Megasquirt Staged injection issues?
07-11-17, 10:59 PM
#1
Staged injection issues?
On my setup I am running ID850 primaries and ID1700 secondaries. I plugged the information into tuner studio in accordance to the attached data sheets at the base pressure I’m running. When the secondaries come on you can see in the VE table in the attached msq and picture the obvious valleys the rich spots create by causing me to take fuel out to keep the same AFR as prior to staging. The engine has currently only seen 7 to 9 psi boost but the values are lower than in vacuum which cued to me that something is wrong. I am not sure how the code works but it doesn’t seem able to calculate a smooth transition. Or do I have some settings off somewhere?
Today I did an experiment and at cruise which normally operates only on primaries, I gave the table a value of 50% When doing this, the AFR richened from 16 AFR to approximately 12.5. Normally when doing this shouldn’t the value be relatively unaltered?
I have notice around the 20% values in the table when the secondaries first come online, the pulse widths are close to 1.1 or around about. Wouldn’t this qualify as “small pulse widths?” what I am getting at is, why are you able to add small pulsewidth data for the primary injectors only, when the secondaries are also at times in this rage?
Finally I think the last question. When you have primaries large enough to supply all the fuel needed below 100kpa is there any reason to engage the secondary’s in vacuum at all?
Today I did an experiment and at cruise which normally operates only on primaries, I gave the table a value of 50% When doing this, the AFR richened from 16 AFR to approximately 12.5. Normally when doing this shouldn’t the value be relatively unaltered?
I have notice around the 20% values in the table when the secondaries first come online, the pulse widths are close to 1.1 or around about. Wouldn’t this qualify as “small pulse widths?” what I am getting at is, why are you able to add small pulsewidth data for the primary injectors only, when the secondaries are also at times in this rage?
Finally I think the last question. When you have primaries large enough to supply all the fuel needed below 100kpa is there any reason to engage the secondary’s in vacuum at all?
07-15-17, 10:18 AM
#2
Engine, Not Motor
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With your secondaries nearly twice as large as your primaries, there is always going to be a bit of fiddling necessary to get them right.
Looking at your stage table, they are being brought in fairly early.
As long as your primaries are not hitting above 90% duty cycle or so, then you can bring the secondaries in closer to positive pressure. Around 90 KPa.
Looking at your stage table, they are being brought in fairly early.
As long as your primaries are not hitting above 90% duty cycle or so, then you can bring the secondaries in closer to positive pressure. Around 90 KPa.
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R_PROWESS (07-15-17)
07-18-17, 09:23 AM
#3
I seem to be having more issues than meets the eye. Upon a high load pull or a high rpm pull Tuner Studio decides to go offline temporarily, but not always. I see the dot in the VE table bog down as if it cannot crunch the data fast enough then TS goes offline and sometimes comes back online after accepting a few prompts. I'm running Ms3-Pro with the provided USB cord and a laptop with an Intel i5 processor so this shouldn't be a problem.
Additionally no matter how high I shift the secondaries engagement point toward atmospheric pressure, I still get the same valley just closer to boost. The only thing I can think to do is engage the secondaries somewhere around 120 kpa or more in order to have the initial percentage value be lower (~5%) without the injectors coming online too low in pulse-width. Does this sound like an safe approach, or is secondary engagement in boost normally something to try to avoid?
I suppose if nothing else works going with 4 ID1300s will give me 100cc more total fuel and be a square setup, but I'm trying to avoid this route as I'm not sure how well i could get the car to idle with primaries that large.
Additionally no matter how high I shift the secondaries engagement point toward atmospheric pressure, I still get the same valley just closer to boost. The only thing I can think to do is engage the secondaries somewhere around 120 kpa or more in order to have the initial percentage value be lower (~5%) without the injectors coming online too low in pulse-width. Does this sound like an safe approach, or is secondary engagement in boost normally something to try to avoid?
I suppose if nothing else works going with 4 ID1300s will give me 100cc more total fuel and be a square setup, but I'm trying to avoid this route as I'm not sure how well i could get the car to idle with primaries that large.
07-22-17, 10:12 AM
#4
Engine, Not Motor
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When TunerStudio goes offline does the Megasquirt reset? I've honestly never seen TunerStudio go offline. Try a different USB cable. Have definitely seen my share of bad USB cables in the past few years.
As long as your primary duty cycle isn't more than 90% or so, you can stage the secondaries at any point.
With 2x the secondary there is almost always going to be some adjustment to the VE table needed.
As long as your primary duty cycle isn't more than 90% or so, you can stage the secondaries at any point.
With 2x the secondary there is almost always going to be some adjustment to the VE table needed.
07-22-17, 11:11 AM
#5
I will try to repeat the situations that caused Tunerstudio to go offline and record it on my phone when I have a helping hand. For what it's worth I have SD logging setup to record anything over 500rpm that I can attach which may or may not reveal he issue. To answer your question, Megasquirt itself does not reset during this and the cars operation appears unaffected. As for the rest of your response, thanks, that's good to know. I will further adjust the staging table to see what works best.
07-24-17, 11:42 AM
#6
I had 2200cc/2200cc injectors and I got a better transition when I brought the injectors in at 50% and then immediately 100%. This kept the injectors out of the low pulsewidth territory where they are non-linear. I looked at my VE map and I still had a little dip where you are talking about, but it wasn't noticeable when driving.
BTW, how do you like that twin disk clutch? I can only hope the twin disk I bought for my V8 drives as nice as the OS Giken i had on the rotary.
BTW, how do you like that twin disk clutch? I can only hope the twin disk I bought for my V8 drives as nice as the OS Giken i had on the rotary.