EFI vs Carb'd

Tpx · 04-24-2008, 09:56:50 PM

If you build an engine with EFI and then you build that exact same engine with a carb instead, what are the differences? In mpg, hp, tq, and all other catagories?

craigblock · 04-24-2008, 10:02:43 PM

It's impossible to say.

Assuming a good tune, the EFI engine will be better in all respects, especially emissions and driveability.

Good carbs may be able to approach EFI driveability, but not in all parts of the world. EFI can maintain the correct mixture at the top of a mountain, or at the bottom. That is something that carbs _can't_ do.

pdq67 · 04-24-2008, 10:11:51 PM

And it's been proven several times that a carbed engine will produce as much, if not a schosh more power up TOP as an EFI will, except that you have to really work w/ a carb to get it to run as good as an EFI in the lower and mid range rpm's! It can be done but it's a hassle and you will really need to know how to tune the carb. to do it!

But a carb is a BUNCH cheaper than an EFI!!

pdq67

Gary S · 04-24-2008, 10:15:44 PM

For Emissions, EFI is best.
For mileage, they are probably equal.
For horsepower, probably again equal.
For driveability, I've never driven any EFI engine that is as smooth and responsive as a properly set up carb. No computer means no computer controlled spasms.

ULTM8Z · 04-25-2008, 11:39:27 AM

Quote:

Originally Posted by Gary S

For Emissions, EFI is best.
For mileage, they are probably equal.
For horsepower, probably again equal.
For driveability, I've never driven any EFI engine that is as smooth and responsive as a properly set up carb. No computer means no computer controlled spasms.

I disagree on fuel mileage. I picked up 3-4 mpg in the city and 2 on the highway (highway mileage was already great due to the overdrive trans). Not amazing increases by any means, but you do get some increase. If one is going for EFI just for mileage, it's not worth the initial cash outlay (unless you're able to do it extremely cheaply).

Also, for tune-ability, the EFI has the advantage. The amount of fidelity I have on fuel and spark control is lightyears ahead of a carbed engine- and that's using EFI technology that's almost 20 years old now.

Lowend · 04-25-2008, 12:16:09 PM

The "common knowledge" about carbs making more power was true 10 years ago, its not true anymore. The ability of the ECM to react and the engineering is at a much higher level now. Think about the PC you have now vs 10 years ago.
Sorry folks a good properly tuned EFI wins in every category.

Tpx · 04-25-2008, 01:37:18 PM

Now I just need $2,000 .. I'll just buy a good $400 carb until I can convert over to E-85 and EFI :/

ejpii · 04-25-2008, 02:00:09 PM

I have an old analog Pro-Jection 4 now but I have been looking into these two systems. I like the fuel injection. It also helped me pass the emission test in closed loop. My 383 actually ran cleaner than my wives Oldsmobile Bravada.

EJ

http://www.retrotekspeed.com/index.php

http://www.mass-floefi.com/

ULTM8Z · 04-25-2008, 08:26:40 PM

Quote:

Originally Posted by ejpii

I have an old analog Pro-Jection 4 now but I have been looking into these two systems. I like the fuel injection. It also helped me pass the emission test in closed loop. My 383 actually ran cleaner than my wives Oldsmobile Bravada.

EJ

http://www.retrotekspeed.com/index.php

http://www.mass-floefi.com/

Funny how that works isn't it. Your car would be illegal in Looneyfornia....

Tpx · 04-25-2008, 08:50:14 PM

Quote:

Originally Posted by ULTM8Z

Funny how that works isn't it. Your car would be illegal in Looneyfornia....

Since I live in "looneyfornia" I made sure to get a pre '76 car

Doug Jaynes · 04-26-2008, 11:02:21 AM

EFI gives you far more control of your engine. The ability to control the ignition timing is a huge benefit you get with efi. I have nothing against carbs but Ill take efi every time, givin a choice. Driveability is all dependent on the tuner, and that goes for carb or efi systems. With the right tune up, the efi should be better. very few guys are actually really good at tuning, but lots think they are. Im a caveman on the tuneups, but I got friends heh.

Doug

AJ_72 · 04-26-2008, 12:42:53 PM

Well, keep in mind that computer controlled ignition timing is different than EFI. You don't have to have both. Either will work fine by itself and can be installed either way.

The LS- intake manifold from Edelbrock is a perfect example.

Doug Jaynes · 04-26-2008, 03:49:34 PM

"Well, keep in mind that computer controlled ignition timing is different than EFI. You don't have to have both."

very true. but usually if you run a carb, most folks will run a conventional ignition system. where as with an aftermarket efi system it is likely to be computer controlled fuel and ign. But there are some very trick ignition box's available these days I absolutely agree with you.