There's quite a few vehicles that need this, due to lag in throttle response, when you're say passing.
There's quite a few vehicles that need this, due to lag in throttle response, when you're say passing.
#RESIST
Originally Posted by BehindBlueI's
That's only the graph output of the throttle pedal signal. The problem is that the ECU's response to that throttle signal is NOT linear as the graph you show might imply. Most modern DBW ECU's will not give you the same throttle angle as gas pedal input especially at lower percentages.
I've added a line to the graph - the Orange line is a rough representation of actual open throttle % relative to the gas pedal input. Virtually all DBW ECU's work like this relative to their DBW gas pedal in whatever passes for the 'default' driving mode and even more so in the 'economy' driving modes. FWIW, performance cars tend to suck a lot less in this regard, same for sporty cars when in a 'sport mode'.
So anything like a pedal commander is a matter of making it more like that 1:1 linear grey dotted line in the middle, which is inaccurately claiming the stock ECU is opening the throttle exactly relative to gas pedal input. It is not. The pedal commander or similar will increase throttle signal out of the pedal into the ECU so it more closely matches the actual throttle input.
Different pedal commander modes are available to increase the ramp rate to look like that 'city' graph, which is much like changing the bell crank on a carb or cable throttle body so you have less pedal travel from 0-100% throttle, but it isn't a linear change like that in all cases.
Ultimately it's a matter of changing control input calibrations to match the driver's intent/comfort/habits. Has nothing to do with performance, just comfort and allowing the driver's instinctive control inputs to get the desired result out of the vehicle.
Last edited by JRB; 10-12-2022 at 10:17 AM.
The graph is straight from Pedal Commander's website, but sure it's a generic one to show how the PC works. Even in your graph, there is no point in the PC percentage that isn't attainable by simply pushing more.
PC does not and cannot change the ECU's response to throttle signal. It can only change what the ECU thinks the pedal is at and how fast it got there. If the formatting isn't screwed up, this should illustrate why:
Pedal -------X--------ECU-----Y------Throttle
.................^
.............Pedal Commander
Pedal ---------------ECU-----Y------Throttle
.....................................^
..............................No communication with Pedal Commander, still just whatever the ECU sends.
There is no direct communication between the PC and the throttle. Only between ECU and throttle. It is impossible for the PC to overcome the ECU's programming for torque management, fuel economy, transmission longevity, etc decision making because it "talks" to nobody but the ECU. It can only make the ECU think you stabbed the pedal faster and further. PC ONLY alters X and has zero input on Y.
(Edited to make formatting work)
Sorta around sometimes for some of your shitty mod needs.
Yes. But the marketing leaves a lot open to interpretation, which is why you have posters here arguing it alters other parameters. If you buy one because you want to feel like you pushed the pedal futher and faster without actually stabbing the pedal, or you want help feathering the pedal to save gas on starts, or you just think aftermarket doodad-ery is cool, no problem. If you buy one thinking it overcomes factory settings in or past the ECU, you got snake oiled.
Sorta around sometimes for some of your shitty mod needs.
Yes, that's exactly how a signal intercept piggyback works and I've tried to describe this several times in this line of discussion already. Something like a Pedal Commander manipulates a signal input into the ECU so the ECU does the thing you're (hopefully) wanting it to do.
If you're happy with how your control input feels, gadgets like it are pointless. If you're constantly frustrated by your muscle memory/expectations/preferences in control inputs not matching vehicle response, a pedal commander or similar can make or break how much you like driving that vehicle. I personally hate it when I'm giving 30% pedal and getting 10 or 15% throttle, then another 10% of pedal gives me another 30% throttle. If that sort of thing is of no consequence to you, awesome, don't buy one? :shrug:
Seems we're talking past each other quite a bit here.
Commanded throttle % from the pedal doesn't *change* the factory ECU settings, but the altered signal input to the ECU will absolutely change where the vehicle's at as far as transmission management, torque tables, etc. So while transparent to the layman, it might *feel* like those are changed simply because that altered signal from the pedal commander is putting the ECU into different parts of the map and that changes vehicle behavior in a lot of other ways to match.
Edited To Add- You’re correct that the pedal device does nothing to the signal coming out of the computer. It changes the signal going into the computer. The output from the computer is based on the input it receives.
Last edited by MistWolf; 10-12-2022 at 03:19 PM.
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