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Old 02-09-2009, 11:23 PM   #1
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Default Improving temp sensitivity of EBC

So I have a thought on possibly a cheap(ish) way of how to reduce the ambient temperature sensitivity of an MS driven EBC running open-loop. I'm posting my thoughts here to see if anyone has tried it, or thinks it is plausible.

First of all, before you say it:
- Just buy a real EBC
- Get a MBC
- MS will have this fixed soon (when?)

So here is the idea. What if you use a wastegate actuator with a target pressure that is closer to the target open-loop EBC pressure? If the EBC has to use less duty cycle to reach the desired boost pressure, then overall the system's sensitivity is reduced, and it should be less sensitive therefore to disturbances, like changes in ambient temperature. right?

Allow me to illustrate by example. Suppose that my desired boost presure is 15 psi. Say I have a 6 psi wastegate actuator (unit A), and a 12 psi wastegate actuator (unit B). All else being equal, I tune the open-loop EBC first with unit A, and then with unit B. As one would expect, unit A would require more duty cycle to reach 15 psi than unit B would. Let's say unit A takes 70% duty cycle, and unit B takes 30% duty cycle. The 70% number is based on my current EBC table tuned for ~15 psi.

Since the 30% duty cycle is closer to 0% (the 'natural' boost level of the wastegate controller), would it not be less sensitive to temperature changes, since the EBC has less 'influence'?

The ideal would probably be to use a wastegate actuator that was at the desired boost level, then only use the EBC to keep the gate from cracking open too early. Or, use a EBC/MBC hybrid setup (with a weaker actuator) to achieve similar behavior.
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Old 02-09-2009, 11:48 PM   #2
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There's a few trains of thought on the causes of boost change with temperature:

The solenoid itself changes temperature and this affects the flow of air through the solenoid.
With an MBC bleed type, (read, leak type), the flow of leaking air changes with temperature, changing boost
The density of the air entering the engine changes with temperature. (bigger factory by far)

The stiffer the wastegate, the more stable it will be. This is true on EWG setups as well. So your theory is correct.

To the get a MBC comment I'll add: Get an EWG Closed Loop dual port EWG with MBC FTW.
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Old 02-10-2009, 12:07 AM   #3
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My $4 ebay boost controller should be here thursday...I assume the fixed ebc code will drop that day.
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Old 02-10-2009, 01:25 AM   #4
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Quote:
Originally Posted by patsmx5 View Post
To the get a MBC comment I'll add: Get an EWG Closed Loop dual port EWG with MBC FTW.
I did not expect that one. Damn...


Quote:
Originally Posted by hustler View Post
My $4 ebay boost controller should be here thursday...I assume the fixed ebc code will drop that day.
That would be nice. Thanks for buying the $4 controller so the code is released sooner. So any one heard any word on that BTW? I checked MSextra and did not see anything.
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Old 02-10-2009, 01:37 AM   #5
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They supposedly released the new code for MS2E a month ago. My MBC works fine though, so no reason to change it. Haven't heard if the new MS2E code fixed it, though it was supposed to, people are hesitant to test it obviously.
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Old 02-10-2009, 02:25 AM   #6
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I finally ditched my EBC last week. Went from a 1psi every 10-12 degrees to 1psi every 100 degrees.
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Old 02-10-2009, 06:16 AM   #7
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MBC is controlling boost, or controlled by boost. The MS EBC is actually time controlled boost contro... so which MBC do I get?
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