New wiki and manual has launched! Check it out at http://wiki.speeduino.com
Any questions you have before you begin buying, building and installing.
By LPG2CV
#40445
I think 2 missing teeth with the higher number of teeth, makes it clearer that it is the missing teeth gap.

I think generally speaking at that number of teeth at that rpm, you start to run out of processing power. You get to a stage where you are trying to read the next tooth, before you have finished processing the last one.

So the balance is, more rpm = less teeth. However, you won't compromise the accuracy of ignition timing.
By lsdlsd88
#40451
LPG2CV wrote:
Mon Jan 20, 2020 5:12 pm
I think generally speaking at that number of teeth at that rpm, you start to run out of processing power. You get to a stage where you are trying to read the next tooth, before you have finished processing the last one.
this only applies to a 2560 or is it a limitation of the code? what would happen on a teensy?
By LAV1000
#40513
You need to see it as tooth time and not the rpm of crank.
13.000 rpm x 36 tooth = 468.000 tooth a minute.
60 sec/468.000 = 0.000128 sec a teeth.
And it also needs time to do its calculations to get spark and ignition at the right time.
By JHolland
#40523
Isn't the 360 tooth mounted on the cam? it is on Suzukis with the Mitsu EFI, if so then that would be 25.6us per tooth = 39000 teeth per second. By my calculation, at 16MHz and 1 cycle per instruction that gives 410 instructions per tooth - less when you factor in interrupt latencies - not enough procesing time.
By LAV1000
#40530
theonewithin wrote:
Fri Jan 24, 2020 7:50 am
Your math is way off...


7800 teeth a second.

You shouldn't use . As calculators will see that as a decimal point...
Your right !
It should be 0,000128 sec for a teeth.
And yes that is 7.800 tooth/sec.
#40542
DaveyB wrote:
Fri Jan 24, 2020 7:35 pm
Guys are you saying the Speeduino with the Arduino 2560 hasn't the processing speed for crank speeds at 13,000 rpm?
As above. Not with a 360 tooth wheel.

My bike redlines at 13500 and runs fine no sync issues all the way

12-1 wheel.
Ford Sierra 2.8 V6

Why use the dizzy and TFi? Would be easy to fit a […]

As ric355 says Its the number of write cyles that[…]

Purpose of cap C16 on v0.4.3c?

I had a board laying around so i desolderd cap16 […]

Hi all! I have a 1989 NA6 Mazda MX5, a Speeduino […]

Still can't find what you're looking for?