4WD MODIFICATIONS - POWERTRAIN
This device alters accelerator response without touching fuel injection computer ‘mapping’.
This electronic module fits between an electronically fuel injected vehicle’s accelerator pedal and the engine electronic control unit (ECU). A modern vehicle’s accelerator pedal not an old-style mechanical linkage, bit is a potentiometer, sending voltage to the ECU in accordance with how far the pedal is depressed.
The iDrive module modifies the signal from the pedal, in accordance with the driver-operated menu settings on its dashboard control unit. At its maximum performance setting the iDrive gives full-pedal-depression response with much less pedal travel than standard.
Note that the iDrive module can’t change engine mapping or increase engine power or torque settings: it changes response by making the ECU think it’s getting full pedal when it’s actually getting much less than that.
In effect, the idle to wide-open-throttle (WOT) pedal travel is reduced. This makes the vehicle feel more powerful because a given pedal input produces greater engine response. This feedback is most evident in the low to mid rpm range where most 4WDs spend their time.
The unit is the modern equivalent of what we used to do to race cars and bikes back in the olden days: fit a short-travel linkage or throttle pulley to produce WOT with little pedal or twist-grip travel.
However, these mechanical modifications were crude, in that there was no way to modulate throttle response: it was pretty much flat out or closed throttle, which didn’t matter in a competition vehicle.
The iDrive module is different, because it can be set to give fast-acting pedal response, for harsh acceleration or overtaking, or quite sluggish response, as you might want when climbing up a rocky slope, when you don’t want accelerator pedal ‘bounce’ to affect engine torque very much.
In its Automatic Control (AC) mode iDrive changes the level of throttle performance based on pedal pressure. So if you are in traffic and accelerating gently the iDrive will select setting 1. If you’re accelerating hard to overtake, or towing a heavy trailer the iDrive will select 9.
Some 4WD makers have modulated accelerator pedal control built into their off-road-terrain programs, normally requiring more accelerator pedal travel for an expected amount of engine response, but the iDrive system provides that modulation across all driving situations.
You might wonder why 4WD makers don’t have such pedal sensitivity as a standard feature, but there are probably two reasons why not: economy and emissions.
Having a ‘doughy’ or heavy accelerator pedal with long travel to produce WOT means that most drivers will use only a portion of pedal movement and hence not use as much fuel as they would with a lighter, shorter-travel pedal.
It’s also certain that the delay between accelerator pedal movement and ECU response in standard vehicles – commonly referred to as ‘turbo lag’ – is deliberate. This engineered delay prevents an emissions ‘spike’ that would happen if the engine temporarily over-fuelled before the turbo spooled up and provided a matching amount of airflow.
We asked iDrive Australia about the emissions situation and the company said that preliminary testing showed no change from standard. However, we’d like to see independent testing of that claim.
New vehicle warranty issues will concern some 4WD owners, but since iDrive doesn’t alter ECU settings, only accelerator pedal response, it should have no effect on warranty, iDrive Australia says.
Fitment and initial testing
We chose OTA Team member Darrel White’s 2015 Toyota LandCruiser as the test bed for an iDrive unit.
Fitment involved unplugging the connector on the accelerator pedal assembly, interposing the iDrive module and re-fitting the connector. Using the cable ties supplied the iDrive cable was secured away from the pedals and then the dashboard display was stuck in position.
It took Darrell White all of 15 minutes to install the system.
For initial impressions he chose the very steep climb up the Blackall Range from the Sunshine Coast in Queensland.
The first mode he tried was ‘Automatic Control’ and the improvement in performance was quite pronounced.
Secondly he tried ‘Economy’ and discovered widely varying performance, depending which setting on the scale of 0-9 was selected: at 3 or 4 it equated to the standard performance of a 79, but at full-economy of 9 the vehicle was very sluggish.
It’s probable that a setting of 1, 2 or maybe 3 in the Economy program would be ideal for off-road driving, as the throttle response was smooth and even, reducing the chance of wheelspin.
Next he tried ‘Ultimate’ mode. Even in position 1 the vehicle responded instantly from idle. At 9, the highest setting: “Wow – just wow!” was how Darrell put it. The response was amazing, with just the lightest pressure on the pedal.
“It felt like a remapped or ‘chipped’ vehicle,” Darrell said. “And it’s priced at under 300 bucks.”
We continued to evaluate the iDrive through 2018/19, after which time Darrell took the module off. He reckoned that after the novelty of rapid throttle response wore off, he dialled up so little change to the standard setup, it was hardly worth having theiDrive in place at all.
Other vehicles and other drivers may judge differently, of course.