Help choose: MS-IIE or DIYPNP for racecar?

Questionable idea of the week! I want to Megasquirt my track-only Nissan... but with a twist. I want to use the same ECU hardware for both my current SR20DET and the new NA KA24DE I am in the midst of building. Off season/between events I want to swap drivetrains for different series (think ChumpCar vs. open class hillclimb)

Both stock harnesses use identical ECU connectors, and only a single pin changes termination between them. Both use same/similar high impedence injectors, and both use the same 360 slot cam sensor (and the 24-1-1 that DIY sells fits either dizzy/CAS) SR is coil-on-plug with external ignitor, KA is external coil dizzy.

Thing I definitely want: full sequential fuel injection and MAF elimination, boost control, external MAP sensor.

Things I really like: onboard logging, auto-tuning (love the latest TunerPro, great stuff), and have developed an appreciation for launch control/FFS after using it on my Cobb tuned STi.

So that's what I know I want... now, what do I actually need to make it come true? I already have full engine harnesses for both engine sets, which is why I like the DIYPNP, but maybe a second harness set for the MS-II is still a better deal since 75% of the plugs/sensors won't be used on a racecar anyway.

Thoughts from the collective?

In my experience building a MSII it may be difficult to swap it between engines easily and regularly. The differences in ignition setups you mention between the two engines in particular will require the board to be set up differently (if I recall correctly). You will also have to re-flash the tune each time you swap. MSII will also not allow you to data-log on board (although this isn’t really a big deal, you can easily use a Bluetooth adaptor, phone or tablet and shadow logger or shadow dash to log.

I'm not as familiar with DIYPNP, so hopefully others with more experience (MadScientistMatt) will chime in.

Nissan has several tuning options such as Nisstune or Nismotronic that let you tune the car "realtime" is there a reason one of those off the shelf systems won't work for your needs. I have used the Nismotronic chipped ECU twice and was happy with the results.

I imagine you could create two tunes, one for each engine setup, and just upload from your computer the one that applies.

Is your car an OBD1 setup or is it OBD2?

Nistune

Nismotronic

Price, mainly. Nismotronic is definitely sweet but it would be nearly a grand by the time I bought NismotronicSA and two chipped ECUs

Both OBD1 engines.

Why not buy one ECU and upload different tunes depending on the motor. I am pretty sure you can save the BIN file after you get the car set up. Have one BIN for the DET and another for the KA. Call John at J-K tuning he is very knowledgeable and helpful. Run your scenario by him and I bet he can get you going with one ECU.

Basically all Nissan OBD1 ECU's are the same. I am running a chipped Nismotronic 1994 Altima ECU in my B13 SE-R.

I'm a fan of a simplified wiring harness as you know, so I'd go for the DIY route.. Simplify the wiring harness and talk to Jesse about snagging some of the mil-spec connectors from Centroid, and make the engines have simple and reliable plug to swap..

Ooh, I like that idea. Bulkhead connector motor swaps!.

Ended up buying the DIYPnP ( with 10% off! ), looks like the MS2 didn't have some of the core stuff I wanted. Time will tell if I made the right call! The kit I bought.

A DIYPNP is either a MS2 or a MicroSquirt

You don't need sequential (does not make any more power)

MAF elimination is standard on any MS.

Any MAP can be configured. The internal one works great.

If you want on-board logging you need MS3

Auto tune is a Tuner Studio thing (new release v2.5)

Doing launch control & boost control with a PNP is harder (if possible) than with a MS2.

Changing a tune is as simple as a few clicks.

If a bulkhead connector to facilitate motor swaps is a hot item on the wish list, a PNP box seems anti that. You'd have the MSPNP box in the factory location using factory wiring to the engine bay and beyond to sensors and such; you would have to cut up the factory harness and terminate it at the firewall to use a bulkhead connector. You might as well do the whole thing with a normal MS box, I think.

I'm also curious about this "Centroid" vendor that was mentioned, but the beauty of mil-spec connectors is the chance of using multiple vendors to source connector hardware from possibly more than one manufacturer. Newark.com is a huge purveyor of mil-spec connectors.

I think the DIYPNP will work out well for you; you'll also want to add our trigger disc to use the SR20DET CAS for coil on plug. Our MSPNPs for the SR20DET and S13 KA24DE are based on the same adapter board board; there's only a couple pins that differ between these two ECUs, and we change between the two with jumper wires.

Thanks Matt... I added the additional injector drivers and a pair of trigger wheels when I placed the order