The Endless Argument: EFI or CARBURETION

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Using injectors it provides a precise metered amount of fuel to the incoming air. Unlike carbs with the more air being sucked in tends to increase fuel at a high RPM rate to mix with the air. So the higher you are in the RPMs the more likely you are to run much richer using carbs, leading to the common belief that carbs use much more fuel that injection.
In some ways this is true, as carbs do tend to use more fuel than an injection set up due to jets and bowls as it is not as accurate as a electronically controlled injectors. But using a properly set up multi carb intake and manifold, the carbs will not use much more fuel that a similar set up injection system.

Most people are of the belief that injectors use far less fuel than a carburettor, but again its not entirely correct. If you use a factory ECU and upgrade things like an exhaust manifold, exhaust system and cold air intake the factory ecu may not be able to adjust to this new found effiency. So when you mash the loud pedal it may just dump fuel in making a poofteenth more power but you will be using more fuel.

The factory ECU on all injected cars come with have hard wired protection systems so when your driving your car hard it squirts more fuel in to keep up with the air flow demand and to try to cool the engine as well (more fuel + less air = smaller bang and less heat) so it does not do any damage to the motor.

Now which do you choose?


Well carbs can be quite cheap to set up as a side draught carb manifold are a snap to make or adapt to almost any engine. Carbs themselves can be quite cheap as there are lots of damaged bikes and rusting Alfas and Fiats about. Rebuilding a carburettor is quite simple as well, there are off the shelf kits available for almost all carburettor systems.

If you need increased fuel flow its very cheap to increase the jetting of the carbs or replace the jets for larger ones. Doing so is a bit like increasing the injector size, but too big and you will constantly run rich and flood the carbs, and sometimes the engine, with fuel. too small and you will strangle the mid to top end of your engines power band.
Getting the mixtures right on carbs, especially multiple carbs, can be quite difficult. Its a matter of fine tuning and tweaking each one to get it right until you have the best balance. As of late it is becoming increasingly difficult to find old school carbie tuners who know what they are doing or have experiance with your particular set up.

You also have to check the carbs on a regualr basis to make sure they haven’t gone “out of tune”, meaning through regular driving and vibrations they may come out of tune requiring adjusting again to get back to the correct mixtures.

With carbs usually you lose a fair bit of low down torque until about the middle of the rev range when the carbs really can open up and let rip. So driving around town may not be the best thing with a multi carb’d engine. On a winding road or at the track the carbs would really excel. Also as you have very minimal electronic trickery to restrict anything you dont have a rev limiter so there is no fun police if you spin it too hard. Be aware though that the car may lean right out causing major damage if you over rev the engine…



On the other hard setting up individual throttle bodies (ITBs) and injection is quite expensive. First up you really should a have a programmable ECU, which can take a sizable chunk of cash depending on which brand you buy. Then the ECU has to be set up, which requires wiring and tuning.
If you have a programmable ECU that can plug into a lap top computer you could have a go at tuning the ECU yourself. But this is fraught with problems as pushing it too much one way or the other you may end up with a very expensive paperweight on your hands.

But using a programmable ECU you have infinite control over the engine than you would if using a carburettor-based system. You can control how much fuel goes in at specific RPM, specifically when the fuel goes in so if you have large duration cams you can time it so its in between the rotations, you can also control the spark. In fact, with most modern ECU’s there really isnt anything you can’t control.

Again with ITBs and injection you can also get a precise amount of air and also have the correct amount of fuel to air mix in the combustion chamber.

Once the programmable ECU is tuned correctly it is saved as a tuning map and is a set and forget system. Meaning that once the tuning is done you do not have to adjust it again unless you change something on the engine.

Unlike carbs or multiple carbs, using injection and ITBs you have a good even spread of power and torque all the way through the RPM range instead of having nothing down low and all the power up high in the RPM range. So that means that you have adequate low end torque to pootle about town in and taking off from lights without out revving the crap out of it.

FORCED INDUCTION
Having not seen a decent suck through or blow through turbo set up in a long time, the black art of turbo charging a carbie engine is almost gone.
With a carbied turbo engine you have 2 options, suck through or blow through set up. A suck through system is just that it sucks air and fuel through a carburettor first then through the turbo to be pressurized and fed into the engine. This is a cheap and simple way to set it up, but is quite in-efficient.

A blow through set up has the carburettor after the turbo (much like a conventional injected set up) and air is forced into the carburettor. This way is a much better set up and much more efficient than a suck through system, but is more difficult to set up as the carburettor must be able to take boost and work under pressurized conditions.



A turbocharged injection engine as you already know is much easier and much, much more efficient than any turbocharged carbie set up. The injection system already has an intake chamber or plenum already able to take boost, and you can control the fuel and boosted air intake at a much more managable rate.

With injected engine you can run a supercharger, compared with a carbie system its almost impossible on a small capacity engine to run a supercharger efficiently.

I HAVE THE POWER!
A multi carbed or ITB’d N/A engine in terms of power output, there really isnt much in it at all. Both will make similar levels of power at almost similar RPM limits.

A turbo carbie engine is really only going to make a few HP more than a similar sized multi-carb’d or ITB’d N/A engine. Looking at some old fast fours from the early 90’s the average power output of a 2ltr carbie turbo engine was around 200-250hp. Nowadays the skies the limit for a injected turbo engine and you can buy a car off the showroom floor with more power from similar or less capacity and NON-TURBO!
So a injection setup may be more expensive to set up initially, but once its all in place you dont have to do anything after that except enjoy the sweet trumpet music.

Carbs are cheap to set up, can be a barstard to tune and get right. But when done correctly run they will sweetly and have the most insane raucous bark to them everyone will know you mean business.
What’s the better option? Well, thats for you to decide!

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In complete honesty, I don't know too much about the mechanics and technicals of cars, but articles like these help me learn a lot. I'm too lazy to go around looking for articles like these but thanks a lot for sharing them.