Maybe I missed this part but are these numbers for end of injection?

If so, at higher loads when the fuel pulse gets "wider", the beginning of the fuel pulse will happen earlier and the end of the fuel pulse will stay at the specified numbers BTDC with these settings thus making sense on the "lower to higher" (270-330) numbers in the table.

If they are for beginning then it would make sense to inject earlier at higher loads "Higher to lower" numbers.

The other question I have is... In the case that the base map has a 180 injection angle: Do we have to add/subtract 180 degrees to get to the desired number?

If we had to then a 330 target would be a 150 in the table.

Time to get an O-scope LOL...

 

Yes, this is end of injection and I had this same thought after asking.

In the illustration 270 degrees is where the port is fully open, so for example, If you fixed end of injection at 270…

At idle there is ample time, the beginning of the PW may make it to the port as it is just opening or fully open.

However at higher RPM, with the same 270 end of injection, the beginning of the lengthened pulse may reach the port too soon.

This is because the injector has to start opening sooner to provide more fuel as the load increases,

To remedy the PW reaching the port too soon, you have to shift the entire PW back by ending injection later in the phase (~330 deg.) I see that shifting the PW forward (sooner) would just exacerbate the issue.

OR

Fix injection at ~330 deg. If the PW has time at higher revs to make it through the port, it certainly does at lower. With that said, I’m not sure if there is any advantage to this. Not likely, my assumption is it’s best to inject as soon as possible into highest port velocity.

I could still be completely misunderstanding this, but this is my best stab at it.

 

Thanks! That was a great explanation!!! No way to misunderstand it... Thanks again!

 

Found this also...

 

Back from the dead. Any results from people messing with this ?

 

I wanted to update this and note that there is a discussion on the Link forums on this topic.

The Link ECUs rotary settings default to 130 degrees before TDC or 'BTDC'. In other words the value entered into the ECU is basically saying “inject this number of degrees before TDC.” I personally had this twisted despite the MS3pro tooltip telling me exactly that.

1. They control the beginning of injection point NOT end of injection.

2. This is open port injection

The objective is to inject as soon as the overlap period ends or in other words when the exhaust ports trailing edge gets closed off. This happens to be around 130 degrees BTDC on an un-ported exhaust port.

The logic is instead of controlling the injection from the tail end, one can do this predictably with beginning the injection as soon as the exhaust port closes and it will start injecting no sooner than that regardless of duty cycle.

I set my Ms3pro to inject “beginning of squirt” and adjusted the table to 130 degrees after the conversation with the moderator Adamw on the Link forums. I am assuming the Haltech can do the same.

Feel free to read the thread for yourself as he explains things in thorough detail.

https://forums.linkecu.com/topic/205...ection-timing/

 

interesting, Mazda has this in the Service Highlights book, not sure its easier to look at of not, lol

 

If I am understanding this correct. On a Haltech "end of injection" style, the stage 2 injectors angle numbers should be a bit smaller than primary? Which would fire them sooner since they are further away, am i on the right track?

 

Injecting sooner would be a larger number.

Injection style doesn't change this.

"Degrees before TDC" For example: 200 degrees would be sooner than 100 degrees upon approach to TDC (zero)

This is why secondary values are typically slightly larger.

 

Like Jon Snow, I know nothing... that said

do you take into consideration the "wetting" of the seals for lubrication with premix?
Do we want to inject past port closing or just before opening so that the side seals (in a side port) or apex seals (in a semi or full pp) get some cooling and lubricating effect from the fuel?

 

this channel is neat, he tests all kind of things, but he just did injector timing,

 

or alternatively

.

 

I wanted to take the time to update my previous illustration from 2019 upon further understanding.

I hope this makes it easier to understand Links beginning of injection strategy.

Although not illustrated exactly, If you begin the injection at exhaust port closure between the 180 and 90 Before TDC illustrations (the rotor apex would look like it's touching the top line of the exhaust port) then you would have until the intake port closes somewhere between 90 and 180 After TDC to get the entire pulse width into the combustion chamber. Keep in mind you may have to factor in fuel transit times through the runner and porting also changes timing.

The reason I labeled the timing marks the way I did is due to what the ECU is asking. "The injector timing in degrees Before TDC." The injector timing is measured with respect to the spark event. a value of 130 would mean 130 degrees ahead of the TDC event which would also mean a value of 180 would be earlier yet etc. etc.

An advantage to 'beginning of injection' is being able to use a singular value as the exhaust port closing angle is a constant, it's the tail of the injection event that alters.

Keep in mind this is obviously open port injection.