1. I'm building my MS2 V3 and I'm stuck on step #65 do I need to do any of this step.

2. If I'm not using a BAC do I need to do step #62.

3. As for the boost control mod where is the best place to mount that.

All of this will be running a TII engine w/no emissions

Thanks
-Josh

 

This should help with the BAC questions:
http://www.aaroncake.net/rx-7/megasq...AndModding.asp

As for the boost control, I generally mount the MOSFET on one of the ends of the case either to the left of the DB37 or to the left of the DB9.

 

Thanks Aaron

I did read your write up (awesome work, it helped a ton)

Just to clarify if I leave out step 62 & 65 it will work just the same, no need to jumper any of the open spots?

The only thing I found was the wording for step 59, I'm taking it means do not install.

Do not install the jumper mentioned in step 22 and ignore that step entirely.
As step 50 suggests, install both the hall/coil/optical trigger circuit and the VR trigger circuit in step 51. Follow step 50-b when building the hall/coil/optical circuit so that you can use the Stimulator. We will ultimately only use the VR circuit when the 'Squirt is in the car.
In step 52, follow the instructions in the blue box to the right to configure the 'Squirt to accept an RPM signal from a coil/points/optical. This is so the Stimulator will still work.
In step 54, use the stock values for R4 and R7 because we are using the GM IAT and CLT sensors.
In step 59, to not install D8.
In step 62, follow the instructions in the blue box titled "PWM Idle Valve Users Only" to install the PWM idle valve mod. This step instructs you to install a TIP120 (or equivalent) in place of Q4.
Skip the installation of Q20 in step 74.
In step 75, install a jumper instead of R39
While you don't need to, you might as well install the high current ignition driver in step 65. In 65-d, don't bother installing any jumpers. Ignore the note about adding a pullup resistor.
In step 69, install the PWM flyback circuit. Then follow the instructions in step 70 to install the standard flyback circuit. Install the clamping circuit in step 71.
At this point your Megasquirt is assembled and should run using the Stimulator. You can now move on to modifying it for the RX-7.

 

Honestly, I would really suggest using the BAC valve.

But if aren't going to mod for it, then you will want to install D8 in step 59, follow the non-blue box instructions in step 62, install Q20 in step 774 and install R39 in step 75.

 

Agreed. Using the BAC valve (especially in closed-loop idle-speed control mode) will make the car a lot more drivable, and will make it act a lot like a modern car does from the factory.

Ken

 

Here is a little background on the engine and car. The car is a "79, the engine is from my deceased 87 TII.

I was last running the TII stock port stripped of all emissions, no BAC, electric fan, FMIC, S5 turbo and mani, Rtech 1.7, 720's in the secondaries, 3" DP, and other goodies.

The car would start up and idle at 600 rpm no problem, lights on, fan on, heater fan on, all lights on. No matter the temp. This is why I would like to go without the BAC.

The new for the "79 are Turbonetics 62-1, HKS mani, 850 primaries, 1600 secondaries, Still stock port, I have a Innovate lm-1 and the auxbox. I got a EGT probe, the boost controller mod. And probably a few other things i've missed.

The car will be for fun weekend outings, maybe some track time fingers crossed.

So will the Megasquirt run the engine without the BAC the same as the stock ecu? if so I'll continue without it

Thanks, Aaron and Ken for your help!

I'm having a BLAST building this! I hope this is more user friendly/intuitive than the Microtech I have been helping a friend with.

 

Did all of the second part. Tested with the stim and all is good now on to the rotary mods. Whoo Hoo

 

Yes, you should be able to make the engine idle at 600 RPM with high loads without the BAC. But it will need to be tuned richer then if you had the BAC. The BAC is also a great asset for cold starts as it can regulate the idle on a cold engine, give you that initial burst of air while cranking and create a high cold idle (if you wish).

 

Thanks for the input. I might rethink the BAC.