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Thread: Megasquirt: Is it for you? v. reference

  1. #1
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    Megasquirt: Is it for you? v. reference

    This is the beginning of a megasquirt reference page for 4age. This is by no means enough to complete a setup. This is merely enough information that should let you know whether or not MS is something you should be interested in. If you need any clarification or would like a section added please let me know. Others are welcome to contribute to this. Celica_fiend and i will put this in the ref section in about a week along with posts that have technical info not mentioned by me.

    Don't ask me how to make your setup work, that is up to you. If you read the instructions and the message board you shouldn't have any problems.

    Enjoy!
    Kanji > Trevor

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    *Megasquirt and your 4age*

    This is a reference page about how megasquirt works and what it can do for your 4age. Most of the information in this abridged guide can be found on the many megasquirt websites. However, the information is usually overwhelming for someone who just wants to know what MS is, What it does, benefits it has and what you can do once you install your MS. This guide is meant to be a "Should I consider MS?" type of reference.

    I have installed a silvertop 4age with MS2 and EDIS (more on that later) into my zenki 86. I will be drawing from my own experiences, both good and bad, and hopefully give the reader a better (more personal) view on what is involved. The car runs well and I'm pretty sure it could take my corolla xrs even though the fuel map isn't tuned 100% and i haven't worked out ignition timing yet (its static at 10 BTC)

    * What is Megasquirt?

    Megasquirt is a standalone EFI system that can be used on any car/bike/snowmobile ect.
    Everything about MS in completely universal, that is, the guys with the mustangs, corolla's, ATV's will all use essentially the same system. Megasquirt is meant to be a very "DIY" EFI control system. You can build your MS from scratch or you can buy a premade unit from a couple of guys on Club4ag or buy companies that sell pre-assembled units on the internet.

    * How does it work?

    Megasquirt works essentially like any other standalone albeit with less features and, as a result, less potential complexity. The MS decides how much fuel to inject based on a number of factors that YOU input. Simply put, for most applications, it cross-references the MAP pressure reading (the vacuum in your intake manifold) and RPM. Once it knows what value is in that box, it multiplies that by a factor relating to outside air temperature. All those boxes are called "bins" and that table is called a "Volumetric Efficiency" table.

    This can mathematically be expressed as

    fuel injected = (Fuel constant X [map value X factor] X RPM X [Air temp X factor] X [VE bin/100])

    The above equation is valid for a situation such as cruising when the throttle position does not change. In other cases, the "acceleration fuel enrichment" is multiplied in there as well. Accel enrichment just means that when the car is accelerating more fuel is added. Alternately, there is a "Deceleration enrich" value to input (this is what to modify if you want to shoot fireballs on upshifts)

    The same VE table is used for the spark advance. The user inputs how much spark advance he needs for every RPM Vs MAP reading.

    Below is an example of an AFR map. VE and spark maps look are almost identical (except the numbers inputed are for VE and spark advance...duh ^_^)






    Okay! Now we know why were reading this!


    *What can MS do for my car?

    In my case, MS is the reason the car can run right now. When I bought my ST, i didnt have the ECU, the AFM, the ignitor, the harness ect. This is common for many of the imported engines that we get here. Also, electronic parts seem to have a bad habit of being mixed up with different engines ect ("Blacktop coming with silvertop loom" was the most recent one i read about)

    MS is very simple. Parts you need for MS to work are:

    TPS
    Coolant temp sensor (mine's from a cavalier or something, i dont even know, dont care either)
    Air temp sensor (bought new from ford)
    Ignition system (we'll get into this later)
    O2 sensor (can use narrow-band or wide-band)
    Injectors and obvious stuff like that

    The nice thing about MS is that being completly user configurable, you can literlly take these parts from any junkyard car and have it work perfectly on MS.


    Example: Setting the TPS

    Computer: Close throttle and click "ok". (We click "ok")
    Computer: Open throttle 100% and click "ok" (we click "ok")

    and thats it. Done. We just took a TPS from a Yugo and made it work with MS (Were Yugo's FI or carb? ... whatever ... in soviet russia, gas injects you!)

    For me, being able to use anything in conjunction with MS was a huge selling feature. I never want to have to wait for stuff to be flown from Japan so it'll work with my engine swap. Now, if something breaks, i just go to the junkyard, get the part off the first car I find, and be on my merry way.

    *Ignition systems!

    As for ign system we have 3 choices:

    1. Dont play with it; leave it to the stock ecu
    2. Let MS control the stock components.
    3. Use a system from another car (FORD EDIS system is the most popular and is what i use).

    1. Don't play with it.

    Self explanatory. The MS controls the fuel input and the stock ECU controls ignition. This approach could be good if someone only wanted to control fuel (running ITB's or something). This approach is by far the most simple and you can retain all your stock components.

    My car, in its last days of being a daily driver, cost me over $1000 in repair bills for the 20 year old electrical system. 86 is a damned good car, but 20 year old ignitors are 20 year old ignitors. Many people will disagree with me on this, I can't speak for them; only for myself. All i know is that stranded car + car in vancouver + my house in delta + bitchy gf bugging me to get a new car is something i never need to do again.


    2. Let MS control the stock components.

    In this case, the user configures MS to control all the standard 86 components. Essentially it tells the ignitor when to fire, for how long and with how much advance. If someone were turboing their 86 and needed fuel adjustabilty and wanted to retard the timing under boost, this is something they should consider.

    This setup could have worked on my ST if I had the ignitor and wanted to deal with replacement dizzy caps from god knows where (as a sidenote i heard 3SGTE ones work....i think).

    3. Use another ign system

    This section will be focused on the ford EDIS system as it is on my car and i prefer to only talk about things i have done myself.

    EDIS is a distributorless ignition system found on many of ford products in the 90's (from escort to the crown vic). EDIS comes in 3 different flavours, EDIS 4, 6 and 8 (corresponding to the number of cylinders it needs to fire). Unless you plan to do something REALLY brave with your 86, you are only interested in EDIS 4.

    EDIS is a very very very simple system. Below is a wiring schematic. As you can see, we are only dealing with 4 parts. A crank trigger wheel, a VR sensor, the EDIS module and coil packs. The crank trigger wheel is steel with a bunch of teeth sticking out of it. One of the teeth is missing though. The VR sensor picks up on the changing magnetic field produced by the spinning trigger wheel (the closer the teeth get to the VR sensor the stronger the magnetic field is) and the missing tooth tells the EDIS where the engine is in its stroke. The VR sensor sends an AC voltage (changing magnetic fields cause AC power, think alternator ^_^) to the EDIS module, and from there the coil's fire and the engine runs!





    Benefits:

    -Simplicity
    -Ease of install (adamturbo welded mine for me and did a great job)
    -availabilty of parts (I took mine from ford escort)
    -Still fires perfectly at 9000rpm in my car


    Drawbacks:
    -you have to make a bracket for the vr sensor
    -you have to get the trigger wheel welded to you crank pulley.
    -your ignition system is not jDm tYte anymore

    I chose to go with EDIS because i didn't want to use parts from an engine that wasn't sold here. Simple. Also, if my coil packs die, i can go to a DSM, WRX, miata ect and pull thiers for $25.


    *Conclusion

    Megasquirt is a viable alternative to using stock engine management. As well as offering more versatility than the stock system, it can also allow you to use replacement parts from any EFI vehicle (good thing when dealing with 20 year old cars).

    Be aware however that although MS is simple and easy to use, an interested person MUST read the instructions in full and understand what they are doing. There are a bunch of MS guys on DK who all have different things going from turbo bluetops to ms's ST's to 16v with ITB's. I'm sure if you have any questions they will share their expertise on the subject.

    By now, you should know whether or not MS is right for you. If you are interested, you need to start reading and soaking up as much knowledge as you can.

    Also, be advised that tuning MS takes alot of time and effort to do properly. Sketch and I were out until 4am one night working on the VE table, cold start enrichment and accel enrichments. Budget time to tune your car.

    USEFUL LINKS

    http://www.msefi.com

    http://picasso.org/mjlj/?q=node/2

    http://megasquirt.sourceforge.net/extra/index.html

    http://www.bgsoflex.com/mjl/mjl_edis_summary.html

    http://msefi.com/viewtopic.php?t=5417
    Kanji > Trevor

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    Blitzed, AWESOME post!
    "mmmango!"

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    lolosaurus thx :bashful:

    How's yours coming along?
    Kanji > Trevor

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    very slick.. I like it.

    heck, I even learned stuff..

    Brett
    '87 AE86 - GTSR5 - Daily Driver
    '72 RA21 Celica - 'Ill build it one day'
    '73 RN27 Hilux - Restomod in progress
    '80 MX32 Cressida - Next in the project queue
    '91 SV25 Camry All-Trac - Winter DD

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    Nice write-up! Glad to hear your setup works well.

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    Awesome post.. someone sticky this up!! (where's the bukkake smilie when you need one ) I feel a lot smarter now after this post. :e


    Follow my Supra Antics on Facebook ---> HERE!

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    looks good, but don't forget this link...

    don't forget what has become pretty much the standard for hooking up a MS to a stock 4age;

    http://members.cox.net/jdlaugh/index...figuration.doc

    How do you like V2 vs V1? I noticed the 12x12 AFRs, I'd like that.

    Neil
    Uber D.I.Y. Zenki Turbo
    Squirted since '03

    "When I'm old enough to get my drivers license, I'm going to drive the car allllll over DisneyLand, and their ain't no-one whose gonna stop me!" - my 5yr old son 09/16/2005

  9. #9
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    Quote Originally Posted by neil85ae86
    don't forget what has become pretty much the standard for hooking up a MS to a stock 4age;

    http://members.cox.net/jdlaugh/index...figuration.doc
    he didnt.. he linked to james' Project thread on msefi.com in the last link in his post

    Ive gotta compare pinouts to ae86 pinouts on that one and I'll be runnin the '85 off mine.

    Brett
    '87 AE86 - GTSR5 - Daily Driver
    '72 RA21 Celica - 'Ill build it one day'
    '73 RN27 Hilux - Restomod in progress
    '80 MX32 Cressida - Next in the project queue
    '91 SV25 Camry All-Trac - Winter DD

  10. #10
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    Quote Originally Posted by neil85ae86

    How do you like V2 vs V1? I noticed the 12x12 AFRs, I'd like that.

    Neil
    I started with V2 and to be honest I've used very little of what was available to me. The 12X12 tables were superfluous for me as i didn't need to be so precise with what tuning i have done so far. 12X12 would be better for boosted engines though...

    As a sidenote, megasquirt by itself is meant to utilize a NB O2 sensor. While it was nice to know if i was rich or lean, it wasn't any help beyond that.

    If i had to do it again I'd get a wide band just because i'd be easier to tune. If i was boosting I'd 100% get a WB.
    Kanji > Trevor

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    blitzed24/7 can you pm me your msn addy.. you might be able to help me with a minor ms problem i'm having.. i'm semi stumped...
    1987 Corolla GTS Hatch | 1985 Corolla GTS Coupe | 1987 Corolla GTS Coupe | 1992 Tercel CE | 1992 Paseo | 2003 Corolla CE | 1974 Corolla 4 Door | 1978 Corolla Coupe | 1979 Corolla Hatch SR5 | <3||||||1990 Miata |||||| <3
    I like Toyota's wanna fight about it?

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    post the Q here because if you don't get it, chances are someone else won't get it either.

    but if u want it its twsnboy@hotmail.com
    Last edited by blitzed_24/7; 01-25-2006 at 06:03 PM.
    Kanji > Trevor

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    i'll post the q when I get home from work
    1987 Corolla GTS Hatch | 1985 Corolla GTS Coupe | 1987 Corolla GTS Coupe | 1992 Tercel CE | 1992 Paseo | 2003 Corolla CE | 1974 Corolla 4 Door | 1978 Corolla Coupe | 1979 Corolla Hatch SR5 | <3||||||1990 Miata |||||| <3
    I like Toyota's wanna fight about it?

  15. #15
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    agreed

    Quote Originally Posted by blitzed_24/7
    I started with V2 and to be honest I've used very little of what was available to me. The 12X12 tables were superfluous for me as i didn't need to be so precise with what tuning i have done so far. 12X12 would be better for boosted engines though...

    As a sidenote, megasquirt by itself is meant to utilize a NB O2 sensor. While it was nice to know if i was rich or lean, it wasn't any help beyond that.

    If i had to do it again I'd get a wide band just because i'd be easier to tune. If i was boosting I'd 100% get a WB.
    Ya, I got away with a NB for a while. I ran it against a wideband at the dyno so I knew the correlating voltages so that was a help. Last year I bought a wideband, it's the only way to go. For $199 the Innovate LC1 is perfect for interfacing with standalones.

    Neil
    Uber D.I.Y. Zenki Turbo
    Squirted since '03

    "When I'm old enough to get my drivers license, I'm going to drive the car allllll over DisneyLand, and their ain't no-one whose gonna stop me!" - my 5yr old son 09/16/2005

  16. #16
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    Quote Originally Posted by neil85ae86
    Ya, I got away with a NB for a while. I ran it against a wideband at the dyno so I knew the correlating voltages so that was a help. Last year I bought a wideband, it's the only way to go. For $199 the Innovate LC1 is perfect for interfacing with standalones.

    Neil
    Yah, next time i do MS (prolly on an EJ20 in a GC8!) ill get a WB so matter what. Also, last time i checked, MS is implementing a "self learning" feature where you just input the afr you want at a given point, and the computer will adjust the VE automatically to reach that setpoint. They've had that system around for a while on the more expensive SDS systems but obviously it'll take a while for MS to get up to par with the AEM's and the Motec's and the rest of 'em.
    Kanji > Trevor

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    Quote Originally Posted by pitobread
    blitzed24/7 can you pm me your msn addy.. you might be able to help me with a minor ms problem i'm having.. i'm semi stumped...
    Heh my problem resolved.. problem was not getting tach signal through a sparkandfuel.com harness (which TTC bought and was supposed to be plug and play) turns out the harness was NOT wired correctly! He had NE pin 24 and OX pin 23 reversed.. which in turn has burned out the o2 sensor part of both my and TTC's MS because it was sending a 12v signal to the 5v input of the o2, and that only one problem we have had with this kit.. there were a few other things.... I made my own harness, and everything works ok now with the exception of the o2 functions, but at least it runs half assed now.

    Solution to this problem, do not buy stuff from Sparkandfuel.com

    Diyautotune.com is the man, I bought my MSv3 kit from him and he even helped me troubleshoot a competitors mistake.. A++++
    1987 Corolla GTS Hatch | 1985 Corolla GTS Coupe | 1987 Corolla GTS Coupe | 1992 Tercel CE | 1992 Paseo | 2003 Corolla CE | 1974 Corolla 4 Door | 1978 Corolla Coupe | 1979 Corolla Hatch SR5 | <3||||||1990 Miata |||||| <3
    I like Toyota's wanna fight about it?

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    Quote Originally Posted by blitzed_24/7
    Yah, next time i do MS (prolly on an EJ20 in a GC8!) ill get a WB so matter what. Also, last time i checked, MS is implementing a "self learning" feature where you just input the afr you want at a given point, and the computer will adjust the VE automatically to reach that setpoint. They've had that system around for a while on the more expensive SDS systems but obviously it'll take a while for MS to get up to par with the AEM's and the Motec's and the rest of 'em.
    Ya, that's the closed loop functionality that's been around since MSnS came out. It's awesome for dialing in fuel economy. I run that against my 8x8 AFR table in my older version MSnS.

    I took my car out today with 440cc injectors in place of the old 365s without a retune, and you could hardly tell the diff thanks to the closed loop.

    Neil
    Uber D.I.Y. Zenki Turbo
    Squirted since '03

    "When I'm old enough to get my drivers license, I'm going to drive the car allllll over DisneyLand, and their ain't no-one whose gonna stop me!" - my 5yr old son 09/16/2005

  19. #19
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    Quote Originally Posted by neil85ae86
    Ya, that's the closed loop functionality that's been around since MSnS came out. It's awesome for dialing in fuel economy. I run that against my 8x8 AFR table in my older version MSnS.

    I took my car out today with 440cc injectors in place of the old 365s without a retune, and you could hardly tell the diff thanks to the closed loop.

    Neil
    Is that right?? Wow, thats amazing. I thought it was only for that "self learn" mode that they are still working on. Haha, funny how everytime i log on to teh internetz i learn something new about MS

    Injector change eh... in open loop you can feel the difference eh? How are you AFR's? How much authority does your WB have? Prolly a lot I'd imagine..... I set my NB at ~15%
    Kanji > Trevor

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    Quote Originally Posted by blitzed_24/7
    Is that right?? Wow, thats amazing. I thought it was only for that "self learn" mode that they are still working on. Haha, funny how everytime i log on to teh internetz i learn something new about MS

    Injector change eh... in open loop you can feel the difference eh? How are you AFR's? How much authority does your WB have? Prolly a lot I'd imagine..... I set my NB at ~15%
    My AFRs are pretty good, 12:1 on boost, and 15.8:1 on low map cruise, under 62kpa from 2200-4200 rpm, 12-12.5:1 on idle. Makes for ~40 MPG on the highway Once I get the new map closer I'll reduce my authority down to 5%, every 64 events. After it's dialed in I usually shift my entire VE table up by 1, that way it's sort of like a failover, and the correction is always pulling it a little leaner. The other reason I do this, if the wideband sensor ever experiences a hick-up, which does happen quite frequently, it gives a full rich signal to the MS, 10:1 AFR instead of giving a lean reading.... so correction tries to lean out the motor, I'm pretty disappointed that Innovate didn't think of that scenario when they designed their system!
    Uber D.I.Y. Zenki Turbo
    Squirted since '03

    "When I'm old enough to get my drivers license, I'm going to drive the car allllll over DisneyLand, and their ain't no-one whose gonna stop me!" - my 5yr old son 09/16/2005

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