TrickerZ

iTrader: (6)

So, for my new motor (built 1.6L) I'm planning to build a MS-II for the better resolution, closed loop idle/boost and to do sequential spark and injection.

I've found how to do the spark and injection here:

Sequential Injection Code for MS2
MS2-Extra Ignition Hardware Manual

I plan on doing it like jbperf does with a separate DB-9 connector for spark and injection.

A few things I looked for and couldn't find a good answer are:

What's the best way to do active baro correction? Is it even worth it? I thought adding it would be as simple as getting another MAP sensor and soldering it over the other one, then just keeping the output leg off and soldering it to another input with possibly some stuff in between, but it doesn't look like it.

My second question is with feeding a MAP signal to my DO progressive WI controller. I didn't realize I got the one without the MAP sensor, so can I just tap the signal from the MS? Any mods I need to do to keep the signal to the MS from dropping or is it not parasitic? Or can I just pass the MAP signal to another pin and have the DO read that?

I'm also looking for a good trigger wheel setup (preferably 60-2). DIY autotune says I need to hack my CAS to use only 1 trigger per rev, but do I need to keep both CMP and CKP signals? I would assume I just need CMP.

My plan is:
MS-II PCB3.0
EBC
Closed loop idle (does 1.6 IAC need upconverter board? I'll probably just get it anyway)
fan control
sequential COP
sequential injection
baro correction (maybe)
60-2 trigger wheel
DO progressive WI
table switch would be nice so I can have street and track at flip of switch

Matt Cramer

That's pretty much it. Bring the signal in to JS5 or JS4 with a duplicate of the filter on the MAP sensor.

Can it work with a 2.5 bar MAP sensor? If so, you can try splitting the signal. Worst case is you may need to use an op amp to make a voltage follower circuit that isolates the MS's signal from external noise.

The 60-2 would be your CKP (crankshaft position) signal, so you'd need a 1 tooth CMP signal to go with it.

AbeFM

iTrader: (3)

Good plan. I've yet to see a single miata with GOOD closed loop idle. It could be argued no one has set it up right yet, and that may be, but I haven't seen it. For the timing accuracy, it's worth it. I've heard good things about the boost control.

As I've been trapped in the mountains before, running dead lean, and unable to restart the car until I either dropped altitude or turned off the baro correction, I would say to skip it. :-)

That's basically what I did, it worked well, saves space. Very happy with how it came out.


Sure, Matt's a good guy to ask. I'd probably just get a second one to be safe, but if the input is appropriate, it would be interesting.

Why 60-2? I'm not a fan of just throwing more teeth at the problem. The increased accuracy between a 36-1 and a 60-2 is very minimal, and the overhead, even the added mass, in a 60-2 (while also minimal) is a cost you don't need.

Matt, curious your thoughts here. Why give up the miliseconds to process more interrupts....

TrickerZ

iTrader: (6)

Matt, thanks for the info. What is your feeling about baro correction? Worth it? Does it actually work? The DO kit is a 2.5BAR kit, so I'm pretty sure the input should work. I can always hook it up and find out. If it doesn't kick in at the right time or it screws with my MS signal, I can always take it out and spend the extra $ on a standalone MAP sensor. I just feel it's a waste if I don't have to.

That's what I hear. It's possible I'll never have a great idle, but if it can keep my car from stalling when A/C is on, I'll be happy. I just don't want my car running at 1500RPM idle to keep my A/C from killing my car at a stoplight. I've thought about adding some code to just increase the idle when an input is triggered if I have to.


Good to know, I think I'll be skipping that then. I thought baro was supposed to INCREASE fuel at higher elevations to offset the lack of backpressure in the exhaust?


I'll have to check some info. I believe the manual says it's a 0-5V signal which is what the MS receives, correct?

Also curious. I would think there would be at least a 1/2 degree accuracy increase and quick changes in RPM should be less likely to cause delay, but I haven't looked at the code, so I have no idea if that's true or not.

TrickerZ

iTrader: (6)

I figured I'd just add it since I should still be able to use the lower frequencies.

Yeah, I just threw that in because I could really.

Was planning on getting RX-7 550s, so it'd be high ohm. Should I go low ohm?

I'd change a few things. Mostly the timing map since I don't want to run WI on the street and I'd lean out cruise more than I'd want on a track. Boost targets as well. I plan to tune for economy and then do a full race tune and it'd be nice to flip a switch instead of having to bring out the laptop to change it. Plus it gives me the opportunity to switch if a friend wants to see what the little car can really do.

Matt Cramer

Real time baro correction is nice to have if the car's being driven from one altitude to another, though if you live in flatter areas and don't drive through mountains, it's less important.

Realistically, we haven't noticed much of any functional difference between 36-1 and 60-2 trigger wheels, and we've tuned cars with both.

AbeFM

iTrader: (3)

Again, I don't want to bash the MS-II... But two points, then I'll stop harping: Now, I don't have AC, but I used to - and I DO have a 1200 watt RMS amp and HIDs and I set my idle at ~1050. Yes, it's high, but, it idles like absolute butter, will pull me up any hill in any gear in any weather. I messed with the idle code at length, including writing my own PID code from scratch (which worked well, but, to keep up with the updates and other features I eventually abandoned it)...

Basically, there's a mode which effectively sets the idle screw based only on coolant temp. It works really well, the important thing is tuning the map so that when idle dips it makes a lot more power. I want to see how hard it would be to add in something to add a bit to the idle valve, based either on RPM or an input... But I haven't yet. :-)

Same thing I was thinking. I was pretty shocked it didn't. I've read, on the forums, long discussions about if they should add or remove fuel, and while there never was a consensus, they did something.

If it was written such that there was a table it applied you could edit, I'd say go for it, and tweak it till it works for you. What really happens is there's a table you can't see, burried in the code, and then another table you get that multiplies/adds it (don't recall). So, if you can come up with a table that will JUST undo the hidden one, you could have an effective zero, then make small changes to THAT table, keeping in mind what's really going on and... And, well... I just turned mine off. :-)

Yep. You may very well be able to share it - each ECU is going to strip some current off it, so each one will likely read a tinsy bit low. Do you care? Maybe not, like you said, you'll see. Personally, I'd wire up the Baro, lift the pin, and send it to the D.O. instead of the MS, which will allow you to give it to the MS if you want later. You could make a follower (i.e. put in a transistor to be sure you can supply the current to both), again, not sure it's worth it. When you're talking $20, just do it right.

Remember, the two computers might not have the same grounds, so the DO might not agree what the MAP is reading. Thankfully it's probably not as picky.

[/quote]
You're talking variations in the tooth edge to tooth edge, not the overall spacing. The teeth are every 10 degrees apart on a 36 tooth wheel, the accuracy of the teeth is well well within 1/2*. Actually think about this: If your teeth are off by 1*, and you have 60 of them, you see 1*/5* = 20% error. If you have 4 teeth like I have on the OEM wheel, you see 1*/90* ~ 1.1% error. So, the computer with a 60 tooth wheel is going to see the rpm jumping all over the place (4000 RPM, 3500 RPM, 4600 RPM) tooth by tooth, and then have to smooth it all out in software.

From a practical standpoint, at low (<2,000) rpm, I see some jitter. Above it, my accuracy is well within 1*. You really want the minimum number of teeth that will do the job, and when you're thinking "RPM", do you really mean "the RPM which the engine was at while the piston was 2/3 of the way down its exhaust stroke", or do you mean the general speed of the motor? If you had a high speed thermometer, and measured the "temperature" of some water, it would read 517*, -78*, etc etc as various molecules hit it, but what you care about is the RPM on the time scale of one engine rotation.

Best answer of all is Matt's - on the dyno, it doesn't show up. :-) If I had my way, I'd have a ~16-20 tooth wheel.

Things are complicated enough, why make it worse? :-) Really, it'll probably help - I've just yet to see someone throw it on a car and suddenly the RPM's stop hanging at 2,500 or stalling on a sudden input. That's not an "accuracy" or a "frequency" thing, it's the control routine doing the wrong thing. I wouldn't say not to get it, but if your choice is between buying that or "wasting" money on a MAP for the D.O., fix the water injection.

Save your I/O. use it for a clutch switch for launch control or your street/strip switch.

Larger injectors make idling harder, they spew more fuel in a short time. High ohms are harder to control, and there's more inaccuracy in the fuel, where a few percent matters.

I've been running Evo8 injectors. Cost me <$100, they are 550cc's, one year old (low miles), and my car purs like a kitten. I don't see the downside.

Makes sense. Yeah, you're probably right. To quote MS's site, loosely, tuning for best power and tuning for best economy are the same thing. Not strictly true, but very close to true. Certainly not running the WI, or at least the ability to have the car switch maps when you run out of water, is a good idea.

Really, use your right foot to control if you need WI - stay out of high boost. But putting a manual switch on the same line as the water-tank level (or whatever) would let you accomplish both, and yes, the dual maps would save your butt and possibly your wallet.

muythaibxr

I believe DIY autotune (Matt specifically) has actually set this up and gotten it working on a Miata.

If someone in my area has a Miata with the frequency multiplier board installed, I will PERSONALLY set it up for that person.

I'm in Maryland, if you're not too far from me I'll make the trip to you and set it up.

There is absolutely nothing wrong with this code, and everyone who has given it a good shot instead of giving up on it has gotten it working with several saying it works better than stock.

Ken

muythaibxr

Incorrect. If you set the frequency super high in the code, the code loses accuracy in control of the valve. For example with a setting of 8 for the frequency multiplier, the code has to change the duty setting for the valve by 3.2% before it actually moves the valve. You will not get good PID control using this method.

The control algorithm works for me, and for several other satisfied users. You refused to take my advice for setting it up, and never sent a datalog so I could actually see what was going wrong, so please stop spreading the inaccurate advice that it does not work. It works when set up properly.

Ken

AbeFM

iTrader: (3)

Sorry, Ken, I'm not trying to imply its utterly broken, I'm saying people have had issues setting it up. The issues I, specifically, have had don't seem to be accuracy related. Probably they are lockout related. :-) You're absolutely correct I haven't gotten it running. I'm hoping to steal Marc's settings once he's got his car dialed in.

Matt Cramer

Well, Jerry did a bit more of the tuning than I did. It doesn't have any issues with the idle hanging high or the like. The A/C feed forward feature we talked about would probably make things even better, but it doesn't stall when you turn on the air conditioning either. You'll find the settings in our '99-'00 base map. We'll be working on a PID idle tuning video too.

muythaibxr

Thanks Matt.

The offer still stands though, I will personally tune any miata in my area running this code.

In the meantime I've been in contact with Marc D, and will try to help him real-time over the phone or IM.

Ken

AbeFM

iTrader: (3)

Ah! I'll have to check out the base map... I've been thinking of switching to TS and starting from scratch. I'm soon to do a motor swap, so I'm not sure how much good it'll do me.

BTW, Ken, any chance of seeing integrated VVT control? The miata guys who've rolled their own say they have to control current and not voltage, but that's the hardware not the software anyway. I'm trying to decide which head to put on this built bottom end. :-)

muythaibxr

If you're talking about on-off VVT, I could get that rolled in pretty easily.

Continuously variable valve timing is quite a bit more difficult, and involves your favorite type of code (PID). I also need people to provide data on how each engine's VVT system works. I know how Toyota works at a high-level, but have not been provided any data at a detailed level on how any of them control the position or read back the position.

As discussed on msextra as well, changing valve timing with MAP will not work because there's no way to solve the "quick blip" case. Changing the position with load will only be supported if you use a MAF (since airflow is airflow and you wont have the ability to be at one load point with 2 or 3 or more different valve timings).

Otherwise I'd have to have a ton of tables, one for each supported valve timing position, which is a nasty kludge and requires a TON of tuning. Very inelegant.

Ken

Matt Cramer

Not sure if Jerry sent you the details of when we had a Miata running on MS1, speed density, and an external VVT control board, but I'll get them passed on to you if you don't already have them.

As for how the Miata's VVT works, short version is, it's a spool valve operated by PWM. It has one inlet and two outlets connected to a double acting rotary actuator on the cam. At somewhere close to 50% duty cycle, it locks the cam in place. Applying full duty will cause the cam to advance, while turning the solenoid off will send oil the other way and retard the cam. The rate at which the cam advances or retards will depend on the duty cycle - 25% duty cycle will retard the cam more gradually than 0%, for example. Toyotas also appear to be spool valves. Since the PWM controls the *rate* of advance rather than the *amount* of advance, it can't be run in open loop and get good results. I don't have very much information on what is going on inside the ECU itself other than it is using a closed look feedback mechanism based on the different cam and crank positions to monitor timing.

muythaibxr

But what does the cam wheel look like? Is it a single tooth or?

How did the external VVT board handle quick changes in load? Even if I delay changes in the position until after quick transients are done, the fuel is still wrong until everything is back to steady-state unless you use a MAF.

Ken

Matt Cramer

The VVT Miatas have the exact same trigger arrangement as the '99-'00 Miatas, so you have two teeth on one side and one tooth 180 degrees from them.

I'll have to check about just how quickly the cam could change position. There wasn't a huge difference in VE as the cam angle changed, and practically no difference in spark angle needed.

muythaibxr

That's a bit surprising (the VE comment). The point of the angle changing is for better airflow, which would mean better VE unless I'm horribly misunderstanding something.

Ken

AbeFM

iTrader: (3)

Matt did a pretty good job explaining it, as I understand it. There are a couple guys who've rolled their own, I don't know if they are willing to share code.

As I understand it, you control current and not voltage to the valve, otherwise it's just how he described.

If it were tied ONLY to RPM it would be much much better than full advance full retard. RPM and TPS would likely give you some reasonable chance of approximating MAF - not a great one, but something, certainly if you had slow changes you'd be ok.

The cams look different, with the sensor in a different place, but they are the same pattern as the earlier cars. I might be able to get a log... I've got someone tweaking one of my boards to put in a later model car, if he's successful, or tells me how he did it and I build one of my cards I have a friend with a VVT car I could at least log teeth on. Actually, in parallel I could probably do it easy, or even with an oscope.

The biggest problem is, as Matt said, open loop is basically the same as not controlling it. You can switch it and do see some gains (Matt Yates has done this with a Hydra)... Of course, two things to keep in mind:

1) The VVT cams are quite a bit better than the regular cams (the MSM cams are also decent, but fixed)
2) There are much better and much cheaper options for aftermarket cams on the 99-00 and MSM heads.

The small difference in VE is confusing, but it could be the cams are kinda wide in the first place? Unlike Honda, the valves are identical, less RPM dependence.
-Abe.

TrickerZ

iTrader: (6)

So after all this info, my plan is:
MS-II PCB3.0
EBC
Closed loop idle with upconverter board
fan control
batch ignition
sequential injection
whatever trigger wheel I can get and not have to mod like hell
DO progressive WI off the MS (to me, this is cleaner. I'd rather build a circuit than have to worry about 2 MAP sensors)
still unsure if the table switch is possible

If the table switch is possible, I like Abe's idea for attaching it to a switch on the water tank as well as having one in the cabin. That way I can have it auto adjust timing if the water runs out.

Does anyone have a 1.6 with MS-II? I'd like to take a look at an MSQ, but every thread I find with MS-II is an NB.

What mods do you have to your board Abe? I'd probably be interested in looking at your MSQ too.