It is currently Sun Dec 16, 2018 12:50 pm



Post new topic Reply to topic  [ 27 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post subject: Re: methods to control boost
PostPosted: Thu Apr 12, 2018 11:33 pm 
Offline

Joined: Wed Dec 06, 2017 1:55 pm
Posts: 40
ECU Model: S100 Pro
Hy guys,

Tomorrow i will do some driving and maybe get some logs.
But i will try to explain myself again.

The wg spring is set to 20psi

The turbo being small starts to open further the wg at around 6200. So the boost will drop.

So during dyno we set the pwm to 90 at 6000 to 7500 to help keeping the wg closed. And it worked. Boost came up normally and kept at 20.

When driven on the road. The boost will start to go over because the air speed is different fron the dyno. Infact this does not happen on lower gears. This happens on higher gears and goes up depening on speed.

Now i need to start using a closed loop control. If any one can guide me as to where to start from , it would be easier.

I dont want boost by gear or speed. I just want 20 psi all around.

Thanks and good day.


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Fri Apr 13, 2018 3:33 am 
Offline

Joined: Tue Jul 26, 2011 10:15 am
Posts: 126
ECU Model: S60 Pro
Firmware Version: 71
Cpur wrote:
When driven on the road. The boost will start to go over because the air speed is different fron the dyno. Infact this does not happen on lower gears. This happens on higher gears and goes up depening on speed.

As I think it was mentioned before, this is nothing to do with air speed. It is to do with the load being generated on the dyno, or not enough.

My car was mapped for 1.3bar on the dyno. It has an external WG with the spring set to 1bar. When I got the car back, it was generating 1.8bar+ on the road in the higher gears.

I disconnected the boost control and had the car mapped elsewhere as the guy was a muppet and everything is all correct now.


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Fri Apr 13, 2018 6:53 am 
Offline

Joined: Thu Jul 28, 2011 4:10 am
Posts: 872
ECU Model: S100 Pro
Indeed, the engine doesn't know if it's on a motorway or dyno, all it sees is an acceleration rate. Nothing to do with air speed, I suspect the dyno operator used and acceleration rate similar to how the car accelerates in 2/3rd gear. If you held the engine at an rpm on the dyno the boost would rocket I suspect.


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Fri Apr 13, 2018 10:03 am 
Offline

Joined: Sun Jan 27, 2013 6:08 pm
Posts: 265
ECU Model: S60 Pro
Firmware Version: 29
Very difficult for dyno's to reproduce similar load to that out on the road. By their very nature most dynos are minimal load to start with ie. just moving a bloody heavy roller faster and faster. Better ones will be water or electrically braked to add load but if its not enough or to much the results are artificially skewed! Also most dyno guys would hate to load a car up in top gear and hold it so everything stabalises - its a hell of a lot of stress.........but so is WOT - flat out down the Hanger Strait at Silverstone!


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Fri Apr 13, 2018 1:29 pm 
Offline

Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2913
Location: Norn Iron
ECU Model: No ECU
Any decent dyno should be able to apply as much load as you'd ever want against an engine...ie hold steady state sites.. As to whether the operator chooses do to that though is another matter

I know many years ago I had mine on a dyno just testing a few things, and we decided to see if it would hold mine at around 5000rpm. ( Dynapack ) and it did no problem, but it felt horrific in the car !
Probably no worse than doing the same on the road at high speed though lol.

But mapping should always be finalised on road or track, unless the dyno operator really is clued in and knows how to make things work. It seems very few are.


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Sat Apr 14, 2018 1:31 pm 
Offline

Joined: Wed Dec 06, 2017 1:55 pm
Posts: 40
ECU Model: S100 Pro
Hi guys,
today i tried it on our local race track.
We managed to make the Tc and Launch work fine. However on boost control I am still stuck .
Details:
Turbo with mechanical actuator set by spring to 20psi.
The solenoid in off (no current) lets the air from the compresor side go to the actuator
When the solenoid is switched on, the air coming from the compressor will be blocked , and the actuator will be exhausted.

Is there anything wrong in this setup?

Regards


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Sun Apr 15, 2018 5:52 am 
Offline

Joined: Sun Jan 27, 2013 6:08 pm
Posts: 265
ECU Model: S60 Pro
Firmware Version: 29
I may be wrong, but the way I read it, is your base WG pressure is 20psi ie. without any electronic control you should get 20psi. The solenoid is venting WG line pressure so will increase actual boost pressure above 20psi.
Usually in these systems you have low spring / base pressure and the bleed off will increase it to the desired level where it can be controlled via PWM duty.


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Sun Apr 15, 2018 7:13 am 
Offline

Joined: Thu Jul 28, 2011 4:10 am
Posts: 872
ECU Model: S100 Pro
If the engine boost is dropping below 20psi waste gate setting at high rpm it's because it can't, no amount of pwm will change that.


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Sun Apr 15, 2018 8:33 am 
Offline

Joined: Wed Dec 06, 2017 1:55 pm
Posts: 40
ECU Model: S100 Pro
@rob
When i did it with open loop and gave a 90% where it was tailing of , that managed to control an keep the boost at 20.

Thanks


Top
 Profile  
 
 Post subject: Re: methods to control boost
PostPosted: Sun Apr 15, 2018 1:30 pm 
Offline

Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2913
Location: Norn Iron
ECU Model: No ECU
Draw a full schematic of your boost control system.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 27 posts ]  Go to page Previous  1, 2, 3  Next

Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Theme designed by stylerbb.net © 2008
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
All times are UTC - 5 hours