WizardBlack Posted April 23, 2009 Share Posted April 23, 2009 I am not sure on that one, but I will comment on the beta stuff... Why can't they just give us a wretched pulsewidth fuel map!?!? I don't care what VE numbers you put in, it isn't ACTUAL VE unless you tweaked a lot of other factors right. It's just a stupid unitless scalar multiplier for pulsewidth. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 24, 2009 Author Share Posted April 24, 2009 LOL. VE is a reasonable facimile of PW. But you are right, it's just a VE that is used to calculate PW based on other settings that may or may not be accurate. Ultimately, it's the WBO2 that tells you how correct it all is. That's why I concentrate mostly on the AFR table and then spend a lot of time making sure the AFR target matches the actual AFR. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted April 24, 2009 Share Posted April 24, 2009 Let me ask this question. Last time I loaded the msq and disconnected the laptop, the AMC and O2 control were enabled, and autotune was enabled. With the laptop disconnected, is MSII auto tuning (VE map tweaking) or is it just O2 compensating (closed loop) based on the AFR map(without actually flashing the VE table)? I am a bit confused as to how and what happens when the laptop is disconnected. With those settings, it is using O2 correction to adjust the fuel in closed loop, and the AMC feature updates the VE table in flash. I am not sure on that one, but I will comment on the beta stuff... Why can't they just give us a wretched pulsewidth fuel map!?!? I don't care what VE numbers you put in, it isn't ACTUAL VE unless you tweaked a lot of other factors right. It's just a stupid unitless scalar multiplier for pulsewidth. Mostly because of the programmers have a preference for model based programming. Right now there isn't much that relies on the number being an actual VE, but some new code features being tested are going to use true volumetric efficiency for a couple of acceleration enrichment functions. A normal pulse width table is only the real pulse width at a single temperature anyway. It is possible to make a few changes to the code to use a pulsewidth table, but so far we haven't seen either anyone attempt to make this mod to the firmware or come anywhere close to convincing the programmers there is any advantage to a pulse width table. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 25, 2009 Author Share Posted April 25, 2009 Thanks Matt, after about a week of Closed Loop driving with AMC on, the VE map has changed slightly, and I was able to create an AFR map that cruises in the 14.8 range and smoothly transitions to richer mixtures on the map under load. There are no more hiccups, or burps. It is running great. It feels better than the factory tune on my WRX. I have been getting between 20 and 21mpg around town. Not even driving conservatively. I think I'm going to post my EGO control and AMC settings soon. They seem to be working. Interestingly, the VE in the 2300rpm range are very high relative to surrounding points. It must be a resonance point in the cam exhaust and intake manifold, designed in by Nissan for efficiency in the cruise range. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 25, 2009 Share Posted April 25, 2009 A normal pulse width table is only the real pulse width at a single temperature anyway. It is possible to make a few changes to the code to use a pulsewidth table, but so far we haven't seen either anyone attempt to make this mod to the firmware or come anywhere close to convincing the programmers there is any advantage to a pulse width table. True, it is modified by air temp, coolant temp, etc. However, I can tell by looking at the map if it looks right; based on the engine, injector and basic mod condition. I used to tune for a living, so I guess most 'squirt guys probably don't have the same basis for what gives them a good feel after looking the maps over. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted April 25, 2009 Share Posted April 25, 2009 Thanks Matt, after about a week of Closed Loop driving with AMC on, the VE map has changed slightly, and I was able to create an AFR map that cruises in the 14.8 range and smoothly transitions to richer mixtures on the map under load. There are no more hiccups, or burps. It is running great. It feels better than the factory tune on my WRX. I have been getting between 20 and 21mpg around town. Not even driving conservatively. I think I'm going to post my EGO control and AMC settings soon. They seem to be working. Interestingly, the VE in the 2300rpm range are very high relative to surrounding points. It must be a resonance point in the cam exhaust and intake manifold, designed in by Nissan for efficiency in the cruise range. Glad to hear it's working out for you! Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted April 27, 2009 Share Posted April 27, 2009 Just depends on what sort of maps you're used to - there are a couple other ECUs that use VE tables too. Quote Link to comment Share on other sites More sharing options...
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