Let's discuss spark advance
#143
2 Props,3 Dildos,& 1 Cat
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Joe,
While you're working on timing... shouldn't you be working on INJECTOR timing? There are likely both efficiency and smoothness benefits.
The MS3 can do that too.
Here's mine:
![](https://www.miataturbo.net/attachments/megasquirt-18/60936d1354202085-lets-discuss-spark-advance-y8s_inj_timing_2012-11-29.jpg)
I created a rough ignition diagram for the 2001 with VVT to generate it.
![](https://www.miataturbo.net/attachments/megasquirt-18/60937d1354202085-lets-discuss-spark-advance-ignition_miata_2001.jpg)
The collective googles suggest that you want the squirt to END just before the intake valve opens. Depending on where your intake cam is opening (this information is available various places like SOLOMIATA if you want to do it yourself and calculate the squirt durations in terms of RPM and cam angle.
While you're working on timing... shouldn't you be working on INJECTOR timing? There are likely both efficiency and smoothness benefits.
The MS3 can do that too.
Here's mine:
![](https://www.miataturbo.net/attachments/megasquirt-18/60936d1354202085-lets-discuss-spark-advance-y8s_inj_timing_2012-11-29.jpg)
I created a rough ignition diagram for the 2001 with VVT to generate it.
![](https://www.miataturbo.net/attachments/megasquirt-18/60937d1354202085-lets-discuss-spark-advance-ignition_miata_2001.jpg)
The collective googles suggest that you want the squirt to END just before the intake valve opens. Depending on where your intake cam is opening (this information is available various places like SOLOMIATA if you want to do it yourself and calculate the squirt durations in terms of RPM and cam angle.
#145
Boost Pope
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Bear in mind that I recently made some significant changes to my AFR Targets table, which have not yet had time to be fully integrated into the VE table. Also, I think a went a bit too low on the MAP threshold for transitioning out of stoich, I may bump that up a few kPa- it's coming in way before WOT.
Actually, now that I think about it I may just leave it like this and let it richen the VE table slightly, then once I'm done with VE Autotune, change it back to 14.7 across the board and use TPS > 90 as the switchpoint out of closed-loop. That way below 90% TPS it'll seek stoich, but > 90% it'll go open-loop and be slightly rich.
Ok. Here's the corrected AFR:
![](https://www.miataturbo.net/attachments/megasquirt-18/60977d1354230230-lets-discuss-spark-advance-afr.gif)
(note that because the AEM UEGO is a piece of ****, and I'm too lazy to come up with a custom calibration for it, the ACTUAL AFR which results is about 0.6 leaner than the target at stoich. Thus, 15.3 = 14.7. My narrowband sensor confirms this, and I assume this miscalibration to be more-or-less linear.)
VE:
![](https://www.miataturbo.net/attachments/megasquirt-18/60953d1354210016-lets-discuss-spark-advance-ve.gif)
and Spark:
![](https://www.miataturbo.net/attachments/megasquirt-18/60954d1354210016-lets-discuss-spark-advance-spark.gif)
Again, these are all works in progress, not finished product.
![big grin](https://www.miataturbo.net/images/smilies/biggrin.gif)
(Why the hell don't I have my own smiley on this forum?)
Here's what I'm running at the moment (end of squirt):
![](https://www.miataturbo.net/attachments/megasquirt-18/60955d1354210016-lets-discuss-spark-advance-injtime.gif)
Looks a lot like yours, actually.
Last edited by Joe Perez; 11-29-2012 at 06:04 PM. Reason: I had the dumb.
#156
Boost Pope
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Mine is the gauge style, 30-4100, which the manual claims has a linear output from 0v = 10:1 to 5v = 20:1 when in mode P0 (default). Here is the chart printed in the manual:
![](https://www.miataturbo.net/attachments/megasquirt-18/61307d1354562099-lets-discuss-spark-advance-aem.gif)
It is most definitely supposed to be linear, it just sucks.
#158
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This guy claims 38mpg+ at cruise using a NBO2 (14.7AFR) primarily by tuning timing: Hydra, 38mpg+, power and smoothness like no other
Unfortunately he doesn't really discuss his methodology or even provide the resulting timing map.
Unfortunately he doesn't really discuss his methodology or even provide the resulting timing map.
#159
Boost Pope
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It may well be that the newer ones suck less, I honestly don't know.
Incidentally, you mentioned "the old AEM UEGO with out any serial output" previously. Looking through AEM's current offerings, it does not appear that any of their wideband systems offer a serial output, except for the Wi-Fi and OLED versions, and those are only via USB. Am I missing something?
Incidentally, you mentioned "the old AEM UEGO with out any serial output" previously. Looking through AEM's current offerings, it does not appear that any of their wideband systems offer a serial output, except for the Wi-Fi and OLED versions, and those are only via USB. Am I missing something?