Car ECU clock generator speed?

Hi. I'm not familiar with these clock speeds, but, reading your question, another point came up to me.

43 KHz is probably far more than the required speed for a car ECU to work properly. It probably was chosen at that time because the generation of processors at that date.

I agree with the argument that a PC working with more programs opened is slower. However, a PC handles with lots of things that serve only to make funny colored pictures on the screen to that pieces that stand behind the keyboard. If you disable graphics processing, sound, peripherals like mouse and keyboard, any processor can do lots of things. In your example, if the ECU controls 10 control loops, and each loop takes 10 clock ticks to be executed, you still would end with a total control frequency of 430 Hz. Imagine an engine running at 5000 RPM, 83 Hz, and see that it still can handle, with safety margin, the engine control. (I know I am talking about very vague and some kind of invalid arguments, but I a just simplifying things to type faster).

I woulndt worry about it too much. If you are interested in adding features to the control card, It is obviously necessary to replace all the stuff. But only talking about speed, it will not be a problem.

Same engine with a carb and higher volume fuel pump had a very noticable difference over ecu and FI. Hence assuming the ecu did not handle it correctly. Fuel injection is a modern commodity, not a necessity. Where I am custom building already, getting the ecu up to par on old chips would be great to have a simply powerful FI setup. I did find a 1mhz clock on a 1990's sound card that is just over 1mhz, it even looks like the 43khz one on the ecu board. There are 11 functions for this particular car ECU setup that I have counted, possibly others for the dummy lights...up towards 20 things to do would be no surprise.

I can only assume this, but even contemplated a heatsink and fan just for the car ecu and trying out something 20 times the speed on the board. It is not as extreme as it sounds (possibly pun intended)

I think you are way off base on your quest. First, the clock frequency really has no more bearing on engine performance than adding a tomato to the gas tank.

Most embedded processors use the system clock (or a divided version of it) as a timer. Increasing the system clock will throw off the software timing and destroy the performance of the car. Chances are the clock frequency you see is really a primary clock that is multiplied a number of times by a phase lock loop circuit. It is not like a desktop PC where increasing the system clock boosts performance. How do I know? I do this stuff for a living. Trust me.

What you want to do is search the web for something called a performance chip for your year/make/model of car. They are actually a ROM with a remapped fuel curve. From the factory the car is tuned more for economy and remapping the ROM tables can boost performance at the expense of fuel economy.

However, unless the car is already turbocharged, remapped fuel tables only results in a very modest gain in performance (5% or so). The chip manufactures like to brag about lots of horse power, but chances are you will not see the increase they claim. There is only so much you can get out the engine. If it is turbocharged, then there is a lot more you can do to boost power. Most of the enhancements are mechanical (i.e., wastegate, fuel injectors, larger turbochargers, etc.), but remapping the fuel tables plays an important part. The ECU will also control things like soft rev-limiter cutoff point, idle speeds, etc. However, the performance boost lies in the fuel/air mixture curves and there are aftermarket companies that spend a lot of time and effort creating new curves to boost performance.

I am curious what the year/make/model of your car is and what your performance goals are.

You are the closest to the correct answer. The clock speed needs to be at least the speed that you mentioned. The speed is primarily a function of the sampling rate for the sensors. At 3500 rpm the fuel injector is pulsed a total of about 467 times per second. Then you add clock ticks for the speed sensor, O2 sensors, and other more critical sensors.

The ECU also will be preset to a certain pulse per second. This mean if you change freq of the clock everything will be wrong. Say you double the clock and instead of thinking engine is running at 1500rpm, ECU will believe its running at 3000rpm.

Even if that's not the case, ECU will pulse injector wrong since its depend on clock pulse.

Get a aftermarket programmable ECU.