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 Post subject: methods to control boost
PostPosted: Mon Mar 05, 2018 3:31 pm 
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Joined: Wed Dec 06, 2017 1:55 pm
Posts: 40
ECU Model: S100 Pro
Yesterday i had my first hillclimb race .

The escort is unbeilevably fast. I need some help with controlling boost. When we were on the dyno the boost came up at around 3k to 20psi and started tailing of at 6500rpm. We just made the 90pwm on the last 3 colomns. Yesterday i noticed that the problem with misfires was the boost cut. The map was reading even 27psi at around 100mph. I want to control the boost il closed loop to avoid this. Does any one have an example of a pid loop table. I never worked with these . I have to learn. Can any one help?



Thanks and regards

Cpur


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 Post subject: Re: methods to control boost
PostPosted: Mon Mar 05, 2018 5:54 pm 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2913
Location: Norn Iron
ECU Model: No ECU
And what exactly are you using for boost control now ?

And do have a datalog of boost behaviour at present ? Is it spiking to 27psi momentarily or actually holding 27psi ?

And open loop will work perfectly fine and is very easy to do, you just need to sort the duties manually yourself.


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 Post subject: Re: methods to control boost
PostPosted: Mon Mar 05, 2018 11:35 pm 
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Joined: Wed Dec 06, 2017 1:55 pm
Posts: 40
ECU Model: S100 Pro
Hi stevieturbo and all,

On the dyno it was peaking at 20psi and tailing down to 15psi at 6500, so we adjusted the last cells covering from 80-100tps, 5500 to 8000 with 90%pwm, the rest of the cells are 0.
On the dyno this was great as it gave a 21 peak and held at 20 for the rest.

On the road due to ram air effect i am getting access boost. didn't notice that it was haveing a boost limit cut until last Sunday. We were thinking that something in the fuel system must be wrong. But on seeing the log, it was picking up 27psi on the long uphill straights.

I reduce the pwm in those cells to 80 , did it less but still did it. that is why i what to control with closed loop.

Regards
Cpur


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 Post subject: Re: methods to control boost
PostPosted: Tue Mar 06, 2018 4:48 am 
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Joined: Thu Jul 28, 2011 4:10 am
Posts: 871
ECU Model: S100 Pro
I think you need to go back to basics, if you are getting 20psi without the boost control it sounds too high to me, are you getting boost creep because the waste gate isn't big enough. You should be working on the waste gate spring only.


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 Post subject: Re: methods to control boost
PostPosted: Tue Mar 06, 2018 9:28 am 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2913
Location: Norn Iron
ECU Model: No ECU
Maybe his w/g spring is 20psi ?

Again...we need details.

But if your table is going from 0 then to 80/90...then something is wrong.

Whether the w/g is wrong, signal lines, solenoid...something.

And depending on the dyno, you'll usually see more load on the road than dyno so boost will often need adjusted via road/track tuning

But the problem simply sounds like issues with the build/setup as well as possibly in the mapping.


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 Post subject: Re: methods to control boost
PostPosted: Tue Mar 06, 2018 9:49 am 
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Joined: Wed Dec 06, 2017 1:55 pm
Posts: 40
ECU Model: S100 Pro
Actually there is no problem controlling boost. I am trying to make it clear.

Actuator is set to 20psi, at high rpm the exhaust pressure opens it further at so at this rpm only the pwm is set to 90 to help keep the boost at 20. And everthing is ok on the dyno.
Driving at 100mph makes the intake ram air effect build up a further 7psi. Which the ecu does not try to control since it is not in closed loop.

The map i used is only tps vs rpm.
So the ecu is not going to control it.

When driving at 100 mph the wastege can be opened further releasing backpressure and reducing the intake temp because the turbo will generate less heat because the delta press will be less.

Regards


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 Post subject: Re: methods to control boost
PostPosted: Tue Mar 06, 2018 11:59 am 
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Joined: Thu Jul 28, 2011 4:10 am
Posts: 871
ECU Model: S100 Pro
Sorry but 100mph doesn't make 7psi boost :) no matter how out the front of the car the intake is or whatever the nice shape, you will be lucky to see 10mb

You can use speed or gear to adjust the PWM if you wish in turbo settings

But as Stevie says try just adjusting your pwm settings down until you get what you want,


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 Post subject: Re: methods to control boost
PostPosted: Tue Mar 06, 2018 3:45 pm 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2913
Location: Norn Iron
ECU Model: No ECU
Absolute nonsense.

If you have a 20psi w/g and then need to have values of 0..then 90 something is wrong. That is in no way whatsoever normal.

And again, not a hope in hell are you getting a ram effect of 7psi....even if you had an air intake the size of a fog horn on the front of the car.

Boost control will do what you tell it to do...if it isnt, you've either told it wrong or the plumbing/wiring configuration is wrong.


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 Post subject: Re: methods to control boost
PostPosted: Wed Mar 07, 2018 2:58 am 
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Joined: Thu Jul 28, 2011 4:10 am
Posts: 871
ECU Model: S100 Pro
I don't have a turbo but I do note in the manual that that some installations / valves work the wrong way round and can be corrected in the software, perhaps this is the issue, therefore the 90% is only 10%, just an idea.


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 Post subject: Re: methods to control boost
PostPosted: Wed Mar 07, 2018 7:13 am 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2913
Location: Norn Iron
ECU Model: No ECU
It all boils down to plumbing, config and tuning all need to be correct.

And it is very apparent they are not correct at present given what has been described


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