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May 02, 2024
we've all seen it, the car rolls around on a dinosaur with 200 horsepower and some newly installed engine mods, some guy with a laptop sits there and pushes some buttons, some cool noises, maybe some flames later, Now you have 800 horsepower, but how's that? It's even possible that it's all in the grave, baby, so today I'm going to talk about ECU


, what it is, how it's done, and why you should have your cartoon too. You know, let's go over the basics real quick. You probably already know this. how a combustion engine works, I mean you clicked on this video but in a nutshell, to generate power you need three things, air, fuel and spark, the combustion cycle starts with the piston above that center or tdc for short , as the piston moves down, the intake valve opens. and causes the fuel and air to be absorbed by the cylinder, the piston rises again compressing this mixture, a spark is produced, igniting it, the gases inside the cylinder expand and push the piston down, the piston rises again pushing the gases out of the cylinder and the cycle continues simple enough right now to get the best performance and efficiency, you need the right mixture of air and fuel.
ecu tuning explained
This is called air fuel ratio or afr, for short, too little fuel or what is commonly known as lean burn. The engine will not make power nor will it overheat and cause a host of problems. Too much fuel or a rich mixture again. Your engine will not generate maximum power and your fuel efficiency will suffer, so your air-fuel ratio needs to increase. be perfect and your reference point will always be the stoichiometric ratio, look at me, I say big words, now this is the amount of air you need to burn completely, let's say a gram of fuel and it will be different for each type of fuel, for For example, to completely burn one gram of gasoline, you need 14.7 grams of air, that is, an air-fuel ratio of 14.7 to 1 or just 14.7, but here is what is not where your engine generates the more power at wide open throttle, that's too lean, it's happy.
ecu tuning explained

More Interesting Facts About,

ecu tuning explained...

The spot is actually around 12.5 or so at idle. 12.5 is probably too rich. Your engine might idle smoother around 14. And if you bolt it to a turbo or something, you might want it to be much richer than 12 when your car is on boost and a lot. thinner when you are not in boost, so it is not just an afr value, it is actually a big table of afr values, this is usually called a fuel table or fuel map, each cell will have an afr value for a speed and given engine load. Let's say you're at 2000 rpm cruising down the highway, so at low engine load compared to 2000 rpm going up a hill, you'll have a different afr value in each of those situations to get maximum power and efficiency in both. scenarios.
ecu tuning explained
Well now that we have air fuel ratio covered let's talk about spark, the timing of that spark or what is called ignition timing is also very critical if the spark occurs too late the piston could be too low in the cylinder and not If it happens too soon, your piston may have to work against the expanding gases on its way back, which can cause detonation and damage to the engine for maximum power. You actually want your piston to be two degrees past that center when the pressure inside your cylinder is at its maximum. maximum, but here's what two degrees past that center, it's too late for the ignition system to fire that spark because the air-fuel mixture inside your cylinder doesn't explode immediately when the spark fires, it actually takes time. for the flame to light. to travel through the cylinder and ignite all the fuel that's there, this is called ignition delay, so to get maximum cylinder pressure when the piston is two degrees past that center, you have to fire that spark very hard. anticipation, so you need to advance timing and normally that's about 15 degrees before top dead center that way, when the piston reaches 2 degrees past that center, the entire fuel mixture is ignited and the cylinder is in its maximum pressure, but like the air-fuel ratio, the 15 degrees advance The timing is not constant as the engine speed or rpm increases, the spark must occur sooner because the piston travels faster, so it needs a More advanced synchronization.
ecu tuning explained
Higher octane fuel. Needs more advanced timing due to slower flame speed in driven applications. You will have a higher density fuel and air mixture, so the flame speed will be much faster. In that case you need to adjust the ignition timing, so the spark should occur later when the piston is closer to top dead center and that's why I also have a table for ignition timing with different values ​​for each engine speed and load, back in the day when cars used distributors and carburetors instead of electronic ignition and fuel injectors, all you needed to adjust the air-fuel ratio and ignition timing was a screwdriver. timing light and a lot of experience, you would tinker with the distributor or the screws, the jets and the carburetor springs until you made more power or blew up the engine in any way, it was pretty fast, but those days are gone and the cars that use that This kind of technology is just sitting in some boomer's garage.
You and I can't touch them, so don't even worry about them. Starting in the 1980s and 1990s, automakers began using something called an electronic control unit, or ECU for short. It's basically a computer that's coded to control pretty much everything. It receives signals from sensors and actuators throughout the car on the engine. The code then reads those signals and compares the actual values ​​to the target values ​​in those tables or maps I just talked about. So for example if your mass air flow sensor or throttle position sensor tells your ecu that you have an engine load of 40 and the crankshaft position sensor tells your ecu that your engine is at 3000 rpm, the ecu looks up the afr value for 40 engine load and 3000 rpm and compares it to the afr value coming from your oxygen sensor and your exhaust system, then makes the necessary adjustments to make sure your car is running as it is supposed to, so if the afr value comes from your oxygen sensor it is 13 while the table says it is supposed to be 11.5.
Your ECU knows that your engine is running too lean, so it sends a signal to your fuel injectors to stay open longer to add more fuel. This feedback mechanism is pretty much how everything else is done. For example, if your engine starts to experience any knocking or detonation, the ECU will receive a signal from your knock sensors and then send a signal to your ignition system to synchronize the engine and stop it, so to tune your ECU, the tuner You need to make changes to the code and the values ​​in those lookup tables and that's how they optimize things like air-fuel ratio and ignition timing at all engine speeds and loads, so let's say you increase airflow by adding a cold air intake that the tuner would then add a little more fuel to even out the airflow and that would give you more power.
Now let's say you added a turbocharger, the tuner would make changes to your ignition timing so you don't blow up the engine on the first pull and adjust your afr and boost pressure to make sure you get the most out of your turbo without destroying your engine. You can even tune it for e85 if you want. It can unlock all the power and potential that engine has to offer and honestly, in some cases. You can get more power from your engine even without making any physical modifications just by


. I'm serious, it's like free horsepower. Now most tuners would tune your car on a dyno.
There are a couple different types that I'm not going to use. Get into this video, but the whole point of using a dyno is to make steady state tuning easier. The dyno would pretty much hold your car at certain revs while you tune it for a different engine load, although it's not impossible with road or track tuning, but it's very difficult to do and there's always that safety factor, but You can't exactly mimic the road or track on a dyno. You know the airflow, the temperature, and the fact that the car is moving, so there are pros and cons to both, but whatever the method.
Tuning goes with the interface, the software, the technique you need to keep in mind that tuning requires a lot of learning and experience, and adjusting the boost pressure, air-fuel ratio or ignition timing are really just scratching the surface , like there are a lot more tables and maps than In the fuel and ignition tables I just talked about, you can do a lot more, like add two-step launch control, add or modify your traction control and once As you start to dive into this, you realize how huge of a rabbit hole toning really is. Most tuners specialize in one car with one engine family and become very good at it because there is simply not enough time to learn everything there is to learn.
Another thing you'll realize is that power racing is actually a very small part of tuning. most of the time is actually spent doing steady state tuning, cold start, idle stuff like that and it looks boring on camera but the power runs are the exciting part and that's what gets the views, it's that's why almost all tuning videos are power run after power run and that's Now you should have an idea of ​​how tuning works and what your tuner does on that laptop. I hope you are learning something from this series of


videos. If I missed anything, let me know or if you have any questions in the comments.
I've been a follower, you know I try to answer most, if not all, questions. Consider subscribing if you haven't already followed me on Tik Tok and Instagram and hey, thanks for watching.

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