whizzybang

Hi all,
I am building my 13bpp miata. Those who are interested can see the build thread over at mx5nutz.com "French Rotary Miata".

I bought a Microsquirt V2 a while ago for a bike. Made the four banger start easily but had to abort mission.

My question is can i use the following setup, at least for run in time :

Microsquirt v2
Zero Split
2 bike coils with two spark plug per coil


Fuel setup will be 4 itb's with 4 injectors, firing in 2 batches, staged.

Basically my whole bike setup.

It seems that if i use the latest firmware (MS2/extra 3.3.3) i can have the "rotary" mode and everything along for our dorito engines.

I still wonder if i can use the microsquirt with the CAS since it only has one VR conditioner built in.

I might add that i would like to avoid heavy mods inside the MS case.

Thanks for those who will schime in.

muythaibxr

I would not recommend running the coils the way you plan on running.

You can run both leading plugs with 1 coil, but not both trailing. They need to be run COP style.

If you're planning on running leading and trailing (which is what I think you're saying) with 1 coil on each rotor, I would not recommend doing that either. Wasted spark coils are meant to have the spark on one plug actually be "wasted."

If you're firing both plugs into an unburnt mixture, then you're not running the coils the way they were meant to be used, which can cause weaker spark on each plug, coil failure, etc... Those coils were meant to have one of the plugs "firing" in exhaust, which actually conducts electricity surprisingly well, and effectively shorts the spark plug on that side of the coil, meaning most of the spark energy goes into the other plug.

If you're running a rotary engine in rotary mode, please just do it right... run one of the following:

FC ignition: 1 leading wasted spark coil and 2 trailing coils fired in FC mode (IGT-L, IGT-T, and coil select for trailing
FD ignition: 1 leading wasted spark coil and 2 trailing coils filed in COP mode
COP ignition (RX8 style): one coil per plug

whizzybang

Thank you muythaibxr.

Since Microsquirt only has 2 spark outputs, i will HAVE to run one coil per rotor ie 2 spark plugs per coil. I never thought about the sparkplug shorted in wasted spark mode, that makes perfect sense.

Inside my MS, there are two BIP373 current drivers. Do you think i can wire 2 COP per driver in logic mode (such as IGN-1A coils) and then run zero split ? I still don't understand how both leading can be run with one coil (thus firing at the same time ?) since when rotor 1 is at TDC and needs firing, rotor 2 is still 60° away from TDC and doesn't need firing.

muythaibxr

You could probably do what you describe with COP coils. I've never tried running any of the rotary modes on a microsquirt. I'll have to check the code to see what it does. Worst case you'd run as a wasted-spark 2.6L 4 cyl and just wire a pair of coils to each output.

At the time when leading would fire on one rotor's TDC, the other rotor still has the "exhausting" rotor face over the leading spark plug. The intake face isn't over the leading plug yet by that point.

Trailing is different because it's further up in the housing.

Ken

whizzybang

I appreciate your help.

What about the CAS ? Would the microsquirt deal with it ?

John Huijben

iTrader: (1)

I thought the microsquirt has 2 VR inputs? Mine does, and according to the pinout here the V2 also does:

MicroSquirt® Wiring

VR1+ = pin32, VR2+ = pin4 ?

If you have 2 VR inputs, you can use the normal CAS without modifying. If you only have one VR input you can still use the normal CAS, but you have to remove 2 teeth on the larger 24 tooth wheel, so it's like a missing tooth wheel, and then set it up as a 12-1 wheel in megasquirt.

muythaibxr

It depends on which uSquirt. If you have the most recent one with the MAX9926 chip (ampseal comes out of the top of the case) you should have 2 VR inputs.

whizzybang

You are right john, i had not taken the time to check since you read everywhere about the zeals board. The second vr input is here.

Thank you guys, now i know i got the right hardware to go forward. Now i got to fab that engine, then i.ll check how to set the ms up.

Cheers

whizzybang

Hi all, gave more thought to the subject. I only need 2 tach events per crank revolution. That means 4 events per CAS revolution. All the events are the same since i use two coils with double outputs, one coil per rotor (or wasted cop). Thus i dont need the second CAS wheel ( 2 teeth wheel). The less sensor the less problems, specially with tach input, very noise dependant. So i only need a wheel with missing teeth. I red around that i can use the 24-2 wheel but since the cas speed is half the crank speed, i dont see how because that would mean 6 teeth equal to half a crank revolution. The resolution would only be 30deg wich is far away from enough Then i thought about fitting a 36-1 wheel to the crank pulley, that would give a 10deg resolution, much better. Thoughts guys ?

elturbonitroso

yes you can use a 36-1 on a microsquirt with the extra code

whizzybang

Youve done it elturbonitroso ? With 0 split ?

elturbonitroso

just run the engine like a 4 cyl. waste c.o.p.

chango de naranjito

Hi, i done that but with 4 coils (ls2 car coils not truck) you have 4 ignition ouputs in the microsquirt v2, w led and aled, you need a 5v pull up with a 1k resistor and you have it. also, you can mod the cas to a 24-2 you just grind off 2 teeth. do not use the second trigger of the cas is a pain in the @#$ for the v2 just grind 2 teeth of the 24 wheel and adjusts the gap of the sensor so the sensor is the nearest possible without touching the wheel that is the way worked for me.with the microsquirt v3 you can use the stock cas as is.

whizzybang

Thank you chango, this is very good info !!
I will use 4x IGN-1A coils so same setup as you.
I am assembling the engine and i still don't know if i will use the CAS with your mod, or a real trigger wheel like the FFE kit. I don't want to blow my engine because of a non precise ignition timing.

When you use ALED and WLED outputs, can you set the split ?

elturbonitroso

If it was me I would Get the ffe kit with the hall sensor and 4 ign-1a coils

whizzybang

I red in the megamanual that the microsquirt v2 cannot handle the hall sensor. Only VR. Did you do this exact setup ?

chango de naranjito

Yes you have to use a vr,if you will buy that kit buy the 36-1 and yes you can set the split because that way is COP

whizzybang

HELLO EVERYONE !!!!!

Just to tell you that it works !!!
Setup is wasted spark, 4 AEM IGN-1A running in pairs (so 0 split), 36-1 custom trigger wheel and one id2000cc per rotor. Pump gas. 3% premix. LC1 o2.



How i put the trigger wheel : put a mark at TDC on front pulley (based on marks at 5 and 20 ATDC).
Put the front pulley at TDC. Put my trigger wheel with the VR sensor in the middle of a tooth. Counted 10 so 230deg delay.
Set -5 for cranking advance so that equals to 5 ATDC.

FIRED RIGHT UP so thank you people who helped me iron out the questions.

SOoooooo happy !!! No i am waiting for the timing light to come for further mapping.

I do have a question though : i am reading between 12 and 13 AFR at 1700rpm idle and 6% tps. With that much overlap, isn't this reading completely false ?? How could i know if i am being rich or lean ?

Aaron Cake

iTrader: (1)

Yes, the sensor is somewhat inaccurate at low RPMs due to the overlap. Same with a bridgeport. Generally speaking if you lean the idle out until the engine starts to surge, then richen it up again until it stabilises, that's about where you want to be. Note the AFRs showed and make that your idle AFR of reference.