Hey guys-I know there are plenty of you out there that could help me out or at least point me in the right direction to a link that'll further explain what I need to do, but I know the FAQ's are a bit out-dated and need a bit of help before I start assembling my EMS and stim...

To be honest, I'm planning on using the MSII V3.0 to control fuel and spark, but I'm unsure about the best (quickest, easiest, or most reliable) method to use a S4 CAS in my application. I've searched, read, and still don't fully comprehend the different modifications to control the CAS with the MSII V3.0. I also can't find the modified assembly instructions/wiring diagrams or schematics to use for controlling a rotary engine. Any help would be greatly recommended...

I've ordered books on reading schematics, electrical projects with "breadboards" and generic circuit boards, and soldering techniques to practice on before I start building the stim and MSII, so I've got some time to plan and figure it out before I actually start working on them. Any help or guidance would be greatly appreciated!

Also, I've got a few questions as to what I can and can't do with the MSII V3.0 that aren't covered in any FAQ's. I can post those later, but if anybody can help me find a thread or threads with some of this info, I'd forever be in debt to you. Thanks again for all your time, help, and cooperation...

 

Easiest method is to chop two teeth off the CAS and use the built in VR circuit on the V3 board.

Better (in my opinion) is to build a 2nd VR circuit and use the CAS unmodified. Makes it easier to swap/replace.

The schematic for this VR circuit is in the FAQ. The modifications needed to run the stock coils are also in the FAQ. The FAQ is a bit crude by all the info is there.

 

OK-I'll most likely take your advice Aaron. I know you know what you're doing. Anyway, I can't find any really good completed pics of the MSII V3.0 and the V1.3 stim. I'm learning how to read the schematics, but it seems to me that the MS circuit board gets it's components soldered in place so they're on the top of the circuit board (where it tells you what version it is), but I must have either a wierd stim or the components are supposed to be installed on the bottom of the stim. I think I just messed it up by soldering the DB37 connector to the top of it (the side with the printed numbers and such). All the diagrams and parts I've found on their website (www.megasquirt.info) don't give me a detailed enough explanation. Did I mess up? If so, can I wire up my own DB37 connector cable with the wires reversed inside to correct it or should I opt for a new stim board? Thanks for your help...

 

OK-nevermind. I had found diagrams and schematics on www.megasquirt.info, but the ones I needed were at DIYautotune.com. I'll have to search more on building the second VR circuit before I tackle the MSII. How would you go about setting up the wheel mode selection for the additional VR circuit on the stim (with the dip switches)? And is there anything else I can do to verify the correct assembly of the stim itself? I've been up all night long practicing soldering, tackling small projects, then I finally found the right diagrams to assemble the stim, so I got that taken care of...

Any suggestions on maintaining soldering tips? I've got two pencil-type irons and the tips interchange between the two. One's a dedicated 25-watt model (a pretty nice one) and the other a cheaper radio shack switchable 15-30 watt version. I've soldered most of the stim with the latter on the 30 watt setting and a smaller 25 watt tip, after discovering the 15 watt setting and smaller tips took too long to make a good connection. It could've been where I'd had the iron on for about nine hours or so, but I've burnt up about three tips tonight even cleaning them off and re-tinning at regular intervals (about every fifth to tenth solder connection). All three were good plated tips, too...

Anyway, as far as the second VR circuit, I don't think I'll have to mod the MS much if any more. I'll be running GM sensors and I know I can calibrate MegaTune to the SE or later model throttle body, but I've got a few more questions about possible functions that I'd like to incorporate into my EMS. For one, I'd like to have a knock sensor or two (one for each rotor housing) to alert me of detonation and retard the timing, lower boost pressures, and eventually inject more water/methanol. That's another question I have-I doubt I could use the MS II to control the components needed to operate a full-scale water/methanol injection system, but if anybody knows an inexpensive kit that would be capable of being triggered from the MSII or even a link or parts and mods list to get the system operational via the MegaSquirt, that'd be great and I'd be forever in debt to whomever could help...

Sorry to bog you guys down with questions (especially you Aaron, you've been EXTREMELY helpful to me since I've joined this forum), but if I were to get the relay board for the MSII, could I use that to power a CO2 intercooler spray bar system that I've designed according to engine load, rpm, boost pressure, intake air temperature, and possibly exhaust gas temp? I'd love to incorporate a variety of detonation prevention measures on my project but I'd have to have them fully integrated with the EMS (preferred) or operated by their own independent management systems as opposed to having to remember to flip a switch or push a button to activate the water/methanol injection and CO2 spray bars...

I'd really like to incorporate the knock sensor into my MSII also-is there a mod to the hardware or a simple method to hook this up so it'll activate a timing retard, boost pressure reduction via electronic boost management system, or the previously discussed detonation prevention measures? One more thing-to keep my boost pressure in check (running a T04E .5/.67 A/R's, 15psi max, hybrid internals, 1.5" schedule 40 pipe and weld el exhaust mainfold, etc), what should I do for an electronic boost management system? I remember hearing that the Haltech unit was a pretty poorly designed open loop system-is there an affordable and reliable alternative that's of a better design (i.e.-closed loop that can be integrated with the MSII V3.0)?

OK-I lied-one more question. I know this one's off-topic, but if you could give me any advice as to what size Tial Sport wastegate I should run and what spring (300HP max at 15psi, shooting for lower rpm powerband, electronic boost controller, etc), I'd greatly appreciate it. I've sent an email to Tial Sport tech, asked around in other sections of the forum, on other forums, etc, and I can't get a definate answer. I think my best bet would be either the 36mm (or 38mm, whichever it is) or the 41mm unit. I've seen guys running 500+HP and WAY more boost using the 44mm version, so I thiink that one's a bit too large for my application-what do you thihk?

Thanks to all who reply with any info-I wouldn't have gotten this far on my project if it weren't for you guys! I truly appreciate all your time, help, and cooperation...

 

I'm not familiar with the 1.3 version stim so I don't know the specifics. But if you have mis-soldered the connector, you'll need to unsolder it and correct the error. You'll need a vacuum desoldering tool and a lot of patience.

The Stim can't provide the signal to the VR circuit, so you would use the "stim for wheel" function in Megatune.

I'm a bit nuts with my soldering irons. I solder everything with a 60W iron at full blast. If you are burning up tips, it means that you aren't tinning them properly. A fresh tip needs to be fully warmed up then thoroughly coated in solder to tin it. Then wipe off all the excess flux with a damp sponge. While using the iron, clean the tip with the damp sponge every few joints. I get in the habit of wiping it off whenever it goes back into the stand. I don't know why you are burning them though. Unless you are using acid core solder? If that's the case, all your connections will be bad and the board is ruined.

Knock sensors are almost useless on the rotary. Don't bother.

To control extra devices like an e-fan, water injection, shift light, etc. you will need to add a transistor to provide the output to the car. Typically a 2N3904/2N2222 is used, with a 1K resistor between the base and the processor output. DIYAutoTune sells little "mod kits" which include all the parts:
http://www.diyautotune.com/catalog/p...ans-p-126.html

And they have instructions on how to use them:
http://www.diyautotune.com/tech_arti...#Add_Output_v3

Your CO2 sprayer is probably just a solenoid, which can be activated using the info above. The output on the 'Squirt can then be set to take a few parameters (two max I think...I am not very familiar with MSII Extra) to decide when to trigger it.

The Megasquirt can control boost fairly easily. There is a target KPA table as well as a KPA vs. TPS table. You'll want the boost control mod-kit and boost solenoid:
http://www.diyautotune.com/catalog/p...kit-p-160.html
http://www.diyautotune.com/catalog/b...oid-p-175.html

The 38MM wastegate should do fine.

 

I think he is talking about the JimStim, which does emulate the VR signal, as well as the 24/2 nippondenso wheel.

 

You're right JWX-I have the Jim Stim 1.3. You're not kidding about the patience with the desoldering methods, Aaron-I've used vacuum bulbs and desoldering braid, and you've got to be careful about overheating sensitive parts too...

It may be the solder I was using-I used mostly 62/36/2 (with silver) in a .022 for small connections and plain 60/40 .032 for the bigger prongs. Both are rosin core. I was looking at the diagrams for the original B&G Stim kits when I started building the stim, then I found the right diagrams at www.diyautotune.com for the Jim Stim. I'm still new to soldering too, but my connections look good and provide a strong mechanical bond. I've noticed the solder with silver (62/36/2) doesn't seem as shiny as the 60/40, but everything else seems to be in order...

Thanks for the links and advise, Aaron. I've been pretty excited since I built the stim and it's gotten me a lot more interested in electronics projects too. About tinning the tip of your iron-should I tin the entire length of the tip to where it screws into the heating element housing or just the contact area? I've been doing just the latter, and the iron sat on for quite a while at times, but I'd wipe the tip with a damp sponge before putting it in the holder. I don't know-if it's not the solder or something I'm doing then it's probably just the cheap radio shack iron...Anyway, thanks again for all the help!

 

Maybe there is something odd about your solder?

When you tin the tip, tin the entire contact surface. This generally means the sharp area. Then immediately wipe off all the flux until you see a shiny solder coating. I don't generally tin the entire shaft of the tip and have never had an issue.

Also, you don't need to throw out a tip when it becomes nasty. Just file or grind it back to a point, re-tin, and continue on.

 

Cool, thanks again for the info. I read somewhere that "eutectic" solder was 63/37 and had the lowest melting point, but I couldn't find that at radio shack. The 62/36/2 was the closest thing to it and was the thinnest diameter they had, so I got that with the .032 60/40. My problem may lie with the cheap radio shack iron-I'll have to get a good one before I assemble the MS. Thanks again for everything...

 

I used a cheap Rat Shack iron for years. A 15W unit with a blue handle. Seemed to do the job. I still take it out for very delicate work since it has a fine tip. Something must be up with your solder...

 

Yeah, I have a pretty nice weller adjustable temperature iron, but I used a radio shack one for a long time.

The radio shack 60/40 solder has always worked fine for me for building MS units though.

 

I think I'll just quit using the 62/36/2 solder and stick with the 60/40, and I'll buy a better iron just to be sure...

Everything on the stim seems to be fine-I got out my fluke meter and tested all I could test, from continuity between jumper terminals and the db37 connector to resistance between all my connections. I didn't really have a good schematic diagram to go by, but from what I could tell it all seems to be in order. My next step is to gather the parts for the 2nd VR sensor conditioner before I assemble the main board. 2Lucky2tha7 was kind enough to PM me a link to a great PDF file with a good layout of the parts needed and schematics and pictorial diagrams of the additional VR circuit, and to a thread he had started that was very similar to what I'm doing. I had already found that thread by searching this forum, but the PDF file is layed out in a manner that's much easier for me to comprehend...

I really appreciate the help you guys have given me-I'd be stuck with a pile of useless parts and electronic gadgets had it not been for some of you. I think I'll go ahead and install the MSII on the NA 13b that I'm installing in the car soon instead of waiting for the turbo engine build. I'll need to find a good place with a great dyno locally to help tune this thing, but I'm not quite to that point yet. I'm sure I can find some good maps to get me started on here once I get that far. Anyway, thanks again for everything guys!