Injector staging.....
10-14-14, 05:01 PM
#1
Senior Member
Thread Starter
Injector staging.....
Really?
I'm working on my friends FD with a Haltech PS1000, and I've just about got the injector staging to work going positive. But then it goes way rich on the negative transition.
And now that I've finally come to grips with whats going on, I have to say that I am extremely disappointed that there is no function in the firmware to do staging properly.
Having not dealt with staged injection before I figured that once I got the table tuned on each side of the staging bar that the transition would be smooth as silk.
Wow was I wrong about that. Totally fell on its face when crossing the staging load point.
Tried the "injector staging made easy" technique, not much change.
Being totally confused I even went as far as to scope the event to make sure the secondary injectors were coming on when they were supposed to.
So then I really started thinking about what could possibly be happening during this staging event. After sleeping on it, it hit me. secondary injectors have not been firing prior to the staging and the inside of the manifold and port are dry. This means that when you initiate the secondary injectors most of the fuel is going to wetting the manifold and port walls until an equilibrium is reached where the wetting and evaporation is equal.
Well with this knowledge I was able to increase the fueling at that point on the table and staging bar to smooth the positive transition. But, and I'm sure there are a lot of folks out there who see this, when going back, (Un-staging), there is a huge rich spike due to more than twice the needed fuel being injected.
Now, why is it that this cannot be accounted for in the firmware?
It seems to me like a function called staging enrichment which includes a table and allows a extra percentage of enrichment and another table for the amount of time for this to decay, or even better number of injection events for the decay. would allow for proper tuning of the base fuel table without the current bandaid approach and a smooth transition.
Then for un-staging. all that fuel that is stuck the the walls doesn't instantly go away after the secondaries are turned off. It will continue to evaporate into the mixture causing a rich condition until it is gone. So an un-staging function that provides dis-enrichment and a decay would be necessary.
Is it just Haltech that suffers this deficiency? Or is this industry wide?
And the instructions that come with the Haltech could also include a little light on this topic as well. Wouldn't hurt for more detail on the transient enrichment too.
I'm sure you all have figured out that I'm venting about this, it's just that my expectations have been dashed.
Victor
I'm working on my friends FD with a Haltech PS1000, and I've just about got the injector staging to work going positive. But then it goes way rich on the negative transition.
And now that I've finally come to grips with whats going on, I have to say that I am extremely disappointed that there is no function in the firmware to do staging properly.
Having not dealt with staged injection before I figured that once I got the table tuned on each side of the staging bar that the transition would be smooth as silk.
Wow was I wrong about that. Totally fell on its face when crossing the staging load point.
Tried the "injector staging made easy" technique, not much change.
Being totally confused I even went as far as to scope the event to make sure the secondary injectors were coming on when they were supposed to.
So then I really started thinking about what could possibly be happening during this staging event. After sleeping on it, it hit me. secondary injectors have not been firing prior to the staging and the inside of the manifold and port are dry. This means that when you initiate the secondary injectors most of the fuel is going to wetting the manifold and port walls until an equilibrium is reached where the wetting and evaporation is equal.
Well with this knowledge I was able to increase the fueling at that point on the table and staging bar to smooth the positive transition. But, and I'm sure there are a lot of folks out there who see this, when going back, (Un-staging), there is a huge rich spike due to more than twice the needed fuel being injected.
Now, why is it that this cannot be accounted for in the firmware?
It seems to me like a function called staging enrichment which includes a table and allows a extra percentage of enrichment and another table for the amount of time for this to decay, or even better number of injection events for the decay. would allow for proper tuning of the base fuel table without the current bandaid approach and a smooth transition.
Then for un-staging. all that fuel that is stuck the the walls doesn't instantly go away after the secondaries are turned off. It will continue to evaporate into the mixture causing a rich condition until it is gone. So an un-staging function that provides dis-enrichment and a decay would be necessary.
Is it just Haltech that suffers this deficiency? Or is this industry wide?
And the instructions that come with the Haltech could also include a little light on this topic as well. Wouldn't hurt for more detail on the transient enrichment too.
I'm sure you all have figured out that I'm venting about this, it's just that my expectations have been dashed.
Victor
10-14-14, 08:35 PM
#3
Senior Member
Thread Starter
Whats working?
Engine runs, makes good power, drivability is OK, well except for the aforementioned injector staging.
I guess if you are willing to settle for "not optimized" it's great!
Injectors are 750/2200, primaries in stock location secondaries in manifold (xcessive LIM) Common mode, right now the staging load is 18kPa(2.6psi), staged dis-enrichment is 0.350mS right now, and according to the instructions it is to account for the secondary latency. Why on earth would you dis-enrich to account for injector latency?
10-15-14, 01:04 AM
#5
talking head
not a haltech or its software fault, just a lack of appreciation within the self tuning society for the role of the end of injection tables and injector latencies
( on other ecus, start of injection )
and also expecting that what you see on the scope. reflects directly as fuel flow
when that concept is especially spoiled by the latencies inherent in bigger and bigger injectors and or even incorrect injector current settings
and also expecting them to shut in the same period they start to flow at
the end of injection angle tables are crude at best and where intended for the stock injector locations and latencies
changing the LIM or injector locations and the injectors themselves would have consequences on the optimum injection angle to ensure no wet walling
since you changed just about everything in that equation
then you would probs need to go back and play the angle map
to find those end of injection angles at each 1000 rpm plot ( using the current fuel table ) that return as leanest on the AFR
once you have the best angle for each 1000 rpm // join up your trends
and it can be interpreted as most of the fuel is making the engine to burn
and not wasted as wet walled against manifolds or badly mixed and quenched
once you have the angles.. then go back and trim back your fuel maps to your original target afrs and play your staging trims
( on other ecus, start of injection )
and also expecting that what you see on the scope. reflects directly as fuel flow
when that concept is especially spoiled by the latencies inherent in bigger and bigger injectors and or even incorrect injector current settings
and also expecting them to shut in the same period they start to flow at
the end of injection angle tables are crude at best and where intended for the stock injector locations and latencies
changing the LIM or injector locations and the injectors themselves would have consequences on the optimum injection angle to ensure no wet walling
since you changed just about everything in that equation
then you would probs need to go back and play the angle map
to find those end of injection angles at each 1000 rpm plot ( using the current fuel table ) that return as leanest on the AFR
once you have the best angle for each 1000 rpm // join up your trends
and it can be interpreted as most of the fuel is making the engine to burn
and not wasted as wet walled against manifolds or badly mixed and quenched
once you have the angles.. then go back and trim back your fuel maps to your original target afrs and play your staging trims
Last edited by bumpstart; 10-15-14 at 01:13 AM. Reason: oopsy
10-19-14, 06:06 AM
#7
When moving the primaries to the LIM, you need to get the injection angle correct. It's a much less forgiving location than the iron.
Dis-enrichment for staging is described in the manual. I'll agree that it's a little crude but the results can be very effective.
Every new software I've ever picked up I bitch about. "Why do they do this? This is stupid! Why didn't they just do this?" In the end, once you wrap your head around the front end and come back to the fact everyone is getting to the same point through different means, they all can be made to work. We have cars winning road racing and autox championships with the Sport. So they can be made to transition smoothly. Best advice I can give is to set it on a proper load control dyno and sweep back and forth across the staging point at various RPM until you get it right. Also, don't neglect the Staging Bar Injection Time map. It's beneficial in smoothing the transition.
To bumpstart's point, Haltech has taken the work out of it with the Elite. Everything is done in the background. Now we just need to wait for the crowd that says they want control over the staging and the software should allow them to do what they want.
Dis-enrichment for staging is described in the manual. I'll agree that it's a little crude but the results can be very effective.
Every new software I've ever picked up I bitch about. "Why do they do this? This is stupid! Why didn't they just do this?" In the end, once you wrap your head around the front end and come back to the fact everyone is getting to the same point through different means, they all can be made to work. We have cars winning road racing and autox championships with the Sport. So they can be made to transition smoothly. Best advice I can give is to set it on a proper load control dyno and sweep back and forth across the staging point at various RPM until you get it right. Also, don't neglect the Staging Bar Injection Time map. It's beneficial in smoothing the transition.
To bumpstart's point, Haltech has taken the work out of it with the Elite. Everything is done in the background. Now we just need to wait for the crowd that says they want control over the staging and the software should allow them to do what they want.
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