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Radio Shack EFI computer

Discussion in 'The Garage' started by K1Orion, Jan 29, 2004.

  1. K1Orion

    K1Orion 1/2 ton status

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    I got the March issue of Car Craft this week. Its got an article about a couple guys selling a DYI Radio Shack kinda kit for a MPFI computer called the Megasquirt( /forums/images/graemlins/grin.gif). Basically you solder it together and use it to control the fuel on a EFI setup. Ignition is your choice, not controlled by the umpooter.

    In the article they put together a TPI setup for $1500. They used a $200 base and ram. $260 new SLP runners, $421 for new 38-lb/hr injectors and $20 here and there for sensors and stuff. It looks like a cool way to control and tune a EFI setup for cheaper than some stand alone computers or a factory setup and burning chips.

    Go buy a Car Craft for the brief overview they give or go to the links given in the article.http://www.bgsoflex.com/megasquirt.html is the megasquirt page or http://www.members.shaw.ca/megasquirt/manual/mtabcon.htm to read through the instruction manual.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    You can buy a complete TPI setup and be into it for $500 or less. Not sure how their setup is any better, except most components are new. Then again, for another $500, you could replace all of the parts in a TPI system I imagine.

    Gotta qualify my statements, haven't read the issue yet, but ECM controlled timing is one of the great aspects of EFI. Might as well run a carb if all you want to do is dump gas and keep it simple in theory on a SBC Chev.

    From what I gleaned from skimming the megasquirt page, it's for DIY's that want fuel injection on something that never had it, like a BOP V-8.

    In actuality, for a Chev V8, which TBI and TPI applications were standard, it would be easier in many applications to simply run the stock stuff. Everything needed is already used, so it's a straight across swap.

    Don't get me wrong, I like DIY stuff, but if the setup was more than just a fuel controller, I'd be more impressed. Burning PROM's is no more complex than what the megasquirt will have you doing, and you can be up and burning PROM's for $150. The interfaces that are out there (which use a laptop, as does Megasquirt) for the GM ECM's are very simple and easy to understand, and of course windows based.
     
  3. 69K5

    69K5 1/2 ton status

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    ive been to there website before. it looked pretty cool. i asked my dad about it (electrical engineer) and he said it was doable. he didnt know about my part(motor) but building the computer was easy,
     
  4. K1Orion

    K1Orion 1/2 ton status

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    Dorian,
    I just figured I'd post this in case others might be interested. I was unaware that burning PROMs could be done so readily and inexpensively (maybe there's $$$ to be made here /forums/images/graemlins/thinking.gif)

    And from what I took from the article, you could use this computer to control any MPFI setup, TPI just being the example they used. This might be of more interest to somebody who wants a "homebrewed" MPFI for a BBC, although TBI seems to work fine for most people around here.

    And like you mentioned, this setup included all new injectors and sensors, which certainly isn't necesary. That price also included a new MSD6A but not the fuel delivery system.
     
  5. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    It's not multipoint. It has two injector circuits that can be run so they pulse in unison or offset. In other words, it's just like GM's TPI. There are two banks.

    I did a lot of research on them about a year ago. I'll probably still end up buying their kit but I'm working on building my own because I want it to control electric fans.

    I'm going to do a TBI setup because I want the simplicity of TBI. I can bolt it to any kind of intake and if it gets finicky I can just stick the carburetor back on there. The limiting factor of a TBI setup is that no one makes a 2barrel one bigger than 2.125" which is smaller than the secondaries on a Quadrajet.

    You can "build" the MegaSquirt for under $150. The rest of the cost is in the rest of the parts. IE: intake, throttle body, fuel pump, et cetera.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes, IMO the real "complexity" of other applications is getting hardware that works. A Ramjet base/plenum would be pretty cool to run on a BBC or SBC (except the exorbitant cost) but other than the Ramjet, there really is no true EFI base/plenum for a BBC, that would be somewhat easy to retrofit. Same goes for other GM divisional engines. You can use a single plane intake, and put injectors into the bosses cast into many newer intakes, but you still have to come up with fuel rails, some way to handle ignition, throttle position, and so on.

    I'll have to read the article, but if they are going to the effort of using the TPI hardware (which means SBC only) then why wouldn't you use all the other stuff off the same assembly? /forums/images/graemlins/confused.gif

    As to cheap PROM burning, the reason people get into it is to get it right in their application. To fine tune a PROM to your combo, like GM did to each of theirs, can take upwards of 100 burns. Make a small change, try it, read data, repeat until desired result is achieved. The "aftermarket" PROM burners are really going to have a hard time "nailing" the correct parameters the first try, there is just too much that needs to be modified bit by bit. (spark timing, injector pulse width, TCC command, engine temp, and so on)

    I remember seeing one online place that would actually send you a burnt PROM after you sent the current PROM data to them, and keep doing it until it was right, but obviously that is costly and time consuming on their end. Since every vehicle is different, whats right in an '88 Camaro with a 355 isn't going to be right for my K5 with a 355. It might be close, but it could just as easily be enough off to cause other issues.

    *I* think it's going to be pretty neat to actually start burning PROM's, and watching how the engine is performing and what can be improved. But obviously it's not something you can just do in 15 minutes, you've got to be willing to spend some time on it, just like an EFI swap in the first place. /forums/images/graemlins/smile.gif
     

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