Any questions you have before you begin buying, building and installing.
User avatar
By Noruvi Garage
#53041
Hi. I want to set up a Speeduino v0.4 for my ca18det powered Nissan 200sx. I have never wired up a standalone ecu before and need some questions answered:



The injectors I’m running are 444cc GTR ones. I checked the resistance to be 2.0 ohms on all of them. If I understand correctly, for these to work with the speeduino, I need to wire in extra resistors to exceed 8 ohms. The stock wiring on the car has a single injector resistor unit which is mounted in the engine bay. Can I use this? Or If I should wire in individual resistors on the injector signal wires, I would need >6 ohm resistors for each injector? Would it work with 2x >12 ohm ones where the signal wires are spliced into 2? (One for each set of 2 injectors)



The engine has coil on plug. Will the sequential (COPs) configuration be best option? There is also an ignition module in the stock wiring harness. Can I forget about this?

Can I use the stock CAS or is it best to install a VR sensor?


The engine doas not have a crank position sensor as far as I know. Is this needed?


I’m also not sure which other inputs are required. I now have a z32 maf. Does the built in MAP-sensor on the speeduino replace this input as a means of controlling the engine?

Is there anything major I have missed?

Sorry for all the dumb questions
-David
User avatar
By Chris Wolfson
#53047
May I inform you that great care has been taken to answer all your questions? There is something called a WIKI, some call it a manual. Any information you may need is there. Your job is to apply the information to your own project. Sometimes, if you want to use parts from your stock installation, it helps to look into the cars workshop manual.

https://wiki.speeduino.com/en/home

Good luck!
User avatar
By PSIG
#53053
+1. Indeed, the Wiki and searching these forums are sources of both specific and general concepts. You want to understand the concepts more-so than the specific way something could be done. Add info from your vehicle's manuals for more concepts that are specific to your hardware.

So to grasp the freedom aftermarket systems can give, we aren't looking for "connect wire A to terminal 1", but rather that we need to apply a 5V high signal to terminal 1 to make the gizmo work a certain way. Now we have multiple options and can do it any way we like.

Using your injectors as examples, yes, your stock injector resistor box can be used with Speeduino in the same way it was used originally. Those resistors are sized to ensure proper function of the injectors, not meet some system limitation. So, you can use that box, or four 5-ohm 25W wire-wound resistors (calculator results based on 2A at 14V), or other option; because the concept is to regulate the power through the injectors with enough but not harmfully excessive power in whatever way works. The average amp limit for most boards is around 8A per channel, so that's not a concern.

Other questions often solve based on what your goals are. Your coils could be sequential COP, or wasted-COP, depending on your crank and cycle signals. Your COP driver could be your original ignition module, which is wired and functions exactly like the popular Bosch "211", and signaled by Speeduino in the same way the original ECM did. Speeduino uses MAP, not MAF, so that's not an issue, and so on.

Have fun reading the info that applies to your project (read lightly, just let it flow), and you'll see the picture of what the system looks like and how it works as it all begins to make sense conceptually. 8-)
By theonewithin
#53059
I will add.

As you read through the wiki, if you come across something you don't understand just keep going.

It's expected you would read the wiki a number of times so everything makes sense as the information can't be delivered in a way that can be understood straight away.
By theonewithin
#53167
Noruvi Garage wrote: Fri Sep 17, 2021 3:38 pm Thanks a lot for the info! I have read some on the wiki since I posted this and gave gotten most of my questions answered :D
Good work!

The wiki is definitely the first place to check when you have questions.

If something is missing there or unclear then hit up the forum.

Hopefully someone will update the wiki as things are found wanting.

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