GM's new turbo engine rewrites the rules of torque control-and locks out tuners | Hacker News Reader

GM's new turbo engine rewrites the rules of torque control-and locks out tuners

carsandhorsepower.com

34 pointsAnumbia59 comments

This article is covering two different topics and trying to make it seem like one thing that it is not...

1. GM is using an ML model for their "torque management" which is a fancy of of saying a linear feel pedal. 2. This new generation of ecu has more encryption... every new generation of GM ecu has more lockouts.

The author alludes to how tuner will not be able to beat GM's torque mapping controls with aftermarket tuning. Sure... but often times turners are not targeting the drivablity mapping of an OEM tune, they are targeting fuel, ignition, and or boost mapping to compensate for better fuels, more VE (turbos), or other power adders.

TBH on flagship sports cars, we are on the knifes edge of optimizations for most platforms; most aftermarket solutions are now just lop-siding the maximized "any condition" performance OE's seek for simply more power. Power that typically will sacrifice either low end, drivability, and or reliability. The sweet spot for performance tuning now a days exist in the middle range of vehicles for most manufactures where engines are not focused on their ultimate tuning potential VS reliability.

This all being said, these torque management strategies are nothing new, GM is just using fancy math blocks within their ecu that can account for more inputs and a higher resolution. Modern standalone ecus like Emtron and Motec utilize these types of torque strategies to better pair with modern high end transmissions like the 8hp90 and DL800. These transmissions need to communicate with the ECU to ensure power delivery from the engine works with shifting performance and clutch engagement.

OEM's are still worried about emissions, aftermarket tunes are not.

For example, enabling power enrichment at less throttle opening will improve performance and allow you to run a little bit more timing, but also increase hydrocarbon emissions.

There is the big one - OEMs have to meet mandated emissions regulations and governments check (see VW). Aftermarket legally has to meet the same regulations, but in practice (at least so far) they mostly have not been checked, and if they are checked it is only after they have sold something and got it installed on a car, while OEMs get checked before they sell anything. Which is to say aftermarket is generally just trading power/fuel efficiency (often both) for worse emissions.

Yes and no...

Look at Holley aka Dinan aka APR. They are a publicly traded tuning company. The aftermarket tuning they offer meets emissions standards while still offering better performance than OEM. So yes they are not "legally" required, they still do it to meet state and national laws and to avoid toe stepping.

Yes the little guy tuners don't really care about NOX emissions guidelines mostly because they have no way of measuring the difference their tunes may produce. At the end of the day most OE emissions systems will catch these emissions, and pretty much all aftermarket tuners do not endorse removing emissions systems. to say a tune, or aftermarket parts result in worse emissions is not really the truth. to say the end user removing their cats or emissions systems results in worse emissions is true.

A few years ago all the chip your truck billboards I saw were about removing the EGR value for more power, so they for sure were endorsing removing emissions systems. Though this was about diesel engines and I understand the EPA cracked down on those hard a few years ago. Perhaps the only tuners left put some effort into emissions.

Absolutely, in the past some tuning companies had no issue recommending removing emissions equipment, but then standards and laws changed and most if not all companies complied. Banks power is a good example of a diesel tuner who does not advise on removing EGRs.

In the area of emissions management aftermarkets have found symbiosis. Not only has there become aftermarket manufactures of higher performing both in emissions and performance catalytic converters (G-Sport by GESi). But alot of tuners acknowledge that engine performance can be improved with a well catalyzed exhaust system.

It would be an interesting reverse engineering challenge, 20 years down the road when it is more accessible.

I spent 1.5+ years on my 2005 car's ECU to reverse engineer most of the maps, since no public tuning files existed. I then went and spent 1 year on the TCM for which again, no tuning files existed. With the patent files, I was able to discover the algorithms and maps, and am even in IDA as I write this, and in Ghidra emulating some code.

If you have anything written on this, I’d love to read it.

Haven't we been using electric motors and smaller turbos to get around lag? I drove a 3 cylinder MHEV EcoBoost that seemed to use the electric motor(s?) quite well. It seems like a good idea in theory, though I can understand the negatives of electrifying the powertrain. Definitely an interesting topic.

I remember hearing about the days of the early 911 Turbos (if my memory's correct) where you'd get a bunch of boost all at once... We've definitely come a long way!

This plans for premptively spinning the turbo - which requires electric ones.

You could always do what race cars do, put an electric motor on the turbo so when you go back on the throttle, you get instant boost.

You can use antilag as well to achieve the same effect without electric turbochargers

Bad for emissions though so it'd never be OEM.

Edit: Also bad for the valvetrain. 4T engines aren't really meant to be run as 2T..

Isn't anti-lag (the type that invokes combustion in the exhaust, anyway) terrible for turbochargers, long-term?

It's bad for everything but it's awesome

Porsche is doing that on a road car now. It can also act as a generator to limit maximum boost instead of opening a wastegate.

https://www.motortrend.com/news/2025-porsche-911-gts-t-hybri...

Audi has been shipping electric compressor for 5 years now. They are prone to failures and they are on second revision now.

https://en.wikipedia.org/wiki/List_of_Volkswagen_Group_diese...

That's a different design; Audi uses a separate electric supercharger to fill in boost while waiting for its conventional turbochargers to spool up. Porsche is using a motor/generator built in to a turbocharger to spool it faster, and to recover energy at maximum boost.

F1 is getting rid of that system (MGU-H) for 2026 because it was costing the teams too much and it never seemed relevant to passenger vehicles.

When a tech path costs too much for F1, that's a good sign you won't be seeing it in a GM product any time soon.

OP system is just using a computer to get on the gas a little faster when the driver hits the pedal quickly.

Whatever F1 does or doesn't do has had extremely little relevance for passenger vehicles for at least the past 30 years.

I was thinking of that when I wrote the comment! I've heard of electric turbochargers, but I'm not sure how good they are under real-life conditions. Directly using heat energy from the exhaust (as opposed to introducing electric conversion losses) seems wiser to me. Part of me has always liked making use of what would otherwise be wasted to entropy.

In theory (though not a mechanic, just have an interest in this), the best middle-ground would be to retain the same design but add a motor to the turbocharger shaft which would mainly be reserved for spool ups -- is that what they're doing?

What you've described is exactly how the F1 MGU-H works (as I posted below). F1 is getting rid of it next year because it costs too much for an F1 team which should tell you a little bit about the complexity involved.

GM is doing nothing of the sort, it's just an ECU map. Guessing here, but if driver presses on the gas quickly (throttle accel > some set value), juice the engine map to create extra exhaust pressure to spool up the turbo impeller. It's all software.

It all sounds quite complex when you can just drive the wheels with a motor directly.

Actually all of the car sounds really complex. How about we just pull it with a bunch of horses?.

Horses are really complex beasts too, better just walking around.

The human mind is complex as heck, we should give up on harvesting them for walking.

Horses are very fuel inefficient. Sure they burn 100% renewable hay/oats, but they burn a lot of them. Worse they burn them even at idle so those who don't use their horse constantly still pay for the fuel.

Horse emissions are really bad too.

In your opinion, where does "the buck stop"?

I feel similar to you in that complexity over time only locks out the user.

However I certainly do not miss a choke or having to mess with a carb in general on my road going vehicle.

I don't miss that either (in fact, I know the ECU can do a much better job), but I do enjoy engaging with the car, and thus drive a manual transmission. I'm fairly confident I can get better efficiency and control as opposed to the same transmission with a computer changing gears for me.

From what I've heard, it's somewhat of a rarity in the US, but it's very widely used in Europe.

Well, from what I understand, the car I drove did. I believe the motor was hooked up to engine's output shaft in some way, so they could work together to generate torque. The gearing seemed very low for the displacement (even had a 6th gear!), so it would suggest they were making good use of the electric powertrain.

> leverages predictive algorithms and real-time combustion analytics to not only reduce turbo lag but actually anticipate it.

You know what that means: There will be lag in all unanticipated situations.

there always was. However the way you drive is not very unique and so odds are they have anticipated everything you will do in the real world. (this doesn't mean they can solve lag for all those situations, only that they already know about them: if they can't anticipate it is because of some other factor).

Let's not fool each other: it's for people who can't anticipate.

From a technical/algorithmic POV - this doesn't sound particularly remarkable, because it sounds about the same as how modern CPU's "boost" themselves.

And actually, I think there is similar tech in "speaker systems" already. An "older" one that I've read about is from RCF (an old+big Italian company with systems ranging from desktop to festival size), and they call it [Bass Motion Control](https://www.rcf.it/en/art-9-series);

> The BMC method works by creating a complete map of the dynamic behavior of the woofer, to generate a custom algorithm that only limits over-excursions. This gives total freedom of signal reproduction to the transducer. When high-pass filters normally protect the woofer motion from becoming destructive but change the phase behavior, the new BMC algorithm breaks conventional rules.

Now I don't know how effective RCF's approach truly is, but another company that is doing "big-things" is Dirac. They released a blog post about a year ago titled [Boosting Audio System Sustainability with Dirac](https://www.dirac.com/blog/boosting-audio-system-sustainabil...), and there is a section called Enhancing performance with optimized components;

> By employing Long Short-Term Memory (LSTM) neural networks, we can make the driving force on the voice coil (the part of the speaker that turns electricity into sound) more consistent, improving the mechanical design and compensating for magnetic limitations.

> NLC adjusts the voice coil current to correct force factor irregularities (inconsistencies in the voice coil’s efficiency) without requiring complex mechanical measurements. In tests with an otherwise suboptimal driver, our technology reduced distortion by 10 dB, nearly matching the performance of a well-designed driver.

Yes, because GMs problem has been too little AI in their engines.

Given the recent past about sensors and reliability I’m adding even more will be great for reliability and cost.

I’m sure this design came from the committee of geniuses who brought us the wet belt.

Rant over. (Sorry)

It's so they can sell you subscriptions for different engine behaviour profiles and for unlocking the full engine power.

Sounds fascinating, and slightly terrifying to drive. Don’t think I’d be able to resist doing some software quality testing.

It sounds similar to what transmissions already do. There's a lot of "prediction" getting the car ready for what the driver is likely to do next.

Dual-clutch transmissions especially need to anticipate the next move as either an upshift or dowshift.

This is just extending that idea to the engine itself.

This is stupidly redundant in the age of electric vehicles, especially now that there are plenty of price parity options even without subsidies.

Nobody is buying a Corvette because it’s the most sensible car for their needs.

It's the opposite, people only by corvettes because it's the most sensible option for their needs.

They need a fast sweet car, and not spend hundreds of thousands of dollars.

Ultimately it's rooted in the need for procreation, social status, and play.

I have never seen someone within procreation age drive a corvette.

In the 2008 financial crisis the owner of the building I worked in had extra cash on hand so he walked into the Chevy dealer and walked out with the Corvette they had in display for $35k which he thought was sensible.

I’m optimistic and hopeful about electrification, but gas cars are simply not going anywhere soon.

Increasing their efficiency might not be the ultimate endgame, but it sure is a positive increment.

The switch happens slowly and then suddenly.

People pick the best option, while worse option can creep from being awful to just a close second, and then suddenly become the best option.

There's a critical point at which there's enough EV infrastructure to overcome objections, available cars become cheap enough, and then there's hardly any reason to pick gas cars that are slower, laggier, noisier, smelly, more expensive to run and can't be refuelled at home.

Sort of. While electric cars are great, the type of person who buys a $3,000 car cannot afford the cheapest electric car for about 10-15 years after that tipping point, even after you account for gas savings. So new cars are likely to switch suddenly, it still will be a decade before that catches up. The average car in the US is 12 years old.

Even the type of person who buys a 3 year old car cannot (will not?) afford a payments on a new car accounting for the gas savings. They will buy what they can get - but they also will influence the market as they are likely to be sensible (often a new car is not sensible) and so willing to pay extra for the EV, and this in turn will put pressure on the new cars since trade in value is very important to most people who buy a new car (which is sensible, but it is the banks forcing this on the buyers)

Maybe? I can see what you’re saying, but the real world can move as slow as sludge at times. These aren’t smartphones that are relatively easily produced, shipped, and purchased by users.

Second order effects like load on an aging power grid could easily cause speed bumps.

I hope you’re right, but I don’t know I could bet on it

The over the years Corvette has often got the best MPG of any car in GM's lineup. Thus a few people have bought one for the fuel mileage which is sensible. Though with the cost you need to drive 50,000 miles per year to make it sensible over something else.

As a part of my capstone class in undergrad we toured a gm plant with our sponsor. And our sponsors were total jerks to the employees they met. I don't think with that much animosity directed at their workers management really has time for innovating.

That's really awesome! For last century's technology. Will they make a Stanley Steamer version too?

The "locks out tuners" bit is pure click-bait non-sense. Tuners will either work around the sensors (as they have for decades) or replace the ECU with any number of aftermarket models.

The best way to lock out tuners would be for the stock ECU to provide as much power as possible.

Although with turbocharged engines, you can turn the power up to the point where longevity goes way down. Still, you could give people a power limit knob they could turn at their own risk to have access to the whole Pareto frontier of performance and longevity. That'd leave no room for tuners.

Giving users a knob that essentially amounts to "reduce the life of your engine" is a terrible idea. Most people are SUPER ignorant about their vehicles and would be pissed when their turbo died early because they assumed a higher number on that scale was better without trying to figure out what it is.

To get the most power out of an engine you disregard emissions standards, the manufacturer can't do that without getting fines and recall orders.

Emissions are tested on a standardized driving cycle that doesn't include full-throttle acceleration, so emissions at full throttle aren't counted. Which is reasonable: high-performance cars spend only a tiny fraction of their time at full throttle so it doesn't contribute much to overall emissions.

> Emissions are tested on a standardized driving cycle that doesn't include full-throttle acceleration

Depends on the car. See Supplemental Federal Test Procedure US06[0], required by the EPA for light-duty vehicle certification since 2007.

It is also largely irrelevant in the real world: nobody is going to tune a car to have mediocre part-throttle performance but then go all-out on full-throttle.

0 - https://www.epa.gov/vehicle-and-fuel-emissions-testing/dynam...

It has a 10 second 0-50 mph section, which for the kinds of cars we're talking about (those that people might buy aftermarket performance ECUs for) isn't close to full throttle.

As I said, “depends on the car.”

There are at least two problems with this. First, the history of tuning suggests there is no level of stock performance that enthusiasts will be happy with. They will always want more than the OEM provides.

Secondly, there’s a reason you see this with EVs (Tesla’s “ludicrous speed” mode) but not ICE cars apart from “sport modes” and the like: the ICE cars can’t be offered with the knob you suggest, because the car has to meet emissions requirements at any tuning level, and any level of tuning is going to have a performance/emissions trade-off.

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