When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Thanks for sharing the logs. I've tried to do the math on injectors and coil amp draw but still found myself guessing a bit on total circuit load given they are all firing at different times.
I was thinking of doing the R3 for my street car, but this thread has me questioning. where did you put the R5 in a street car? I assume it's too big for the stock location.
I think it really depends on what you intend to do from a wiring perspective. If you are going R3 instead of plug n play elite 2500 (e.g. keeping most of stock wiring), then R3 gets it done with a little cleaner install (no relay box needed and integrated wideband). If you have a custom harness and have more accessories you want controlled by the ECU without needing to add more relays (water meth, fans), then I'd go R5.
If going for more of a full car re-wire with almost everything controlled by the ECU, then you need to add a dedicated PDU on top of the R5/R3 either way.
I know an R3 will fit in stock location. Still trying to figure out R5 / PD16 location. Probably battery in one bin and electronics in the other. Or find a way to use the glove box area.
I was thinking of doing the R3 for my street car, but this thread has me questioning. where did you put the R5 in a street car? I assume it's too big for the stock location.
we make a bracket that fits the R5 in the stock location on an FD 100% bolt on.
Thanks for sharing the logs. I've tried to do the math on injectors and coil amp draw but still found myself guessing a bit on total circuit load given they are all firing at different times.
some people will tell you that you need 100amp relay for 8 coils... the most i have ever seen at 4400hp (3200lb car running 3.87@201) is 42 amps which is 8ms dwell with the coils off a single output, at that point some people move the coil power supply direct to battery, i wire them so the customers have the options to power them either way..
18 XX racing injectors (2ohm coils) will pull 32 amps at 75% duty at 9000rpm so that goes past the limits of the single output,
If going for more of a full car re-wire with almost everything controlled by the ECU, then you need to add a dedicated PDU on top of the R5/R3 either way.
i dont know what you guys are putting in all your "Street" cars to require more outputs...
take this example... full street car, indicators, head lights, tail lights (even this shitty usa ones that take up extra outputs) DBW etc etc 2 speed elixer fuel pump module (uses 2 DPOs)
only thing that is not off the ecu is the power windows which i could have done but the owner alredy had them wired to the power post...
Thanks for sharing the logs. I've tried to do the math on injectors and coil amp draw but still found myself guessing a bit on total circuit load given they are all firing at different times.
the injectors are kind of simple, you use Ohm's law. V=i/r, or in our case Amps = Voltage/ Resistance
at 12v a 15ohm injector uses 0.8amps. x4 if you had a typical 13B, 3.2amps.
you'd want some safety factor, so maybe you have it on a 10a circuit? Mazda had it on a 30A circuit, but its the injectors and all of the solenoids and the air pump, so its like 0.8 amps times the 23 things on there, or about 23amps
the injectors are kind of simple, you use Ohm's law. V=i/r, or in our case Amps = Voltage/ Resistance
at 12v a 15ohm injector uses 0.8amps. x4 if you had a typical 13B, 3.2amps.
you'd want some safety factor, so maybe you have it on a 10a circuit? Mazda had it on a 30A circuit, but its the injectors and all of the solenoids and the air pump, so its like 0.8 amps times the 23 things on there, or about 23amps
the injectors are kind of simple, you use Ohm's law. V=i/r, or in our case Amps = Voltage/ Resistance
at 12v a 15ohm injector uses 0.8amps. x4 if you had a typical 13B, 3.2amps.
you'd want some safety factor, so maybe you have it on a 10a circuit? Mazda had it on a 30A circuit, but its the injectors and all of the solenoids and the air pump, so its like 0.8 amps times the 23 things on there, or about 23amps
As with coils this isn't the correct way to find practical current draw of the injector circuit. Proposed duty cycle, dwell/dead time, etc should be addressed if you're taking the time to plot this properly else you get the less informed quoting bonkers circuit capacity on things like 4 IGN1As.
just finished wiring up another car with and R5 and NO PDM...
full street/strip 2012 camaro, low beam, hi beam, USA tail lights that flash the brakes as indicators that uses up 1 extra output, fog lamps, exhaust cutouts, wipers, line lock, water pump, thermo fan, trans fan, trans brake, 8 coils, 16 injectors, even powered the power windows off the r5 using a switch over digital relay... only thing i couldnt do off a hco was interior light, but i will use a LED light and a DPO and power coming from the power window supply which will be fine with no relay
just finished wiring up another car with and R5 and NO PDM...
full street/strip 2012 camaro, low beam, hi beam, USA tail lights that flash the brakes as indicators that uses up 1 extra output, fog lamps, exhaust cutouts, wipers, line lock, water pump, thermo fan, trans fan, trans brake, 8 coils, 16 injectors, even powered the power windows off the r5 using a switch over digital relay... only thing i couldnt do off a hco was interior light, but i will use a LED light and a DPO and power coming from the power window supply which will be fine with no relay
Lots of it comes down to E-experts and Inexperience.
Like people running 70amp relays for 4 IGN1A coils lol
Lots of it comes down to E-experts and Inexperience.
Like people running 70amp relays for 4 IGN1A coils lol
For sure on the second statement, on the first I'd say if someone wants to power factory control modules the Nexus' are completely capable. If you're trying to move towards/build a modern style BCM or something then they fall well short for street use.
i dont know how much more modern you can get than a 2012 Camaro but zero issues running everything off it.. dont know how much more street you need to be but lo beam, hi beam, blinkers, fog lights, tail lights makes it pretty street car...
i dont know how much more modern you can get than a 2012 Camaro but zero issues running everything off it.. dont know how much more street you need to be but lo beam, hi beam, blinkers, fog lights, tail lights makes it pretty street car...
All of your insight has been huge for my planning. I'm working on the planning for the install of an R3 in my 2 rotor street car. Going through NSP and documentation for the R3 and what outputs allow for what AMP draws. I've been planning on keeping some of the chassis functionality off of the PDM already, like HVAC, windows, audio and Wiper motor, but otherwise on the PDM.
Am I interpreting correctly that you could use the 4 left over injector outputs, 4 left over IGN outputs, and 6 DPOs for 2A and 3A PDM control functionality in addition to the 4x25A and 6x8A HBOs? If so, there shouldn't be any problems running any of the headlight, turn, tail, brake lights with these outputs as long as they're on LED bulbs.
Between those outputs, and the IC7 updates they've made allowing for use as an IO expander, my thoughts were that you should be able to use the IC7's assignable inputs directly from the stock combination switch and pass that back the R3, even further reducing the complexity of the wiring since you'd just need about a foot of wiring to go from the combo switch connector into the IC7 and no need to go all the way back to the R3.
Last edited by EYandura; Feb 12, 2025 at 10:35 AM.
