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Why would anyone use a carb?

Discussion in 'Intermediate CJ-5 and CJ-6 Tech' started by jragain, Sep 24, 2008.

  1. Sep 24, 2008
    jragain

    jragain Member

    Billings, Montana
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    Jul 16, 2008
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    I want better throttle response from my 304. I have read lots here and elsewhere about the relative merits of MPI and TBI, and why either is better than running a carb. But I still see Edelbrock and Holley selling very expensive carbs and carb intakes. So, my question: setting aside the obvious difference in cost, why would anyone prefer to run a carb over either MPI or TBI? Thanks.
     
  2. Sep 25, 2008
    bobracing

    bobracing web wheeler

    Richland, WA
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    Oct 28, 2007
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    simple, no sensors, wiring or computer needed
    a lot of forms of racing still use carbs
    up until the mid 80s most cars had carbs, there is still a lot of them around, all the Jeeps this board covers came with carbs.
    and of course cost, a cheap FI setup will cost 3 to 4x what a carb will and only goes up from there. That is a lot of money for a vehicle that may only see very little difference between a carb and FI.
     
  3. Sep 25, 2008
    Brian P

    Brian P Member

    Clarkdale Arizona
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    I know that fuel injection is superior overall but I am just old school enough that I cut my teeth on carbs, I am comfortable with early carbs and understand them. I am particularly fond of the old YF as it is easy to calibrate for elevation and responds well to custom tuning.

    For me it is more a matter of personal preference on the old jeep, Like bias ply tires a properly calibrated application compatible carb simply and predictably gets the job done under all but the most extreme / technical applications.

    A properly calibrated carb with a patient foot on the skinny pedal is capable of exceptional efficiency and all around performance...................I just like them :)
     
  4. Sep 25, 2008
    Chilly

    Chilly Active Member

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    I find a carburetor's springs and gravity more reliable and predictable than herding electrons through a PCU, wire harness, connector blocks, injectors, and sensors. Don't get me wrong, I'm a fan of electrons. Magnets wouldn't work worth a darn without them. But I like things as simple as possible.

    I'm sure throttle response and fuel economy would be improved with fuel injection but I'd have to save a LOT of fuel to justify the expense. Many of us just don't put enough miles on our Jeeps to justify the expense. Throttle response is improved by swapping in a 401 too. But the carbed 304 does well enough to get me by so a FI upgrade would be nothing more than a project for me.

    Please excuse me while I refill my headlamps with whale oil. Probably wouldn't spill so much if I upgraded to those fancy pneumatic tires.

    Chilly
     
  5. Sep 25, 2008
    DrDanteIII

    DrDanteIII All work and no jeep makes jack a dull boy Sponsor

    Milford NJ 08848
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    I originally had my mind set on an FI swap.

    But once I got my car tuned in on my 304, I wouldnt trade it for the BEST FI swap. Its simple, reliable, works fine in 95% of the off road situatuions I encounter, easy to trouble shoot, and the best part is, its already on my motor. My jeep fires quickly, idles smooth, and had great throttle response. And if my carb is for some reason beyond repair, there are hundreds of thousands of fords and AMC's in junkyards with the same carb on top of thier motors.

    Admitedly. an improperly functioning Carb can give major headaches, but its nothing compared to an improperly functioning FI system.
     
  6. Sep 25, 2008
    aallison

    aallison 74 cj6, 76 cj5. Has anyone seen my screwdriver?

    Green Cove...
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    Given the same money for money, I still don't know if I'd go with FI setup. I like simple to work on. Carbs are much less likely to break down on the trail. A good, well tuned carb, IMHO, will be almost as good as a FI motor.
     
  7. Sep 25, 2008
    $ sink

    $ sink Gazillians of posts

    Virginia Bch
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    Classic vehicles... old school technology

    while lifting the hood on a flatty or early 5 and seeing a elctronically controled FI engine is cool, it saddens the heart of some to see.
     
  8. Sep 25, 2008
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    You could write pages on this topic... don't want to offend anyone here, but this is my opinion.

    I'm sure that if digital computers were around when the internal combustion engine was invented, the carburetor would have never existed. The carburetor is basically a mechanical computer - it takes in signals and adjusts the air-fuel mixture accordingly. However, such a mechanical device is very limited in the responses it can make to its inputs. It also has lots of moving parts, and has very limited sources of power for its responses (foot pedal, engine vacuum, Benoulli effect). There's no way that a carburetor will ever be able to operate as close to optimum as EFI, due to its inherent limitations. Also, EFI will be considerably more durable and dependable than mechanical devices ever will be.

    IMO the only reasons that carbs are still around are 1) 'correct' restorations and 2) the owner/mechanic's lack of abilities and/or resources. Again IMO, EFI systems are no more complicated than mechanical systems (carburetors), they just use a different technologies. You can go EFI if you want to - and get flawless no-pump cold starting, better economy, higher compression ratios with the same fuel, more horsepower, operation unaffected by shaking or attitude of the vehicle, lower failure rate, continued parts support, and faster diagnosis. Up to you... both of my carbureted vehicles are going EFI as I have the time to convert them.

    Carburetors ... fractious, fiddly, fragile beasts. 20th century stuff. Yes, why would anyone use a carb?
     
  9. Sep 25, 2008
    Dummy

    Dummy I kick hippies

    Escondido, CA
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    Dec 5, 2004
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    Go find a Chevy from the early '80s with a 305 V8 and yank the Q-Jet for $25. Throw a $25 Napa rebuild kit on the carb, then slap it on your 304 with a $15 adapter plate. It's more than 10X cheaper than injection and you'll hardly notice the difference until you go almost vertical.

    Injection is nice, but I can make most of my stuff run very well with a carb. You've just got to put a little time into it.
     
  10. Sep 25, 2008
    hudsonhawk

    hudsonhawk Sponsor Sponsor

    Dallas, TX
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    The short answer is becasue you want too.

    I personally prefer FI. Buthen I am very at home with computers and electronics. I am running a Megasquirt on my CJ that I built myself. I know what every component does, how to fix it if it fries and even what parts I can use for replacement if I have to.

    My last trip to colorado I ran in elevations from 6K ft to 13K+ feet. The only thing I had to do was maually adjust the idle screw when I got to the camp ground the first night. The EFI took care of everything else for the altitude change.

    I have had no problems driving up stuff that every carburated vehicle in the group choked and sputtered on. The engine will continue to run even whentehjeep is laying on its side and allow you to drive out of bad situations. (thsi is from personal experience too.) Yes Carbs are good. But I will take EFI over one any day.
     
  11. Sep 25, 2008
    NorCoJeeper

    NorCoJeeper Member

    Ft. Collins CO
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    When I did my 302 swap, I pulled the Megasquirt 5.0 fuel injection system and installed a carb so I had one less thing to worry about during the "new car blues" phase of getting everything sorted out again. I ran the FI on the 302 for several years, boy what a difference going back to carb was! The most noticeable thing is that the fuel mileage is horrible. That injected 302 in a 6500 pound truck with 42" tires got 14mpg. In my little CJ with 35's, the same engine with a carb gets 10mpg even after a lot of tuning. The carb is also real bad on long, steep climbs, the engine will die from fuel starvation. Never had that happen with FI. Like Hudson, I've also driven my fuel injected truck out of obstacles when it was basically laying on it's side. The fuel injection is going back on soon.
     
    Last edited: Sep 25, 2008
  12. Sep 25, 2008
    jragain

    jragain Member

    Billings, Montana
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    [QUOTE=... both of my carbureted vehicles are going EFI as I have the time to convert them.
     
  13. Sep 25, 2008
    jragain

    jragain Member

    Billings, Montana
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    And when you have the time to convert them, will it be to a TBI system or multi-port?
     
  14. Sep 25, 2008
    NorCoJeeper

    NorCoJeeper Member

    Ft. Collins CO
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    If you need some decent feedback on current EFI systems, this months Hot Rod has a run down on what's available now and reports on three or four installations. Lots of good info.
     
  15. Sep 25, 2008
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    Oh. The V8 (CJ-6) will be GM TBI, basically the same system that their 305/350 V8 would get. I'm conflicted about the 258 pickup. It will probably be TBI too, unless I find an XJ donor cheap, then it will be Mopar MPI with the HO head.
     
  16. Sep 25, 2008
    Cantilope

    Cantilope Member

    My Jeep can...
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    I have a '72 CJ that I have been driving since 1991. In those years I have gone through 3 carbs. This last time (about 2 years ago) I sprang for the expensive MPFI…

    Here are the pros… The Cons

    Better throttle response Expense
    Quicker warm up
    Reliability
    50% increase in MPG
    Smoother Idle
    I can pass emissions with no problem
    Id guess 25-50 HP gains (seat of pants)
    Readily available parts
    Adjusts for elevation
    Easier to adjust (if I had to)
    Doesn’t flood when I climb
    Looks cool when I open my hood
    My kit fits 304, 360, or a 401

    My 304 now, is nothing compared to the 304 it was under a carb. I am not saying the EFI is for everyone, but my jeep has been around longer than my wife. I intend to be buried in it when I die. I did pay a pretty penny for this system, but really no more than you would spend on a set of tires and wheels. With gas at $4 a gallon, I am saving $1 per gallon so based upon my calculation I will pay it off in less than 20000 miles and get all the other benefits that come with technology.

    In fact I would go so far as to say this EFI saved my jeep. I hated everything about the way it drove before, from climbing steep hills to just getting it started after sitting for a few weeks. Even after I would get it started it would fill my garage and house with Carbon Monoxide. I let it sit for almost 5 years. My EFI was the first step that got me rolling on my frame up modded resto. I decided to build a Jeep around my motor, not a lot of people would do that to a carbed 304.

    You want to know why you put EFI on a Jeep, let’s take a ride in mine and I will show you… I’d put my EFI 304 up against a carbed 360 any day, and get 16+ MPG doing it.
     
  17. Sep 25, 2008
    72_CJ5_MUD

    72_CJ5_MUD Gunner

    now Central Florida
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    Have been driving since 1966 and had my 72' CJ-5 since new.

    I have enjoyed my 258 (+.030) with the four barrel Holley and Offenhauser intake since installation in 1974 and finally replaced the original Holley with ANOTHER new Holley last Spring 2008! May be running the smallest jets Holley offers... but the results are fantastic! Lottsa torque and response!

    Have had this ol timer CJ-5 all over The United States including Alaska! Have only suffered timing issues (easily advanced or retarded as needed) and NEVER had any problems with inclines or otherwise! Love my Holley Four Barrel and only thought about a change to injection due to advancements.... but have stayed with the HOLLEY! Just cannot bring myself to make any changes with the fuel delivery at this time!

    Gunner :flag:
     
  18. Sep 25, 2008
    zila

    zila I throw poop

    Rock Springs,...
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    My opinion is that carberueters are not much mo ethan a controlled leak. When I get the coin I will have a throttle body on mine..
     
  19. Sep 25, 2008
    pathkiller

    pathkiller Banned

    Lorton, VA
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    By that reasoning you can also rightly claim that a TBI is just an electronically controlled leak. TBI is really nothing more than a computer controlled carburetor.
     
  20. Sep 25, 2008
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    True in the broadest sense, though the GM TBI does include spark control and a knock sensor. There's nothing like that on a carburetor. Plus the TBI has more inputs than a carburetor, so it makes better informed responses.
     

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