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EFI vs. Carburetor results
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Posted by: Aussie XAXB

Here is an interesting article I found at the Comp Cams website.

http://www.compcams.com/Community/Ar...?ID=1248088065

I have long been of the contention that the best benefit of EFI is more accurate fuel metering for emissions and fuel mileage. When it comes to power though and engine requires a specific air/fuel ratio that is optimum (stoichiometric) and whether that mixture comes from a carb or EFI doesn't matter to the engine.

This is another article that backs my notion. The test was with a 454 so the effects would be enhanced on a larger engine than a smaller engine. A carb intake was modified for EFI injectors. This way all that needed to be done was remove the carb and put on the throttle body for the FAST EFI system.

The results were once again negligible. The gain in going from the carb to the FAST system was 6 - 8 HP and 6-8 ft. lbs. of torque. The FAST system is $2000 more than going with a carb. Hardly worth it in my wallet.

In a similar dyno test on a smallblock Ford in an article I have at home a complete EFI system with Edelbrock Performer EFI intake was removed from the engine and replaced with a carb and associated intake manifold. The difference between these two set-ups was 2 - 3 HP and ft. lbs. of torque sometimes leaning in favor of the EFI, sometimes in favor of the carb throughout the RPM range.

For those here that are not old enough to have been around when carbs were the norm this should be some helpful info on deciding which way to go when deciding from scratch when building an engine. After all, all of the great history of the musclecar era and most of drag racing was set with carbs.

For those not old enough to have been there when the law was passed, the auto makers were required by law to go to fuel injection in order to build cars with better emissions starting with 4 cylinder engines in 1981 and the rest I believe by 1986. Ford's last carburetor on a production car in the US was in 1985. Any performance gain was not the inspiration or else the manufacturers would have gone to it on their own.

If nothing else perhaps this post will help some to understand why so many of us old farts stick with our carbs.

Steve

Posted by: oldtimer

Hey, watch who your calling an old fart. Very interesting!

Posted by: Joel5.0

Quote:

Originally Posted by Aussie XAXB

If nothing else perhaps this post will help some to understand why so many of us old farts stick with our carbs.

Steve

AMEN..........

PTC......I know I do.

Great article BTW. Thanks.

Posted by: Aussie XAXB

Quote:

Originally Posted by oldtimer

Hey, watch who your calling an old fart. Very interesting!

LOL, comparatively speaking in relation to the mostly 20-somethings that populate most Mustang boards we are viewed as such.

Otherwise I still feel 19 myself.

Thanks Joel. I see you are among the die hards.

In the article that I have at home between the 2 piece EFI intake and carbed intake I feel that is definitive proof that the theorietical ram affect is not occuring as is touted for the purpose of the long and twisty runners of the EFI intake. Laws of physics just doesn't support it due to the shape of the runners and structure, nor does what happens on the dyno. I contacted Ford about this (I work for them) and mentioned that a lot of money could be saved in material costs by no longer designing huge intakes that do not gain any advantage.

Steve

Posted by: ExBamaGal

I'll have to take a look at this when I get more time. Hubby is wanting to switch the 85 to a carb. Thanks for posting the info!!

Posted by: Aussie XAXB

In my opinion there is less to go wrong with a carb compared to EFI. There are no sensors to fail, no computer glitches, no electric fuel pump problems, and no solenoid problems. Basically once you bolt it on and set your idle mixture and throttle setting for idle, provided the jetting is good for your set-up, you forget it. Trouble shooting is certainly much more of a breeze. A personal preference I have is that a carb has more of a "machine" look to it than EFI, which makes the engine look more like a brute.

Steve

Posted by: Joel5.0

Quote:

Originally Posted by Aussie XAXB

In my opinion there is less to go wrong with a carb compared to EFI. There are no sensors to fail, no computer glitches, no electric fuel pump problems, and no solenoid problems. Basically once you bolt it on and set your idle mixture and throttle setting for idle, provided the jetting is good for your set-up, you forget it. Trouble shooting is certainly much more of a breeze. A personal preference I have is that a carb has more of a "machine" look to it than EFI, which makes the engine look more like a brute.

Steve

That first statement is wrong...very wrong......it shouldn't be an opinion..... it's a fact.

(If I remember my "chances for defects" class that well).

If you compare both systems from a reliability point of view, the carb not only outperforms EFI but, is a more sophisticated and troublefree alternative. Let's see........
EFI = Input sensors, output devices, a couple of miles of wiring, thousands of connections, voltage requirements, grounds, programming............ to do the same job a 12"x4" box like device does..... plus a customer (engine) demand self-adjustment capability.

Which one is the more sophisticated system?

Posted by: Aussie XAXB

I'm sorry but I have to disagree. I would say it is more of a 9" x 9" x 4" box.

Sophisticated? The lowly antiquated carburetor? Nah, I have to say EFI is much more sophisticated, and it is it's elaborate sophistication that introduces a greater number of variables to malfunction.

Since I love analogies....

I equate it to tying your shoes. The carburetor is a direct method of introducing fuel into the engine. It is the same as grasping your laces in your hands and tying them.

EFI, to me, is devising some type of gripping mechanism with sensors so that it can tell it has the laces, and then writing a program to be executed by a computer for the remote device to manipulate the the laces into the desired configuration and hoping it can account for variables such as the foot being on the floor, on a chair, or held in the air.

Personally, grabbing the laces with my hands gets the job done no matter what the circumstances. Having to rely on all the components of the automated system makes me feel apprehensive. Too many things to go wrong while trying to accomplish such a simple task.

Am I weird? Well, that's how I see it.

Steve

Posted by: hyper 289

I put '91 Mustang fuel injection on my '65 Mustang, and got 18 MPG as opposed to 14 MPG with the carburetor. Of course I can't tune a carb. to save my life!

Posted by: Aussie XAXB

EFI can maintain the required stoichiometric fuel mixture throughout the RPM range of the engine better than a carb so naturally better emissions and fuel mileage is a result and a reason for switching.

It looks exotic in an old car like that too if that is a desire.

While building my wife's 331 for her '66 Mustang though fuel mileage was never a consideration.

Welcome to the site! 289 is an excellent engine!

Steve

Posted by: Joel5.0

Steve;

Thought you would enjoy reading this http://carcraft.com/techarticles/849/. Although it's a 2001(I'm guessing) article, most of the things expressed about both (carb & EFI), still hold true to this day. DYT?

Posted by: Aussie XAXB

Excellent article and thanks for posting the link to it. I saved it in my time capsule folder to see how things pan out in the years to come in regards to the various views.

There is a lot of good perspective there from the guys from various backrounds speaking on various contexts for carbs and EFI. That made the article pretty thorough.

I have to agree with most of what was stated.

One of the other things that appeals to me about carbs is that they have more of a "machine" look which adds to the appearance of the engine which is mechanical. That may be just my taste though.

Steve

Posted by: BIGJ

they both have their advantage and disadvantage......personally I like EFI cars, seems like more options for tuning, changing jets suck!

Posted by: Aussie XAXB

I thought this was worth bumping up.

Steve