Injector scaling and latecy for different injectors.
Jul 10, 2006, 07:15 AM
#46
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Gotcha! I was trying to make it a lot harder than it was.
Small sample of my idle voltage. Idle jumps from 937.5 to 968.75 in this log:
14.1469
14.1469
14.2202
14.2202
14.2202
14.1469
14.2202
14.2935
14.1469
14.1469
14.3668
14.2935
14.2935
14.1469
14.0736
Under WOT the voltages go down a little:
RPM TPS Battery
4562.5 100 14.0003
4781.25 100 13.8537
5000 100 13.927
5187.5 100 13.8537
5406.25 100 13.8537
4125 100 13.7804
4218.75 100 13.8537
4406.25 100 13.7804
4625 100 13.7804
4812.5 100 13.7071
5031.25 100 13.7804
I am running a 2 year old 680mj. Just food for thought... kinda boring here at work today
Small sample of my idle voltage. Idle jumps from 937.5 to 968.75 in this log:
14.1469
14.1469
14.2202
14.2202
14.2202
14.1469
14.2202
14.2935
14.1469
14.1469
14.3668
14.2935
14.2935
14.1469
14.0736
Under WOT the voltages go down a little:
RPM TPS Battery
4562.5 100 14.0003
4781.25 100 13.8537
5000 100 13.927
5187.5 100 13.8537
5406.25 100 13.8537
4125 100 13.7804
4218.75 100 13.8537
4406.25 100 13.7804
4625 100 13.7804
4812.5 100 13.7071
5031.25 100 13.7804
I am running a 2 year old 680mj. Just food for thought... kinda boring here at work today
Last edited by justchil; Jul 10, 2006 at 07:22 AM.
Jul 10, 2006, 03:00 PM
#47
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What is the relationship between the injector scaling value and the AFR values in the Fuel Map? Is it a linear relationship?
for example, let's say that I am running larger-than-stock injectors on my car which have been tuned via the fuel map only, not via rescaling the injector size. Does increasing the injector scaling by 10% then mandate reducing the fuel table by 10% to keep the AFR the same?
l8r)
for example, let's say that I am running larger-than-stock injectors on my car which have been tuned via the fuel map only, not via rescaling the injector size. Does increasing the injector scaling by 10% then mandate reducing the fuel table by 10% to keep the AFR the same?
l8r)
Jul 10, 2006, 03:29 PM
#48
Originally Posted by Ludikraut
What is the relationship between the injector scaling value and the AFR values in the Fuel Map? Is it a linear relationship?
for example, let's say that I am running larger-than-stock injectors on my car which have been tuned via the fuel map only, not via rescaling the injector size. Does increasing the injector scaling by 10% then mandate reducing the fuel table by 10% to keep the AFR the same?
l8r)
for example, let's say that I am running larger-than-stock injectors on my car which have been tuned via the fuel map only, not via rescaling the injector size. Does increasing the injector scaling by 10% then mandate reducing the fuel table by 10% to keep the AFR the same?
l8r)
If you tuned your map for your injectors (and performance) without the scaling, then you would indeed need to go back and alter the Fuel map if you used the rescaling feature..
If the car was already tuned for 550 injectors, and you added 780's, then rescaling the injectors should bring the tune "Close" to where it was before you added the new injectors, however a retune would be recommended (and likely necessary)
Make any sense?
Jul 10, 2006, 03:39 PM
#49
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Yes, makes perfect sense. I was pretty sure that was going to be the answer, but I wanted to make sure. 
The car was doing pretty good on the current tuning methodology until I had the head ported. Now the idle is back to being somewhat erratic - to the point where even upping the idle RPM target is of limited help.
Looks like I get to tune my car from scratch. Oh well, I guess I can post my maps after I'm done then. I shouldn't complain too much, though, the latest round of mods have pushed my VE to ~109% across most of my powerband.
l8r)
The car was doing pretty good on the current tuning methodology until I had the head ported. Now the idle is back to being somewhat erratic - to the point where even upping the idle RPM target is of limited help.
Looks like I get to tune my car from scratch. Oh well, I guess I can post my maps after I'm done then. I shouldn't complain too much, though, the latest round of mods have pushed my VE to ~109% across most of my powerband.
l8r)
Jul 10, 2006, 04:00 PM
#50
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Alright, before I dive in, I would like to briefly summarize my understanding of injector scaling on our Evos. Anyone please feel free to jump in to correct any misconceptions:
- For 780cc injectors I will need to adjust the "Injector Scaling" value from 513 (stock) to something between 600 and 660.
- I may need to adjust the "Injector Battery Voltage Latency Compensation" table to help dial in the idle - If idle fuel trims are positive (lean), then this likely needs to be increased slightly around the 12-13V range to enrichen idle
- May need to adjust the "Accel Enrichment" value (increase) if I start seeing lean conditions on throttle tip-in
- Assuming a stock-injector based fuel map, I now need to dump some 100 Octane gas into the tank, then drive around to dial in the fuel table at partial throttle and WOT.
l8r)
- For 780cc injectors I will need to adjust the "Injector Scaling" value from 513 (stock) to something between 600 and 660.
- I may need to adjust the "Injector Battery Voltage Latency Compensation" table to help dial in the idle - If idle fuel trims are positive (lean), then this likely needs to be increased slightly around the 12-13V range to enrichen idle
- May need to adjust the "Accel Enrichment" value (increase) if I start seeing lean conditions on throttle tip-in
- Assuming a stock-injector based fuel map, I now need to dump some 100 Octane gas into the tank, then drive around to dial in the fuel table at partial throttle and WOT.
l8r)
Jul 12, 2006, 09:11 AM
#51
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Here are the injector battery comps that I have scaled via numbers only. I pulled the data from the AEMPro software. These should be good starting numbers.
Let me know what you think. I've attached the xls file.
Ivan
Let me know what you think. I've attached the xls file.
Ivan
HTML Code:
Note: PTE780/880 calculated from 680/1000 Offset and scaled to match factory ECU 7v 9.4v 11.7v 14v 16.4v 18.6v Stock 1.680 1.032 0.672 0.432 0.264 0.144 PTE1000 2.186 1.281 0.771 0.458 0.283 0.172 PTE880 2.186 1.325 0.833 0.534 0.351 0.231 PTE780 2.186 1.369 0.895 0.610 0.419 0.290 PTE680 2.186 1.413 0.957 0.687 0.486 0.349 MSD750 2.186 1.302 0.781 0.452 0.256 0.126 RC720/900 2.186 1.518 1.032 0.694 0.443 0.268 RC1000 2.023 1.079 0.641 0.367 0.181 0.049 RC1200 2.186 2.085 1.581 1.060 0.713 0.471 Holey788 1.903 0.952 0.573 0.353 0.193 0.093 HKS1000 2.109 1.189 0.812 0.583 0.382 0.248 FIC650 2.100 1.071 0.633 0.353 0.175 0.044 FIC850 2.031 0.971 0.591 0.334 0.195 0.106 FIC950 2.186 1.220 0.706 0.425 0.274 0.175
Jul 12, 2006, 10:15 AM
#52
Originally Posted by Ivan_C
Here are the injector battery comps that I have scaled via numbers only. I pulled the data from the AEMPro software. These should be good starting numbers.
Let me know what you think. I've attached the xls file.
Ivan
Let me know what you think. I've attached the xls file.
Ivan
HTML Code:
Note: PTE780/880 calculated from 680/1000 Offset and scaled to match factory ECU 7v 9.4v 11.7v 14v 16.4v 18.6v Stock 1.680 1.032 0.672 0.432 0.264 0.144 PTE1000 2.186 1.281 0.771 0.458 0.283 0.172 PTE880 2.186 1.325 0.833 0.534 0.351 0.231 PTE780 2.186 1.369 0.895 0.610 0.419 0.290 PTE680 2.186 1.413 0.957 0.687 0.486 0.349 MSD750 2.186 1.302 0.781 0.452 0.256 0.126 RC720/900 2.186 1.518 1.032 0.694 0.443 0.268 RC1000 2.023 1.079 0.641 0.367 0.181 0.049 RC1200 2.186 2.085 1.581 1.060 0.713 0.471 Holey788 1.903 0.952 0.573 0.353 0.193 0.093 HKS1000 2.109 1.189 0.812 0.583 0.382 0.248 FIC650 2.100 1.071 0.633 0.353 0.175 0.044 FIC850 2.031 0.971 0.591 0.334 0.195 0.106 FIC950 2.186 1.220 0.706 0.425 0.274 0.175
Wow, very nice. My 780's are very close to the PTE780 numbers.
Jul 12, 2006, 10:22 AM
#53
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One thing I noticed, you can't set them to those numbers exactly. You can input the exact numbers but it will change to the next actual value in the rom.
Jul 12, 2006, 11:19 AM
#54
Originally Posted by Ivan_C
One thing I noticed, you can't set them to those numbers exactly. You can input the exact numbers but it will change to the next actual value in the rom.
Jul 12, 2006, 11:23 AM
#55
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Could someone please answer my earlier question? I need to know if I understand the process before I start making changes to my car...
Thanks in advance.
l8r)
Thanks in advance.
l8r)
Jul 12, 2006, 11:30 AM
#57
Originally Posted by Ludikraut
Alright, before I dive in, I would like to briefly summarize my understanding of injector scaling on our Evos. Anyone please feel free to jump in to correct any misconceptions:
- For 780cc injectors I will need to adjust the "Injector Scaling" value from 513 (stock) to something between 600 and 660.
- I may need to adjust the "Injector Battery Voltage Latency Compensation" table to help dial in the idle - If idle fuel trims are positive (lean), then this likely needs to be increased slightly around the 12-13V range to enrichen idle
- May need to adjust the "Accel Enrichment" value (increase) if I start seeing lean conditions on throttle tip-in
- Assuming a stock-injector based fuel map, I now need to dump some 100 Octane gas into the tank, then drive around to dial in the fuel table at partial throttle and WOT.
l8r)
- For 780cc injectors I will need to adjust the "Injector Scaling" value from 513 (stock) to something between 600 and 660.
- I may need to adjust the "Injector Battery Voltage Latency Compensation" table to help dial in the idle - If idle fuel trims are positive (lean), then this likely needs to be increased slightly around the 12-13V range to enrichen idle
- May need to adjust the "Accel Enrichment" value (increase) if I start seeing lean conditions on throttle tip-in
- Assuming a stock-injector based fuel map, I now need to dump some 100 Octane gas into the tank, then drive around to dial in the fuel table at partial throttle and WOT.
l8r)
For 780 cc injectors, I would guess 680-750 would be closest (about 10-20%)
Use the chart that ivan posted as a reference, the most critical values you need to get dialed in are the 11v and 14v ones.. depending on your idle speed and quality of your alternator, the voltage should be somewhere under 12v to just over 13v at idle.. increasing the value, lets the ECU know there's more latency and therefore should cause it to run richer..
Jul 15, 2006, 07:56 PM
#60
Out of curiosity, has anyone switched to Ford/GM style injectors? For most of the RB setups I have done along with old school 280zxt stuff, I used to swap to GM/Ford style injectors as they are much cheaper to purchase($59/per). It requires only a cusom rail and slight mod, if any, to the intake manifold. I was usually able to just change the O-ring on the manifold side to make them work. It depends on the size of the injector tip vs. injector hole in the manifold. A hand drill was an easy fix. Here is a cheap source for GM/Ford Injectors.
RACETRONIX
RACETRONIX