how-to: ECU-based direct boost control
I already do this with my BEC table. I don't start correction until 1.5 psi of error. My base WGDC are great - my car actually has a great boost curve with BEC zero'ed out. I only get oscillation when I "turn on" error correction. Hence my question about the correction interval.
There's a couple of non-obvious things as far as configuration goes, but I'm sure someone will post up a user-friendly explanation once v7 is officially out.
That's what I will do. Thanks. When I get a chance to datalog (my Evo is not daily driven), I will post my results.
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Yeah, those are pretty minimal values already. Does changing the interval to 2 stop the oscillations?
Exactly. That's what I did.
-3.0888 0
-2.7027 0
-2.3166 0
-1.9305 0
-1.5444 +1.0
-1.1583 +0.5
-0.772201 0
-0.3861 0
0 0
0.3861 0
0.772201 0
1.1583 -0.5
1.5444 -1.0
1.9305 -1.5
2.3166 -2.0
2.7027 -2.5
3.06467 -3.0
With an interval of 1, my boost is pretty good but I still get some oscillation between 23-25 psi (desired is 24.1). My boost curves are actually the best when I zero out my BEC. But I prefer to have some closed loop feedback.
-3.0888 0
-2.7027 0
-2.3166 0
-1.9305 0
-1.5444 +1.0
-1.1583 +0.5
-0.772201 0
-0.3861 0
0 0
0.3861 0
0.772201 0
1.1583 -0.5
1.5444 -1.0
1.9305 -1.5
2.3166 -2.0
2.7027 -2.5
3.06467 -3.0
With an interval of 1, my boost is pretty good but I still get some oscillation between 23-25 psi (desired is 24.1). My boost curves are actually the best when I zero out my BEC. But I prefer to have some closed loop feedback.
I still had oscillation with an interval of 2. I will try 3 next. I have to use small BEC values. I can change my boost by almost 1 psi with just a 1% WGDC change. The Ingersoll solenoid is very sensitive to WGDC. I suspect the GM 3 port is less sensitive. But the Ingersoll solenoid does not require any resistors to wire up. Same solenoid that Perrin uses.
I still had oscillation with an interval of 2. I will try 3 next. I have to use small BEC values. I can change my boost by almost 1 psi with just a 1% WGDC change. The Ingersoll solenoid is very sensitive to WGDC. I suspect the GM 3 port is less sensitive. But the Ingersoll solenoid does not require any resistors to wire up. Same solenoid that Perrin uses.
Just because it doesn't require a $2 resistor doesn't make it a wiser choice. Running the GM 3-port with a 5 ohm resistor is about the fastest responding BCS you're gonna find. People that pitch the 'no resistor required' marketing are really trying anything to make their product sound better.
Just because it doesn't require a $2 resistor doesn't make it a wiser choice. Running the GM 3-port with a 5 ohm resistor is about the fastest responding BCS you're gonna find. People that pitch the 'no resistor required' marketing are really trying anything to make their product sound better.
When MrFred did his UBER bench testing he noticed that 5 ohms seemed to work fine with the GM 3-port and the stock ECU BCS circuit. The less resistance we add to the circuit, the faster the BCS can respond, just like injector voltage/latencies. It's been a while so I'd re-confirm with MrFred if you want.
Here is the old thread:
https://www.evolutionm.net/forums/ec...ting-data.html
Pretty sure its in there somewhere.
Last edited by Jack_of_Trades; Aug 28, 2009 at 05:59 AM.
I would say that if you use an interval of '1' that going to the 5 ohm resistor would be the most useful since you obviously are looking for the fastest reaction time for your corrections. If you are using anything higher than 2, I wouldn't see much of a need really. That's just my observation.
I would say that if you use an interval of '1' that going to the 5 ohm resistor would be the most useful since you obviously are looking for the fastest reaction time for your corrections. If you are using anything higher than 2, I wouldn't see much of a need really. That's just my observation.
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I've heard from several people that have been running the GM 3-port for quite some time with no resistor and not fried ECU, so it seems that wiring the GM up without a resistor is ok. However, for those who prefer to error on the cautious side, a 5-ohm resistor in-series gives almost the same response time as no resistor.