There is a company called Megasquirt that sells kit to build your own Ecu that you can taylor to your needs for only around $200 and sum odd dollars.


http://www.bgsoflex.com/megasquirt.html

 

my car doesn't need an ECU

 

i've actually kind of wondered about those megasquirt ecu things. could you put together some sort of homebrew fuel injection system for a 12a? i'm sure it wouldn't be the most efficient use of time and resources, but it sure would be nifty.

 

It's a stand alone. Ive heard good things about it. A bunch of guys got them in a group buy off the SA22C list a few years back. Perfect for cheap bastards like us. They were supposed to come out with an ignition kit too (ala MSD) but I dont know if they ever did.

FB Drifter---- I dont need one either.

 

ecu's are for sissies. j/k!

 

Why would you want an ecu when you have the all powerful carb. Nothing beats a carb when it comes to raw power. Its a proven fact. Ever wonder why most serious drag racers never use a fuel injection system (ie, the pro's).

 

uh oh, I see a FI/Carb debate starting up here.

 

Why? Because their classes dont allow it. Something about about holley putting a few bucks into the NHRA. Why? If the rules change and people can run Fuel Injection in those classes, then holley wont sell nearly as many carbs. Holley is out there to sell its product, and keep it that way.

Fuel injection can allways yield more power than a carb, period. I dare you to give me one source that has proof that a carburator can yield more power than fuel injection.

 

Holley also does EFI.

The issue with EFI in racing is that it is too easy to surreptitiously include things like traction control, throttle stops, etc. Stuff that might not be legal for a particular class.

Lots of racing classes that allow EFI often have a "spec" ECU that can be confiscated and retistributed at any time.

 

Yes its true that holley does sell EFI, but thats not where they make most of their money. They make most of their money from their carbs. On top of that, holley efi kits IMHO, are really nothing spectacular either. Theres really not much to be said about throttle body injection, with todays technology.

I mean, if everyone was allowed to run fuel injection in every class, there would simply be no reason to run carb at the pro level at all. Holley would loose a TON of money if that happened. Its in their best interest to keep these carb classes going.

 

Hmm -- NASCAR runs naturally aspirated carbs (with restrictor plates on superspeedways), a live rear axle, and doesn't allow big front and rear wings. Therefore these must be the most advanced items available -- FALSE. What the motives are for the rules can be questioned indefinitely, but the key here is that many racecars perform not because of, but in spite of the rules.

As for why fuel injection is better than a carb -- it's simple. A carb requires a narrowing somewhere in its throat to create a venturi. In the venturi (Bernoulli's principle), the air speeds up, dropping it's static pressure, which draws fuel into the airstream. In fuel injection, this restriction isn't needed. No restriction = more airflow. More air is the most important part of making more power (since dumping in extra fuel is simple), therefore injection will make more power all other things being equal.

As for carbs being used on dragsters -- the fastest ones don't -- top fuel runs injected nitro methane.

 

yep, I belive that debate is done.

 

in the near future, i'm going to be getting a TWM DCOE throttle body, with rails and reg and injectors and using a megasquirt to make it all work, and then once that works, i'm gonna look for a streetported 13b, and then turbo it

i'll keep ya'll updated.

 

I have a 12a car with fi and megasqirt in my shop it's jayroc's from here on the forum.

 

So, jorx what can you tell us about jayroc's car?
How does it work? How long did it take to tune?

 

i have a gsl-se and do i get rid of my computer and also my air flow meter

 

Sure, if you want to. Or you could give the complete car to your neighbor.

 

oh good lord, F1 cars are 3L have 10 cylinders and put out close to 1000 horsepower with fuel injection.

Get real. The big dog classes at drag racing are FI too.

The only REAL reason I can see carbs even being used anymore especially by NASCAR is they are keeping the carb companies going. Plus, there are some people that won't put a FI system on their aging muscle car.

If I had the time, I would FI my RX-7. Better mileage and more power.

 

Carbs have the advantage of being cheap and easy. To properly tune a fuel injection system is vastly more expensive than dropping on a cheap *** Holly with massive jets. Thats the main reason why carbs are still around.

 

do megasquirts use an o2 sensor? i'm really only passively curious. around here with all the good roads in the hills, fuel injection has a marked advantage in that it compensates for altitude better than a carb

 

This is true -- somewhat. Carbs are usually cheaper (sometimes much cheaper). You can just slap a carb out of the box on your 350 Chevy and it'll run OK. Getting it all tuned just right, however, especially if you're running something that isn't common and you're running a Weber carb can be very expensive, especially if your time is worth money. The array of chokes and jets and time you'll need to swap them and make back-to-back runs either on a 1/4 mile or dyno is staggering. I know -- I have a pair of Weber 36 DCDs, and they're still not tuned just right.

That megasquirt looks great!

 

The hardest part of a 1st gen Megasquirt installation is coming up with a suitable intake system, throttle body, injector mounts and rails, high pressure pump, etc... The Megasquirt itself is pretty straight forward.

Intake options:
1.) Throw out the stock carb, adapt a down-draft throttle body setup from another vehicle. This is probably the lowest $$ solution, with the least gains as well.

2.) Custom-fabricate an intake to suit. If you have this capability, this is an excellent option.

3.) Buy a custom intake and throttle body setup (TWM?). More expensive, but certainly a very appealing solution.

For the fuel system, you could mount a GSL-SE style external pump in the stock location, and use the existing lines. Another alternative is to leave the stock low-pressure pump to feed a header tank in the engine compartment. A high-pressure efi pump then feeds from and returns to this header tank.

Once those issues are sorted out, wiring up the MS is pretty straightforward. Now if you have a GSL-SE, the install is much easier, as all that hard work is done.

There are ignition options available now for either wasted spark (Ford EDIS-based), or distributor versions, although neither has provision for the rotaries split timing.

 

if you had a gsl-se, there wouldn't be much of a point, though, correct? i always thought of a megasquirt as an inexpensive replacement for a carb solution or an uparade from a superghetto fuel injection like a 914.

 

Why convert a gsl-se?
1.) Full control over fuel mapping - not possible with stock setup, even with a s-afc or equivalent.
2.) More flexibility in intake ducting, as the flapper-door AFM is no longer needed.

Plus a number of other goodies that the MS provides: Flood-clear mode (a big plus with a rotary), wideband O2 support, rpm-triggered outputs for aux port control, coolant-temp triggered outputs for electric fan control...

Still, it's not a 'plug-n-play' setup. You need to build the controller, harness, and perform the installation. Oh, and to answer your earlier question, narrow-band O2 sensor input is standard, although not mandatory for operation.

 

I helped inastall a MegaSquirt on my buddy Tim Schuh's '84 GSL-SE. While we were at it, we grafted on an FC intake for the larger throttle bores, and of course the AFM goes away. He was able to tune it for 20 or so more HP, but we're having some trouble with temp compensation at the moment. It was tuned when it was cold, and now that it's warmed up, it's down on HP. Haven't figured out if the custom temp sensor curves (he used the factory Mazda sensors rather than the spec'ed GM sensors) are wrong, or the bias resistors, or what the problem is.
There are several FCs running the MegaSquirt, and at least one throttle-body injected 12A. See the 'success stories' page at http://www.megasquirt.info/itruns.htm
It lists 7 1st and 2nd gens running MegaSquirt.

Lots more info at http://www.megasquirt.info/ and a Yahoo! Group at http://groups.yahoo.com/group/megasquirt/

I intend to use a MegaSquirt when I put all the GSL-SE stuff in my '79 GS.