BAC operating freq
Just took my valve off, it definitely moves, about 1/4 inch total. I'm not sure how far its supposed to move though.
I was using the Idle Valve Test under the Advanced menu.
I was using the Idle Valve Test under the Advanced menu.
Joined: Mar 2001
Posts: 31,833
Likes: 3,232
From: https://www2.mazda.com/en/100th/
Yeah, the BAC does work. I can apply straight up 12v to it and it opens wide up. My Megasquirt has a rather robust TIP120 transistor to drive the BAC. Plenty of current capability at 8A/80W.
There are quite a lot of other settings:
Idle Open Duty %
Idle valve closed duty%
Idle activation RPM adder (rpm)
Ilde activation TPS threshold (%)
Close delay (sec)
Leave valve closed above: (rpm)
For this # of seconds: (sec)
Min Duty for PID(%)
RPM with valve closed(rpm)
RPM with valve open(rpm)
PID delay (sec)
Crank to run taper
PID ramp to target time
PID control interval
Proportional Gain
Integral Gain
Derivitave Gain
PID lockout rpmDOT threshold
PID lockout max decel load(%)
PID disable RPMdot
There are quite a lot of other settings:
Idle Open Duty %
Idle valve closed duty%
Idle activation RPM adder (rpm)
Ilde activation TPS threshold (%)
Close delay (sec)
Leave valve closed above: (rpm)
For this # of seconds: (sec)
Min Duty for PID(%)
RPM with valve closed(rpm)
RPM with valve open(rpm)
PID delay (sec)
Crank to run taper
PID ramp to target time
PID control interval
Proportional Gain
Integral Gain
Derivitave Gain
PID lockout rpmDOT threshold
PID lockout max decel load(%)
PID disable RPMdot
Please do. I've been tweaking the PID values for a while. I thought I'd finally gotten them, as the idle is no longer hunting around, but I'd like to see what others have done.
It wasn't 78Hz, as I found in Aaron's write up. Its 91.5Hz, I've found that only a small range of duty cycle has an effect on idle... when I get home, I'll take a screen shot of my graph/table.
Mine at least hums when set at 244 
I'm going to have to try that now. I wonder how strong the idle will be now...
That would double your cost of the vehicle James. In my opinion though, anything's better than stock or Rtek.
I'm going to have to try that now. I wonder how strong the idle will be now...
Originally Posted by sharingan 19
Stuff like this is exactly why I'm leaning towards doubling the value of my car and going with a Motec.
It does work at 244Hz. It's the other values that need adjusting. Most oeprate 100-300Hz. That's why stock it is so quiet.
My haltech would sometimes work at 244Hz (~4ms pulses), but I had electrical issues and could never get it consistant. It was barely audible at that level. I run it now at 100Hz and it works fine, but makes a louder humming noise. I can hear it over idle.
My haltech would sometimes work at 244Hz (~4ms pulses), but I had electrical issues and could never get it consistant. It was barely audible at that level. I run it now at 100Hz and it works fine, but makes a louder humming noise. I can hear it over idle.
I set that **** to 91.5Hz. Every time I come to a stop now, the RPMs drop right down to 750 and hold nicely. On startup she revs to 1500 and holds there until warmed up. Before I changed it, RPMs would drop down when coming to a stop to around 500 or lower, then it would chug back up to around 750, but then it would hunt really fast once it got there. Also, don't even get me started on how hard cold starts were...
I also used the 3D map view and saw that the rest of my map looked like the aerial view of a forest, so I sat down and smoothed everything out. I also set the MAP averaging factor to 65, which makes highway driving more stable. Before doing that, the AFR would go up to the high 15's, low 16's, then it would suddenly dip down to the low 14's, even 13's sometimes and I'd get the surges. My car drives so much smoother now
I also used the 3D map view and saw that the rest of my map looked like the aerial view of a forest, so I sat down and smoothed everything out. I also set the MAP averaging factor to 65, which makes highway driving more stable. Before doing that, the AFR would go up to the high 15's, low 16's, then it would suddenly dip down to the low 14's, even 13's sometimes and I'd get the surges. My car drives so much smoother now
So I started to get the motivation to bug people to go out and try this again... just to see how close we are.
Its a little warmer outside these days, so can someone with a stock ECU make this happen? Just unplug your BAC, throw a multimeter on it using the AC voltage function, and look for the frequency (if your multimeter supports it).
Thanks to anyone that'll do it... I'll owe you a beer.
Its a little warmer outside these days, so can someone with a stock ECU make this happen? Just unplug your BAC, throw a multimeter on it using the AC voltage function, and look for the frequency (if your multimeter supports it).
Thanks to anyone that'll do it... I'll owe you a beer.
Wow... like I'm a post ***** or something.
Thanks... this forum has a bunch of vaginas for moderators. After 10 years, I'm leaving... I know, you'll be better off without me.
100 views on this in 48 hours, and nobody with a functioning BAC valve will take 10 minutes of their time to figure this out for me. Got it.
It's been fun (mostly).
Thanks... this forum has a bunch of vaginas for moderators. After 10 years, I'm leaving... I know, you'll be better off without me.
100 views on this in 48 hours, and nobody with a functioning BAC valve will take 10 minutes of their time to figure this out for me. Got it.
It's been fun (mostly).
244Hz? 
I don't have a stock car with stock ECU. Also don't have an oscilloscope...
Unfortunately, nobody cares about the BAC. Everyone rips it off and makes a "crappy idle" thread.
I don't have a stock car with stock ECU. Also don't have an oscilloscope...
Unfortunately, nobody cares about the BAC. Everyone rips it off and makes a "crappy idle" thread.
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