I was interested in getting one of these board but from i can see there is nothing that the rotary can benifit from it. Seq fired injector are not possible and coil on plug is kinda already there. Not sure what else the ms3 can do thought.

 

How is seq injection not possible?

I've written code to do it with the ms3x board and staged injection and will be testing that on my rx7 as soon as I receive the header I'm missing on my ms3 daughtercard.

The MS3 being faster has helped make my engine run a bit smoother. My hope is that the sequential fuel makes low revs a bit more responsive to sudden throttle movements.

SD card datalogging can help you get a much better tune as well since it logs a lot faster.

You'll also want to check out this page:

http://www.ms3efi.com/product.html


In addition, spark is a bit more accurate since we're using the XGATE coprocessor to do all spark and fuel outputs. That's a 50MHz main processor and 100MHz coprocessor just for toggling outputs where before we were using the main 24MHz CPU to toggle the spark outputs along with all the other code that runs on that processor.

Ken

 

Hmmm. Hope I'm not premature. My MS3 rx7 is running full sequential with Jean's quad injector driver. Idle is smoother than it was with MS2. Acceleration to 8000 RPM in the driveway seems good, but not enough room to do much tuning. Tomorrow is a track day to do extended tuning. Race weekend at the end of the month.

Love the SD card logging. That was my primary motivation to go MS3. Bye bye Palm Pilot for on-track logging.

 

How simple or hard would it be to install and set up ms3? I currently have ms1 with an unmodded cas on a 1988 rx7 and low impedence injectors. Sounds like ms3 is very promising.

Thank you,
Jose Nieves

 

@Darren - I haven't run MS3 yet, but all the rotaries I've done on MS1/e/hr and MS2 have been great. If you're looking at building a track car setup where transient fuel control / amenities aren't a priority, a well tuned MS1/2 is more than enough imo. Also I would highly recommend EDIS-4 for signal conditioning / spark. I've run it in both boosted and n/a setups with great success.

Ive found that low rpm performance with the stock manifolds/ports is pretty poor across all series engines, regardless of engine management. Changing over to a home built 5/8" ID 43" runner primary manifold with 130cc injectors on my 12a with MS2 provided rock steady idle down to around 450rpm. None of the characteristic rotary brup,brup,brup at all. High vacuum / high velocity seems to be the best way to get really good idle out of a rotary. My $0.02.

@Ken - do you know if the MS3 would be technically capable of full control of a 92-95 FD3S solenoid rack/accessories? I'm stuck between a rock and a hard place with the stock management on my FD project and I'm very reluctant to drop $700+ on a PFC when equivalent funding on a MS could spank the processing pants off of a PFC, but I want to retain stock sequentials, turbo precontrol/etc/etc...

 

Thanks for the info but I am very familiar with ms. I have been using it for the 5 years I just finally upgrading to ms2. I was just wondering if I should skip right to ms3 while I have everything apart. I do long for low end performance my old setup was a halfbridge with gt42 turbo. I didn't do to bad with it even with a poor engine. 400whp @ 15psi.

My new setup is 13brew with he351vgt turbo on it. Engine has a very light port job, no exhaust porting. Looking for more low end and quick spool. My target is to get the same 400whp but with a broader power band.

 

If you're switching from MS1, you'll have to do a little rewiring and maybe a mod to your 2nd trigger conditioner circuit, and then redo all your settings and import your fuel and spark tables, but it's not THAT difficult.

From MS2 you would be able to just swap the MS2 out and swap the MS3 in, load the old msq, verify your settings, and away you go.

MS1 is more difficult because it's so much different from MS2 and MS3.

Ken

 

IMO, my MS3 runs my engine much better than my MS2. The MS2 was fine, but the MS3 runs much smoother and more responsively, and that's without having switched to sequential yet. I expect it to get better once I do switch.

I recommend against EDIS in almost all installations as it's completely unnecessary given that the hardware already on the engine works fine.

I know it can control the engine itself (spark, fuel, etc...), but I don't know for sure about the rest. If you can point me at an FSM I'll take a look and see what is involved.

Ken

 

Is there a write up for that mod. I'm excited to go to ms3 but just need the help to switch.

 

@ken - I've got a hard copy of the FSM and also a pdf of a "best of FSM" for the FD, which contains most necessary information on pages 38-43. Please PM me if you'd like me to email you a copy.

In summary, there are 5 outputs necessary to control the sequentials. Two of these outputs are PWM, and the remaining 3 are discrete I/O.

The two PWM channels feedback based on 3 sensors - CAS, TPS, and MAP. The information they poll are boost pressure and "basic output duty signal", which I feel can be emulated through something like fuel load %. TPS, according to the FSM, looks like it is only used as an input to determine WOT condition. PWM duty varies from 5% to 95% on these two valves. Nowhere in the FSM does it give specific numbers to give ideas to staging points, however this could be determined experimentally through data logs fairly easily. It is not clear if these two PWM channels are mirrors of each other or independent.

Additionally, there are a slew of other discrete I/O things to control on this engine, including
- dual throttle solenoid (prevents cold start engine raping)
- fuel pump opening relay (dual fuel pumps)
- pressure regulator control system (increases fuel pressure for hot starts)
- AWS (accelerated warmup system)
- purge control (fuel tank emissions purge)
- air pump relay (emissions)

So obviously I wouldn't be able to do all that with the 6 spare outputs on the MS3, but it seems like the sequentials control is within reach- what do you think?


@ken/jsnow - The reason why I advocate EDIS is due to its ease of setup, packaging, and ruggedness. I went through a significant amount of trouble with the stock 12-2 CAS on an old build, eventually having to forge a new path and use filtering capacitors to get a stable signal. EDIS just works and I've lab tested stable PIP from over 2 inches away and with very poor VR sensor alignment. Is it necessary if you really know what you're doing? No. Is it more expensive? Yes. But I have found it to be very reliable and easy to use and therefore I recommend it based on that.

 

My question is do I hook up ms3 the same way ms2 should be hooked up as far as inside the box and wiring? I have mine setup to run a stock cas with a vr conditioner. It also runs low impedence injectors. I'm going to buy the ms3 version 3.57 from DIY. Will that be plug and play considering my harness is already setup?

Thank you,
Jose Nieves

 

I still recommend strongly against EDIS. It's unnecessary and prevents proper operation of trailing ignition with programmable split in addition to not allowing for things like negative split.

We have all the nits worked out with the conditioning of the stock signals, so I always recommend using those (not 12-2 btw... 12+1).

I think as far as I/O goes, We should be able to control the sequential turbos if you know what you're doing with the spare outputs. We have generic mappable PWM and on/off I/O support and we have enough spare outputs to do it with.

Ken

 

If you're not going to run sequential fuel, yes, it'll run with the same harness and mods as ms2 with ms2/extra. I ran my rx7 like that for a long time with ms3 before adding the ms3x to switch over to sequential fuel.

Ken

 

So with all the new output that ms3 has. 3rotor setup should be easier to do. I know you can without trailing.

 

Yeah, I have not yet, but for the 2.0 firmware I plan on adding a "rotary mode" to the MS, so you can set it up by how many rotors you have instead of trying to convert to settings for piston engines, and I intend to support full leading/trailing ignition on up to 4 rotors.

I could probably add 3-rotor support in the meantime for 1.1.

Ken

 

Your're the best Muy. Glad to have a someone who likes us rotary nuts.

 

That's awesome!!!