Zdyne Open / Closed loop question
08-05-2003, 09:27 AM
#14
3.0 BAR
Join Date: Apr 2003
Posts: 2,260
Re:Zdyne Open / Closed loop question
Sure, no problem..
Closed loop: This is a "mode" the ECU sits in while you're less than 80% throttle. It is classified as being an "economy" mode, basically, trying to get the perfect A/F ratio (14.7:1) by using readings form the O2 sensor. I've not gone through the PM6 code for open loop, so I'm a bit tentative on the table part, but it's been talked about that they use the tables as a reference point, still using the interpolation routine. This routine being that it takes the 4 surrounding values ans averages them together for the exact pulse width, or timing advance.
Open Loop: This "all out" mode of the ECU. It is activated at 80%+ throttle. This is strictly grabbing values from the tables using the interpolation routine described above.
The delima with closed/open loop tuning is since the ECU is compensating for values in closed loop, it's hard to get proper tuning. And boosting at part throttle (which is very easy on most HMT kits) it makes a mess of the A/F ratio. This is why a way to disable closed loop, and throw your ECU strictly into open loop is being sought after. With this, one would be able to have much more solid value sfor part throttle.
Closed loop: This is a "mode" the ECU sits in while you're less than 80% throttle. It is classified as being an "economy" mode, basically, trying to get the perfect A/F ratio (14.7:1) by using readings form the O2 sensor. I've not gone through the PM6 code for open loop, so I'm a bit tentative on the table part, but it's been talked about that they use the tables as a reference point, still using the interpolation routine. This routine being that it takes the 4 surrounding values ans averages them together for the exact pulse width, or timing advance.
Open Loop: This "all out" mode of the ECU. It is activated at 80%+ throttle. This is strictly grabbing values from the tables using the interpolation routine described above.
The delima with closed/open loop tuning is since the ECU is compensating for values in closed loop, it's hard to get proper tuning. And boosting at part throttle (which is very easy on most HMT kits) it makes a mess of the A/F ratio. This is why a way to disable closed loop, and throw your ECU strictly into open loop is being sought after. With this, one would be able to have much more solid value sfor part throttle.
08-05-2003, 03:34 PM
#15
0.0 BAR
Thread Starter
Join Date: Jul 2003
Posts: 23
Re:Zdyne Open / Closed loop question
Yeah sorry I'm being stupid, I won't be able to drive the car right at all.
Good closed / open loop explanation there. I'll go with my initial idea about the O2 simulator if I can make one. Otherwise I'll just get the car trailered to the garage.
Good closed / open loop explanation there. I'll go with my initial idea about the O2 simulator if I can make one. Otherwise I'll just get the car trailered to the garage.
08-05-2003, 10:13 PM
#16
1.5 BAR
Join Date: Dec 2002
Posts: 1,002
Re:Zdyne Open / Closed loop question
you will be able to drive fine to the exhaust shop w/o a o2 simulator, lots of ppl drive to the exhaust shop wo/a dp and o2 hooked up.
unless you exhaust shop is in another state i dont see a need to make a o2 simulator.
unless you exhaust shop is in another state i dont see a need to make a o2 simulator.
08-06-2003, 02:30 PM
#17
0.0 BAR
Thread Starter
Join Date: Jul 2003
Posts: 23
Re:Zdyne Open / Closed loop question
Yeah, but remember I've fitted a S/C, not a turbo. As soon as I open the throttle any I'm gonna make a small part of boost, I don't have a safe zone like below 3000 rpm or whatever. I can't risk Zdyne running in limp mode & not providing coverage for boost in these conditions - I don't wanna blow my engine. Plus the CEL will make the car run bad, but 'bad' as in no fuel? Crap retard ignition? I dunno.
Exhaust shop is 10 miles from my house, most of which is 60mph or 70 mph roads.
Exhaust shop is 10 miles from my house, most of which is 60mph or 70 mph roads.
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