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That question has been asked alot :
What is better, EFI or Carbs ?
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CARBS
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I think it is a personal preference. Carbs are easy to hold,
take apart, put back together again , clean up etc...
Must be maintained regularly reguarless if the car is used or not.
Most people do not understand carburators sufficiently to really
get their cars running nicely. I see nothing but performance problems
from alot of people. Some people buy the aftermarket dual carb kit
without fashioning some kind of filter that would get fresh air from the
outside, like the original setup. What is usually installed are overly
large carburators with low profile tiney circumference filters that get
hot air that is floating up from the engine. To top it off, inconjunction
with overcarburation a high speed jumbo cam gets installed that
needs tons of air to make the car just go, vacume is nil. The resulting
engine is one that will run like a dog in the city but at highway speeds
feels OK and at higher speeds feels great. These errored mods usually
have lots of flat spots and run very badly for routine driving.
The word is ; be CONSERVATIVE when carbing an engine. An original
32 carb can wayyy outperform a 40 carb. You will see the bigger carb
advertized as performance. This is performance if the small engine is
going highspeed only but they would perform well with some of those
jumbo engines some of you guys build 2000 -2300cc. The reason for that is
the engines require lots more air flow and the smaller original carbs
may make the engine bog down at higher speeds even though neck
snapping torque is present at every light and stop sign. The vacume
in this combination is quite large and fuel economy would be enhanced
but at high speed, the engine would require more air than that is
flowing through the carbs for correct volumetric efficency. The engine's
air to fuel mixture would be way off and cause the car to bogg. Big
carbs for big engines. Large carbs on a smaller engine missmatch
is most common.
Keep the conservative original cam unless you buy an offroad cam.
High duration cam kills your vacume and makes your engine run
badly because the fuel mixture in idle is way off. These cams are
designed for higher speed power but at lower speed it may run
like a dog at various degrees, depending on what performance
level cam you have installed.
If I went carbs, I would put the original type setup, but if that were not
an
option I would go conservative aftermarket and have some kind of
air filter assembly fashioned by a sheet metal shop. Would keep the
original type cam spec. I would make sure that my chokes are adjusted
correctly
and my jets and power valves are correct. Some people over jet and cause
lots of performance problems.
Carbs must not be set up lean because a lean condition usually
means a meltdown death sentence for the heads. A carburated
system keeps it's gas hot because a good amount of gas sits
in it's carb container and fuel lines in the engine compartment.
This has the propensity of fuel vapor lock in hot weather. This
system also uses more gasoline than the EFI type of fuel delivery.
I would choose a two stage carburator for each bank of cylinders, this
would give me higher vacume at slower speeds thus give me very, very
nice all around city performance but if I felt the need for speed,
It would open the secondary larger stage(floor it) and let lots of gas
and air to flow in. This is just like those spread bore carbs on those
Detroit monsters. I would not know where to get this but you
can ask the list.
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EFI
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Ultimately, I would prefer my EFI over carbs anytime because it is
already well suited for performance of our engines and gives great
gas mileage even though one has tweeked it like I have done before.
My car starts just as I turn the key and has been working like this
for almost two years. This system cools the The heads by injecting
cool fuel into the head runners and intake valves. The fuel is cooled
by it's fuel recirculation ring that keeps fuel moving around and
around from the gas tank, thus cool fuel is always spraying thus
keeping vapor lock incidents rare.
With this system, the engine can be leaned out alot and still keep
overheating and engine knock ( pinging, pinking) to a minimum.
All around performance is very good on a good working system.
The problem people have with this system is that mechanics
are usually unfamiliar with the system so the owner has to fix
it his or her self or go to familiar carbs
As little as two years ago I was not familiar with this system at
all or any Fuel injection system for that matter. My engine has been
running beautifully even at dangerous speeds, I still cannot kick the
habit of going 95 mph, I did that today.
To be familiar and to fix this system you must ask questions, get
data, print and write everything down, do everything the "experts"
ask and do it right and not half way or comprimise. I have acummulated,
notes from the internet and from the "experts" that measure now
around eight inches of paper, some of it is hodge podge and the other
is organized in bookform. I have given advices well as taken. Some people
do not heed the advices and warnings on this system because of
either lack of interest or laziness.
These are very old systems that require full wire work and analysis of each
component We can advize you on this, all parts are available one way or
another.
When everything is all done as per the advices then this
system does not need to be touched for years during strong driving.
The main drawck of this system is learning what everything does, it is like
a very old person with many maladys. 30 Plus years do tend to take it's
toll on wiring and components but when it is going good, good will
stay for a long time.
I get 34 miles per gallon (HWY) on my system when I install my lean
virgin pressure sensor and 25 miles per gallon when I install my
frankenstiened pressure sensor that is adjusted rich in addition
to the full enrichment option . My System did not have full enrichment
at the this sensor but it was incorporated at the throttle switch so I have
two enrichment systems. I tried to add a third but failed it was
getting way too much gas when I floored the accelerator,
engine would bog and cough out gas from the exaust. This
last setup is for power and speed and not for economy.
As you can see, this system is easy to tweek, other things beside the
pressure sensor can be tweeked or frankensteined.
I hope this helps you.
LEON MARTINEZ
1969 SQUAREBACK EFI/AUTO
SAN DIEGO AND TIJUANA