Conversion of 12a carb to 12a FI?
 

I was wondering if anyone has done this. I hear a lot about the 12a to 13b swaps but not too much about a conversion. I'd do the 13b swap but I am too low budget and I think that a conversion would be cheaper.

If anyone has done this i'd like to find out what they had to do, and about how much it cost...

Thx.

The tricky thing about setting up an FI system on the carbed cars (at least, a stock FI system) is the wiring. It's the same kind of wiring nightmare you get when you're putting a 13b TII into a carbed 1st gen.

I don't know much about aftermarket FI systems, but from what I've read, not many people have adapted one to fit the 12a. I know some guy on e-bay was selling a "bolt on" 12a Rx7 FI system, but I never heard much about it.

If you're not afraid of having to wire up an ECU and related sensors, and probably doing some custom fab on a few things, it should be do-able. Sorry I couldn't help more :p:

Jon

I have priced it out, over $2000 with decent brands. I was thinking about doing an IDF or DCO style throttle body, Haltech F series fuel management blow through turbo.

If you like I can break the pricing down for you.

sure if you don't mind, that would help me out a bit.

thx!

Throttle body $450
Injectors $300
Fuel management $700-$1000
Manifold $200 if you don't have one
Fuel rails $200
Misc. hosing, clamps $100
Fuel pump $150

Total $2100 of new parts. I would imagine that you could get some of those used, but most parts are hard to find or rarely in use so you would have to get them new. This also doesn't cover installation or tuning, both require mucho experience and skill.

I also probably missed a couple of things, this list was made of the top of my head, so I apologize if I did.

I hope this helps.

now subtract 300 - 500 from the management.... megasquirt is your friend :D

2k for a FI conversion is very high. I wouldn't spend that much unless I was running 300+hp.. For these cars, you don't need to go all out. Simple is good.
Used parts and a megasquirt ECU.. The whole schebang can easily be done for under 1k.
You just gotta do your homework.

I wanted to do the FI in a blow through for tuning and some other variables that happen with carbs. But you are right, $2k is too much just for better starting, MPG, etc. etc.

My car will never be a quarter mile monster or win any dyno contests, I just want it to be fun to drive.

Thats the same way I wouldve done it for my blowthrough too. I had started with just the carb, which got me the manifold and everything, then I was going to blowthrough that, then eventually throw the throttle body in there, but thats the same thing I was thinking.

~T.J.

you may find going with a custom set-up like I amto be much cheaper than buying it and just bolting it together. All up I think I'll probably be into mine for about $700 Canadian, certainly no more than $1000 total. This is with a few really good finds, but I'm also getting hit with customs on everything bought from the US so that makes it a bit more pricy.
Grant

well I got all winter to figure something out.

Thanks for the help

If you can hold out for a little longer I will have my system done and then I will build you one.

I'm hoping to have my adapter plate machined by the end of this weekend. It holds 4 fuel injectors, a nitrous injector. It bolts to the stock 12a intake manifold, and the throttle body bolts to the top. I would be able to make any kind of arangement for your throttle body depending on which one/which size you want to use. I'm using a throttle body out of a 92 corsica cause it was free.

I can sell you a plate and computer for $250. If you use differnt parts (fi's, tb, maf) I would probably take your parts and calibrate them on my engine. Then return you the whole bolt on kit.

There are a few options for the display. I have a PC in my car and a touch screen. I think I'm going to use that for my control. If not I'm planning on mounting a gutted Gameboy Advance on the dash, adn the buttons on the wheel. Things displayed will be, temp's, fuel consumption, fuel ratio, hp, 0-60, lateral g's (2 axis accelerometer), miles to fill up, mpg, etc.

There will bea built in nitrous controller, so hook a button up to the computer, and hook the solenoid up to the computer and your done.

Let me know if your interested, kincaid05@hotmail.com

Here is the computer i'll be using. http://www.elektronikladen.de/en_kit08.html

Silly question, but why use a HC908 eval board when a megasquirt IS an HC908?

Would it be possible to use stock FI parts from a FI rotary??? If you could make an adapter to mate the LIM of a FI rotary to a 12A block, you could in theory use all the other FI parts to make it work. The crank angle sensor replaces the dizzy, use 2nd gen coils, S4 or S5 lower intake, upper intake, and TB, matching MAF, and an addapter to mate the lower intake to the 12A. This should work.

There are many ways to do it. I have seen a nice conversion using a GM TBI grafted onto a stock carb manifold. Ran very well and looked stock.

All depends where your fabrication strengths lie. I have a friend currently grafting a set of motorbike TBs onto a TWM twin DCOE manifold. Yum Yum

cause i like to do things the hard way, and im not sure if megasquirt is open source, i have ideas for my own software

Totally open source. Do what you want. that's what has evolved it to where it is. Between the different code bases there is most of what you want, bar support for the mazda CAS (which was my job [hangs head in shame]). In assembler and C, might as well use what you can, unless you are either

a) ace embedded programmer
b) Daft as a brush
c) bit of both :-)

More seriously people opting in has helped build in several sections to the code that are really useful for rotaries, so having an extra set of coding hands at the MS pump is a good thing, especially with the MSII processor coming down the pipe next year.

Yeah, there's lots of FI stuff going on these days. It is really gaining momentum, especially megasquirt. The next UMS will be 100mhz! That is crazy fast for a car ECU.
If I ever get around to getting a ported motor, I am going to try and get a friend of mine to work on a quad TB setup with adjustable pri/sec linkages. It would be fun to play around with, I think.

I'm with Bill on this one. If you truly have the skill to pull this off entirely on your own, then at least grab the code and take a look through it. It'll save you countless hours of work. Of course, the embedded code is only a fraction of the entire job. You need hardware to run it on, proven input/output circuitry, tuning tools (pendant, laptop, pda...). I'd hate to guess the hours involved, but 1000+ certainly doesn't seem unreasonable. What's your time worth?

Opting in, as Bill says, would be best. There is no shortage of 'ideas guys' dreaming up all sorts of weird and wonderful additions to MS. Unfortunatley, the vast majority of the ideas guys are either unable or unwilling to move beyond the idea stage. That's fine, as ideas are great in their own right, but what's needed is more sets of 'coding hands'.