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BMW DBW without external driver?

Posted: Tue Sep 20, 2016 1:20 pm
by RHD
Did i read or hear somewhere this is possible? if so what models??

Re: BMW DBW without external driver?

Posted: Tue Sep 20, 2016 1:31 pm
by Karel
RHD wrote:Did i read or hear somewhere this is possible? if so what models??
Well, i was thinking about it too. Also wanted to use it on my 2JZ-GTE VVT-i with ETCS throttle body .....

Whats the problem ?

1) the current may be too high for normal AUX output. (not my case)
2) If you use only one output, you can only open the TB, and the closing is just on the backpresure spring, what can be slow in some cases (also not my problem)
3) many (if not all) Electronic TB are slight open when no current, and you may end with too high idle speed even on 0° ignition (thats my problem)

If i am using the DBW module, i can virtualy switch the polarity of the motor and close it more, so i can regulate the idle speed down, the response od the TB is faster on closing.

May be if you will use some BMW intake control motor equiped with link arm, you can make your own adjustable if the stock is not, and you can set the start opening like you need, and then just use one output for opening.

for example this one has no adjustment on this link arm

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if you use this, you can set the start position
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Re: BMW DBW without external driver?

Posted: Tue Sep 20, 2016 2:25 pm
by Jadzwin
Yes it is possible. You need to use external MOSFET transistor that will be able to provide enough current for BMW ITB motor. The throttle opens using this transistor and closes using the spring. The spring is very stiff so the closing is quite fast.

The trick is to use 4 flyback diodes with the MOSFET connected in series.

Re: BMW DBW without external driver?

Posted: Tue Sep 20, 2016 2:42 pm
by RHD
ok great! I actually have an s54 ITB actuator in my hand the spring is not very strong but i assume the actual ITB's also have a spring that will increase the tension

can you please show us a wiring sketch??... im not sure exactly what you mean with the 4 diods etc and do the Mosfets need any resistors??

Re: BMW DBW without external driver?

Posted: Tue Sep 20, 2016 3:57 pm
by Jadzwin
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Re: BMW DBW without external driver?

Posted: Wed Sep 21, 2016 8:18 am
by RHD
thank you that is very easy :)