Hi guys -

been signed up and reading her for a week or so. THis is an *excellent* forum for megasquirt support on the rotaries... I've read Ken's work quite a lot on MSEFI.com, you guys are in good hands!

that being said, I don't want to ask questions that are already explained, I just want someone to check our work!

We're working on a 1987 RX-7 turbo. MS-I v3.0 is installed, it's running 024s9 Extra firmware (I plan on updating this tonight) configured per the FAQ in this forum...

Car has 550cc primary injectors, low impedance. (I forget the size right now of the larger secondaries - but these don't matter for starting, right?)

We modified the CAS by cutting 2 opposing teeth, roughly 90* from the two tooth sensor at the top of the CAS. I stabbed the CAS such that, with the crank pulley at TDC marks, the 3rd tooth AFTER the missing tooth is centered on the VR sensor. Triggers in the wheel decoder config are set to 11/1, 5/7.

Trigger angle set to 60* and fixed angle locked at 0 degrees.


We ran late last night getting the fuel pump relay powered properly, so we didn't have much time for tweaking the settings - we spun the starter and checked for valid RPM input, it was there!! (important MS milestone)

Then we attached the plug wires on the leaders, GOOD HOT SPARK!!

All temp sensors registered properly...


so we attached the injector clips, crossed our fingers, hit the starter, it sputtered and backfired. It was midnight and I had to be at work at 08:00 this morning, so we called it a night and considered it "almost ready"

I figured I'd updateyou guys on our progress, ask for any suggestions at our current phase in the project, and hopefully tonight go home, reflash to newer firmware, and go driving/tuning!

Any and all input is welcome. Again, thanks to you guys for a good HOWTO and excellent online discussions,

-scott

 

with the CAS stabbed the way you have it stabbed, you should use a 60 deg trigger angle, and wheel decoder settings of 1,3 7,9

The 11,1 5,7 settings are for people stabbing the CAS as you would stock. If you're using those settings the way I think you stabbed the CAS, your ignition is 60 degrees too advanced.

If you're planning on using trailing ignition, I'd recommend upgrading to my 026i_mod firmware. 024s9's rotary trailing won't work right due to some bugs that I fixed in the 025 series. Also, 026i_mod has my gradual staging transition code, which people have used with success. Since you already said you're going to upgrade, you should be all set with this firmware version.

something in the 029 series should work fine too since you cut 2 teeth out of the CAS (there is potential trouble with the second trigger decoder in the 029 series, but since you're using the missing tooth decoder, it's most likely fine). The 029 series also has the code I added for a second parameter for staging (MAP only).

EDIT: Keep in mind that I haven't tried the 029 series successfully yet. Tofuball and I are having slight problems with it... while it should work with your setup, I just wanted to reiterate that I've not successfully tried it yet.

Aside from those things, it seems like you're well on your way! Let us know how it goes.

Ken

 

I think you want to set your triggers to 1/3, 7/9. I'm running a modified CAS just like you guys and those are the settings that Ken told me to use. Other than that everything sounds good. I'd stress that you go over your wiring with a fine toothed comb, 4 times is what it took me. ;-)
-John

Edit: well crap, I just type too slow! :-P

 

Ha - awesome. After reflashing tonight, I'll reset the triggers properly in the wheel decoder and we'll give it another try.

Thanks for the help guys, I appreciate it!

-scott

 

well, we reflashed to te new firmware, verifyied all the configs, entered the new correct wheel settings - and hit the starter.

Fired right up, settled down into a smooth idle. Sounds kinda like a healthy 4-banger - doesn't skip a beat.

now I have some ignition timing queswtions, however. Tyler assures me that the two marks on the flywheel are 5 and 20 degrees AFTER top dead center?!?!?

What exactly should I be claibrating timing to? if the first mark is indeed 5 AFTER, then I need to set my fixed angle to "-5" and adjust the CAS or trigger angle until the timing light shows us on that 5-after mark, right? will the motor run OK at 5 after??

I'll be doing some searching here in a bit, but if anyone can point me in the right direction, I appreciat it.

thanks again, this was easier than I expected.

-scott

 

that is correct, those timing marks are at 5ATDC and 20 ATDC. Just set fixed angle to 5 atdc, and turn the CAS until the marks line up, and set fixed angle back to -10, and you're all set.

The motor runs great at 5atdc, Actually the whole reason I added the idle-advance feature is because the motor likes to idle between 5 atdc and 3 btdc (depending on the AFR you're idling at), but usually you have the places near idle in the map around 12-20 degrees...

tofuball's S5 NA idles extremely smooth at -5, as do my S4 NA and my friend's S4 NA.

 

Just thought i would ask something here. This is my car that we are working on.

Aparently my TPS sucks. Were using the stock s4 tps, and it is very hard to use. Any idears?

 

What problem specifically are you having with it?

 

Looks like the TPS sensor allows for maybe 3/4" movement - when the throttle travels more than double that?

So we get full TPS at what amounts to maybe 1/4 of the throttle travel. It's almost like an on/off switch, but it IS a variable TPS, goes from 0-100% very quickly. So the annoyance is that Flood Clear kicks in if you move the throttle even slightly. I increased it to 250adc counts. Mechanically, I'm not sure if the TPS sensor is touching what it should be...

anyhow, it's a minor problem - the motor starts up so easily and steady with no pedal. These rotaries aren't that hard to tune - took a few tries to get the timing just right, but now it's purring like a kitten!

We even cold-started with the CLT showing 40 degrees. Fires right up!!

Tyler, fix those brakes so we can go out for a drive,

-scott

 

yeah, that's the narrow range TPS... it works fine for accel enrichment as you don't really need any above the point where it disengages.. at least in my experience.

Most likely the TPS set up fine... I agree about the flood clear thing though, on my S4 I have the flood clear point set to 254.

Tofuball's car and one of the cars I test the plug 'n play units on both start right up as well, although tofuball's car doesn't have the thermowax, and right now his BAC valve is disabled, so we have no fast idle on his car.

 

After playing around with the VE mpas yesterday, puttering up and down the driveway with no brakes (LOL) I have to say, the MS runs these motors very well...

usually I spend the most time on the "puttering around" portion of a VE map, WOT is pretty easy once you have a basemap that lets you get it on/off a trailer, or out of a parking spot, without any hiccups... (low RPM, varying vacuum, etc.). Anyways, I'm officially ready to take it out with a wideband....



For anyone whose considering MSing your 13B, it works great just like advertised here. Good support here too, I had to read for a few hours to understand the quirks/differences of a Rotary engine - but as far as Megasquirting goes (I've done around 40 installs, built around 80 units) it's a very clearcut setup and works well as advertised.


MAKE SURE you get the wiring correct. V3 MS wants an INVERTED VR signal to be properly in time with the CAS - otherwise you'll get lumpy timing (shows up as a repeating pattern on the RPM data in your logs).

Also, MAKE SURE if you're not grounding to battery, that your grounds are all in check - this is the single most comon problem I find on all the cars I work on - you MUST have as close to zero ohms between block and chassis, and between, chassis and battery. We've had no tach spikes, the tach signal scopes very clean, and ground is a true zero volts...


We'll post up after we get some street tuning, and get a chance to open up the staged injectors.

thanks,
-scott

 

Let me know how my staged injection transition code works out for you when you get to tuning that. So far all the feedback I've gotten on that feature says it works great, but never hurts to have another datapoint.

Also, just out of curiosity... are you using the 026i_mod firmware or one of the official releases?

 

Ken, we're using your 026i_mod version!!

We have to fix the brakes (bleeder screw broke off in the caliper), and install a wideband - but we'll post feedback for you, for sure, on the staged injectors setup.


Speaking of which - since Tyler runs slightly smaller-than-usual secondary injectors, do you have a recommended staging config for his smaller ones? Or is there a post here somewhere that deals with tuning the staged injectors? I've done dual table, but since this is my first rotary - this is my first time using the staging code.

thanks again for your help,
-scott

 

All the help you need should be in the first staged injection screen when you press "F1"

the main thing you need to change due to having larger injectors is the scaling factor.

To calculate the scaling factor, do the following:

(Primary flow / (Primary Flow + Secondary Flow)) * 512

So for that car:

(550/(550 + 689) * 512 = roughly 229

So for that car, a scaling factor of 229 should do the trick...

I'd also suggest that if you use RPMs for the staging point, you stage at around 4200-4300 rpms, and set a transition length of 25 ignition events.

Once I've checked out 029g on the bench, you should move to that, as it has a second parameter for staging as well.... based on MAP... so you can select "above this rpm AND above this kPa, stage," or you can select "above this rpm OR above this kPa stage"

 

Cool, thanks for the guidance on staging; we would like the ability to stage based on MAP.

If you have any testing you'd like us to do, let me know. -scott

 

If you want, you can stage ONLY on kPa instead of using rpm... that's up to you really... then you can just stage at like 100kPa or something. I'm just saying, if you want to stage on RPM AND kPa, that feature is in 029d+