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Old 01-24-2009, 01:48 AM   #1
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Default An idea to fix the **** boost control...

Ok, with the GM boost control solenoid, voltage=closed, no voltage=open, correct? So what if we simply set the duty cycle to full boost in cold conditions, then when it gets warm out, we use a variable resistor to de-amplify the MS output, thus allowing for more boost. This means we could have an infinite amount of boost controller maps for any temp.

I know its a pulse width output, and a resistor wont actually change the duty cycle (right?), but I figured maybe changing the amplitude of the pulse will make the solenoid react slower/weaker, allowing for more boost?

Then again will this effect when you have the solenoid closed (100% duty)?

Or will it not work at all?

I would love to have some way to make the MS boost control better lol.

EDIT-----

Is there such thing as a variable low pass filter (make the circut maybe, a filter like this is made up of a resistor and capaciator in series right? What if the resistor was adjustable?)? I know amplifiers can vary the freq. it filters out... that would directly be able to change the pulse the boost solenoid sees... but I don't know how to implement something like that...

Im just throwing out ideas...
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Old 01-24-2009, 01:53 AM   #2
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It's more complicated than that. The best/simplest thing you could do, IMO, would be to have an extra solenoid that swtiches between to different MBC's (or EBC's) so that you can switch to a cold and hot setting. IE-set one MBC for 12 PSI when it's 80*F out and set the other MBC for 12 PSI at 40*F and use a solenoid to switch between them. Not ideal though.
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Old 01-24-2009, 01:57 AM   #3
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Quote:
Originally Posted by patsmx5 View Post
It's more complicated than that. The best/simplest thing you could do, IMO, would be to have an extra solenoid that swtiches between to different MBC's (or EBC's) so that you can switch to a cold and hot setting. IE-set one MBC for 12 PSI when it's 80*F out and set the other MBC for 12 PSI at 40*F and use a solenoid to switch between them. Not ideal though.
For that you could just use brains idea of a MBC and EBC... if my idea really more complicated than so be it, it would just be interesting to have a quickly, eaisly adjustable boost control with infinite adjustment.
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Old 01-24-2009, 02:17 PM   #4
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Just wait..... Keith is working on a PID control for Idle, once done he's going to copy it over to boost control problem solved.

OR you could get a superior way of applying Forced Induction, i.e. a Supercharger
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Old 01-24-2009, 02:53 PM   #5
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A real simple solution would be to just get rid of the GM solenoid and get a much better solenoid.

The GM solenoid does a shitty job at holding solid boost.
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Old 01-24-2009, 03:36 PM   #6
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Quote:
Originally Posted by spike View Post
A real simple solution would be to just get rid of the GM solenoid and get a much better solenoid.

The GM solenoid does a shitty job at holding solid boost.
A solenoid is only as good as what's controlling it. MegaSquirt's issue is the code is rubbish, not the solenoid...
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Old 01-24-2009, 03:40 PM   #7
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Quote:
Originally Posted by spike View Post
A real simple solution would be to just get rid of the GM solenoid and get a much better solenoid.

The GM solenoid does a shitty job at holding solid boost.
The DENSITY of the air going in the engine increases as ambient temps drop. More in, more out. More out without opening the wastegate more means a % of the "more" goes across the turbine, performing more work, hence more boost.
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Old 01-24-2009, 03:50 PM   #8
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Quote:
Originally Posted by richyvrlimited View Post
A solenoid is only as good as what's controlling it. MegaSquirt's issue is the code is rubbish, not the solenoid...
I don't know about that,but I could be wrong.

Last summer,I went with a friend to have his Megasquirt tuned,I removed his GM solenoid,installed the Mac Valve,the tuner set the frequency for the new valve,made a dyno run and the new valve gave a smoother,more rock solid boost ramp,boost also came on earlier.His tuning map was not changed at all except for setting the frequency for the new solenoid.

Having quality parts do make a difference.
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Old 01-24-2009, 07:40 PM   #9
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Quote:
Originally Posted by spike View Post
I don't know about that,but I could be wrong.

Last summer,I went with a friend to have his Megasquirt tuned,I removed his GM solenoid,installed the Mac Valve,the tuner set the frequency for the new valve,made a dyno run and the new valve gave a smoother,more rock solid boost ramp,boost also came on earlier.His tuning map was not changed at all except for setting the frequency for the new solenoid.

Having quality parts do make a difference.
thats not the problem im trying to fix... read my post and pats post please.
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