Pedal Commander discussion

[JRB]

*MADE INTO IT'S OWN TOPIC - BEHINDBLUEI'S**

Also I should remember that mine is getting to be kinda old now.
It drives great when you are driving it, just if you just slap the pedal it is obvious it is not attached to a long rod that is attached to a lever working and accelerator pump...

You'd never miss carbs again if you experienced the same truck with a properly configured pedal commander, or one that was re-tuned to totally do away with the drive-by-wire pedal 'commanded throttle' and 'actual throttle' mapping. Modern tech and a 1:1 pedal:throttle mapping is very impressive for throttle response and control. Sadly most OEM's tune DBW pedals to be basically nothing for the first 20% of pedal travel, then maybe something in the middle from 20-70%(ish) and then finally above 70% throttle it'll go 'okay, okay, I'll give you some power'. The reasons why are obvious to anyone who's driven in traffic in the past 10 years.


Edit: Carbs on big ass V8's will always sound and smell perfect in their own right, but that's best enjoyed on an old enthusiast car and not in a workhorse truck these days.

[JRB]

Okay, that explains how my box-stock Ram 1500 works. It's actually fairly difficult to maintain a steady speed on anything but a windless, flat road. Cruise control does a much better job, which is why I use it so much.

It's still kinda cool to see the tach wind up to ~6300 rpm before shifting in a full-size pickup.

It'd be worth looking at a Pedal Commander for your truck. It's basically a programmable logic controller that goes between your DBW throttle pedal and your ECU so it's sending the right stuff to the ECU to actually make the throttle do what your foot is telling it to.
It doesn't change ECU tuning or permanently alter electronics. Their first iterations left something to be desired and the Goldilocks settings were hard to find, but now it's a matured tech and works pretty well especially on 5-10 year old vehicles where they've had time to fine-tune the exact settings for those vehicles.

[BehindBlueI's]

It'd be worth looking at a Pedal Commander for your truck. It's basically a programmable logic controller that goes between your DBW throttle pedal and your ECU so it's sending the right stuff to the ECU to actually make the throttle do what your foot is telling it to.
It doesn't change ECU tuning or permanently alter electronics. Their first iterations left something to be desired and the Goldilocks settings were hard to find, but now it's a matured tech and works pretty well especially on 5-10 year old vehicles where they've had time to fine-tune the exact settings for those vehicles.

I don't understand how a pedal commander can do anything other than make it like you've pushed the pedal further and/or faster. It can't make the ECU do anything different since it's just feeding it a signal. Instrumented testing seems to back that up vs 'feels' in that the throttle doesn't open any quicker, etc as just pushing the pedal further and once you're at 100% you're at 100%. I test drove a truck with one and honestly don't get the point other than it 'feels' faster because you pushed the pedal 1/4 of the way and got the result of pushing it 1/2 way or whatever.

[Erik]

It'd be worth looking at a Pedal Commander for your truck. It's basically a programmable logic controller that goes between your DBW throttle pedal and your ECU so it's sending the right stuff to the ECU to actually make the throttle do what your foot is telling it to.
It doesn't change ECU tuning or permanently alter electronics. Their first iterations left something to be desired and the Goldilocks settings were hard to find, but now it's a matured tech and works pretty well especially on 5-10 year old vehicles where they've had time to fine-tune the exact settings for those vehicles.

Interesting. I daily drive a 2016 Grand Cherokee SRT with (I suspect) a mild tune from the prior owner. I wonder what this would add. Throttle response is definitely not linear. It's more of an upward slope that starts off very (too) mild and then shoots straight up.

[JRB]

I don't understand how a pedal commander can do anything other than make it like you've pushed the pedal further and/or faster. It can't make the ECU do anything different since it's just feeding it a signal. Instrumented testing seems to back that up vs 'feels' in that the throttle doesn't open any quicker, etc as just pushing the pedal further and once you're at 100% you're at 100%. I test drove a truck with one and honestly don't get the point other than it 'feels' faster because you pushed the pedal 1/4 of the way and got the result of pushing it 1/2 way or whatever.

Your throttle pedal input is counted as 'commanded throttle' in the ECU, and this is two variables, both actual throttle input level and how quickly it was moved to that input.
The ECU then bounces that 'commanded throttle' value against every other parameter that's going on (RPM, intake temp, injector duty cycle, current driving mode, speed, knock count, cam phaser angle, etc) and gives you whatever actual throttle angle the factory mapping says to give you - at low throttle input, you're very unlikely to be getting a matching throttle angle at the throttle body.

The Pedal Commander basically has a 'reverse mapping' of what the ECU will do with actual throttle angle @ the throttle body, and based on your pedal input, the pedal output will be adjusted by the pedal commander to tell the ECU whatever it wants to hear to provide the actual throttle angle being input into the throttle pedal.
So when you test drove that truck, what you were feeling was 25% gas pedal giving you 25% throttle instead of 25% throttle doing basically nothing and 50% gas pedal finally giving you 25% throttle, or thereabouts.

Since it's matured a bit they also offer different 'tunes' so you can tinker with it to match your tastes. But it's not for everyone. If you find yourself annoyed by the inconsistent throttle behavior vs gas pedal input in newer vehicles, it's worth a look though.

My preference will always be to custom tune the PCM/ECU to just get rid of all throttle management, so 30% at the gas pedal gives 30% throttle every single time regardless of anything else.

Interesting. I daily drive a 2016 Grand Cherokee SRT with (I suspect) a mild tune from the prior owner. I wonder what this would add. Throttle response is definitely not linear. It's more of an upward slope that starts off very (too) mild and then shoots straight up.

Last I checked, 2015+ Chrysler products are a PITA to tune. It requires physically removing the PCM and 'bench flashing' it to unlock it, or buying a whole new PCM that's pre-unlocked for your particular make model (the latter is preferred so you can keep your original ECU 100% untouched).
So unless you've found other signs of aftermarket changes that'd be best optimized with a tune (aftermarket intake kit, exhaust work, signs of things being worked on and returned to stock, etc) I strongly doubt it has a tune, because it's a real commitment to tune those.

[MistWolf]

I don't understand how a pedal commander can do anything other than make it like you've pushed the pedal further and/or faster. It can't make the ECU do anything different since it's just feeding it a signal. Instrumented testing seems to back that up vs 'feels' in that the throttle doesn't open any quicker, etc as just pushing the pedal further and once you're at 100% you're at 100%. I test drove a truck with one and honestly don't get the point other than it 'feels' faster because you pushed the pedal 1/4 of the way and got the result of pushing it 1/2 way or whatever.

With a mechanical connection the throttle opens to let in air as quickly as you can stomp the pedal to the floor whether airflow and fuel flow can keep up or not.

However, Jeep, Ram & Dodge vehicles use a fly by wire pedal. There is no physical connection between the pedal and the throttle. Throttle position is controlled independent of the pedal. Yes, the pedal tells the computer what you're asking for, but the computer decides what you get. It's like getting your Halloween candy from your mother. You tell her you want all five of your Snickers bars right now and she gives you half of one now and the other half after you do your homework.

When you stomp on the gas, you're asking the computer for tire spinning acceleration right now. But instead, the computer opens the throttle and feeds in the fuel at a much slower rate than you ask for because the traction control mommy says "tire spin is bad for my little boy." Traction control also tells the computer to limit engine power when tires spin under slippery conditions or when a drive wheel is lifted while off-roading. It's really frustrating.

Something like a Pedal Commander lets you change that. You can set it up so the Pedal Commander tells the computer to open the throttle right now when you stomp on the gas, giving you faster throttle response. It's not about making a 1/4 push on the pedal feel like a 1/2 push, it's about the throttle responding to your inputs as fast as you make them.

A Pedal Commander won't give you any more horsepower or torque or cut out the traction control. But it does give you more control over how horsepower and torque are made available.

[BehindBlueI's]

The Pedal Commander basically has a 'reverse mapping' of what the ECU will do with actual throttle angle @ the throttle body, and based on your pedal input, the pedal output will be adjusted by the pedal commander to tell the ECU whatever it wants to hear to provide the actual throttle angle being input into the throttle pedal.
So when you test drove that truck, what you were feeling was 25% gas pedal giving you 25% throttle instead of 25% throttle doing basically nothing and 50% gas pedal finally giving you 25% throttle, or thereabouts.

So couldn't I just quickly stab the pedal to 65% or whatever and be the same?

With a mechanical connection the throttle opens to let in air as quickly as you can stomp the pedal to the floor whether airflow and fuel flow can keep up or not.

However, Jeep, Ram & Dodge vehicles use a fly by wire pedal.

I've owned and driven cars with direct connection, I get all that. I get how a custom tune for the ECU can alter that mapping as well. What I don't understand is how something that can only alter the signal from the pedal to the ECU can do anything other than tell it I pushed the pedal further/and or faster and why I don't just push the pedal further and/or faster to do the same thing.

[JRB]

So couldn't I just quickly stab the pedal to 65% or whatever and be the same?

Maybe. That depends on the original mapping for commanded throttle, throttle input rate, and what the PCM says you get at the throttle plate after bouncing it all through the rest of the parameters involved. The whole point of the Pedal Commander is to remove those variables between your gas pedal input and actual throttle angle.

If your foot gets used to needing certain inputs to get a certain throttle angle, the whole concept of a pedal commander can seem superfluous.
But if you find the difference between throttle input to actual throttle angle to be annoying, and you don't care for the variable amount of throttle you may get at the same gas pedal position, a pedal commander can turn an annoying driving experience into something actually pleasant.

In particular, the throttle mapping of some modern vehicles just drives me nuts in stop-and-go traffic in things like base gate lines. There's no nudging the throttle to move up one car length gently, it's nothing-nothing-nothing until you get to 20-30% throttle and then it snaps the throttle open to 25%-30% and surges you forward like you're some kind of asshole. But there's no changing that in the various GSA vehicles etc where I usually experience those annoyances.

[Erik]

Last I checked, 2015+ Chrysler products are a PITA to tune. It requires physically removing the PCM and 'bench flashing' it to unlock it, or buying a whole new PCM that's pre-unlocked for your particular make model (the latter is preferred so you can keep your original ECU 100% untouched).
So unless you've found other signs of aftermarket changes that'd be best optimized with a tune (aftermarket intake kit, exhaust work, signs of things being worked on and returned to stock, etc) I strongly doubt it has a tune, because it's a real commitment to tune those.

There were definitely some mods done. A very nice catch can, aftermarket PCM mount (incorporated into the catch can mount) and a resonator delete - which sounds awesome, by the way - are the only things I know for sure. Plus ridiculously dark rear tint. I assume a mild tune only because the truck is a beast and a bit faster than some others I test drove. I looked into whether I could track the prior owner down on the GJCSRT forum but it was pretty dead. I haven't had anybody dig into the tune myself and that is beyond my comfort level for anything beyond simple things like tire sizes and gear sets or flashing a tune somebody who knows what they're doing did.

[MistWolf]

So couldn't I just quickly stab the pedal to 65% or whatever and be the same?



I've owned and driven cars with direct connection, I get all that. I get how a custom tune for the ECU can alter that mapping as well. What I don't understand is how something that can only alter the signal from the pedal to the ECU can do anything other than tell it I pushed the pedal further/and or faster and why I don't just push the pedal further and/or faster to do the same thing.

It’s only partly pedal position. It’s also throttle response. Let’s say you stop the pedal all the way to the floor in .1 seconds. The computer controls how fast the throttle plate opens. It might decide the throttle will take a .5 seconds to open and not open the throttle enough, slowing acceleration.

Remember, the pedal is only one input. The computer also gets inputs from the traction control system. There’s G meter measuring vehicle attitude. If there’s too much body sway, the computer will cut back on the throttle and activate the brakes as needed.

The Pedal Commander plugs in between the gas pedal and where the gas pedal plugs into the wiring harness to the computer. It does something to the signals the gas pedal sends to the computer to either increase or decrease throttle response, depending on which setting you select. Set for quicker response, it can get you off the line quicker.

In my Jeep, if I hit the throttle too fast, such as crossing a busy street from a stop sign, the throttle lag can cause my Jeep to bog and I have to kinda feather the clutch to get the revs up. If I had a Throttle Commander type gizmo, I could program it to tell the throttle to act quicker to the pedal inputs and to not reduce the throttle if I punch it too fast.


On another topic- the electric sway bar disconnect. They’re standard on the Rubicon and it’s common for the disconnect to quit working for a variety of reasons. If the motor fails, it’s expensive to replace. Most install a manual disconnect that replaces the electric motor. I’m told the manual disconnect works very well.