Ford V8 Discussion Discussion relating to getting the most out of your Ford-based V8 Miata's engine

EFI or Carb.

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Old 08-24-2014 | 01:43 AM
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MLKNR's Avatar
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Default EFI or Carb.

Yeah yeah, I know a question one should never ask for it will create a war among men. But seriously I'm not looking for what is better but more to hear the Pros/Cons of each. So here's a few details to put the P/Cs together.

1. This will be my first V8 to work on as all other engines were 4cyl.
2. Reliability is #1 for this build
3. Looks are a very close #2, sometimes edging out common sense.
4. Low Priority but a wish item, it to keep the engine bay clean and neat.
Old 08-24-2014 | 10:02 AM
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CARB pro's:
- simple and inexpensive.

Carb Con's:
- Not very precise. You only have 3 metering circuits.
- Cannot adjust for altitude and weather changes

EFI - Just the opposite of all of that.

I'm an Old Guy. I'v been hot rodding cars since the 70's. And I'v always used carbs. That's what I knew, and that has always worked.

For my current hot rod, I went EFI. I wanted something new and different. I started with a Haltech computer and a ready built harness. Now I have a Megasquirt computer, and a hand built harness. The learning curve is steep. Just getting it installed was a lot more time consuming than I thought it would be. And I made a few mistakes along the way.

But now that I'v been using it for a few years, I won't ever go back to a carb. The EFI is so accurate that the power curve is very broad and flat, and the car is just a joy to drive in all conditions.

In about 15 minutes, I'm leaving the house for a drive up Pike's Peak. From 6,200' to 14,100' in an hour. I know the car will perform flawlessly despite the rapid altitude temperature changes. We're going as a group, and I hope I'm not driving behind a carb'ed car, because they really start to stink at about 9,000'.

And, if you want it to look good, you could always install these:
Attached Thumbnails EFI or Carb.-overhaulfinished_002small.jpg  
Old 08-25-2014 | 10:05 AM
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Jim Stainer
 
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+1 to everything Bob said. Back in the day I had 2 different carburetors for my car depending on what I was doing with it. They are nothing but a loosely controlled vacuum leak with no ability to adjust for lots of issues and conditions and give you mediocre performance and drivability at best. EFI not only can adjust for nearly endless situations to make the engine run great it can do so thousands of times a second.

For example on a carb there is 2 metering functions that work together to control your idle (mix screws and speed screw) but in EFI you have a computer looking at dozens of inputs making thousands of calculations and endless adjustments to get it right all the time.


BTW everyone of those pink boxes that is not touching anything is a click button that opens up to a logic table that the computer uses to come up with the right solution.



Some are simple and some are not but the point is the system can adjust for endless variables. So yeah there is a VERY good reason they don't make them like they used to.
Attached Thumbnails EFI or Carb.-2ljrhav.jpg  

Last edited by charchri4; 08-25-2014 at 10:26 AM.
Old 08-25-2014 | 09:17 PM
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OMG I think I just leaked a bunch of oil all over the garage floor.

Old 08-26-2014 | 05:22 AM
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Don't be silly they make those for EFIs too and probably cheaper. Of course the ones that look that sexy are only for LS engines...
Old 09-26-2014 | 05:09 PM
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Well found out that sey aircleaner sits around $500+. So until I win the lotto I'll stick to a round filter.

Finally got an answer from Edelbrock on their EFI carburetor. $2500 w/fuel sump.
Old 09-26-2014 | 05:23 PM
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Jim Stainer
 
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How good are your fab skills? Check this out:

Budget LS1 cross ram intake
Old 09-26-2014 | 08:11 PM
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What engine are you going to use?
Old 09-26-2014 | 10:11 PM
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Ford 1992 302
Old 09-27-2014 | 08:07 AM
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You could always use one of these Spectre 9804 - Free Shipping on All Orders @ JEGS , & build a cold air kit for it. A lot of other variations here: http://www.summitracing.com/search/b...g&autoview=SKU

Last edited by tbone heller; 09-27-2014 at 08:13 AM.
Old 09-27-2014 | 11:55 AM
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Originally Posted by MLKNR
Finally got an answer from Edelbrock on their EFI carburetor. $2500 w/fuel sump.
The EFI "carburator" is a mixed bag. They're really easy to install, look clean, and seem to perform fairly well on a mild engine. But, you're back to a wet manifold; and that's fine if your engine isn't too radical.

A "big" engine has big ports and big valves, with a big plenum. That makes great power at the top end. But you lose intake charge velocity at the bottom end. The charge moves slow enough that the fuel falls out of suspension. That's why big carb engines idle at 1200, and don't run well around town.

A direct port engine doesn't have those issues. The fuel injectors are fairly close to the intake valve. Even at low rpm's it will run well.

My engine makes over 600 dyno proven hp. It has a big cam, with big ports, and no plenum. It idles very smoothly at 800rpm, and will run at 2,000 rpm all day long, getting 20mpg. But when you mash the throttle...
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