Injector Scaling Formula
#1
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Injector Scaling Formula
Hello,
I had a question how the Injector Scaling formula was figured out?
EcuFlash has 29241/x. Is 29241 a fundamental number somehow? Or found in the ECUs code?
It seems like everyone enters numbers way smaller than the injectors measured flowrate.
In the DSM world we use the formula 31050/x. This gives a number that is spot on the actual measured flowrate with aftermarket injectors.
Example:
EVO 8 USM 0x39=57, 29241/57=513cc, 31050/57=545cc
EVO 6 TME 0x36=54, 29241/54=542cc, 31050/54=575cc
DSM 95-99 0x45=69, 29241/69=424cc, 31050/69=450cc
Does anyone know where 29241 came from?
Thanks very much for any info.
I had a question how the Injector Scaling formula was figured out?
EcuFlash has 29241/x. Is 29241 a fundamental number somehow? Or found in the ECUs code?
It seems like everyone enters numbers way smaller than the injectors measured flowrate.
In the DSM world we use the formula 31050/x. This gives a number that is spot on the actual measured flowrate with aftermarket injectors.
Example:
EVO 8 USM 0x39=57, 29241/57=513cc, 31050/57=545cc
EVO 6 TME 0x36=54, 29241/54=542cc, 31050/54=575cc
DSM 95-99 0x45=69, 29241/69=424cc, 31050/69=450cc
Does anyone know where 29241 came from?
Thanks very much for any info.
#2
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Unfortunately I do not know the answer to your question.
I am thinking your number is more accurate, but I have the same
question for 31050... Where does it come from?
I am thinking your number is more accurate, but I have the same
question for 31050... Where does it come from?
#3
Evolving Member
Thread Starter
Unfortunately, I think it was found by:
0x45 = 69 x 450cc = 31050
I can't find any constant near that size.
31250 would be a divisor of clock freq, like how we have 15625 baud for logging.
But I don't think thats applicable.
I thought the Evo8 injectors flowed 560cc.
0x39 = 57 x 560cc = 31920
29241 seems way to small.
0x45 = 69 x 450cc = 31050
I can't find any constant near that size.
31250 would be a divisor of clock freq, like how we have 15625 baud for logging.
But I don't think thats applicable.
I thought the Evo8 injectors flowed 560cc.
0x39 = 57 x 560cc = 31920
29241 seems way to small.
#4
Evolving Member
After many attempts to scale my PTE780's correctly I stopped at 713. Now that explains why 713 works best for me!
29241/41=713cc, 31920/41=779cc
Any info about latency?
Last edited by Biggy VIII; Jun 7, 2009 at 08:53 AM.
#5
Registered User
the JDM Evos (7-9) are scaled to 542cc which is pretty close if you use 31050
however where do you get the 0x39=57 piece? that has me a little confused.....
EVO 8 USM 0x39=57, 29241/57=513cc, 31050/57=545cc
Last edited by rolly1818; Jun 7, 2009 at 03:35 PM. Reason: changes
#6
Evolving Member
Thread Starter
#7
Registered User
0x39 is the hex value for injector size from the flash image. 57 is 0x39 in decimal.
57 base 10 = 39 base 16
57 base 10 = 39 base 16
the AUDM and JDM are both 542cc/min stock. any feedback on this?
our injector latencies are slightly different as well.
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#8
Evolved Member
This is an interesting thread, so I did a hex search on my AUDM9 rom for the three factors mentioned.
29241, no hits.
31920, no hits.
31050, multiple hits.
So, if 31050 (hex 794A) is not just a bit of op-code, it looks like it may be the correct scaling.
Over to the dis-assembles now I think.
29241, no hits.
31920, no hits.
31050, multiple hits.
So, if 31050 (hex 794A) is not just a bit of op-code, it looks like it may be the correct scaling.
Over to the dis-assembles now I think.
#9
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this is very interesting. So my pte680cc injectors should be scaled at 622. Whats more interesting is that you can actually put that number in.
Now I gotta figure out a formula for lat.
Now I gotta figure out a formula for lat.
#10
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Hello,
I had a question how the Injector Scaling formula was figured out?
EcuFlash has 29241/x. Is 29241 a fundamental number somehow? Or found in the ECUs code?
It seems like everyone enters numbers way smaller than the injectors measured flowrate.
In the DSM world we use the formula 31050/x. This gives a number that is spot on the actual measured flowrate with aftermarket injectors.
Example:
EVO 8 USM 0x39=57, 29241/57=513cc, 31050/57=545cc
EVO 6 TME 0x36=54, 29241/54=542cc, 31050/54=575cc
DSM 95-99 0x45=69, 29241/69=424cc, 31050/69=450cc
Does anyone know where 29241 came from?
Thanks very much for any info.
I had a question how the Injector Scaling formula was figured out?
EcuFlash has 29241/x. Is 29241 a fundamental number somehow? Or found in the ECUs code?
It seems like everyone enters numbers way smaller than the injectors measured flowrate.
In the DSM world we use the formula 31050/x. This gives a number that is spot on the actual measured flowrate with aftermarket injectors.
Example:
EVO 8 USM 0x39=57, 29241/57=513cc, 31050/57=545cc
EVO 6 TME 0x36=54, 29241/54=542cc, 31050/54=575cc
DSM 95-99 0x45=69, 29241/69=424cc, 31050/69=450cc
Does anyone know where 29241 came from?
Thanks very much for any info.
#13
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Thread Starter
OEM injectors are most always dead on.
I'm not talking about advertised flow, but actual measured flow at 43.5 psi base fuel pressure.
There is definitely a scaling formula, all I am saying is 31050/x seems more accurate then 29241/x.
Last edited by Ceddy; Jun 9, 2009 at 04:05 PM.
#14
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I always thought the difference was largely based on the evos having a lower fuel pressure of 38psi IIRC. I could easily be wrong though.
This is why my DSM with evo8 injectors is scaled to 545, not that it didn't run beautifully at 513, but my fuel trims seem better at 545. Until I read about the difference in fuel pressure I always just assumed I had a boost leak.
This is why my DSM with evo8 injectors is scaled to 545, not that it didn't run beautifully at 513, but my fuel trims seem better at 545. Until I read about the difference in fuel pressure I always just assumed I had a boost leak.
#15
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