Guru needed!!! using bcs pwm signal for secondary injectors?..
Jan 16, 2012, 09:13 PM
#17
1- To protect your ECU, you should build a small PCB with some extra transistors to drive the new set of injectors.
2- With a small 741 alike op-amp, you should be able to read load (IPW) on any original injector, a capacitor can do the average value and a potentiometer can adjust the trigger for the 2nd set of injectors when needed...
Hope it helps.
Cheers.
2- With a small 741 alike op-amp, you should be able to read load (IPW) on any original injector, a capacitor can do the average value and a potentiometer can adjust the trigger for the 2nd set of injectors when needed...
Hope it helps.
Cheers.
Jan 17, 2012, 08:40 AM
#20
I would be very concerned about it being at a fixed frequency and not driven at the same frequency as the normal injectors. Especially if you are talking about putting these injectors in the runners where the fuel doesn't disipate evenly into the airflow.
Think about this for a second. If it is running at 20Hz, that means at 1200 RPM, you are getting one injection per cycle and would be considered "batch fire" injection. Double it and at 2400 RPM, you are getting one injection event per intake stroke.
Above 2400 RPM, lets say 4800 RPM with a 50% duty cycle. Every other intake stroke is getting ZERO fuel and it only gets worse as engine speed increases.
Also, this idea of putting a 25 ohm load in series with the injectors in parallel is a bad idea. You would be giving the injectors about 2 volts to open and close and the rest will be disipated in the resistor. The injectors won't even open with less then about 8 volts. Sure, it might be 28 ohms, but your power ratio is terrible.
There are some serious flaws to this plan.
Think about this for a second. If it is running at 20Hz, that means at 1200 RPM, you are getting one injection per cycle and would be considered "batch fire" injection. Double it and at 2400 RPM, you are getting one injection event per intake stroke.
Above 2400 RPM, lets say 4800 RPM with a 50% duty cycle. Every other intake stroke is getting ZERO fuel and it only gets worse as engine speed increases.
Also, this idea of putting a 25 ohm load in series with the injectors in parallel is a bad idea. You would be giving the injectors about 2 volts to open and close and the rest will be disipated in the resistor. The injectors won't even open with less then about 8 volts. Sure, it might be 28 ohms, but your power ratio is terrible.
There are some serious flaws to this plan.
Jan 17, 2012, 09:25 AM
#21
I just realized that it's a dead end. That circuit can only support a maximum of about 0.5amp of current but even a single high impedance injector will need around 1.2-1.5amps.
It's easy to get around the set frequency. It's just math and logging of IPW.
(WGDC/100)*50= WGipw in mIlliseconds.
(60/RPM)*2= MAXipw per RPM
So to log actual IPW of the added injector would be:
(WGipw/MAXipw)*100
-Jamie
It's easy to get around the set frequency. It's just math and logging of IPW.
(WGDC/100)*50= WGipw in mIlliseconds.
(60/RPM)*2= MAXipw per RPM
So to log actual IPW of the added injector would be:
(WGipw/MAXipw)*100
-Jamie
Last edited by Dynotech Tuning; Jan 17, 2012 at 09:41 AM.
Jan 17, 2012, 04:48 PM
#25
I still think if some one was able to program some EGR or FPR control we could use them are output controls with a injector driver box.
http://www.fjoracing.com/products/injdrvr/
http://forcedfour.com/4channelinjectordriver.htm
http://jbperf.com/p&h_board/v2_0.html
here is a picture on how the ecmlink guys are controlling the egr and fps output
http://www.fjoracing.com/products/injdrvr/
http://forcedfour.com/4channelinjectordriver.htm
http://jbperf.com/p&h_board/v2_0.html
here is a picture on how the ecmlink guys are controlling the egr and fps output
Last edited by ezz-e; Jan 17, 2012 at 09:04 PM.
Jan 18, 2012, 10:39 AM
#27
FWIW, if it were possible to up the frequency to around 80Hz I think you could uses either output as a PWM output to control an additional injector driver box that controlled injectors in the intercooler pipe.
The other option here, use injector scaling in the alt maps to accommodate the injector change. Simply use this output to activate an additional injector controller (turn on a relay) and use the original injector signals to control the secondary injectors. If you used the same injectors for both sets and they are good injectors, that's about all that would be needed as the normal injector comps would handle the latency. The alt maps would simply need to activate the EGR output to turn on the additional injector controller and then double the injector size.
The other option here, use injector scaling in the alt maps to accommodate the injector change. Simply use this output to activate an additional injector controller (turn on a relay) and use the original injector signals to control the secondary injectors. If you used the same injectors for both sets and they are good injectors, that's about all that would be needed as the normal injector comps would handle the latency. The alt maps would simply need to activate the EGR output to turn on the additional injector controller and then double the injector size.
Jan 18, 2012, 10:43 AM
#28
FWIW, if it were possible to up the frequency to around 80Hz I think you could uses either output as a PWM output to control an additional injector driver box that controlled injectors in the intercooler pipe.
The other option here, use injector scaling in the alt maps to accommodate the injector change. Simply use this output to activate an additional injector controller and use the original injector signals to control the secondary injectors. If you used the same injectors for both sets and they are good injectors, that's about all that would be needed as the normal injector comps would handle the latency. The alt maps would simply need to activate the EGR output to turn on the additional injector controller and then double the injector size.
The other option here, use injector scaling in the alt maps to accommodate the injector change. Simply use this output to activate an additional injector controller and use the original injector signals to control the secondary injectors. If you used the same injectors for both sets and they are good injectors, that's about all that would be needed as the normal injector comps would handle the latency. The alt maps would simply need to activate the EGR output to turn on the additional injector controller and then double the injector size.
MrFred said that the frequency can be changed with a patch and you've seemed to become well versed with the coding...think you can find a way to edit it?
-Jamie
