will Microsquirt do what I need???

[krom]

I've been searching, but cant seem to find any details about using launch control in a microsquirt.

I am looking to go efi on a snowmobile we drag race. its a 2 cylinder 2 stroke with 180 degree firing.

its currently using an msd ignition and gigantic carbs.

my research shows that I will be able to use 2 gm coils from an ls1 or truck engine, 2 injectors, and some gm sensors to get this working, but I haven't been able to find if the stock timing pickup will be usable, or how the controler will respond to not having an iac, (there won't be a map sensor either, just barometric pressure)

the microsquirt website shows launch control as available, but there is no mention of how to implement it, (looking for a function like the msd's 2 step)

Is there any way to datalog a run, if so can additional sensors be used (looking to log driveshaft speed and engine rpm at least)

would a different version of hardware be better suited?

Thanks

[Matt Cramer]

I've been searching, but cant seem to find any details about using launch control in a microsquirt.

I am looking to go efi on a snowmobile we drag race. its a 2 cylinder 2 stroke with 180 degree firing.

its currently using an msd ignition and gigantic carbs.

my research shows that I will be able to use 2 gm coils from an ls1 or truck engine, 2 injectors, and some gm sensors to get this working, but I haven't been able to find if the stock timing pickup will be usable,

Do you have any information on the pickup - tooth pattern, sensor type, etc? Worst case is you may need to swap to something like a 36-1 crank trigger.

or how the controler will respond to not having an iac,

Just turn the IAC off. You could then use the IAC channel as a spare output.

(there won't be a map sensor either, just barometric pressure)

In that case, you can use alpha-N fueling or a MAF.

the microsquirt website shows launch control as available, but there is no mention of how to implement it, (looking for a function like the msd's 2 step)

Yes, that's pretty much how it works. You just wire an input like FLEX or one of the spare ADCs to a switch to ground and set it up in TunerStudio.

Is there any way to datalog a run, if so can additional sensors be used (looking to log driveshaft speed and engine rpm at least)

It can data log with a laptop or smartphone. RPM will be logged automatically; it has to have RPM to run the engine. Driveshaft speed isn't easily picked up with a MicroSquirt.

would a different version of hardware be better suited?

Thanks

An MS3 could log to an internal SD card and is easier to configure for driveshaft speed. Your call as to whether the extra features are worth the extra price tag, though.

[24c]

I am looking to go efi on a snowmobile we drag race. its a 2 cylinder 2 stroke with 180 degree firing.

This guy is raving about his Microsquirt v3 conversion on his two stroke twin Banshee, goes by the name of Whitbread on this forum.

[krom]

Do you have any information on the pickup - tooth pattern, sensor type, etc? Worst case is you may need to swap to something like a 36-1 crank trigger.

I've attached a pic of the flywheel and timing pickup. its a 190 ohm coil. that reads a single tooth on the outside of the flywheel

It can data log with a laptop or smartphone. RPM will be logged automatically; it has to have RPM to run the engine. Driveshaft speed isn't easily picked up with a MicroSquirt.

is there any way to use one of the other sensor inputs (used for cam sensor) as a drive shaft speed input?

are there any issues using 2 ls1 coils, and 2 injectors (looks like either hi-z or low-z would work) and running sequential (I assume this would require a trigger wheel with far more teeth)

[dontz125]

Yeah, that's a long tooth ... I can sell you a little adaptor to install inline between the VR sensor and the 'Squirt, but you'd still only have a single pulse per rev.

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Could you possibly double check that you only have a single tooth on that wheel? If you have a 180* twin 2T, that thing should be firing wasted spark = twice per rev, which should in turn mean 2 teeth.

The fellow in 24c's link pressed a 36-1 wheel onto his flywheel. If you have the headroom inside your cover, that might be the best bet.

[Matt Cramer]

Currently, the only way to bring a speed input into an MS2 would be to create some sort of 0-5V analog signal. The firmware does not support using the cam input for vehicle speed at present.

[dontz125]

Take a look at an LM2907 frequency to voltage converter. As the name suggests, you can set it up to return a voltage when triggered by pulses.

[krom]

UPDATE..

I posted the wrong picture of the flywheel, it uses 2 timing pickups, and several teeth.

[24c]

krom,

2 pickups at 90º don't make a 180º twin, but there are a couple of teeth at 180º, so you could use one sensor, and remove the surplus teeth.

If I wasn't going to turn down the stator & press a toothed wheel in place, I think I'd use the tooth at 5-6 o'clock, the one 180º opposite, and the bottom sensor to give a two teeth one sensor arrangement.
If you have a spare stator, then you could experiment with this set up.

Mike

EDIT missed a bit!

[krom]

Just incase I wasn't clear in the first post. the engine is an inline twin with a 180* firing order. Looks like I'm going to add a trigger wheel, as it will take the least amount of experimentation

[24c]

krom,

That's the best option, better resolution, very flexible and reliable set up with a VR.

Mike

[krom]

I sent an email to diyautotune this morning, but haven't heard back yet, since you guys seem so much more helpfull I'll ask all the questions here

The engine is a 2 cylinder 2 stroke, 180* crankshaft, with 2 spark plugs and one injector per cylinder. that we plan on running at 9,800 rpm. both spark plugs in each cylinder fire at the same.
We will be running ID1000 injectors.

Will any of these ignition solutions work at this rpm?

diyautotune ign4 coil pack with 2 of Bosch BIP373 Coil Driver Mod Kit (or QuadSpark Four Channel Ignition Module)

VW 032 905 106 - 4 tower wasted spark logic coil

4 GM LS1 coils

Or is there a better way I haven't found yet?

I was planning on using a 36-1 wheel mounted to the stock flywheel. What pick up would work best? Will the magnets and stator under the flywheel cause interference issues?

[dontz125]

Unless I'm going blind, you could probably mod that rotor to a 4-1 wheel. Are there 3 leading edges at 90* to each other? Might be easier that fussing around moving the pickup coil, since any 36-1 wheel is almost certainly going to stick out further than the current teeth.

Any of the ignition systems you listed would work. My only concern with any CDI+carbs to TCI+EFI project is electrical power - inductive coils are a LOT hungrier than CDI systems, and of course you have to feed the pump and injectors. What sort of output does your stock alternator have? If this was an AC CDI with charging coils in the stator, you might be able to use those cheap CDI modules for Chinese monkey bikes and trigger them from the 'Squirt.

[krom]

I'm not worried about electrical power on this project.

This is a drag race only engine. we will be running total loss off of a battery until I can figure out how to use the stock stator power without using the stock ecu.
It started life as 155hp at 8100 rpm, we are aiming for 220 at 9700 rpm

It was factory built with EFI.
The stator has 2 ignition charge coils, 2 fuel pump power coils, 2 injector power coils, and lighting coils.
The stock ecu has cdi circuitry to take 30 vac supplied from the stator and ramp it up to 200vac for the coils.
It also has a regulator rectifier to take the 20vac from the fuel pump coils and deliver 12vdc to the pump, and another one to power the injectors.
The stock ecu is locked, and no one that I know of has hacked it yet, neither the stock throttle bodies or injectors flow enough for our goals.

Current practice for a build like this is to use an msd ignition system, and gigantic aftermarket carbs.

I can mount a 36-1 wheel to the end of the flywheel (sandwiched between it and the recoil cup) or remove the flywheel and stator completely and have a replacement made that is just a trigger wheel and hub.

[dontz125]

*scratching head* Bit of a Rube Goldberg ...

Ok, well you've got dedicated power to the pump and injectors. The lighting coils can probably drive the coils and the 'Squirt - I'm assuming you have on the order of 100W at 12vdc from that section. If the lighting coil is AC, you should be able to drop in a normal bike regulator. If the lighting coil is weak, you still have the option of using eBay monkey CDIs to drive your ignition.

As to the trigger wheel, if you have the room a Hall Gear Tooth Sensor is probably your best bet. The various flailing magnets etc in the rotor shouldn't be an issue - they don't seem to interfere with the stock VR sensors, after all.

[24c]

dontz125, you could make it a 4-1 set up, but one of the teeth is slightly longer, but I understand about triggering off the edge, so it would work too.

krom, I would still go with a tweaked stator, reduce the diameter slightly, and use a laser cut wheel pushed onto it. It doesn't matter what sensor you use, as long as you have enough trigger voltage at cranking, otherwise it won't start.
I would suggest before you mod stuff, you get some info on the existing set up at cranking speeds...
What voltage does it generate at cranking at the sensors?
What does the wave form look like on an oscilloscope?

Just out of curiosity, 155 hp is a 500cc twin, & 220 hp is a 500cc four cylinder two stroke in my book, so is yours a 800cc N/A twin...thinking Rotax 800!

[dontz125]

dontz125, you could make it a 4-1 set up, but one of the teeth is slightly longer, but I understand about triggering off the edge, so it would work too.

Those are each of them almost certainly 'long' teeth, so you'd be looking at edge triggering in any case.

[krom]

from the service manual:
all tests to be done using fluke 77, and peak voltage adapter, at cranking speed (which means while pulling the recoil)

MAG Primary Coil (Harness Side)* 172-233V
PTO Primary Coil (Harness Side)* 172-233V
Charge Coil (1) 30.2-36.9V
Charge Coil (2) 32.0-39.1V
Lighting Coil 5.4-5.8V
Ignition Timing Sensor (1) 4.3V
Ignition Timing Sensor (2) 4.4V
Injection Coil 15.3-18.7V
Fuel Pump Coil 19.2-23.5V

running test
Lighting Coil 14.8-22.2V (@ 2000 RPM)


This is a max effort race build, so there is no going back to stock, or worries about ever being able to use it for anything but drag racing


155 hp from a 500 twin is pretty impressive, how high do you have to turn to get those numbers?

FWIW its not a rotax, we're arctic cat guys

[24c]

Ignition Timing Sensor (1) 4.3V
Ignition Timing Sensor (2) 4.4V
....

155 hp from a 500 twin is pretty impressive, how high do you have to turn to get those numbers?

Looks like the stock VRs have enough voltage to trigger the MicroSquirt.
...
Around 11,000 rpm.

[piledriver]

Lack of a hole looks the same as a tooth to a Hall sensor...

Perhaps a small amount of "lightening" is in order.

You can read a missing tooth wheel made from a 32 pitch RC truck steel spur gear to >15K with a homemade 8mm Hall setup made from an allegro ATS667 sensor, as long as the "missing tooth" is actually filled in. If it's actually missing (grind out a tooth) it jacks up the AGC and it cannot see the wheel reliably at all at any RPM.

The teeth are ~1/8" apart and pointy. Drilled 1/8" holes would work far better, just skip one.
You don't need 36 teeth, 4-1 will run, 6-1 or 12-1 will probably provide all the resolution you need.