AEM boost control
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From: Wilmington NC/ Carolina Beach
Originally Posted by Knyght
You can use a MBC but dont expect the AEM to control it, heh
They have some nice in car MBC's out there..
They have some nice in car MBC's out there..
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Originally Posted by Knyght
I was told not to run the GM solenoid higher than 85% duty and no lower than 10%
Hmm.. mine doesn't overheat(on my DSM) and it's on 10% at idle
It sounds like sheet but it works all the same. It never heats up to the point it would melt anything though, maybe just the heat from normal under hood temps
It sounds like sheet but it works all the same. It never heats up to the point it would melt anything though, maybe just the heat from normal under hood temps
Originally Posted by MalibuJack
I guess nobody really knows the size resistor needed (milliamp output of the driver to actuate the boost solenoid)
you have several methods for boost control (it works similar on the UTEC) you can use a GM solenoid or the stock solenoid, the stock solenoid would be a bleed system, the GM solenoid would be a restrictor system.. You can run an MBC in parallel with the GM solenoid so if the solenoid is closed at 100%, it bypasses through an MBC and will get the max boost you set on the MBC.. If you have an external wastegate, and you can plumb the GM solenoid as a bleed system also to correctly actuate the ports on the external wastegate.
Here's the issue, and this probably applies to everyone using the solenoid, if you want to get the best boost response (open loop or closed loop) you need to set the duty at or near 100% for some portion of part throttle and in your low load, this will allow the boost to ramp quickly then vent as the boost needs to be regulated. But if you drive the solenoid at full current that the stock solenoid uses (Default settings on the AEM, and the default driver output on the UTEC) you would find the solenoid gets very very hot.. since the current is too high it will eventually burn out the solenoid or melt something, if you can reduce the output of the driver, or limit the current with a resistor, so its only enough current to correctly actuate the solenoid, it won't get much warmer than the ambient temp under the hood.. Only on the UTEC, the driver output voltage/current is fixed and not adjustable (since its assumed to be the stock solenoid) so what I'd need is either the current required to drive the solenoid, or the resistor value used to limit the current to it.
you have several methods for boost control (it works similar on the UTEC) you can use a GM solenoid or the stock solenoid, the stock solenoid would be a bleed system, the GM solenoid would be a restrictor system.. You can run an MBC in parallel with the GM solenoid so if the solenoid is closed at 100%, it bypasses through an MBC and will get the max boost you set on the MBC.. If you have an external wastegate, and you can plumb the GM solenoid as a bleed system also to correctly actuate the ports on the external wastegate.
Here's the issue, and this probably applies to everyone using the solenoid, if you want to get the best boost response (open loop or closed loop) you need to set the duty at or near 100% for some portion of part throttle and in your low load, this will allow the boost to ramp quickly then vent as the boost needs to be regulated. But if you drive the solenoid at full current that the stock solenoid uses (Default settings on the AEM, and the default driver output on the UTEC) you would find the solenoid gets very very hot.. since the current is too high it will eventually burn out the solenoid or melt something, if you can reduce the output of the driver, or limit the current with a resistor, so its only enough current to correctly actuate the solenoid, it won't get much warmer than the ambient temp under the hood.. Only on the UTEC, the driver output voltage/current is fixed and not adjustable (since its assumed to be the stock solenoid) so what I'd need is either the current required to drive the solenoid, or the resistor value used to limit the current to it.
1) AEM can use the GM solenoid with either a bleed or restrictor system. You have the choice.
2) There is no need to run a MBC with the GM solenoid and AEM as you can set it up such that a high duty cycle is open. The AEM manual shows the different options for plumbing the boost solenoid including an external wastegate.
3) IMO, there is no need to run 100% duty cycle. As a matter of fact, AEM does not recommend running past 85%. I get excellent boost response at 50-60% duty cycle. The highest duty cycle I run is about 60% and as low as 15%. AEM can be configured such that high duty cycle equal high boost or low duty cycle equals high boost.
4) AEM allows you to change the frequency of the current going to the solenoid, which then allows you to use different solenoids including the OE version. FWIW, I was never able to get the OE solenoid to control boost properly. My guess is that the UTEC does not operate at the proper frequency to properly control the GM solenoid.
Originally Posted by Richard Sierra
I think you may be confusing the Utec with AEM. I’ll try to point out some of the errors stated above.
1) AEM can use the GM solenoid with either a bleed or restrictor system. You have the choice.
2) There is no need to run a MBC with the GM solenoid and AEM as you can set it up such that a high duty cycle is open. The AEM manual shows the different options for plumbing the boost solenoid including an external wastegate.
3) IMO, there is no need to run 100% duty cycle. As a matter of fact, AEM does not recommend running past 85%. I get excellent boost response at 50-60% duty cycle. The highest duty cycle I run is about 60% and as low as 15%. AEM can be configured such that high duty cycle equal high boost or low duty cycle equals high boost.
4) AEM allows you to change the frequency of the current going to the solenoid, which then allows you to use different solenoids including the OE version. FWIW, I was never able to get the OE solenoid to control boost properly. My guess is that the UTEC does not operate at the proper frequency to properly control the GM solenoid.
1) AEM can use the GM solenoid with either a bleed or restrictor system. You have the choice.
2) There is no need to run a MBC with the GM solenoid and AEM as you can set it up such that a high duty cycle is open. The AEM manual shows the different options for plumbing the boost solenoid including an external wastegate.
3) IMO, there is no need to run 100% duty cycle. As a matter of fact, AEM does not recommend running past 85%. I get excellent boost response at 50-60% duty cycle. The highest duty cycle I run is about 60% and as low as 15%. AEM can be configured such that high duty cycle equal high boost or low duty cycle equals high boost.
4) AEM allows you to change the frequency of the current going to the solenoid, which then allows you to use different solenoids including the OE version. FWIW, I was never able to get the OE solenoid to control boost properly. My guess is that the UTEC does not operate at the proper frequency to properly control the GM solenoid.
I run my solenoid at 70% on the UTEC, but the default "ECU" value on the UTEC is wanting to keep it "On" (100% duty) so I had to override that, but I don't have the same flexibility you have with the AEM (IE inverting the value so 100% duty is open)
My example of the MBC was to prevent a solenoid from seizing closed and overboosting, you can use the MBC in parallel to set an upper limit slightly above the level you intend to control (Sorry about the confusion there)
Anyway, from looking at the stock ECU's output, its just an on/off 12v signal, the current to drive it is basically to engage the solenoid, only the current for the factory solenoid is higher than the GM solenoid, so when it operates "Normally" with the stock ECU (and the UTEC) it literally stays closed and energized at idle and closed loop fuel control by default..
Do you have any idea roughly how much voltage or current that frequency to actuate the solenoid (GM) would result in? Or are you referring to the frequency in reference to the duty cycle?
Originally Posted by Knyght
Hmm.. mine doesn't overheat(on my DSM) and it's on 10% at idle
It sounds like sheet but it works all the same. It never heats up to the point it would melt anything though, maybe just the heat from normal under hood temps
It sounds like sheet but it works all the same. It never heats up to the point it would melt anything though, maybe just the heat from normal under hood temps
Anyway, I won't post in this thread anymore because its not really about the AEM, just a query for information that nobody apparently has anyway.
Originally Posted by Knyght
Aight, sounds to me it's more of a problem with the UTEC/stock ecu and not the AEM or the GM solenoid specifically.
Originally Posted by MalibuJack
Do you have any idea roughly how much voltage or current that frequency to actuate the solenoid (GM) would result in? Or are you referring to the frequency in reference to the duty cycle?
You don't need a MBC for overboost with AEM because it has a user defined fuel cut at whatever boost level you desire.
I think you would prefer AEM over UTEC, you should give it a try. I have a UTEC on my Subaru and it is primitive compared to AEM.