I've been researching for a while and I currently have an 86 mazda rx7 non turbo (Series 4) and I picked up a motor from a 91 rx7 non turbo (series 5) so there is a bit of a tech to overcome since they use different electronics so I want to overcome this by megasquirt. I saw this check list so maybe it can help narrow what I'm talking about down. I found what I need to do to modify the ECU to take the air temperature thermistor for a bias resistor change. When the manual says stock mazda sensors that work, which series is it referred to? let alone turbo or non turbo app.

1. What year/make/model/engine/tranny? (Pretend your at the parts store, ordering a starter.) If this isn't the original engine/electronics let me know that too.

1986 Mazda Rx7 non turbo transmission/starter
1991 Mazda RX7 non turbo 13b 2 rotor wankel engine

1. Are you looking to control fuel only, ignition only, or fuel and ignition? Is there anything beyond these features that you are looking to control - fans or boost, for example?

both, fuel and ignition. I could use a control for a dual electric fan (I may swap out for a single) and I will need a controller for my auxillary ports/VDI actuator. I can wire up a DC airpump that will create the air pressure to open the vacuum solenoids but I need something that can act as an RPM switch to activate the pump that will activate the aux ports.

1. What are the engine details (type, number of cylinders, previously fuel injected or carb'd?)

* Displacement: 2600 cc
* Injector Size: 460 cc/min
* # of Cylinders: 4
* # of injectors: 2
* Squirts per cycle: 2
* Injector Staging: Simultaneous
* Engine: 4-stroke

2. What type of ignition system does your car run- where is the crank angle sensor (CAS) or distributor trigger wheel, and what type is it (Optical/LED Sensor? Hall Sensor? VR Sensor?)

There is a crank angle sensor, I have both the S5 and S4 CAS. and I would utilize my stock coils but I could always downgrade to the 1st gen 13b ignition system which is a distributor system. not 100% if it will bolt up to my front cover or not.

3. How many teeth/windows/slots and what orientation does the CAS, crank trigger, and/or distributor wheel have? (any missing? all evenly spaced?)

I will have to count them, I want to assume they are evenly spaced. I have read through some rx7 forums that you need to modify it to work properly, again don;t know if they are talking about s4 or s5 and turbo or non turbo

4. Is there a distributor? Single/Multiple Coils? Coil on Plug?

multiple coils, if easier I may go to a dizzy setup

5. Does this engine have a fast idle valve (IAC)? If so, how many wires are connected to it?

there WAS a fast idle cam in conjunction with a coolant operated switch as part of stock throttle body but I have modified/simplified it and then ported and polished it.

so no.

6. Rate yourself 1-5 on technical confidence in yourself. 1 being "I can't paint by numbers" and 5 being "I can probably build a car from scratch if I have the right documentation, and I'm resourceful enough to do some research and find some of my own answers." I need to know this as some of the 'less traveled' roads will require you to make modifications that in some cases I haven't performed myself yet and based on this response it will help me to know whether this type of solution is for you or not. I challenge you to 'stretch yourself' a little bit. You won't ever learn anything (about yourself and your abilities) if you don't try to do things that you're not quite sure you can do... and then find that you can.

4 to 4.5, trained mechanic with an education involving engine airflow aka "horsepower engineering" and basic tuning and dynanometer usage.

7. Are you looking to build your own ECU from a kit or buy a pre-assembled ECU?

kit, my roommate is an electrical engineer and has built them in the past and said he would build me one for fun.

8. Are you open to retrofitting a different ignition system such as the Ford EDIS distributorless system or one of our crank trigger kits if it is determined that the MegaSquirt will not properly (or easily) control your factory ignition system? Many factory systems MegaSquirt can simply take control of, some it cannot. EDIS to the rescue! It's cheap, simple and works great!

no. but I am torn between modifying the CAS or adding in the 2nd VR circuit


okay last questions, when it refers to sensors it doesn't talk about the map sensor if I can use my stock map sensor. stock it runs a vane airflow sensor (YUK!) and a map sensor but I can just run the stock map sensor and toss out the vane airflow sensor, would I need to get a GM 1, 2.5, or 3 bar map? What vehicles came with them from the factory? What TPS should I use? s4? s5? or GM?

I wanted to go MSII with a V3 board and it isn't a daily car so the BAC has been removed.

 

There's a lot of questions here, most of which can be answered with the Megasquirt FAQ on this site.

Don't bother with the stock sensors. Use the GM ECT and IAT. No modifications of the 'Squirt are necessary to do this and the sensors are available at any auto parts store, as well as the pigtail that connects to them.

The 'Squirt provides several aux outputs you can use to control the e-fan and aux ports/VDI.


Either CAS will work unmodified. Don't downgrade to a dizzy (but yes, they fit fine in the 2nd gen front cover).

There are two wheels; a 24 tooth and a 2 tooth. You don't need to modify the CAS. The 'Squirt has one VR conditioner built in, and you will add another using an LM1815 as described in the FAQ.

I suggest you retain the BAC and mod the FIDLE circuit on the 'Squirt to use it. Having idle control is kind of nice.

Go with the 2nd VR. Experience has showed that it is more noise immune, and of course it's a lot easier to swap a CAS when it is unmodified. If your roommate is an electrical engineer, making the 2nd VR circuit is a trivial.

The 'Squirt has an integral MAP sensor. You will eliminate the AFM and run a vacuum line to the 'Squirt. I suggest going with a full range TPS.

Put the BAC back.

 

I had read around on their site and through the various FAQs, I just want to cover all my basses before I do some drastic change. I was reading around and was under the impression that only MS1 could operate the BAC.

 

Nope, MS2 can operate the BAC just as well. For MS1 and MS2 you have to have a transistor that can handle the current requirements though.

Ken