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***Carbs or Injection?? Which is Best?
We get asked this very, very often. We recommend our alcohol modified carburetors. Of course it is up to you, but
we recommend you consider these factors. Many racers prefer carbs for their simplicity and consistency. We have
all seen the injection guys chasing some problem with a bad connection, bad sensor, or a dirty injector, or?, and
losing races trying to get their fuel injection worked out. As a full service engine shop and "horsepower
provider", we have the option to choose to go with injection or carburetors. We are fully capable of doing
either. And we prefer carburetors for several reasons.
Both carbs and injection put fuel in the motor- or I should say that
they put fuel into the airstream that the motor draws in. Don't think that injection forces fuel into the motor
to make more power, that is not how it works. Anyway we feel we have worked out the mixture ratios with our methanol
conversions to make the best power from off the corner to the end of the straight. We exclusively do this by using
the air correction system as designed in the carbs from Japan. This is not your father's Holley on some 327 Chevy.
These carbs are state-of-the-art instruments highly refined over many years. So why spend more just to hassle with
laptops, maps, failed sensors and finicky injector nozzles???? If they have them so worked out, why then do they
have to now use 8 injectors??? And what do you do at the track when it won't run??
Better Power with Fuel Injection?- In our dyno testing, we have been able to make better overall power by replacing the injection
with a set of FTZ carburetors, even after extensively remapping the FI systems. We have seen this same result with
injected Yam R6's, Kaw 636's and Honda 600RR's. Excellant throttle response and great starts can be acheived with
these carbs as well.
More power with fuel injection?...... No. or we would be using it.
Another important reason is simply- Carbs are a lot cheaper, and
we feel that the money could be much better spent on something like the cylinder head- which HAS PROVEN to be a major factor in making
more power.
And another big factor is troubleshooting. Methanol can be problematic as we all know, and can chalk up in your
fuel system very quickly if allowed to sit, draw moisture, etc. We feel that a most guys can figure out what is
wrong with their carbs if there is a problem, say at the racetrack.
This preference with carburetors was further backed up last fall
when we did extensive flowbench work, and saw less airflow with the throttle bodies across the board. These high
rpm motors are very sensitive to changes in the intake tract, especially since they do not have the advantage of
being force-fed from a ram-airbox being pressurized by going 160+ mph..They are very dependant on the sonic wave
action in the intake tract. The nozzles actually disrupt airflow and some of the airboxes fitted with them also
make a mess of the "ram" tuning that is so important---and airflow is the main factor what makes one
motor run better that the next.
Remember, these motors are no longer in the bike- which is the
only application that they were designed for.
All of the big races won by our guys, last year and this, were won with our carburetors.
Why spend more for less? There is better places to put the money.
We usually can put our Alcohol conversion set up on carbs done by
other shops. Just send them in, we have a very fast turnaround time on carbs.
Call on for more information and current prices on our carburetor
conversions, including the new air correction jet modifications.
If you are not using a FTZ motor- You
are not as fast as you could be!!
We can arrange to have a truck line pick
up your motor, at your place, for "no hassle" shipping to us.
FTZ Performance, Inc. 573-334-5439 9:00
to 6:00 Central time
This is a recent post I put up on the Maximumdirt.com website:
PostPosted: Sun Apr 08, 2007 8:02 pm Post subject: R6 Alcohol Fuel
injection vs carbureted
Hi Red Dragon,
This is the kind of question that should be on a technical forum like this, and one that we are asked many, many
times. I am going to attempt to bring you up to date on our thoughts on this subject-which happen to be shared
by many others- at the risk of getting another black eye from some of these “keyboard experts”. And I hesitated
even to put this up thinking someone would take it as bashing the FI guys. And maybe this will free up our phone
load a little answering this very same question, lol!. I will be putting up a new page on the subject on our web
site which will contain this post as well.
I think that electronic FI is the way to go- on your truck, street bike, and maybe even your outboard motor. Cold
starts, emissions, mileage, and on today’s sportbikes; compensating for that 160+mph air getting rammed into the
airbox-something they rely heavily on for making their power. And remember gasoline has to be metered to a much
closer ratio than methanol, especially on a street vehicle. But, none of this really applies that much to an alcohol
microsprint does it? We recommend and sell carburetors for the 600cc motors. And we do quite a few conversions
fitting carbs to injected type motors, with very good results. We could use injection same as anyone else, if we
saw the need to.
We have all seen guys go fast and win with both carbs and injection. Many people follow the “Keep It Simple Stupid”
rule and go with carbs as they feel they can deal with them better if they have a problem trackside.
In the last few years, Mike Gigot, Mike Dicely, Don Guhl, and many others have all worked very hard, and made great
progress to make FI more reliable and more consistent. They are all good guys, believe in their product, and should
be proud of their work. We just choose to go another direction with the induction system. Problems? There is no
perfect induction system, or one that can’t act up, or be abused. We are still talking about a very complicated
electronic/mechanical system. How many sensors and nozzles and connections are on that harness? And what really
happens when all those inputs are fed to that chip? At the Nationals a few years back we had one of my top runners
who was experimenting with EFI throw a rod in one of our trusty F3 motors- because of a FI wiring connection came
slightly loose, and causing a harsh misfire at high rpms (fuel related). And I thought we probably had the race
won, until that little t*rd in the punch bowl. My comment was: “If we just had kept the carbs on it, this would
not have happened.” But carbs can get dirty, worn and screwed up too..... Direct in-cylinder injection would be
cool but that is another subject.
Anyway, they both put fuel in the motor, and both can be made to work well. Deciding which is “best” is not going
to be the easiest question to answer.
More power with Injection? Not in our testing. Our best overall horsepower has been made with our carbs- but then
that is also the system we use most and have came to rely on. Just as with the exhausts, someone will tell you
they get more power with carbs, another guy will say they have found better power with “Fuel Injection” over “carbs”.
This is a “generic” statement that I can have a problem with- not every builder’s carbs are the same, just as FI
systems can be vastly different- so this makes this a very complicated subject. When I hear a generic statement
like that I always think: Okay, Who’s carbs? On what motor? Were the carbs set up right? How much time did they
spend on each? And finally, what are they trying to sell you? (-and of course the same can be said for us.) Every
FI system is different, and every provider has a different idea of how to set it up and map it, and the combinations
are in the thousands. Does your FI guy really know exactly how much fuel your motor needs?- at every rpm and at
every throttle setting? and with different exhausts? Are the sensor input corrections really working like they
should? Leaves a lot of questions open doesn’t it?
Carburetors are not dependent on a man programming exactly when to put the fuel in- other than some simple jetting
changes. They work off of pressure differentials. (look up Bernoulli’s principle). When the motor is “off the pipe”
it will not take in much air. So there is not much fuel going in either. When the motor “hits” or gets in it’s
torque range, it will start pulling in more air faster, depressing the pressure in the throat, allowing more fuel
to be “pushed” in by atmospheric pressure. Kind of a fuel injection provided by nature’s physics. A century of
tuning and design experience has gone into these modern carb designs. When we first examined the Yamaha R6 carbs,
I took one and sawed in right down the middle with the bandsaw. I remember saying that I had never seen a more
bass-ackward set of carbs. Did anyone ever notice the emulsion tube is made inside out? But I later came to appreciate
them. I never assume the Japanese don’t know what they are doing, and they have been building the best carburetors
for nearly 50 years. We do our R6 carbs totally different from any others I have seen. As far as I know, we are
the only one utilizing the air correction system with alcohol, as the designers at Keihin intended. This is a tuning
aid that does much to flatten the fuel delivery curve to match engine demands and helps with the self compensating
aspects that carbs have. This is not easy to do with carbs, but it can be done, darn close especially with methanol.
Year before last we had probably 200 guys racing with our R6 carbs all of them running the same main jet, and most
the same needle position- all year long. It wasn’t until we came up with some significantly different R6 cylinder
head mods last year, did we see a need to change the jetting considerably.
Excellent throttle response and great starts can be achieved with these carbs as well. FI in theory should have
an advantage with fuel atomization and weather/altitude correction but we haven't seen enough of that benefit to
warrant the switch.
Actually, the main reason we see better power with our carbs has got nothing to do with the mixture. That’s right-
but I will try to address that on the new web site page. These posts seem to quickly get too long.
And don’t think that just changing the induction system is
going to make a stock motor run like a well built on. Won’t happen.
Carbs are Cheaper.
Yes carbs are cheaper and we feel that the money could be much better spent on something like the cylinder head-
which has proven
to be a major factor in making more power. Or just get yourself some better tires. This is not Nascar or Indy cars
with near unlimited budgets, so I am not big in running up the costs without some good "bang for the buck".
Another problem with the injection, that I think the FI guys might agree with me on, is what I call the “tinker
factor”. Some guys just can’t resist getting in there and jacking with the map, fuel pressure, etc. until they
get things all screwed up. But guys will screw up their carburetors as well. And then there is the guy that wouldn’t
even clean his old nasty carbs, but then they want to get all “hi-tech” and peck around on a laptop seeking some
magic numbers for their FI map! As my Dad used to tell me” It takes all kinds to make a world” and ain’t it the
truth.
My recommendation is to put carbs on it, keep ‘em clean, and GO RACE. Lord knows there is enough things to tinker
with on a racecar- like How ‘bout the CHASSIS!
If I can quote myself on another post: “So it really boils down to who do you trust, and who you think has the
best knowledge, skills, equipment, experience, and drive to give you the best goods.”
Perhaps this will help to decide which system might be right for you.
I will put the link to the web page on the FTZ Micro Sprint web page.
Good Luck!
Jon Fitzpatrick
www.ftzracing.com
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