Pedal Power

My Best Advice – Don’t Buy This!!

G’Day, Chris here again.

It’s not often I’ll tell some-one to not buy an accessory for their 4WD, hey its what we do and it’s fun setting up your tourer with some of the latest gadgets. But there are some product offers that will just leave an empty feeling in your wallet and senses, consider ‘Pedal Power’.

Throttle position upgrades are one, either via ECU re-mapping and/or plug-in devices.

They’re a waste of money and a sham if I may say so. With many years of experience and qualifications in electrical and electronic fields to support my argument, please allow me to explain.

Pedal-Power-tnail

 

Modern vehicles including most newer 4WDs run an electronic throttle that sends an output signal to the ECU, your main vehicle computer. As you lower your foot down the electronic signal is sent to the ECU to calculate how much throttle body movement should be actioned, how much fuel and many other sensors adapt and respond to this movement. This signal is small but finely tuned by the vehicle makers to give a smooth response and feel along with appropriate power when required. Even the ‘back pressure’ or force required to push the accelerator down is finely tuned for driver comfort.

 

 

Now many 4WD owners with turbo diesel vehicles are always looking for that little extra get up and go to pull their van, camper, or just their own heavy laden vehicle along a little more briskly. This is perfectly fine to seek more power, and there are many safe options that can be used to further tune and extract more efficiency out of modern engines. We ourselves offer a number of engine performance options, but I am a staunch believer in safe upgrades, strong business ethics and delivering value for money.

And this is where the difference lie, a vast difference between tuning and improving engine operating efficiency versus these deceitful little pedal devices. You see, where you can vary engine operating efficiency through fuel delivery, air flow and pressures and timing where applicable then you are in fact changing the outcome in a real, measureable way. Subtle changes in air fuel ratios can make significant differences to a diesel engine making towing much smoother and acceleration more responsive.

These plug-in pedal signal modifiers do none of that. That’s a fact.

The little device in your electronic pedal is nothing more than a simple potentiometer in reality.

The electronic signal they provide is probably easier to visualise through a basic graph as below, where you see a standard accelerator signal rise as the pedal is pushed further to the floor. Different manufacturers use different systems, but for the sake of explanation let’s say the signal goes from 0.0 volts (idle) to 5.0 volts (full pedal).
Throttle_Percentage_Graph

As can be seen in the graph on the green line, the standard signal rises as the pedal pressure increases from 0% to 100% on the scale.

What these plug in devices and/or re-mapping of your ECU does is simply take that signal, put it through a smart micro-processor and send out a modified signal to the ECU in its place. The use of a micro-processor allows the unit to be adjusted such that signal can be varied across different points to provide different sensory outcomes. I say sensory because that is all it is, the personal sense that the performance is better.

If you look at the orange line, this is a visual example of a basic variation. You can see a ramp up in initial output with low throttle input giving the sense of better throttle response and acceleration from a standing start. It has nothing to do with actual engine performance or efficiency.

The red line shows a more aggressive pattern, where accelerator response is very sharp and continues to drive the signal up higher across the throttle input scale.

The blue line is starting down from the original ‘green’ graph line as you can see. Why? This is sold as a ‘rock-crawling mode or similar, where the accelerator signal is less reactive allowing for smoother operating over rough terrain. All these outcomes can be achieved at the pedal via plug-in device, or via re-mapping the ECU where the signal is ultimately processed.

So why is this a sham?

Because it does nothing more than do what you can do yourself. Back in the ‘old’ days of cable throttles where if you wanted to go faster off the line you would just put your foot down harder. Nothing has changed with electronic throttles. If you want to zip off the line, then plant your foot. If you want to manoeuvre slowly over rocky terrain, push the pedal less. If you want to go up a hill a little faster and change gears less, put your foot down slightly. It’s what you’ve been doing all along.

These devices and ‘re-mapping’ do nothing more than trick your engine into thinking you have pushed the pedal harder than you in fact have.

So handing someone $400, $500 or even $800 of your hard-earned dollars is wasting every cent.

So when next considering a diesel performance upgrade, ask your store ‘expert’ the question “Does this modify the throttle signal?” and if it does put your foot down and drive away.

You’ll save yourself money to put towards real engine operating efficiency performance upgrades.

See you Outback,
Chris

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