ITT: Injector Timing table tuning
06-26-2015, 12:09 PM
#41
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<p>Also, how come no one googled.</p><p>http://www.msextra.com/forums/viewto...34&t=49578</p><p>
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</p><p>All the angle values in MS are referenced to TDC at the end of the compression stroke/beginning of the power stroke. Usually, your intake valve will begin to open slightly before TDC, just before the intake stroke, at around 360°. The intake valve is open during the whole intake stroke and a few degrees during the compression stroke. So, when referenced to the TDC on the compression stroke, we can say that the intake valve opens at around 370° and closes at around 130° (depending on your cam specs). Usually, you want all the fuel to be injected just before the intake valve start opening. So, if you use the setting "End of Squirt", you will want a table that has about 360° everywhere as a starting point. As RPM goes up, you will want the fuel to have more time to sit on the hot intake valve to evaporate, so, you will want the end of squirt to be advanced vs the opening of the intake valve. So, as RPM goes up, the values in the table will goes up too. A rule of thumb is to add 10°per 1000 RPM. <br /><br />I'm not sure if all of this hold true in semi-sequential, but the concept should be the same. <br /><br />Hope to help!<br /><br />Sam</p><p id="242">
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06-26-2015, 12:11 PM
#42
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<p>Here some of your stuff you forgot braineack.</p><p>http://www.msextra.com/forums/viewto...31&t=38399</p><p>
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</p><p>Here's mine:<br /><img alt="Image" src="http://www.boostedmiata.com/gallery2/d/13698-1/injection_timing.JPG" style="border-width:0px; margin:0px" /><br />end-of-squirt<br /><br /><br />valve opens 5° BTDC. So at idle it's at 370-375° which is that assumed golden rule of 10° before valve opens. I inject 5-10° earlier every 1000RPM or so, and stop adding after 5K, as I keep reading there's no benefit after that point. In boost I kinda guessed the angle - but borrowed ideas from a Nissan GT-R injection timing map on how best to handle mine, by moving the starting point 10° earlier for every few psi or so.<br /><br />my latest dyno going from non-timed batch injection to seq. fuel: </p><p id="257">
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06-26-2015, 04:28 PM
#45
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This thread was started because 18 saw a change in Off-Idle lean-out with change in inj timing.
I also had interest due to the comment about a 20% torque increase in cruise with inj timing change by Arghx7.
Now I'm getting the feeling that the Brain / Reverant table would be hard to improve upon, and likely not worth much effort.
@18psi, what was it you saw on off-idle leaning improvement?
I also had interest due to the comment about a 20% torque increase in cruise with inj timing change by Arghx7.
Now I'm getting the feeling that the Brain / Reverant table would be hard to improve upon, and likely not worth much effort.
@18psi, what was it you saw on off-idle leaning improvement?
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06-26-2015, 04:37 PM
#46
This thread was started because 18 saw a change in Off-Idle lean-out with change in inj timing.
I also had interest due to the comment about a 20% torque increase in cruise with inj timing change by Arghx7.
Now I'm getting the feeling that the Brain / Reverant table would be hard to improve upon, and likely not worth much effort.
@18psi, what was it you saw on off-idle leaning improvement?
I also had interest due to the comment about a 20% torque increase in cruise with inj timing change by Arghx7.
Now I'm getting the feeling that the Brain / Reverant table would be hard to improve upon, and likely not worth much effort.
@18psi, what was it you saw on off-idle leaning improvement?
Years ago, when I had RC550s, stock fuel system, and MS2E, I played with the number of injections per cycle. I didn't have sequential back then, it was batch.
I switched between 2 squirts/cycle, and 4 squirts/cycle.
4 was a pain to tune. But the motor JUMPED off idle way better than it ever had. Also, when I let off the gas and it returned to idle, it was like a diesel in that it just fell and landed there, no dips or oscillations. But it was a huge pain to tune, I ended up going back to 2 squirts/cycle.
Made me wonder about sequential improving idle.
I'm waiting for my ECU to return, DIY AUtotune had to repair the knock module in it. I'll play with 1, 2 and 4 squirts/cycle and report my findings when I can. But ECU won't be here till next week.
EDIT: I forgot this part, with 4/cycle, it reminded me of the off-idle response of my old Isuzu trooper with a tiny 2 barrel, manual secondary carb. It was awesome off-idle.
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06-26-2015, 04:37 PM
#47
I'm gonna test it again today, but when I switched from the DIY injector timing map to the Brain/Rev map immediately after startup my car ran stupid rich.
I switched back yesterday and this was confirmed.
But after idling a bit, I swept the injector timing table like I described, and noticed.....nothing changing
Today I'll make sure it was JUST the timing table affecting post start/warmup uber richness and nothing else.
I switched back yesterday and this was confirmed.
But after idling a bit, I swept the injector timing table like I described, and noticed.....nothing changing
Today I'll make sure it was JUST the timing table affecting post start/warmup uber richness and nothing else.
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06-26-2015, 04:42 PM
#50
I'm gonna test it again today, but when I switched from the DIY injector timing map to the Brain/Rev map immediately after startup my car ran stupid rich.
I switched back yesterday and this was confirmed.
But after idling a bit, I swept the injector timing table like I described, and noticed.....nothing changing
Today I'll make sure it was JUST the timing table affecting post start/warmup uber richness and nothing else.
I switched back yesterday and this was confirmed.
But after idling a bit, I swept the injector timing table like I described, and noticed.....nothing changing
Today I'll make sure it was JUST the timing table affecting post start/warmup uber richness and nothing else.
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06-26-2015, 04:44 PM
#52
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<p>No I mean in G's thread. Where we talked about sequential. And that when in MS3x fully sequential mode squirts per cycle doesn't do anything.</p>
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06-26-2015, 05:04 PM
#55
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<p>Hmmm, how about instead of silly data logging lets just look at the code 
</p><p>As you see here when setting to full sequential squirts per rev gets set to 1. So no amount of datalogging will change that fact.</p><p>
</p><p>And actually if you look at the rest of the code. If sequential is on Semi-seq (what you normally use for batch fire miata setups) then the squirts per cycle doesn't do anything either.</p><p>Another interesting tid-bit:</p><p>
</p><p> </p>
</p><p>As you see here when setting to full sequential squirts per rev gets set to 1. So no amount of datalogging will change that fact.</p><p></p><p>And actually if you look at the rest of the code. If sequential is on Semi-seq (what you normally use for batch fire miata setups) then the squirts per cycle doesn't do anything either.</p><p>Another interesting tid-bit:</p><p>
</p><p>ReqFuel >>= 1; // semi-seq squirts half the fuel every 360deg compared to seq every 720deg</p><p id="584">
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06-26-2015, 05:09 PM
#56
<p>Hmmm, how about instead of silly data logging lets just look at the code </p><p>As you see here when setting to full sequential squirts per rev gets set to 1. So no amount of datalogging will change that fact.</p><p></p><p>And actually if you look at the rest of the code. If sequential is on Semi-seq (what you normally use for batch fire miata setups) then the squirts per cycle doesn't do anything either.</p><p>Another interesting tid-bit:</p><p></p><p> </p>
</p><p>As you see here when setting to full sequential squirts per rev gets set to 1. So no amount of datalogging will change that fact.</p><p></p><p>And actually if you look at the rest of the code. If sequential is on Semi-seq (what you normally use for batch fire miata setups) then the squirts per cycle doesn't do anything either.</p><p>Another interesting tid-bit:</p><p></p><p> </p>Also I run MS3 PRO, and previously ran MS2E. What is the code you posted for?
Anyways, I'll test it anyways as now I'm curious. It's simple enough, I've already spent more time typing about it than it would take to test, so enough. Will post what I find when I get my ECU back. Until then if someone else wants to do a 5 minute test, great.
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06-27-2015, 02:55 AM
#59
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ITT: Injector Timing table tuning
I didn't even know where to find the code. I'm used to reading block diagrams for controls. Thanks for chiming in.
Regarding the torque change with injection timing at part load: that was from sweeping injection timing on a loading dyno. I don't remember the exact speed and MAP but it wasn't in boost.
Does that indicate that injection timing is key to making a bunch of torque? No, it means that on that particular setup, if you're far from optimum you will know it. These are not stock injectors btw, they are EV14's, flow rate escapes me at the moment as its Ryephile's car not mine.
It's also a 1.6 with stock head and MS3 sequential fuel - to my knowledge the only such MS setup in the world. 1.6 may be more sensitive to injection timing than 1.8.
So maybe the reason sweeping injection timing on your 1.8 isn't making such a noticeable difference is because the port and combustion chamber mix better than the 1.6 (ie more turbulent kinetic energy).
Regarding the torque change with injection timing at part load: that was from sweeping injection timing on a loading dyno. I don't remember the exact speed and MAP but it wasn't in boost.
Does that indicate that injection timing is key to making a bunch of torque? No, it means that on that particular setup, if you're far from optimum you will know it. These are not stock injectors btw, they are EV14's, flow rate escapes me at the moment as its Ryephile's car not mine.
It's also a 1.6 with stock head and MS3 sequential fuel - to my knowledge the only such MS setup in the world. 1.6 may be more sensitive to injection timing than 1.8.
So maybe the reason sweeping injection timing on your 1.8 isn't making such a noticeable difference is because the port and combustion chamber mix better than the 1.6 (ie more turbulent kinetic energy).
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