With regard to modern ecu technology.....

There has been a bit of confusion here with regards the word resolution.

Yes, modern ecus have more mapping points as explained before but this
is nothing to do with resolution it just means you have more numbers in
the table(s) to play with to fine tune problem areas in the map.

Resolution is actually the accuracy and ability of the ignition and injectors
to be timed accurately and more at finer intervals.


All ecus are high speed (relatively ) computers with dedicated
timing hardware as part of the micro processor.
The hardware timer is continuously clocked at a speed depending on the
micro processor type and design.
(FYI This timer system is called input capture/output compare or TPU)
This timer is used to reference all measurements and outputs.
To some extent this timer can be rescaled to give different values but
the software ususally configures this for the following values
due to limitations of the design.

Here are the hardware timer values for some ecus....

Weber L1 - 8 Microseconds = 125,000 per second.
Weber L6 - 4 Microseconds = 250,000 per second.
Weber L8 - 4 Microseconds = 250,000 per second.
Weber P8 - 2 Microseconds = 500,000 per second.

SECS S8 - 0.05 Microseconds = 20,000,000 per second

As you can see above, as stuff gets newer, it gets faster and that means
better accuracy and stablity.

Ok, I now need to explain how this timing is used for the different ares....

FUELING

(keeping it simple and excluding corrections etc...)
(all calculations and figures are rough examples)

After calculating the map table point from RPM and LOAD (map/maf etc)
and then interpolating from the table points around it, a value is arrived at.
In Weber ecus this value is only a single byte which means it can only
have a data value of 0 to 255.
This means you ONLY have 256 possible injector times.

Now, as most injector duration ranges as from about 2 to 20 milliseconds
this means that you have a range of 18 milliseconds and...

18 milliseconds divide by 256 = 70 microseconds

As the hardware timer tuns faster than this actual reduced resolution,
we need another value in the software which is called the multiplier.
On weber ecus this is typically set to 32 or 64 microseconds to give us
our 256 possible injector values.

From this you can see that the weber system is only capable of a
reletively crude injector timing accuracy.

On small injectors this isnt too much of a problem as these large interval
steps only increase fuel slightly.
When larger injectors are added, you begin to loose accuracy.

Modern ecus have larger map table values and using the S8 as an example,
it has a word value (as apposed to a byte) to store the fuel value
which has 65336 combinations allowing the multiplier to be smaller
giving better resolution.



IGNITION

This is where modern ecus have the biggest edge.

The above map table data size problems apply to ignition table values aswell
but the real gain is that the higher timer speeds in moder ecus allow
greater ignition timing accuracy especially at higher RPMs.

The ignition angle is calculated from the map and the current time it
takes between 2 crank teeth is measured.
This crank time is then divided by the number of degrees advance
required and a second timer is loaded with this new value.
When this second timer has gone to zero, the ignition coil is fired.

The higher the RPM the less time there is to divide into ignition advance
degrees which reduces accuracy.
As the timer runs faster, you have more resolution to be accurate in
a modern ecu.

As an example the L8 has 0.2 degrees map resolution but at high rpm
at around 5000 rpm the actual possible error value from the desired angle
is could be as high as 1.5 degrees !!!!!

As (for example) the S8 has a timer that is running 40 times faster, the
error is reduced by the same factor size.
This means it has a mappable accuracy of 0.1 degrees right upto its
12000 rpm designed rev limit.




SUMARY

WIth regards to injector accuracy, this makes only a minor problem for
large injectors on systems mapped by people who pay attention to detail
on older ecus.

With ignition accuracy, this means the det limit can be mapped too more
precisely and a reasonable accurate comfort zone added.

Although high timer resolutions give advantages, the real advantage of
modern ecus are accesability, extra features etc.....


*** I have used the S8 as an example as I have no direct experience of
the internal workings of any other high speed modern ecu that I am able
to publish without upsetting someones copyright LOL.