the car behaves rather rowdy with partial throttle and then hits a "wall" where it stops, vs the other where the entire gear/pedal feel is re-"scaled" if you will to make it smoother.

If the driver is requesting 750 ft lbs of torque, but the table is limiting it to 500 ft lbs at a given RPM and gear, then all that happens is the largest torque request able to be made from the driver demand table, which is based on RPM and throttle pedal position, would be 500 ft lbs of torque.

The PCM will still see the actual throttle pedal position. It’s completely unchanged. It just caps the maximum torque request that the driver demand table is able to for a given gear and RPM.

If you look at it with some kind of arbitrary numbers, it looks like this:

At 3000rpm and 25% throttle pedal, maybe the driver demand table is requesting 250 ft lbs of torque. If I’m in first gear and my limit at all RPMs is 350 ft lbs, then nothing happens. I get my request of 250 ft lbs of torque, the throttle blade opens to the value to generate 250 ft lbs of torque, and everything happens normally.

If I increase my throttle pedal input to 75%, maybe my torque request jumps to 500 ft lbs, which is higher than my 350 ft lbs limit in first gear. All that happens is my torque request is limited to 350 ft lbs. The throttle blade will only open as far as the models tell it to open to create a torque request of 350 ft lbs. The PCM still sees a throttle input of 75%.

In the second scenario, the pedal would feel dead after I’ve passed a throttle pedal input to create a 350 ft lbs torque request. But if I’m asking for 350 ft lbs in first, and all the tires can handle in first is 350 ft lbs…then it doesn’t matter. The logic did its job.

 

[Angrey]

If the driver is requesting 750 ft lbs of torque, but the table is limiting it to 500 ft lbs at a given RPM and gear, then all that happens is the largest torque request able to be made from the driver demand table, which is based on RPM and throttle pedal position, would be 500 ft lbs of torque.

The PCM will still see the actual throttle pedal position. It’s completely unchanged. It just caps the maximum torque request that the driver demand table is able to for a given gear and RPM.

If you look at it with some kind of arbitrary numbers, it looks like this:

At 3000rpm and 25% throttle pedal, maybe the driver demand table is requesting 250 ft lbs of torque. If I’m in first gear and my limit at all RPMs is 350 ft lbs, then nothing happens. I get my request of 250 ft lbs of torque, the throttle blade opens to the value to generate 250 ft lbs of torque, and everything happens normally.

If I increase my throttle pedal input to 75%, maybe my torque request jumps to 500 ft lbs, which is higher than my 350 ft lbs limit in first gear. All that happens is my torque request is limited to 350 ft lbs. The throttle blade will only open as far as the models tell it to open to create a torque request of 350 ft lbs. The PCM still sees a throttle input of 75%.

In the second scenario, the pedal would feel dead after I’ve passed a throttle pedal input to create a 350 ft lbs torque request. But if I’m asking for 350 ft lbs in first, and all the tires can handle in first is 350 ft lbs…then it doesn’t matter. The logic did its job.

That's what I'm getting at, it does re "scale" the APS so to speak, otherwise, as you pointed out, it would simply act like the original full sauce all the way up until you exceeded the limit and then just be dead travel after that.

 

[mejohn50]

That's what I'm getting at, it does re "scale" the APS so to speak, otherwise, as you pointed out, it would simply act like the original full sauce all the way up until you exceeded the limit and then just be dead travel after that.

The pedal is dead after the torque request exceeds the torque limit. That's precisely what it does and I did say that in the post you quoted.

The PCM still SEES the true throttle input. It is limiting the maximum torque request that can be made. That's all it's doing. It's not re-scaling anything or any other trickery. Once the the throttle pedal input to the driver demand table generates a torque request that is higher then the torque limit for the gear and RPM, the pedal is done and more input will do nothing. If that happens at 50% throttle, then the remaining 50% do nothing until the driver demand torque request is lower than the torque limit.

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