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-   -   MS3 EBC Issues (https://www.miataturbo.net/megasquirt-18/ms3-ebc-issues-80434/)

DNMakinson 09-01-2014 09:04 PM

[QUOTE=Rick02R;1162929

Perhaps my cold side location for the EBC solenoid is too far from the turbo? I really doubt it.

[/QUOTE]

I don't understand why you wouldn't use the compressor outlet port for the pressure source to drive the wastegate can.

DNM

Braineack 09-02-2014 07:49 AM

because it's not an ideal location to source boost from.

DNMakinson 09-02-2014 08:19 AM

From the standpoint of turbulence, or boost droop? Or other?

As far a droop, I contend that it's not important in this case as we are adding EBC.

Seems to me that the highest pressure, fastest inner control loop would be ideal.

I'm open to learn.

Braineack 09-02-2014 08:22 AM

you're probably right when it comes to using EBC.

richyvrlimited 09-02-2014 09:08 AM

Disagree, if you're using the hotside, you're asking the PID routine to account for another variable.

DNMakinson 09-02-2014 11:24 AM


Originally Posted by richyvrlimited (Post 1163071)
Disagree, if you're using the hotside, you're asking the PID routine to account for another variable.

Being Temperature?

ScottyP3821 09-02-2014 03:11 PM

1 Attachment(s)
Run the wastegate vaccum right before the throttle body then into your solenoid and put the soleinoid so there is less than 1.5ft of hose to reach the actuator. Cap the hole on the turbo after. If I need to draw a picture I will.

https://www.miataturbo.net/attachmen...ine=1409685087

Rick02R 09-02-2014 08:13 PM


Originally Posted by ScottyP3821 (Post 1163192)
Run the wastegate vaccum right before the throttle body then into your solenoid and put the soleinoid so there is less than 1.5ft of hose to reach the actuator. Cap the hole on the turbo after. If I need to draw a picture I will.

https://www.miataturbo.net/attachmen...ine=1409685087

Done. Possibly ~2' of hose to get nice routing.

More guess and check with PID. Possibly narrowing the scope. Seem to have decreased the amplitude of the oscillations but the periodicity is exactly the same. They don't seem to increase like they were under the old firmware.

richyvrlimited 09-03-2014 04:07 AM


Originally Posted by DNMakinson (Post 1163101)
Being Temperature?

No, the wastegate, rather than it staying relatively static, it'll be a moving target as it opens to bleed off boost rather than staying open.

Moving targets are harder to hit.

DNMakinson 09-03-2014 06:52 AM


Originally Posted by richyvrlimited (Post 1163422)
No, the wastegate, rather than it staying relatively static, it'll be a moving target as it opens to bleed off boost rather than staying open.

Moving targets are harder to hit.

I totally do not understand what you are saying here. The sole purpose of EBC is to modify the action of the waste gate.

richyvrlimited 09-03-2014 09:05 AM


Originally Posted by DNMakinson (Post 1163429)
I totally do not understand what you are saying here. The sole purpose of EBC is to modify the action of the waste gate.

Yes, and it does so by using a piece of code, and some clever maths.

Assume your target is 200kpa. With just the wastegate you hit 170kpa, but that tails off to 150kpa due to boost droop from the location of the WG signal.

That 200kpa has to be hit with lots more changes in EBC duty, than if you hit a relatively flat 170kpa across the board i.e. no boost droop.

Anything you can do which will make the PID loop not have to work as hard will make your life tuning the thing that much easier.

ScottyP3821 09-03-2014 09:40 AM


Originally Posted by richyvrlimited (Post 1163450)
Yes, and it does so by using a piece of code, and some clever maths.

Assume your target is 200kpa. With just the wastegate you hit 170kpa, but that tails off to 150kpa due to boost droop from the location of the WG signal.

That 200kpa has to be hit with lots more changes in EBC duty, than if you hit a relatively flat 170kpa across the board i.e. no boost droop.

Anything you can do which will make the PID loop not have to work as hard will make your life tuning the thing that much easier.

This^

DNMakinson 09-03-2014 10:20 AM

OK, but not an additional variable, just a different one. I now understand what you are saying.

I am thinking more in terms of the longer time constant invloved with the supply at the cold side vs hot side.

For me, possibly application specific, I think the work done by the EBC solenoid and control will be much greater bringing on earlier boost, than holding boost. Also, I have boost creep, rather than droop.

Plan to certainly use the advice in this thread when I set up my EBC, just wanted to understand the driver for that fine point.

Chiburbian 09-04-2014 12:04 AM

Fixed my tuning laptop and I am back at it. I progressively lowered the sensitivity until I got to 50 and I was still getting some oscillation so I started at zero and started working my way up. Ended at 30 before I got home tonight. I am pretty happy with how it's holding boost steady on prolonged pulls but it seems to be overshooting quite a bit on mid throttle now. I will do more over the next couple days. Btw, I believe my sensitivity was well over 100 when I started a couple weeks ago is it's far lower than I expected it would be.

ScottyP3821 09-04-2014 02:55 PM


Originally Posted by Chiburbian (Post 1163820)
Fixed my tuning laptop and I am back at it. I progressively lowered the sensitivity until I got to 50 and I was still getting some oscillation so I started at zero and started working my way up. Ended at 30 before I got home tonight. I am pretty happy with how it's holding boost steady on prolonged pulls but it seems to be overshooting quite a bit on mid throttle now. I will do more over the next couple days. Btw, I believe my sensitivity was well over 100 when I started a couple weeks ago is it's far lower than I expected it would be.

Post a data log and or vid. Ill tell you whats wrong with it. Also for removing oscillation add I


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