Carbs
+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast
Results 1 to 14 of 43

Thread:
Carbs

  1. #1
    Senior Member Flat Fan's Avatar
    Join Date
    Nov 2009
    Location
    Agua Dulce
    Posts
    269

    Default Carbs

    I know this is a dumb question, but I have to ask it. Why is the jets and squirters different sizes from the primary to the secondary. The reason I ask this is because I've seen some carbs have the same sizes for the squirters and jets. Why can't you just have the same sizes for both, is there a right and wrong.
    Thanks in advance

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,840

    Default

    Quote Originally Posted by Flat Fan View Post
    I know this is a dumb question, but I have to ask it. Why is the jets and squirters different sizes from the primary to the secondary. The reason I ask this is because I've seen some carbs have the same sizes for the squirters and jets. Why can't you just have the same sizes for both, is there a right and wrong.
    Thanks in advance
    No such thing as a dumb question----just dumb answers and you came to the right place for that! Primary and secondary differ due to engine requirements thru the rpm range. There are exceptions to the rule. Side slung, butterflies open at same time for drag apps, worked carbs that are built for idle to W.O.T. in a heart-beat. But to generalize the question, if you are cruising along at 2800 rpm do want the same amount of air/feul as if you nailed it for a race. M

  4. #3
    Cantard 71hallett's Avatar
    Join Date
    Mar 2008
    Location
    snow bank
    Posts
    5,017

    Default

    Just to add to what Mark posted...

    You will also notice that most carbs also run power valves in the front. That is another reason your seeing the 8-10 jet size differences.
    Another is air bleed sizes are also usually different from front to rear which gets back to what Mark was saying in his post.

    Most "race" carbs are pretty square but the "street/strip" stuff is built this way for fuel/cruise purposes.
    Quote Originally Posted by gn7 View Post
    It would be a balmy 85* in Steel's shop if he would move a little faster

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Member
    Join Date
    Jun 2008
    Posts
    32

    Default

    "No such thing as a dumb question----just dumb answers and you came to the right place for that! "

    LOL,
    Another couple semidumb questions about carbs from the noobie gallery.

    What is the reasoning behind spread bore carbs?

    In a well engineered carb at least with vacuum secondaries doesn't it all sort of equal out anyway?
    If this is tourist season, why can't we shoot them?

  7. #5
    Senior Member Factory1's Avatar
    Join Date
    Oct 2008
    Posts
    1,134

    Default

    For a dedicated drag motor, I prefer to plug the power valves, and run the jets and squirters square (all the same).

  8. #6
    steelcomp was here
    Join Date
    Dec 2007
    Location
    n/e TN
    Posts
    26,470

    Default

    Quote Originally Posted by TollyWally View Post
    "No such thing as a dumb question----just dumb answers and you came to the right place for that! "

    LOL,
    Another couple semidumb questions about carbs from the noobie gallery.

    What is the reasoning behind spread bore carbs?

    In a well engineered carb at least with vacuum secondaries doesn't it all sort of equal out anyway?
    Small primaries provided good throttle response and good economy for around town driving and highway cruise. They also sounded cool when you mashed the gas...buuhhwaaaaaahhhhhhh
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  9. #7
    Member
    Join Date
    Jun 2008
    Posts
    32

    Default

    They do sound cool, I love the sound of a motor sucking through a carb better than the throaty rumble of the exhaust.

    So the reason for the question. I'm swapping out my old troublesome 650 holley 4011 spreadbore on my bonestock 8:1 454. Pretty tame motor for this place, but it's in a cabin cruiser and that's the way I roll, LOL

    I'm torn between the 650 4175 spreadbore or the more conventional 4160 in either a 600 or 750. I don't run this motor much past 3200 or so. The 4011 is a bit of a bastard child of the holley family and I would like as conventional and easy to tune and fiddle with replacement as I can get instead an oddball.

    I'll need an adapter of some sort to fit a square bore. I'm interested in economy more than performance but it is my impression, since I run that boat at a steady state, that tuned correctly it may not make much difference. Interested in the opinions of my betters.
    If this is tourist season, why can't we shoot them?

  10. #8
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    Quote Originally Posted by steelcomp View Post
    Small primaries provided good throttle response and good economy for around town driving and highway cruise. They also sounded cool when you mashed the gas...buuhhwaaaaaahhhhhhh
    When I first started driving, my Mom drove a 455 GS Buick. I use to take the air cleaner cover and flip it over for a little Sat. Nite cruizing. I forgot to flip it back one nite. She gets in it to go to church the next morning with a some of her women friends. She punches it getting on the freeway, and she tells me they all about had heart attackes. Couldn't drive that thing again for about 3 months.



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

  11. #9
    Senior Member Flat Fan's Avatar
    Join Date
    Nov 2009
    Location
    Agua Dulce
    Posts
    269

    Default

    Quote Originally Posted by 71hallett View Post
    Just to add to what Mark posted...

    You will also notice that most carbs also run power valves in the front. That is another reason your seeing the 8-10 jet size differences.
    Another is air bleed sizes are also usually different from front to rear which gets back to what Mark was saying in his post.

    Most "race" carbs are pretty square but the "street/strip" stuff is built this way for fuel/cruise purposes.
    Is that the same reason why the squirters are different sizes too because of the power valve is in the front.

    Here is my last question, sorry for asking so many. I recently got a blown motor, I bought a pair of AED 750 blower carbs, when we first started it they backfired, so the carb guy I went through upped the jets to around 10 sizes and the sqiurters 2 or 3 sizes, but on the sqiurters he squared them up. What is the advantage of doing this.
    Thanks again

  12. #10
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    Quote Originally Posted by Flat Fan View Post
    Is that the same reason why the squirters are different sizes too because of the power valve is in the front.

    Here is my last question, sorry for asking so many. I recently got a blown motor, I bought a pair of AED 750 blower carbs, when we first started it they backfired, so the carb guy I went through upped the jets to around 10 sizes and the sqiurters 2 or 3 sizes, but on the sqiurters he squared them up. What is the advantage of doing this.
    Thanks again
    Although a lean condition will cause it to backfire (thru the carb), AED's are usually pretty close out of the box. Because you have "blower carbs" they are manifold referenced. Don't know your current jet size or power valve restrictor size, but it sounds as though he just fixed it by dumping fuel. Were these carbs new and un-molested or did you by them from someone who told you they are "blower carbs"



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

  13. #11
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,840

    Default

    Quote Originally Posted by Flat Fan View Post
    Is that the same reason why the squirters are different sizes too because of the power valve is in the front.

    Here is my last question, sorry for asking so many. I recently got a blown motor, I bought a pair of AED 750 blower carbs, when we first started it they backfired, so the carb guy I went through upped the jets to around 10 sizes and the sqiurters 2 or 3 sizes, but on the sqiurters he squared them up. What is the advantage of doing this.
    Thanks again
    The more responses the more questions you will have and that is not a problem here. Its winter and alot of good (some bad) guys willing to lend a hand. My question would be, did it pop thru the carbs or thru the exhaust? Motors back fire for alot of reasons and intake and exhaust pops or flames narrow it down alot.

  14. #12
    Senior Member Flat Fan's Avatar
    Join Date
    Nov 2009
    Location
    Agua Dulce
    Posts
    269

    Default

    Quote Originally Posted by gn7 View Post
    Although a lean condition will cause it to backfire (thru the carb), AED's are usually pretty close out of the box. Because you have "blower carbs" they are manifold referenced. Don't know your current jet size or power valve restrictor size, but it sounds as though he just fixed it by dumping fuel. Were these carbs new and un-molested or did you by them from someone who told you they are "blower carbs"
    Brand new carbs

  15. #13
    Senior Member Flat Fan's Avatar
    Join Date
    Nov 2009
    Location
    Agua Dulce
    Posts
    269

    Default

    Quote Originally Posted by ol guy View Post
    The more responses the more questions you will have and that is not a problem here. Its winter and alot of good (some bad) guys willing to lend a hand. My question would be, did it pop thru the carbs or thru the exhaust? Motors back fire for alot of reasons and intake and exhaust pops or flames narrow it down alot.
    It popped through the carbs.

  16. #14
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,840

    Default

    Quote Originally Posted by Flat Fan View Post
    It popped through the carbs.
    Then more than likely you had a lean condition and sounds like you are on the right track with going fatter. That is of course if the timing is right. Also the tune is correct.

+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95