this is a reply from a person who is not willing to acept that EFI is the now... carbs were in the 60s... there is a really good reason why ALL newer cars have EFI, carbs were dead 30 years ago... take te time to learn it.... JMHO

well said

The reason OEM auto manufacturers use Mass Air Flow fueling models in their production EFI systems its that they measure the actual mass of air the engine consumes allowing the EFI system to exactly match the correct amount of fuel to the incoming air charge to maintain the target air fuel ratio the original calibrators wanted for the engine.

This approach means the engine will meet emission standards everywhere and anywhere on the planet irrespective of altitude, temperature, or barometric changes hour to hour. Only Mass Air based systems can do this because only Mass Air based systems directly measure the air mass actually entering the engine.

When you operate the engine at higher altitudes, although the throttle response will remain the same, power output will diminish because of reduced air supply (thinner air). An internal combustion engine requires 10 lbs of air per minute, properly fueled, to produce 100 hp. When you go to higher altitudes and the air density decreases, so to does the amount of air the engine injests and therefore so to does the horsepower. That's why piston engine powered aircraft used Turbos and Centris. They replace the air mass lost at altitude so the engine has comparable power to what it had at lower altitude.


Ed

What I love about my Holley carb is that it requires constant attention, fiddling, and periodic rebuilding. Plus, it has the unique ability to just break down and spring a fuel leak when it had been untouched and sitting in my climate controlled garage for weeks bone dry. You have to love that in order to appreciate a carb. I would never put up with that crap on my other "normal" cars, but with the Cobra it's kind of like "ok, I get to yank the bowls off again, hurray.":LOL:

Both of my daily cars have EFI.

The number of issues I have seen with customers EFI cars, I still prefer carburetors.

A single 4 barrel carb won't cause single cylinder misfiring or flooding like a stuck open injector. Guess what happens to the engine.

Oh, and when she's not leaking, the ethanol in the gas is eating up the cheap pot metal that Holley seems to use. Here's a pic of my metering block that kept clogging up the air bleeds with mysterious chunks of white crap. Hmmmm, wonder what that stuff is. This baby wouldn't even clean up either. The replacement metering block has been holding up much better though. And, yes, that's Ellie's white fluffy butt in the background.:cool:

http://www.clubcobra.com/photopost/d...ngblock001.JPG

Patrick
 

Being 67 I was quite particular about wanting a carb.....particularly the Holley. I grew up working with them which also included the old carters, quadrajets and enjoy the tinkering as you say. They can be touchy devils occasionally but if you know them, you can figure it out. To me, it's part of me enjoying the car. With that being said, my wife treated me to this for Christmas. A new 870.

Well, that's a beauty. I wonder if the chunks of pot metal in the air bleeds will be dark blue instead of white.;) That said, I still love my Holley, I just enjoy complaining about her.

I think I see the problem Patrickt. The two main jets are clocked incorrectly!

The jet on the left has its screwdriver slot clocked at approximately 2 o'clock and the one on the right is clocked at approximately 10 o'clock. This potentially sets up a trans dimensional vortex while the engine is running that sucks the cheap plating, that Holley uses, off the metering body replacing it with some form of white inter-dimensional waste material.

Who knows for certain but possibly under full throttle an Einstein-Rosen Bridge could appear in close proximity to the mis-clocked main jet originated vortex potentially penetrating the protective bubble of another universe in close proximity to our own. If that would happen it's possible a small black hole could form swallowing the entire Holley carburetor — perhaps even the air cleaner!

Your friend in time and space,


Ed

You can always count on you guys to take it to the next dimension. Even at that why buy a cobra buy a corvette they come with EFI. I admit I am old school cool that is why I bought a cobra.

Back before emissions and carbs were on everything I used to run a little marvel mystery oil in my gas. I wonder if an additive similar to that would help with that white build-up? Of course, when the fuel evaporated then you would have a slight film of mystery oil left over.

Tom

If you want to extract every bit of efficiency from your engine, then EFI w/spark control is the only way to go.

However, when EFI fails, you are towing it home, unless you are carrying a spare replacement EFI system in your trunk and the tools needed to make the swap. Meanwhile, that simple distributor and carb has the advantage of being able to be fixed with duct tape, fingernail file, epoxy, and paper clips if need be.

I am rolling the dice and going with the Holley Sniper and the accompanying distributor for my car. I am not going to let my lack of knowledge about EFI stop me from trying it out. I'll do the required homework, just like I did when I knew nothing about carbs.

I have the holley sniper with the distrib and really like it.

However, that edelbrock 4 with the intake manifold looks better and the cost is about the same.

Can't believe Rick hasn't talked you into the megasquirt

In order to have a snowballs chance in getting my car to San Marcos this year, I am making use of the keyword, "expediency". This engine build is, eventually, going to be in my 64 Ranchero and I will build another one for the Cobra.

Then the Ranchero becomes the daily driver.

I really want to do 8 stack injection on the Cobra.

I agree with Skuzzy about learning the EFI just like learning carbs. I've been through four barrels, six packs and dual carbs and went with Inglese 8 stack on the Cobra. Knowing up front that I would have to learn it. I'm sure I probably have some hiccups coming but right now it runs great and I love it.

I would first identify a tuner that you have confidence in. Without a tuner that understands a specific system and has a preference you will eventually find yourself up a creek without a paddle.

I think any of the systems you mention are probably just fine but find someone that can tune your car do not go down that self tuning road. Just don’t cheap out...you want to be driving and enjoying not wrenching.

Kind of like the way we and our spouses complain about each other!:LOL:

Thom

If your tuner's tuning expertise is EFI system limited then you have the wrong tuner!

Consider taking a five day vacation and going to a Calibrated Success EFI Training Session <= clickable.

This course is put on by Greg Banish, who is a contract Fuel Systems Calibrator for GM, Ford and Chrysler. He is agnostic to hardware (for the most part) unless it is something bogus like the weed blower turbo's on eBay. Set aside five days, one day up, one day back and three days at the training. Treat the tuition for the training and the travel expense as vacation expense.

When you get home you will have had one of the better vacations you have ever had and you will come home with irreplaceable knowledge of how to tune and manage your EFI system. Greg is well published and you can find several of his books on Amazon, He has tuning DVD's available through Summit and Jegs.

Greg tends to be a clear thinker and a conscise and clear speaker. You will appreciate his speaking style because he does not use 25 cent words when plain english suffices. I have attached a short paper of his on injector slopes, which probably is meaningless to most readers, until you read it and experience his ability to communicate. You will walk away from the document with a WOW moment.

As luck would have it, it turns out the pdf file exceeds our site's 39kb file size speed limit. Here is a link to the file on line. Download it and read it. You will be impressed with the clarity and quality of the communication. Click here => Are All Fuel Injectors Created Equal?

Best part of this whole experience is, this guy does this as a 'for-hire' contractor for the Big 3, sort of a Have Gun Will Travel Fuel Injection, Palidin (for those of you old enough to remember the 1950's TV series) as his day job. He runs the Calibrated Success Training School for guys like us between Motown assignments. He is the real deal! When you are done with the course you will know more about EFI than the tuner you were going to pay to "tune" your EFI system — and guess what? You'll do a better job!


Ed