injector scaling
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Evolving Member
Joined: Aug 2009
Posts: 284
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From: Hokkaido, Japan
injector scaling
Hello guys,
Did you have a happy new year?
sorry for newbie question, I want to make sure about some part of the basis for setting injectors here.
I just wondering which value is suitable for the "injector scaling" and the "latency" tables.
I have a set of InjectorDynamics ID1000 . ( attached pic has the chart for this injector )
First, for the preparation, I set my fuel pressure regurator.
After step 3, I started to tune the injectors from the line of 43.5 psid in the "InjectorDynamics ID1000 Dynamic Flow Data".
At the first setting, AFR was too lean, STFT was repeating to went to 12.5 quickly. So I gradually decremented the scaling while checking the value of AFR and STFT/LTFT.
After setting the Scaling, I started to increment the latency.
And finally the Scaling and Latency tables reached to the values at the bottom of the pic.
From the above results, I noticed questions below :
Q1. Is the Scaling table not for 100% flow rate ( It doesn't include dead time ) value of the chart?
The actual scaling value(812) is not as same as the chart says(1015). It is 80% of 1015 (1015 * 0.8 = 812). The stock Scaling(532) also smaller, it's 90% of "100% flow rate(590)".
So I assume the InjectorDynamics describes it as "100% flow rate" and 80% of it is suitable to the Scaling table. Perhaps the reason is that "100% flow rate" doesn't include "dead time" and the Scaling table need it. Is it right?
Q2. Why the Latency table doesn't match the "dead time" of the chart?
I found that each of the actual latency values are "(dead time) - 100 (usec)".
I want to know why there are 100 (usec) of differences between the "Latency" table and the "dead time" of the chart.
Glad any guidances.
Did you have a happy new year?
sorry for newbie question, I want to make sure about some part of the basis for setting injectors here.
I just wondering which value is suitable for the "injector scaling" and the "latency" tables.
I have a set of InjectorDynamics ID1000 . ( attached pic has the chart for this injector )
First, for the preparation, I set my fuel pressure regurator.
- set my fuel pressure regulator to 48.5 psia.
- MAP reads around 5.075 while idle.
- calculate the differential fuel pressure like this expression : 48.5 - 5.075 = 43.425. ( I set my fuel pressure regulator as close as possible to the calculated value of 43.5 of below expression. )
After step 3, I started to tune the injectors from the line of 43.5 psid in the "InjectorDynamics ID1000 Dynamic Flow Data".
At the first setting, AFR was too lean, STFT was repeating to went to 12.5 quickly. So I gradually decremented the scaling while checking the value of AFR and STFT/LTFT.
After setting the Scaling, I started to increment the latency.
And finally the Scaling and Latency tables reached to the values at the bottom of the pic.
From the above results, I noticed questions below :
Q1. Is the Scaling table not for 100% flow rate ( It doesn't include dead time ) value of the chart?
The actual scaling value(812) is not as same as the chart says(1015). It is 80% of 1015 (1015 * 0.8 = 812). The stock Scaling(532) also smaller, it's 90% of "100% flow rate(590)".
So I assume the InjectorDynamics describes it as "100% flow rate" and 80% of it is suitable to the Scaling table. Perhaps the reason is that "100% flow rate" doesn't include "dead time" and the Scaling table need it. Is it right?
Q2. Why the Latency table doesn't match the "dead time" of the chart?
I found that each of the actual latency values are "(dead time) - 100 (usec)".
I want to know why there are 100 (usec) of differences between the "Latency" table and the "dead time" of the chart.
Glad any guidances.
Last edited by crimson red; Jan 3, 2012 at 12:16 AM.
Thread Starter
Evolving Member
Joined: Aug 2009
Posts: 284
Likes: 21
From: Hokkaido, Japan
The formula for determining the differential fuel pressure may be wrong.
>calculate the differential fuel pressure like this expression : 48.5 - 5.075 = 43.425. ( I set my fuel pressure regulator as close as possible to the calculated value of 43.5 of below expression. )
My current version of the formula is : (differential fuel pressure) = (fuel pressure gauge reads) - ( ( MAP ) - ( Atmospheric pressure ) )
If it's correct, I must re-consider the first post.
>calculate the differential fuel pressure like this expression : 48.5 - 5.075 = 43.425. ( I set my fuel pressure regulator as close as possible to the calculated value of 43.5 of below expression. )
My current version of the formula is : (differential fuel pressure) = (fuel pressure gauge reads) - ( ( MAP ) - ( Atmospheric pressure ) )
If it's correct, I must re-consider the first post.
Last edited by crimson red; Jan 3, 2012 at 07:31 AM.
Originally Posted by L2r99gst
(Original modified slightly by FastFreddie)
1. Choose an Injector scaling number
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to raise your injector scaling number.
5. If idle or cruise trim is positive, then you need to increase the latency value.
6. If the idle or cruise trim is negative, you need to decrease the latency value.
Note: After #5 or #6, you may need to readjust #1 accordingly.
Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.
More latency = more fuel
Lower scaling = more fuel
Latency will roughly affect idle about twice as much as cruise and almost nothing at WOT/high airlfow. It's is inversely proportional to the IPW.
Latency is basically telling the ECU how long the injector takes to repsond. So, if you put in a larger latency value, you are saying 'this injector is slow to respond, so add this amount of time to keep the injector open'. So, this time is basically added to the IPW. That's why it will affect idle more than cruise and WOT. The IPW at idle may be 1ms and cruise may be 2ms, for example. If you are adding 100us (.1 ms) to the deadtime, it's increasing the IPW by 10% at idle ( for a 1 ms IPW).
(Original modified slightly by FastFreddie)
1. Choose an Injector scaling number
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to raise your injector scaling number.
5. If idle or cruise trim is positive, then you need to increase the latency value.
6. If the idle or cruise trim is negative, you need to decrease the latency value.
Note: After #5 or #6, you may need to readjust #1 accordingly.
Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.
More latency = more fuel
Lower scaling = more fuel
Latency will roughly affect idle about twice as much as cruise and almost nothing at WOT/high airlfow. It's is inversely proportional to the IPW.
Latency is basically telling the ECU how long the injector takes to repsond. So, if you put in a larger latency value, you are saying 'this injector is slow to respond, so add this amount of time to keep the injector open'. So, this time is basically added to the IPW. That's why it will affect idle more than cruise and WOT. The IPW at idle may be 1ms and cruise may be 2ms, for example. If you are adding 100us (.1 ms) to the deadtime, it's increasing the IPW by 10% at idle ( for a 1 ms IPW).
Thread Starter
Evolving Member
Joined: Aug 2009
Posts: 284
Likes: 21
From: Hokkaido, Japan
Sorry for confusing you tephra.
In short, what I want to know is how to calculate psid in the flow rate table supplied by InjectorDynamics. Because I must decide which psid(ex. 40.0, 43.5, 45.0, 50.0, ...) to use for adjusting rail pressure by my adjustable fuel pressure regulator.
I thought that it could be calculated by the formula below :
In short, what I want to know is how to calculate psid in the flow rate table supplied by InjectorDynamics. Because I must decide which psid(ex. 40.0, 43.5, 45.0, 50.0, ...) to use for adjusting rail pressure by my adjustable fuel pressure regulator.
I thought that it could be calculated by the formula below :
(differential fuel pressure(psid)) = (fuel pressure gauge reads = rail pressure (psig)) - ( ( MAP (psia)) - ( Atmospheric pressure (psia)) )
I think that negative manifold pressure pulls fuel out of the injectors, on the other hand positive manifold pressure push fuel back into the injectors. but I'm not sure at all.Originally Posted by L2r99gst
(Original modified slightly by FastFreddie)
1. Choose an Injector scaling number
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to raise your injector scaling number.
5. If idle or cruise trim is positive, then you need to increase the latency value.
6. If the idle or cruise trim is negative, you need to decrease the latency value.
Note: After #5 or #6, you may need to readjust #1 accordingly.
Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.
More latency = more fuel
Lower scaling = more fuel
Latency will roughly affect idle about twice as much as cruise and almost nothing at WOT/high airlfow. It's is inversely proportional to the IPW.
Latency is basically telling the ECU how long the injector takes to repsond. So, if you put in a larger latency value, you are saying 'this injector is slow to respond, so add this amount of time to keep the injector open'. So, this time is basically added to the IPW. That's why it will affect idle more than cruise and WOT. The IPW at idle may be 1ms and cruise may be 2ms, for example. If you are adding 100us (.1 ms) to the deadtime, it's increasing the IPW by 10% at idle ( for a 1 ms IPW).
(Original modified slightly by FastFreddie)
1. Choose an Injector scaling number
2. Log trims at idle and cruise
3. If trims are roughly the same, but positive, then you need to lower your injector scaling number.
4. If both trims are roughly the same, but negative, then you need to raise your injector scaling number.
5. If idle or cruise trim is positive, then you need to increase the latency value.
6. If the idle or cruise trim is negative, you need to decrease the latency value.
Note: After #5 or #6, you may need to readjust #1 accordingly.
Note 2: #5 and #6 implicitly answer ludikraut's questions about affecting idle and cruise trims. Basically, let's say that the IPW is 1ms at idle and 2ms at cruise. If you adjust the deadtime to add 100us (.1 ms), then you are affecting the idle fueling 10% and the cruise fueling 5%.
More latency = more fuel
Lower scaling = more fuel
Latency will roughly affect idle about twice as much as cruise and almost nothing at WOT/high airlfow. It's is inversely proportional to the IPW.
Latency is basically telling the ECU how long the injector takes to repsond. So, if you put in a larger latency value, you are saying 'this injector is slow to respond, so add this amount of time to keep the injector open'. So, this time is basically added to the IPW. That's why it will affect idle more than cruise and WOT. The IPW at idle may be 1ms and cruise may be 2ms, for example. If you are adding 100us (.1 ms) to the deadtime, it's increasing the IPW by 10% at idle ( for a 1 ms IPW).
Last edited by crimson red; Jan 4, 2012 at 07:31 AM.
Thread Starter
Evolving Member
Joined: Aug 2009
Posts: 284
Likes: 21
From: Hokkaido, Japan
Thanks, but, ummm...
tephra, you say "38 psi with the vac line connected", that means it's not the differential fuel pressure ( = 38 psi is NOT psid ). Then, which line of the table supplied by InjectorDynamics is suitable for "38 psi" ? How do I chose it?
if I measure the fuel pressure while my car idling, I think I have to get [rail pressure = gauge reads] ( ex. 38 psi ), [manifold absolute pressure] ( ex. 6 psi ), and [baro = atmospheric pressure] ( ex. 14.7 psi ).
Then, calculate the differential pressure : ex. 38 - (7.7 - 14.7) = 38+7 = 45 psid.
Now I have 45 psid, I can chose the line of 45 psid from the supplier table. There are suitable dead times [8V:2720, 10V:1705, 12V:1295, ...].
Am I wrong???
p.s.
I think there are two easier ways :
1) disconnecting vacuum line from the regulator makes calculation easier. 38 is already psid.
But one caveat. The engine must be stopped.
2) using boost pressure reads makes it easier, too. (7.7 - 14.7) means boost pressure.
tephra, you say "38 psi with the vac line connected", that means it's not the differential fuel pressure ( = 38 psi is NOT psid ). Then, which line of the table supplied by InjectorDynamics is suitable for "38 psi" ? How do I chose it?
if I measure the fuel pressure while my car idling, I think I have to get [rail pressure = gauge reads] ( ex. 38 psi ), [manifold absolute pressure] ( ex. 6 psi ), and [baro = atmospheric pressure] ( ex. 14.7 psi ).
Then, calculate the differential pressure : ex. 38 - (7.7 - 14.7) = 38+7 = 45 psid.
Now I have 45 psid, I can chose the line of 45 psid from the supplier table. There are suitable dead times [8V:2720, 10V:1705, 12V:1295, ...].
Am I wrong???
p.s.
I think there are two easier ways :
1) disconnecting vacuum line from the regulator makes calculation easier. 38 is already psid.
But one caveat. The engine must be stopped.
2) using boost pressure reads makes it easier, too. (7.7 - 14.7) means boost pressure.
Last edited by crimson red; Jan 5, 2012 at 06:45 AM.
regardless of the values you get from the injector manufacture, you will need to fine tune using the procedure I posted first.
they wont just magically work...
in which case you might as well just do that from the start...
for 1000cc injectors start with scaling of 1000 (on pump) and roughly copy their latencies in
then tune using the procedure... that will get you a much better result than trying to work out the math for fuel pressures and all that ...
they wont just magically work...
in which case you might as well just do that from the start...
for 1000cc injectors start with scaling of 1000 (on pump) and roughly copy their latencies in
then tune using the procedure... that will get you a much better result than trying to work out the math for fuel pressures and all that ...
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Thread Starter
Evolving Member
Joined: Aug 2009
Posts: 284
Likes: 21
From: Hokkaido, Japan
hmmm...
>they wont just magically work...
your description is consistent with my experience.
My value was settled to about 70% of supplied scaling(cc/min). I wondered whether my formula was wrong or not. so far detailed cause is unknown, but there's significant differences than I thought between theoretical and actual values.
tephra, thank you for explaining patiently!
>they wont just magically work...
your description is consistent with my experience.
My value was settled to about 70% of supplied scaling(cc/min). I wondered whether my formula was wrong or not. so far detailed cause is unknown, but there's significant differences than I thought between theoretical and actual values.tephra, thank you for explaining patiently!
regardless of the values you get from the injector manufacture, you will need to fine tune using the procedure I posted first.
they wont just magically work...
in which case you might as well just do that from the start...
for 1000cc injectors start with scaling of 1000 (on pump) and roughly copy their latencies in
then tune using the procedure... that will get you a much better result than trying to work out the math for fuel pressures and all that ...
they wont just magically work...
in which case you might as well just do that from the start...
for 1000cc injectors start with scaling of 1000 (on pump) and roughly copy their latencies in
then tune using the procedure... that will get you a much better result than trying to work out the math for fuel pressures and all that ...
regarding latency differences, there are two reasons:
1) the scaling algorithm included in ecuflash was incorrect https://www.evolutionm.net/forums/ev...hm-change.html
2) the manufacturer deadtimes sometimes include closing time as well as opening time, whereas ecuflash/ap only deals with opening time..
something like that anyways...
1) the scaling algorithm included in ecuflash was incorrect https://www.evolutionm.net/forums/ev...hm-change.html
2) the manufacturer deadtimes sometimes include closing time as well as opening time, whereas ecuflash/ap only deals with opening time..
something like that anyways...
Thread Starter
Evolving Member
Joined: Aug 2009
Posts: 284
Likes: 21
From: Hokkaido, Japan
Great info!! Thanks!! I've been wondering why there was two definitions for latency.
Another mystery that 10-30% smaller scaling matches well would have some unknown reasons.
Another mystery that 10-30% smaller scaling matches well would have some unknown reasons.
regarding latency differences, there are two reasons:
1) the scaling algorithm included in ecuflash was incorrect https://www.evolutionm.net/forums/ev...hm-change.html
2) the manufacturer deadtimes sometimes include closing time as well as opening time, whereas ecuflash/ap only deals with opening time..
something like that anyways...
1) the scaling algorithm included in ecuflash was incorrect https://www.evolutionm.net/forums/ev...hm-change.html
2) the manufacturer deadtimes sometimes include closing time as well as opening time, whereas ecuflash/ap only deals with opening time..
something like that anyways...
Thread Starter
Evolving Member
Joined: Aug 2009
Posts: 284
Likes: 21
From: Hokkaido, Japan
Hello, Thanks to the nice comment,
Exactly I'm fine tuning the scaling now. Please read my another thread : https://www.evolutionm.net/forums/ec...met-issue.html
I started from x1.31 multiplier and now gradually downing it now. In addition to this, from evoscan logs, I thought that it's necessary for the area of lower MAF Voltage to be more lowered than higher Voltage area and fine tuning it now.
Exactly I'm fine tuning the scaling now. Please read my another thread
: https://www.evolutionm.net/forums/ec...met-issue.htmlI started from x1.31 multiplier and now gradually downing it now. In addition to this, from evoscan logs, I thought that it's necessary for the area of lower MAF Voltage to be more lowered than higher Voltage area and fine tuning it now.
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