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Old 10-05-2006, 07:11 PM   #11
cplagz
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Originally Posted by matt325is

Does this make sense or am I overthinking it a bit? I wish i had my car here to test different types, but it is at my parents house and I'm at college right now...

matt
I think you might be overthinking a bit too much, the excess pressure would return to your boost source would it not, then vent through your BOV?

The two diagrams I posted are out of the Turbosmart eBoost2 manual, method one still has the vent port on the solenoid and uses a Tpiece for signal off the incoming line.

I will probably use the second format.
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Old 10-31-2006, 04:39 PM   #12
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Looking at the boost control duty cycle map that is posted......the values are pretty much backwards of how they should be. The whole point of an EBC is to keep the WG signal completely blocked until the moment when you need the WG to start opening to prevent a spike, and also maintain a specific boost level. (like has been said)

The way the boost duty cycle map above is setup, you have it open 50% of the time at low rpm's, when you'd really want that area of the map to be at 100% since it's below the point where your turbo can even make the amount of boost you want.

Assuming your turbo makes your desired boost level at 4K rpm when the WG is completely shut (removing any boost reference to teh WG) then anything below 4K rpm you'd want to be at 100% slightly tapering to the duty cycle necessary to keep the solenoid pulsing adequately to keep boost at a certain level near or past this point.

This seems completely obvious to me....so maybe i'm missing something about how this DIY stup works?
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Old 10-31-2006, 06:30 PM   #13
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Yes, you are correct. In there somewhere I wrote that it sould act like a supercharger, but more agressively than the first map (with only 50% duty across). Yes, you can make 100% until your certain boost threshold where you see full boost, it would be dumb of me to make a map like that, where someone might just use the values and get boost way before then (an the wastegate would still be shut), and blow up their engine. It all depends on the engine and turbo setup as to where you see your desired boost level.

Thanks for pointing that out, it was something that I forgot to put in there.

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Old 11-01-2006, 04:31 PM   #14
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I assumed you understood it the same way I did....I just didn't see it documented that way.....and didn't understand the supercharger analogies you were using.

If a person would be ignorant enough to use your exact boost control values....they probably won't be able to get megasquirt running anyways, so that issue should cancel itself out the whole point is to illustrate teh concept correctly... and I was confused by the above. I don't mind if my posts are deleted from the thread, if you want to update, and clean things up in the original "article"
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Old 03-13-2007, 02:46 PM   #15
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Matt (or anyone) - I'm trying to understand boost control. The msextra manuals are worthless because the code has been updated several times since the release of the extra manuals.

So in the boost control menu, if Closed loop kpa limit (kPa) is set to 0 (as instructed above), then MS will only contol the solenoid by using the values in the Boost duty target table right?

If yes, then the Boost kpa targe table(s) doesn't need setting up at all. So why then do you have in your wiring diagram the method for switching between two boost tables? Is this just a guide in case someone wants to use it? Because MS only allows one duty target table which is not effected when table switching is active. Have you or anyone found a method of creating two duty tables that can be switched? It would seem better to create a stronger duty cycle table for the track or other needed events.
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Old 07-20-2007, 10:25 PM   #16
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Why some people, systems-manuals says you have to source your boost line from the turbo compressor or just anywhere before the TB???

I don't see any negative thign about connecting in the intake manifold?!

I always ran in the intake manifold, I think it's the best part to source, you want the last minute to cut "overboost" as in the intake it's what the engine it's seenig/taking.

Vaccum won't affect the boost controler at all I think?

Check "port3"



Anyways I'm building my own custom EBC with two selenoids, one of three ways and one from two ways + vent residual pressure when you don't need it, i.e. when vaccum happens and you don't need the WG pressurised.

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Old 07-21-2007, 09:36 AM   #17
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i'd be more worried about the possibility of unregulated boost before the TB then the controller seeing vacuum. I suppose under normal conditions the worst would be a spike that the BOV would sap. Still if something quit working right it would be nice to know that the pressure is being regulated to the source without a bunch of variables in the way.

plus wouldn't that make the throttle seem a lot less linear under boost?
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Old 10-09-2007, 07:18 PM   #18
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Would this type of hookup be better? Author indicates that this way if the solenoid fails, it will simply fall back to your wastegate spring pressure.

http://forums.neons.org/viewtopic.ph...er=asc&start=0

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Old 10-17-2010, 03:51 PM   #19
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has anyone ever used the charcoal purge valve instead?
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Old 12-01-2011, 05:28 PM   #20
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Quote:
Originally Posted by matt325is View Post
Megasquirt Boost Control

For boost control, you will need a 3-way solenoid such as the GM Fast Acting Solenoid (from the GMC Typhoon), GM Part # 1997152 (GM Parts Direct has the best prices, I think its around $13). You will also need an IRLZ44 FET (at Mouser). Along with this FET, you will need a 10k ohm resistor and a 100 ohm resistor, and a 1N4002 diode to make sure there are no voltage spikes back into Megasquirt.

matt
Where does the diode fit into the circuit? It's also in the ms extra diagram but it's pretty vague as to where it should be.I don't see it at all in Matt's wiring.

http://www.msextra.com/doc/ms1extra/...oostoutput.jpg
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