ramius665

I'm interested to hear any good news stories (and bad ones too, I guess) about converting over to using Micro/Mega Squirt.

I purchased a DIYPNP Microsquirt from DIYautotune.com and am in the process of getting everything jumpered correctly for my turbocharged S2 motor. I opted for the sequential injection add-on board and will be using individual COP ignition. Already sourced VAG 1.8T COPs for my application.

Having a bit of hindsight now, I'd definitely recommend the DIYPNP option for someone interested in a replacement drop-in DME solution for a S/S2 that will retain batch fire injection and the distributor-based ignition. Now that I've started to add the jumpers inside the DIYPNP box, it's become apparent a regular MS2/MS3 box would make the ECU side simpler and I still have to fabricate portions of the DME harness.

For anyone using a DIYPNP box, did you successfully retain use of things like your AC? How about adding a variable TPS from the 951 or similar?

I've done a ton of searching and while there are some brief stories out there, I couldn't really find a central thread(s) besides what Dougs951S put together.

azbanks

I don't have answers but I could have written that post. I am in the exact same situation.

odonnell

Paging Doug....

MS has a ton of potential for these cars, because the engines are simple. The harnesses are aging, the DMEs are dying, and you're still stuck with the AFM and whatever performance chips you find on ebay unless you get ahold of a MAF kit. I know I'm definitely going Microsquirt with COP as soon as room in the budget appears.

ramius665

Why microsquirt?

The more I've read on the associated topics of tuning, fuel injection, ignition options and the various mega/microsquirt boxes I'm not entirely sure there's a cut and dried solution for "944s" in general. If I were trying to 'Squirt a 951, I would probably use a 16V flywheel with the 60-2 tooth spacing for ease of tuning. By the same token, if you don't intend to use sequential injection, it's not even necessary to send a cam position signal to the 'Squirt box.

I think the vast majority of information out in the interwebz on 'Squirting your 80s euro car is either incomplete or erroneous. At the same time, BMW guys seem to be having quite a bit of luck with their e30s. It would be really great to find someone here on RL that's pretty savvy with the wiring/input/output portion because that's where the largest gap in information is.

odonnell

I just like Microsquirt because it's a small little thing I can just mount where the DME used to be and it comes with a terminated 8ft harness. It's not super fancy but it accomplishes everything in a tiny and durable package.

For ignition timing, there are trigger wheels made for the 944 that just bolt to the crank pulley, no BS with flywheel teeth. And no more rear mounted reference sensors! There's a nice hall effect sensor that's plug and play with Microsquirt. I mean...theoretically you could even use the stock Bosch speed/ref sensors, they're just VR after all.

After that, all you need is a MAP/IAT from a Chebby and a TPS (such as one from a 951, or a GM TPS mounted on an adapter).

The stock temp sender can be used, just calibrate it using resistance values from Clark's Garage.

You would need wideband o2, dunno if you already have that or not. Kits are as low as $150 from AEM and mount to the stock bung.

For an NA car you need high-z injectors for the Microsquirt batch fire on a 4 cyl. I don't think Microsquirt can handle sequential injection on a 4cyl but Dougs951S is a better source for info like that.

V2Rocket

I'd take an LS1 ECU and reprogram it to run the 944 motor with COP etc before trying to build my own system.
Even the most basic LS1 ECU is 16+ years newer than the 944's DME design, which is a few thousand years in computer terms.

Dougs951S

All of the above is correct, with a few corrections. Microsquirt is just a surface mount version of MS2 and is fully capable of absolutely everything a full MS2 box is capable of, but it fits in the palm of your hand and its waterproof (no more shorted ECU's from rotted battery trays!). Therefore, it is completely capable of sequential spark and sequential COP on a 4 cylinder with a cam synch, as well as batch fire and wasted spark COP on a V8. It will also drive a 4 cylinder tach from a V8 signal. One last thing, while Michael is right about the injectors but I need to add one additional note. Both the NA and the 951 will require new high Z injectors since the microsquirt uses saturated injectors drivers. They will not safely operate any factory 944/951 injector. This is true regardless if you use semi batch fire or sequential. And just to make clear, microsquirt does not require a cam synch to run in semi batch fire mode, it will run better than any DME tune with just a simple sensor on the front of the crank pulley toothed wheel.

Here is an in depth discussion, though the maps and numbers posted are long out of date, the setup information is all true. If requested, I can post all new information on my current tune. I'm interested in sharing more about what I know about this stuff, but I dont know exactly what people are interested in knowing. Read through my guide and if you have questions, please post them. I'm interested in any feedback as to what I can add or if something needs to be clarified or expanded upon.

https://rennlist.com/forums/924-931-...our-944-a.html


You might enjoy reading this too

https://rennlist.com/forums/924-931-...to-my-car.html

ramius665

Doug, I think a comment you made in your second thread summed up my feeling perfectly, "The learning curve is.... mountainous." To my knowledge, you're the only person who has a running, driving 'Squirted car. I'd bet money you're more gifted with electronics and wiring than I am too. Making heads or tails of the wiring requirements for the MS box and how it translates to the DME harness has easily been my biggest headache. Assembling the DIYPNP boards is surprisingly easy and was a pretty enjoyable few hours. Unfortunately, DIYautotune's "tech support" was less than helpful when I reached out to them, so I'm still puzzling my way through some questions.

I was really hoping someone with an S/S2 would pop up and tell us their success story but none so far...

Ultimately, I think MS is an amazingly cost effective solution for some incredible capability. I'm really looking forward to getting my S2 motor up and running. Just wish there were more people out there to help share the load!

ramius665

To bring this back around to one of my burning questions, does anyone know of a car successfully running on the DIYPNP MS box?

grenadiers

I run MSII in my 924 Turbo, semi-successfully! The MSII has the MAP built into the unit. I use a VR sensor on a 36-1 wheel attached to crank behind the pulley. The VR sensor is part of the EDIS ignition system I also use. I use 2003 SRT-4 injectors, with bungs from somewhere, escapes me. I use an LC-1 wide band incorporated into the MSII.

AND, relying on tech support is not going to work, that's not their job. Your job is to fully understand the Mega-Manual, and work with how to adapt their system to your car. Take each subsytem separately works best. Route wires so that there is no interference between engine and body.

The 'semi-successful' part of this, are the ignition and fuel maps, basically, the tuning. Using 'auto-tune' to get a base map, and then tweaking it, will consume more time than the actual install. In my turbo car I made a mistake in not figuring out a rev-limiter. Blew the engine on the track. But, will have another this summer.

Dare

I think I'm behind you by perhaps 4 to 6 months. I plan on megasquirting my 951 as soon as I get it running again on the stock DME. I've just finished a ground up rebuild of my engine harness, which now includes runs for crank position and MAP sensors, and a Zeitronix WB02. My current thinking is to use a B55 DIYPNP, which should simply the rewiring process by allowing me to swap most of the pins over from the stock 35pin connector.

Rebuilding the existing harness taught me a lot about how the factory setup works (including some hidden features that aren't on the factory wiring diagrams). The diagrams look daunting, but once you dig in it's pretty straightforward. It helps to break down the individual circuits and look at them separately.

Please post your progress and questions. I imagine Doug will help out, and maybe there's a question or two I can answer.

Dougs951S

I am not the ONLY person with a squirted car, but I am the only person I know of to have done it successfully and not have any issues with the car. I am more than willing to help guys, I have a pretty insane depth of knowledge concerning this subject so fire away with the more detailed questions.

Building the system and hearing the engine start for the first time is literally only about 1/10 of the battle. Tuning the car takes way, way, WAY more time, energy, and knowledge. Its a good exercise, if you can get your car to where mine is at yourself, you'll never have a problem diagnosing any fuel injection problem on any car ever again. It all seems so simple in hindsight. Its an amazing, super in depth look into how modern digital fuel injection works on a level way more detailed than most people will ever get the chance to experience.

ramius665

So I did a screen grab of the DIYPNP jumper connections for the Bosch 55 pin box. My application has the sequential injection add-on board and will have four individual logic level coils. I'm still not sure what pin to connect the TPS signal from the DIYPNP to on the S2 harness. I'll be using a 951 throttle body and the 951 TPS instead of the S2 one so I know I'll have to rewire that portion of the DME harness. I've attached a copy of the FSM S/S2 DME pin-out for reference to what the jumpers from the DIYPNP go to. Feedback on what's here is greatly appreciated!

Hornung418

Hi, Aaron! Good luck on your project.

azbanks

I am working on a very similar setup, 55 pin DIYPNP play kit.
I will be creating a custom wiring harness and running the wires to the factory 55 pin connector since that will plug right into my MS kit.
I will be running full sequential injection and sequential COP ignition.
I would like to control boost and monitor knock with MS.

I want to make sure I am building my board properly to support the features I plan to use.
I re-read the DIYPNP documentation every couple weeks and it makes more sense every time.