well I guess the MPW is 100ms, because its 2 loops of 50.

But rather than having 75 ms ON and 25 ms OFF, my code does:
37ms ON
13ms OFF
38ms ON
12ms OFF

so still a total of 75ms, but split up.

 

Seems like maybe the better approach is to try changing the time step size that JoeBee showed?

 

but if you just increase the 48 counter to 100 then you get the same resolution as my 2x50 but you get bigger blocks of ON/OFF time.

 

The longer max pulse width, the slower the system can react to boost changes. Rather than more resolution, I think a shorter max pulse duration is better. I'd like to see the max pulse duration cut in half from 50-60 ms to 25-30 ms.

 

When you say boost changes do you mean WGDC changes?

Most changes will be within 5% of the previous value, and my algorithm will still take this into account.

I tried a shorter pulse width (4 by 25 loops) but the latency of the BCS increased the total amount of dead time and thus boost was reduced.

Lets just round the stock 48 to 49 to make things easier, so a total of 50 loops (0-49)

Lets goto an extreme, say have the counter only go upto 9 (0-9 = 10 loops).

So 65,66,67,68,69,70,71,72,73,74 Baseline WGDC percents ALL mean 70% of actual BCS duty. Yes the pulse width becomes 10ms, but a) your resolution SUX b) your latency of the valve now becomes a larger percentage of the pulse width.

edit -
With my system you break the WGDC into 2 (or 4 if your BCS has a very low latency), so 75% becomes 38/50 for the first loop and 37/50 for the second loop.

Now if while processing the 2nd loop the requested WGDC changes, then my code will pick this up and modify the output BCS DC on the fly.

That is of course assuming the change in WGDC wasn't massive, ie 75% -> 35%... 75 -> 70 OR 75 -> 90 would be fine...

 

I was thinking that there may be a happy medium between a somewhat shorter max pulse width allowing a faster response time and the injector latency cutting into the available time. 50 ms seems like a pretty long time for boost control. Maybe 40 ms might be better? Maybe 30? Just a thought.

I'd like to get my hands on a GM BCS and stock BCS to see what latency these solenoids have. Anyone want to send me either stock BCS to test??

 

Don't you have your stocker? Or you havn't swapped it out yet

Ahh ok the reason why I have chosen 4x25 or 2x50 is because 3x33.3333333 is hard to implement...

To get 1% resolution I have gone for a total of 100 loops, 1% is easy then. But then that has to divide easily into even groups, 2x50 and 4x25 are easy, 2.5x40 or 3x33.333 is infinitely harder to count.

edit -
I suppose I could implement it differently - but don't forget this is a critical routine - adding too much code WILL slow it down significantly and thus might impact on the running of the car.

 

You can have my stock BCS, but can't send until I am back in the country this weekend. PM address.

 

Yeah, still on the stock BCS. PMing you my address tomorrow morning. Thanks.

Now just need someone to let me *borrow* a GM BCS...

 

No worries. I should be able to send it out on Monday. Sorry, can't borrow my GM BCS, I am using it. Ha ha.

 

Sorry guyz to bump this, but is anyone encountered synapse bov opening during high load low rom in 5th gear with ecu based boost control??
I feem that the synapse is faster (about 30ms) than the bcs pulse frequency. It is really annoying. I dont want to get rid of this problem by raising preload on my bov, as it will cause surging...