Megasquirt Question. Help!

So I just need a little help getting started. I'm jumping in the deep end with both feet on this one. I'm planning on Megasquirting my Rabbit and my '71 CB750 (and my '81 Scirocco 16vt opnce I figure this crap out). I'm getting help from a friend who is WAY better at dealing with electrical problems than I am, so I'm know we can build one, but which one? I noticed that there's many different varieties to choose from now, and don't know what would be best for my application. First the Rabbit. It's running an n/a 2.0l DOHC 16v, and I'm planning on running GSX-R ITBs. Which megasquirt will be best suited for this application? My CB750 will also be using the GSXR ITBs, and the friend who's helping me wants to put GSXR ITBs and a turbo on his Katana. Which set up is best for these applications?

DIYAutoTune.com (GRM advertiser) for all your needs. Great people to deal with.

My opinion (and I've MS'ed 3 vehicles: 4AGE 20v, 22R, Harley 883):

Rabbit and Scirocco: 3.0 MS1 with MAP Daddy dual MAP sensor, running Squirt-n-Spark code. Bikes: Going to be challenging. I suggest a Microsquirt. Make sure your electrical system can handle an extra 7+ amp drain before you start.

The biggest question is what you're doing for ignition. Lots of VWs use a distributor with Hall effect sensor - is that what's on yours, or are you going with something crank triggered?

Yes, the Rabbit is using the distributor with hall sensor. I figured for now I'd just run the stock ignition and let the megasquirt do the just the fueling. My CB750 is running Dyna electric ignition and I'm fine with leaving that alone. I'm not sure what we're going to do about the Katana, since it will be boosted. so we're probably going to need some sort of ignition control.

Dr. Hess wrote: DIYAutoTune.com (GRM advertiser) for all your needs. Great people to deal with. My opinion (and I've MS'ed 3 vehicles: 4AGE 20v, 22R, Harley 883): Rabbit and Scirocco: 3.0 MS1 with MAP Daddy dual MAP sensor, running Squirt-n-Spark code. Bikes: Going to be challenging. I suggest a Microsquirt. Make sure your electrical system can handle an extra 7+ amp drain before you start.

I was looking into the Microsquirt for the bikes, but didn't see anything on the DIYAutoTune website. I found all the manuals for it, but not how much they are and where to buy it.

Dr. Hess wrote: Rabbit and Scirocco: 3.0 MS1 with MAP Daddy dual MAP sensor, running Squirt-n-Spark code.

This one? http://www.diyautotune.com/catalog/megasquirti-programmable-efi-system-pcb30-unassembled-kit-p-46.html

Yeah, that's the one. The MAP Daddy is sold separately. Get their wiring harness with the labeled wires too. This is the microsquirt: http://www.diyautotune.com/catalog/microsquirt-c-35.html?osCsid=ba079d2958d96f2d27ca2aeff40f8532

for basic stuff an cost savings i use teh ms1 v2.2, the v3 boards are just a bit more fancy an really dont offer anything that you need more than the basic setup. unless you're getting into a crazy setup, i usually will just use/recomend the v2.2.

however, if you are building your board, ive heard from several people the v3's are a bit easier to build an mod later on as well

I think the MS1 will do what you want pretty well on the car, but I also think you're future-proofing yourself a bit better if you go with the MS2. The MS2 not only has a bit better computing power, but also has more inputs/outputs in native form. The MS2 is especially handy if you'll be doing any stuff with GM style IAC motors, which use a stepper motor instead of a PWM setup. If the extra dough for the MS2 add-on isn't in the budget now, you probably won't miss much for now if you go with the MS1. For the bike, the microsquirt is a no-brainer IF you go with injection, IMO.

I give another tip of the hat to DIYAutoTune.

Bryce

MS1 for the Rabbit, I don't use MS2 on anything yet. There just isn't any need when you're already at 'good enough.'

You can use the 2.2 but if you want to mod down the road for added features the little proto on a 3.0 gives you some room before you need to move onto a little breadboard in the case.

If you need any help Corey you know where to find me. Scott is getting good with this stuff as well if you need some help.

As for board version, injectors high or low impedance? Counting on running spark control sooner or later?

v3 is definately not easier to build! There are some very tightly packaged transistors and the components are generally alot closer together. I'm very glad I didn't try to assemble it first.

v2.2 has worked excellent for me running high imp injectors and EDIS ignition. If you are running low impedance injectors or doing anything fancy with the ignition (like COPs) then look further into the v3.

The MS1extra seems to be a very well rounded and complete firmware. Very few remaining bugs and a large user base. I haven't been keeping track of where the MS2 and MS2extra firmware is at the moment.

I've been running v2.2 and MS1extra for over 3 years, no regrets. I've had a v3 and MS2 sitting on the shelf assembled and ready to plug in if I get bored someday. Actually traded it off and then bartered it back at one point, but it's never fired an engine.

For the bikes, Microsquirt! No questions there. All the other arrangements are very susceptible to moisture and knocking around.

Another little note. If you are going to be driving coils, try to run them with an HEI or bosch module. Using VB921's on the MS board seem to be recommended now but they are definately not as robust as the external modules, not as easy to find locally should something fry, and they are better at insulating the rest of the MS components from overcurrent failure.

just my .02 ymmv

Sweet. I'm super busy this month, but the plan is to kick ass in September and have the Rabbit running on ITBs by October. You and Scott will probably be tired of hearing from me by then.

Every car I know of that was built with bike ITB's has since replaced them with a single throttle body. I did it with my VW 16V with GSXR ITB's, My friend did it with his BMW M10. Even with the best tuning they still are a pain in the ass.

I really reccomend starting with the factory manifold and an automatic passat throttle body (it has the TPS) to get it running and tuned. Once you learn how to do it then jump into the nightmare and heartache that is tuning the ITB's. MS uses manifold pressure to control everything and the signal from the ITB's is very weak and non-linear. It really makes it a bitch to get running right.

FWIW on a dyno the 2 liter M10 motor in My friends BMW 2002 made exactly the same peak HP with 40mm GSXR ITB's as it did with one single 325i TB on a E21 intake manifold. The torque curve of the single TB was much better though, Torque came on much earlier. It was also much easier to deal with in traffic.

Tuning ITB's is certainly a Biatch. I'm seriously considering changing my 20v (ITB's) to Alpha-N. The problem is that when a cold front comes through, the MAP reading will change enough to mess up your ultra fine-tuned MAP readings on the speed-density table. A dual MAP helps a lot, but there are still issues.

The VB921s are pretty much gone now - they're discontinued, and we've replaced them with a much tougher transistor that is also what Bosch uses in many of their ignition systems. VB921s were pretty easy to fry, but I haven't had to replace one of the Bosch ones yet. (And I'm the one who handles pretty much all the warranty repairs at DIYAutoTune.)

Corey I have worked on five MS cars. If you need some help let me know.

Hell yeah! I guess I need to start going to the local SCCA meetings again.

"MadScientistMatt" is right on the money, as usual, and he can help you select the right unit!

A little on MicroSquirt... We made a slight circuit change on the hardware (to add additional protection to the bootloader input, which allows field-upgrade of firmware) and to add the new output drivers/logic level output that Matt discussed. Also added is the direct interface for frequency or voltage-based MAF sensors for hybrid modes. All is ready with this, but we are waiting on the contract manufacturer to run the boards. Looks like late next week I will have the new board run in my hands, then we can turn back on the flow of MicroSquirts.

And - just FYI, MicroSquirt has been running all sorts of small engines from 1 to 4 cylinders (and higher), from lawnmower engines in SAE competitions to race motors at 16KRPM. It works with even or odd-fire setups, with the latter seeing a lot of action as of late. I personally have it running my SBC where we are testing a new model-based algorithm to fueling.

• Bruce

how awesome is it that you can get an answer from the Bowling of Bowling and Grippo? MegaSquirt rocks!

AngryCorvair wrote: how awesome is it that you can get an answer from the Bowling of Bowling and Grippo? MegaSquirt rocks!

Actually, I think you guys rock! Megasquirt would not be where it is without people like you who are not afraid to understand and take control of their engines!!

• Bruce

ITB's aren't hard to tune just way different then smaller single throttles. The biggest hurdle is the kind of engines you put them on, usually FAR from stock which are goofy even on a single tb.

Once you get the hang of them and when to use which fueling mode and what type of accel enrichments, they grow on you. My best advice is: if you have anything but stock cams jump right to alpha-n, and if you have a 'race motor' on the street or off use rpm based accel.

Agreed, Megasquirt rocks.

bbowling wrote:

AngryCorvair wrote: how awesome is it that you can get an answer from the Bowling of Bowling and Grippo? MegaSquirt rocks!

Actually, I think you guys rock! Megasquirt would not be where it is without people like you who are not afraid to understand and take control of their engines!! - Bruce

Christ, there should be a rule about engineer on engineer action in this place...

You both rock. [/asskiss session}