Cobb Tuning Hit with $2.9M Fine over Emissions Defeat Devices

So to answer your actual question, while technically actual off road use is still legal a lot of bad actors in the industry used every bit of leeway that the regulators gave them and now this crackdown is the result.

81k tuners which can each flash any number of trucks, and a full emissions delete on a diesel pickup emits ~300x the pollution of an unmodified vehicle. Further, those 750k trucks are providing astronomically more utility relative to their pollution than diesel drivers are getting out of their +XX HP or +X MPG.

Attempting to be more harsh often results in less harsh results.

In particular, turbocharged engines tend to have a lot of extra power potential by increasing turbocharger boost.

The throttle mapping is nonlinear so that something like 10% pedal gives you 50% gas, so it's really hard to control smoothly.

The 1st gear to 2nd gear shift also has really bad rev hang where you have to wait for a very long time in between 1st and 2nd gear before you can engage the next gear. This makes controlling the car at slow speeds to be really jumpy and uncomfortable. Lots of manual transmission cars made after 2010 have rev hang supposedly for emissions purposes.

One way of solving this is to buy a $700 Cobb Accessport and flash your car's ECU with a "stage 1" off-the-shelf Cobb tune. This makes the throttle mapping linear and removes most of the rev hang. These off-the-shelf maps are supposedly CARB compliant.

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Cobb also has a stage 2 tune that requires replacing the turbo-back exhaust of the car (a.k.a. a downpipe/j-pipe), which is less restrictive for emissions and adds a good amount of horsepower. Supposedly these stage 2 tunes and turbo-back hardware are CARB compliant nowadays, but the laws are fairly new so Cobb sold non-compliant versions up to a few years ago iirc. Tuner shops can also create their own non-compliant custom tunes using the Accessport.

It used be that tuning turbos to run 'rich' (more fuel) was the safer move, because lean can cause engine knock; although I don't really know how things are nowadays

It depends.

It’s not that these devices really significantly increase power, it’s that all the mods that do make power are near useless without a tune, and this device allows that tune.

Recent engines may suffer in performance due to the ever stricter emissions standards. Earlier engines from like 10 years ago probably benefited from emissions standards because things like direct injection, higher compression ratio and so on all both increase performance and reduce emissions(this is oversimplified) So in a very recent car a device like this might actually be able to be used to give a “better” tune to the car that sacrifices emissions for performance. It’s like the government and the manufacturer of the car make choices on the trade off between engine performance and good emissions, this device allows you to make a difference choice.

However, that’s not really how I’ve seen these used because that would be a very expensive way to gain a small amount of power. The thing is that with any car from like the last 20 years or more, if you do modifications like high flow exhaust, bigger cams, adding a turbo where there was none or adding a bigger turbo, and so on, will all, almost certainly, decrease the performance of your car if those mods start to add so much air flow that the default tune can’t keep up. It should also be mentioned that running an engine like that will ruin it quickly. If then, you use a device like this to tune the car to suit the mods, you can double or more the performance of the engine.

I’m glossing over a lot of details here, like for instance ecus are sometimes closed loop systems that can to some extent adjust the fuel flow with increased air flow, but it’s likely that the engine will give you an error code and display the check engine symbol. It should also be noted that some ecus will go into open loop when you floor the car, which is when you want the most power. This can be really bad if you have mods that increase the airflow and volumetric efficiency of the engine. Point is, your mods are useless without a tune.

I've got an aftermarket OEM Toyota (Tom's) device sitting between my boost sensor and cam sensor to advance the timing and boost and I've got a throttle advance controller to get rid of the throttle delay in the drive by wire throttle.

And the car isn't fun to drive without those two things. I would just drive something older without all the throttle delay between pushing the accelerator and the car "going"

Yes we have a salvage model 3 Tesla - I'm saving the planet or something. I also have 5 other cars I like to tinker with on the weekends. This will keep happening most likely due to the RPM Act.

If you're not an OEM certifying the car, the EPA is going to keep going after aftermarket tuners; too much evidence to ignore.

Yes. Most turbocharged cars come from the manufacturer with an enormous amount of left-over power. Many "Stage 1" (no hardware, only software) calibrations for a modern turbocharged car like a VW GTI will produce a 30-40% gain in peak torque. This is for several reasons:

* Emissions. A catalytic converter in some ways works as an oxygen capacitor - it "fills" with oxygen while excess O2 is present (for example, when fuel is cut on deceleration or when the car chooses to run lean-of-stoich) and "discharges" while converting excess hydrocarbons to water. There are other extremely complicated principles at play like catalyst light-off and heating, but this is the basic concept.

* This means that an OEM calibration is a careful balance wobbling between lean and rich of stoichiometric operation (called "catalyst stimulation"). However, this is not the ideal condition for producing power. Due to the flame propagation properties of gasoline-air mixtures, gasoline engines produce optimal torque at a mixture condition rich-of-stoichiometric (this is called, counterintuitively, Lean Best Torque or LBT). And turbocharged and high-compression gasoline engines are extremely vulnerable to unstable combustion conditions (detonations and preignition) which are also alleviated by running a richer mixture. The most common way to increase power on a turbocharged car is to change the air-fuel lambda target from 1.0 (stoichiometric) to around 0.84 under full load, then to increase boost to the safe maximum from the turbocharger (or beyond) and timing to the knock threshold.

* There are also obvious warranty and longevity concerns. Running a turbocharger at 70% of its shaft speed maximum will make it last longer than running it at 120% of its shaft speed maximum. Putting 450 ft-lb through a transmission designed to handle 300 ft-lb will break it.