New build for RX8
 

I know this is a RX7 forum and me having a RX8 engine but I think the questions are still relevant. (plus you are the true die-hards) If this is anything RX8 specific, let me know if I'm on the right track.

Hardware

• MS3 v3.0
• Expansion card
• Tiny IOx

Analog inputs
MS3 (6+2) - MAP, IAT, CLT, TPS, Battery, EG01 + *Baro, MAP2
Expansion board (3) - coolant pressure, fuel pressure and oil pressure
Tiny IOx (9) - IAT2, CLT2, Oil1, Oil2, Knock1, Knock2, EGT1, EGT2,

* From my readings, there is 2 spare ADC on the MS3? JS5 (ad7), JS5 (ad6)

Questions
1. RX8 settings should be the same. Why is the leading coils shared (SPARK A) in RX7 but not RX8? Reading the MS3 manual, RX8 have all individual Coil On Plug.

2. Has anyone tried to control the RX8 alternator with megasquirt? I can't find much info on the PWM of the alternator.

3. With the hot exhaust temps, what good EGT boards have people came up with? Is there a CAN for the TinyIOx or circuit to build?

Thanks guys.

From your post, it looks like you have 3 coolant temp inputs, 2 IAT inputs, 3 oil (temp and pressure?) inputs.

The "battery" input is internal to the Megasquirt. You don't need to use a port for it.

As for your questions, I can answer one of them anyway.

The RX-8 uses an individual coil per plug. The FC runs wastespark on the leading. So the FC only needs one leading trigger while the RX-8s individual coils require 2.

I edited the post a bit more. On the exp board, I meant coolant pressure, fuel pressure and oil pressure.

The 2x temp sensors, was to just monitor how the setup is running. ex - Coolant temp before and after the rad, ofcourse the engine only cares the coolant temp coming in, but I'd just like to know the temp coming out. Same with oil.

There is no point with these engines to monitor CHT since we are liquid cooled is there?

To get wideband, the only way is to buy Innovate LC-2 and hook it up to the TintIOx? To build the EGT, looks like it's $30 worth of parts using the AD595AQ amplifier chip.

The LC-2 just connects to the O2/wideband input of the MS3.

Not too much point monitoring "head" temp unless you really want a lot of data to log.

Finally I'm about to start this thing up tomorrow. Found a little tid-bit that may help other RX8 CAS sensor.

Looking at the schematic, you'd (at-least I did) assume the yellow/red is the VR+ signal and yellow/black is the VR- (ground) wire. (basing off the arrows)
But after putting the scope on it, to match the right rise vs fall, yellow/black wire is the VR+ cas signal.