Thread: Anyone used Megasquirt before

Been looking at the megasquirt and microsquirt and trying to figure out this whole standalone thing. Do you have to use MS sensors or can your stock sensors be wired into it? Just looking for some useful info. I'm new to standalone.

I was told they are making a plug and play version of the megasquirt for the b13's??? Please do not hold me to that info but thats what I heard on the underground. If that does happen I will be purchasing one as I've seen what they do with spec miata's and they are great to work with!

DIYAutoTune.com Megasquirt Kits / Assembled Engine Management Systems, Wideband o2 Sensor Systems and tuning products

They have the plug and play version for the blue plug nissan ecu's which includes the B13.

Cheaper to buy the kit and assemble the megasquirt yourself. Almost bought one a few months back but ended up buying a honda AEM box for my B14.

I've been looking at the MS II runs about $400 already built. The only thing I'm really wondering about is the sensors. I can use my nissan sensors except for the cps? How are you running your ignition? Trigger wheel? DIS?

The SR is also a sequential fire motor correct? 1-4; 2-3 fire at the same times. How does that get set up?

nsusammyeb, I've worked with a couple MegaSquirt installations and am pretty familiar with the process. You can usually re-use your stock sensors like the coolant temp sensor, but that's basically the only sensor that people re-use. Most people don't re-use the MAF sensor. They ditch the MAF sensor and go with a MAP sensor and Intake Air Temp. sensor purchased separately.

I'm not sure about the current state of things for the cam angle sensor. You'll want to research the Mega Squirt forums for that info. It might be that you can use it stock without any issues, or it might be that you need to install a different cam angle sensor disc, or it might be that you can use the stock sensor but Mega Squirt can only get crank angle data out of it instead of crank and cam angle data like stock. I'm not sure how things are right now. I can help you find out I bet.

The SR motor is a sequential fire motor, yes. No, cylinders #1 and #4 don't fire at the same time. None of the cylinders fire at the same time. The injectors for the cylinders active in the firing order of 1-3-4-2 sequentially (one at a time) and inject on closed intake valves. Then the ignition events happen sequentially (one at a time) in the firing order 1-3-4-2. None of those events happen at the same time. The reason the injectors can fire sequentially is because the ECU gets cam angle sensor data and knows which valves are open and which are not. The ignition can be done sequentially because the distributor is connected to the cam and can route the ignition events to the proper cylinders.

(Alternatively if you go with a coil-on-plug ignition, the ECU knows where the cam is at any moment because of the cam angle sensor. If you only get crank angle data, then you have to fire the ignition together in "batches" which is referred to as "batch fire" because there's no telling where the cam is, or what cylinder needs the firing event.)

subd for info

Thanks Ben, the install seems pretty straight forward after reading all night last night and this morning. I'm still unsure about the CAS, I read somewhere that you can actually take the photo disc out of our dizzy and replace it with one from a miata I believe.

I stumbled across this for the b13 platform.

DIYPNP ECU MegaSquirt Nissan S13 240SX Sentra KA24DE - eBay (item 330519857461 end time Jan-25-11 14:08:49 PST)

It's actually the Microsquirt module though, which can be bought for less than that and preassembled.

I would like to run COP, and have read numerous times that suzuki coils can be used for this. I've considered DIS as well, as they are easy to come by at the local pullapart on the duratec motors. I'm not sure though how to make that work considering they are 6 cylinders.

HowStuffWorks "Distributorless Ignition"

Coil-On-Plug Ignition

Also curious about the relay blocks. Did the installs that you helped with get these through MS or use existing relays?

Just re-read everything you wrote again...So, batchfire is firing all the cylinders at the same time and only the one that is in proper timing is igniting? This could cause some issues on a rich motor couldn't it?? Backfiring etc.?

Batch fire on a 4 cylinder fires two spark plugs at the same time, and then the other two at the same time. The two plugs fire, and only one is at the compression stroke. The other one is on the exhaust stroke and 99.999% of the time there is no fuel and absolutely not enough oxygen in the cylinder to cause any type of ignition. Many cars work this way from the factory. It is safe.

I'll give you some COP help in my next post after I get back.

For COP there's basically two established options right now. The cheap route and the expensive route.

The cheap route involved getting the Suzuki GSX-R coils, four power transistors (ignitors) or a single RWD SR ignitor or Q45 ignitor which has four built in ignitors.
This option doesn't cost much at all and works well. The only trouble is that you will need to find spark plugs with a removable contact tip and these are expensive or hard to come by in different heat ranges and styles. Also the coils technically have nothing holding them in place except for a weak connection at the spark plug so they can possibly work themselves up and away from the spark plug requiring you to push them down to re-seat them on occasion.
Edit: Damn, I always forget you're likely going to want to also purchase a CDI box to go this route which makes things much more expensive.

The expensive route is to get S15, VET, or 20V coils and a VET or 20V valve cover. This way the coils have the built in ignitors and they mount solidly to the valve cover, and they accept any type of spark plug removing the need for the special plugs with the tips.

yes, just came across your COP thread. Very good info, I think I will use the cdi+cop combo. Looking at your aem wiring diagram I think there may be an error in it. You have the four inputs to the cdi but your outputs (black writing) say "1&2" and "3&4" If I'm not mistaken they should say 1&3 2&4?? Since that is what coils the wires run to?