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Bosch top feed injectors in SR16VE

PostPosted: Fri Sep 10, 2021 2:26 pm
by Formula Student
I've changed my injectors from Nissan side feed injectors which were 850cc to Bosch EV 495cc injectors part no. 0 280 158 187.
The engine is a N/A SR16VE.
Currently the set up is
IJPU - 12
Injector Current - 0
Peak hold ratio - 4
INJ timing position - 0
Fuel used cal - 4000

The bigger injectors were from the engine when it was a 2.0L, however we've gone back to 1600 for now.

Looking through the help it seems the IJPU should be somewhere between 15 and 20. The way I read it, this is a scaling factor to make the numbers in the table bigger so you can get better resolution when tuning. Is this correct.

What I'd like to do is see if anyone can help with a basic set up and "overall trim" to start the engine and get it in a ballpark.

I'll have a crack at it, however any advice is always welcome.

Greig

Re: Bosch top feed injectors in SR16VE

PostPosted: Fri Sep 10, 2021 5:01 pm
by SDean
Hi,

The numbers in the Fuel Table represent of a percentage of the Injector Pulse Width, so if you have 10 in the IJPU and 50 in the Fuel Table, then the ECU will be requesting an injector pulse width of 5msec (Injector Pulse Width), plus the programmed injector dead time (Actual Pulse Width). If the IJPU number is increased to 15, then the same number in the Fuel Table will have a Injector Pulse Width of 7.5msec.

Re: Bosch top feed injectors in SR16VE

PostPosted: Fri Sep 10, 2021 5:23 pm
by Formula Student
SDean wrote:Hi,

The numbers in the Fuel Table represent of a percentage of the Injector Pulse Width, so if you have 10 in the IJPU and 50 in the Fuel Table, then the ECU will be requesting an injector pulse width of 5msec (Injector Pulse Width), plus the programmed injector dead time (Actual Pulse Width). If the IJPU number is increased to 15, then the same number in the Fuel Table will have a Injector Pulse Width of 7.5msec.


Yep, I thought that.
So, if I just divide the 850(old injector) x 495(new injector) I get 1.717
I presume I could just put a overall map trim of 70% and it would be close enough to start, correct?

I'll go through and do a proper conversion after it starts.

Re: Bosch top feed injectors in SR16VE

PostPosted: Sun Sep 12, 2021 6:27 pm
by Formula Student
Has Motec checked the Bosch 0 280 158 187 injectors, and if so do you have the relevant info such as flow at 60psi for example and dead time for battery compensation. I've got a M84 ecu

Re: Bosch top feed injectors in SR16VE

PostPosted: Mon Sep 13, 2021 12:17 am
by NathanB
We have flow data for the 0 280 158 187 injector. At 58.8psi (4 bar) the flow rate is 568cc.

4.0
8V 2280
10V 1400
12V 980
14V 740
15V 600

Dead times at 4 bar differential pressure are as above

Re: Bosch top feed injectors in SR16VE

PostPosted: Mon Sep 13, 2021 8:21 pm
by Formula Student
Thanks Nathan.
That helps heaps.
I saw a Motec sheet for another injector and it also gave flow at different pressures... Do you have that for this injector?

Re: Bosch top feed injectors in SR16VE

PostPosted: Tue Sep 14, 2021 9:45 am
by NathanB
Max flow @ 3 bar 492cc/min
Max flow @ 4 bar 568cc/min
Max flow @ 5 bar 636cc/min
Max flow @ 6 bar 696cc/min

Don't forget the injector latency changes as the pressure is increased. For requests like this, you are best emailing support@motec.com.au for calibration data requests.

Re: Bosch top feed injectors in SR16VE

PostPosted: Thu Sep 16, 2021 6:27 am
by Formula Student
I just want to thank Nathan and the team at Motec for their halp. I emailed support and had everything I need almost straight away.
Great service.