i will admit i have never touched a megasquirt before but have heard plenty about it's flexibility in configurations.

setup would likely have to be a trigger wheel since it will be phased 90* and fire 4 times per single e-shaft rotation(once every 90 degrees of rotation). injection will only be 4 larger injectors, coils might wind up being leading only if the megasquirt can't handle 4 pairs of leading/trailing coils with 6 outputs total.

trying to work out the final details of setting this thing up on paper before i get to work on it.

 

When I was checking the readily available ms2e's I found that they only have 4 ignition channels. That means no leading / trailing on a 4-rotor, it can have 8 ignition outputs, so you can hook 8 coils up no problem, but you'll be running zero split, so it will work for an n/a setup, just not for a turbocharged one.

I believe "muythaibxr" knows more about the matter.

When looking at ecu's it's often easier to check if it can run a V8 engine using wasted spark, any ecu that will run a regular v8 is able to run a 4-rotor, just not always using split timing.

It might be possible to use the original CAS, if not the cas can probably be modified, but with all the fabrication involved with a 4-rotor a triggerwheel isn't really a lot of extra effort and it can make things easier because almost all ecu's can run using a 32-1 triggerwheel.

 

im pretty sure ms3 can do a 4 rotor but you would be the 1st one i think using the ms on a 4 rotor but ken its the expert on this stuff.

 

This is supported in ms3+ms3x.

Yeah, we added a special "rotary" mode (set by setting "stroke" to rotary in the same screen where you set req fuel). That mode supports up to 4 rotors. For 3 and 4 rotors it assumes coil on plug.

So you'd have 8 spark outputs (4 leading, 4 trailing) and 4 or 8 injector outputs (depending on if you're running staged injection or not. I'd recommend running it, it makes low-load tuning a lot easier).

This is only available in the 1.1 beta code, 1.0.x does not have this support. We are planning to make the 1.1 beta code the official stable code next month.

Ken

 

thanks for the update, that's great news!

 

yeah good news... do u even have a 4 rotor?

 

if I was dropping that kind of cash on a 4 rotor and trimmings not sure I would go anywhere else except MoTeC

 

figured the trolls would show up.

for turbo applications i might agree, i wouldn't consider a megasquirt but being n/a i'm not too concerned about burnt out drivers or potential trigger issues. for cost in building it, it's mainly labor.

 

Even with a turbo I would go with MS... The trigger issues/burnt out drivers only really happen when things aren't wired properly.

 

Are you talking to me there?

I don't have one, but I know how it should work and I have an 8 channel scope.

Ken

 

i figure he was asking me, as if i was one of the newbs in the past who thought you could simply stack a motor together with as many rotors as you wanted. or figuring that i didn't have $40k to build one(which, well i don't onhand). but i do have tools, machinery and shops to outsource some of the specialty work to that i can't do.

this is more of a cheap experimental engine to see the capabilities and to work out bugs on first, might even be a cheaper alternative to some of the expensive 3 piece 4 rotor shaft builds. the experiment consists of 2 stock 13B shafts coupled together, phased 90 degrees, balanced and customizing the center iron and stat gear. of course will also have to be peripheral ported and will run 9.4:1 compression(more is not always better). the basic point is, why not let mazda do the majority of the work in making the shaft.. they are cheap after all. if it works and holds 600 naturally aspirated HP reliably, pretty sure it would be the cheapest way to build a 4 rotor engine for the more common people with mortgages still.

if it doesn't work i will be out maybe a few thousand and some old spare parts, but still have fun doing it. i've built over 200 rotary engines, figured post count might point towards some sort of a clue in that regard to those who asked the question.

i like to lay everything out beforehand to know what to expect and what variables will still be in play.

 

Fair enough. In any case, we should be able to run a 4-rotor just fine in the 1.1 beta code. I think if you did it you'd be the first one to try though.

We can support leading and trailing along with staged injection on up to 4 rotors.

 

Cool, i'd be really interested to see how this turns out. I've seen a few people try this before-with varying degrees of success, keep us updated.

 

I have been thinking for some time of doing the same thing, the biggest problem I see from doing it this way as a 2 piece shaft is that the centre plate would have to have a stat gear on each side, I have decided Im going to join two centre plates together to make it easier to acheive this, It would make it a bit more combersome, but probably make it easyer to fix the stat gears to the centreplate, And the shaft I was going to basicly cut the taper off the end of one shaft where the flywheel bolts on and then grind the centre out to match the oposite end of the shaft and then machine a key way to line it up 90 degrees out of phase from the other shaft, then to hold them together make up a large bolt which will run through the front shaft and thread into the rear shaft to clamp them both togther, The only aditional challanges I see is running oil lines to the stat gear bearings in the centre plates which in the scheme of things won't be a biggy, and Im not sure how the front section of the rear shaft will cope with the torque, but I guess you got to try to find out!
The spinoff from using two centre plates joined together is you could potentially run it as a side port by filling the centre ports with devcon then opening them out to match the port of an end plate.

That was my idea of a cheap 4 rotor, be interesting to hear what other people have thought up?

 

or just modify a double sided stat gear and pin it to the center iron. granted it gives less center support but it is still allowable to use a 1.5 size center stat gear. you can run oil lines to the center iron or have the oil feed the front and rear of the motor and have the center as the drain point, running from the back and front of the shaft to the center area.

 

With more and more machine shops sitting idle in this economy, the cost of a 4 rotor is going down rapidly.