Megasquirt Virgin, question thread.

Both of my race cars are running MS3's

You want the MS3 so you can datalog to an an SD card.
Also with the MS3 you can also get the MS3X card with gives you more inputs and outputs, so you can go sequential and do individual cylinder trims, traction control, boost control, flat shift, two step rev limit, ect.
If you are buying injectors new, I would try to get high impedance injectors, so it would be easier to go sequential if you want, other wise you can run low impedance with resistors.
Get the Diyautotune trigger wheel for the distibutor, that's what I run, makes it easy to setup.
You will fire the coil directly from the MS, no igniter needed, you also won't need the MAF anymore.
You are on the right track of rewiring the engine, the easiest was is to add a GM style coolant temp sensor, air temp sensor, and run new injector wires.
A wideband O2 sensor is a must, hook it to the MS so it will get logged, no gauge is needed.

thanks for the info! I do have a wideband, are you running a Distributor still?
I was looking into the GM coilpacks instead of a distrib.


im looking more toward the MS2 because of price point. but I may splurge on the MS3x.

I am still running the distributor.
I wouldn't bother with coil packs unless I could eliminate the distributor entirely, which would mean a trigger wheel on the crank.
If that's what your thinking then I would only go with the MS3 and the MS3X so you could run full sequential with COP ignition.

so to run a dizzy still I have to change out the optical disc on the dizzy shaft?

COP would be nice but not needed. just thought It may be easier haha!

i would love to do MS3 but i don't think its in the budget this round. MS2 should suffice for my power goals and i have a line on a good used unit .

now for base maps.. anyone have a file for 440cc, hx35 and no cams?

Yes it's easiest to change the disc in the distributor to a pattern that works better with the MS.
The MS come with a base map that works for most engines.
You input the engine size, and injector size and required fuel is calculated for you.
You will have to set your load scale for the amount of boost you are going to run.
You look at the O2 data from the logs and tune from there.

The main thing your have to remember is than it's not plug and play, you can't just connect a few wires and run.
You will have to make sure each setting in the software is correct, and create the tune.

cool! very good info!

thanks for the help I think I understand this all more now!

While we are discussing MS, would it be possible to say, run the dizzy as the CAS but use individual coils for sequential?

I thought about that, using the dizzy as a "dud" and running the trigger wheel setup off there.

but that may be v.2 for me!

You could do that. That's exactly what the DIYAutotune trigger disc in the distributor lets you do.
That would allow a stronger spark, but wouldn't eliminate the slop in the distributor gears.

touché! I forgot to account for that issue

So then that wouldn't be feasible for sequential. OK. I'm about to do mega squirt so I'm trying to preplan before I buy everything

Sequential really isn't a big deal. It helps with idle and part throttle emissions. At full throttle, and high rpms, the injectors stay open long enough they always will be spraying against a a closed valve some.

The main thing you need to plan for is how much boost you are going to run, the normal MAP sensor that comes with a MS is a 2.5 Bar sensor, that's good for about 22 psi of boost.
You can get up to a 4 bar sensor, good for up to 44 psi of boost. If you have low impedance injectors, I suggest you run resistors, that's what I use.
Get the GM temp sensors, you will have to enlarge the hole in the intake to a 3/8 npt for the coolant temp sensor. For the ACT you need a 3/8 npt in the air path after the turbo and intercooler.

Yeah I'm already planning on the MAP Daddy upgrade as well as the knock sensor module. I haven't decided on new injectors yet. Are we able to eliminate the CHTS? I was figuring to put the IAT sensor in the IC pipe after the IC. Can it handle two IAT sensors? I'd like to have before the IC and after if possible.

im curious about this too, I don't see any issues ditching it but a forsure yes would be nice

now should I run 440cc or 600cc for the 400whp im looking for?