Boost compensation

Discussion and support for MoTeC's previous generation ECUs.

Boost compensation

Postby uvii on Fri Jul 11, 2008 10:26 pm

I currently use comp1 in the boost function to allow switchable boost levels. This is a 2d compensation. I now would like to add a safety feature that cuts boost if a fuel pump fails. My idea was to use a 2d compensation on boost to pull boost for a given lambda and load. In the motec menus usder boost I now only have comp2 left which is a 1d compensation.

Is there any way to add another 2d compensation to the boost function?
uvii
 
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Re: Boost compensation

Postby John Reed on Sat Jul 12, 2008 6:39 pm

It seems the easiest just glancing at this would be to move your switchable to Comp2 (I am guessing you are only using one axis), and then use Comp1 to achieve your goal. Another way would be to use a differential pressure sensor, and then use that data input to trim boost back if the delta between manifold pressure and fuel pressure deviates. Just my $.02, which is not worth much as the dollar keeps falling. :D
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Re: Boost compensation

Postby uvii on Sat Jul 12, 2008 7:51 pm

Boost switch uses both axis of comp1. I'd rather not have to install another sensor to overcome this issues. Seems there shouldn't be any reason why motec can't do it. Just wondered if anyone had figured out a way to get round this limitation.

I could do an ignition pull with a 2d compensation, but that would leave the car undriveable if the error state got triggured as I would pull all the timing.
uvii
 
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Re: Boost compensation

Postby IJ. on Sat Jul 12, 2008 8:39 pm

Wouldn't it be better to pull the rpm limiter on to 3000rpm instead of pulling timing?
(pull the timing and it'll try and do the antilag thing making more boost)
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Re: Boost compensation

Postby tkkhoo on Mon Jul 14, 2008 8:44 am

What version of ECU Manager are you using? If you are on Version 3.xx onwards, the Boost Comp 1 can be a 3d table while Boost Comp 2 is 2d. You'll have to press "a" in the table and a menu will appear. Just setup the axis whatever way you want and it should do it.

TK
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Re: Boost compensation

Postby uvii on Tue Jul 15, 2008 8:00 am

Ah sorry, when i say 2d/1d I was refering to the measured axis. So 2d is a 3d table, not very clear my mistake.

I really like the rpm limit idea, i'll post up my initial table for comments and reference once i've done it.
uvii
 
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Re: Boost compensation

Postby MarkMc on Wed Jul 16, 2008 11:15 am

Could always use the Max Duty table to kill all boost control based on Fuel Pressure, i.e. when fuel pressure is low max duty for boost control is 0.
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Re: Boost compensation

Postby MarkMc on Wed Jul 16, 2008 11:18 am

Another though. You can always get an unused Auxiliary Output table and do a 0-100% output based on two axes, this can then be the axis for a 2D table in the boost control function.
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Re: Boost compensation

Postby uvii on Wed Jul 16, 2008 6:58 pm

Thanks Mark. I think i'll try the rpm limit first.

Is there any way to drive a light and have it configured for areas of my table where I am RPM limiting. I know it should be obvious when the limiting is taking place but i'd like positive confirmation of what is going on.
uvii
 
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Re: Boost compensation

Postby MarkMc on Thu Jul 17, 2008 10:29 am

Ok Uvii,
Just be a little careful when using the RPM limiter to make sure a noisey axis channel cannot bring the RPM limiter on unexpectedly.

You could setup a simple output based on a table using the "RPM Limit Setting" channel as the axis to turn on your light.
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