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HOW DO I TUNE MY EDELBROCK CARB???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigoltrux77, Aug 19, 2002.

  1. bigoltrux77

    bigoltrux77 1/2 ton status

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    i have an edelbrock performer series carb that i really need to tune. I downloaded instructions at www.edelbrock.com but i dont understand them very well. CAn someone give exact instructions in lamens (spelling) terms? Thanks alot..I love this forum!
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Unfortunately those instructions are about as simply written as they can be. I followed them to the letter and got good results...

    If there is a specific part of the instructions you can't figure out copy and paste that part and we might be able to simplfy or explain it.

    What adjustments are you trying to make? Idle mixture? WOT?

    Rene
     
  3. bigoltrux77

    bigoltrux77 1/2 ton status

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    i dont know where an of these rods etc. are. All i know are the two needles in front and idle on the side. where is everything else? and i dont know what the whole .082" for a certain type of calibration is. I kow i sound dumb..i just dont want to pay someone 50 bucks to do it if i dont have to.
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Most of these carbs come close to where they should be out of the box...maybe a little tweaking here and there. If you look at the top of the carb you'll see two small plates with one screw holding them down flush. If you remove the screws the plates will get pushed up by a spring thats underneath and you'll find the metering rods. The end of the metering rod fits into a jet at the bottom of the float bowl and meters the amount of fuel. The number (.082") is the diameter of the jet. The rod itself is thin on the end and then steps up to a larger diameter. At idle or part throttle the fat part of the rod is in the jet allowing only a limited amount of fuel to be 'metered'. Once you step on the gas a little harder the vacuum signal drops and the spring will lift the metering rod up so the thin part of the rod is now in the jet. This allows much more fuel to be metered.

    Ideally to find the perfect jet and metering rod combo you either need a dyno, some track time, or one of the G-tech jobs...mine seemed to run fine and the only adjustment other than idle mixture I made was the secondary spring. My secondaries were barely opening so I swapped in a stronger spring, this allows the secondaries to open a little sooner and seemed to work well on my motor.

    What are you trying to adjust?

    Rene
     
  5. Pure Insanity

    Pure Insanity 1/2 ton status

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    Start by unbolting the carb and carrying it to the bench. Take a good look at it, slide it to the end of the bench, look at it again, then slide it off the end into the trash can and install a truck version of a Holley. Sorry but thats the best way to tune an Edelbrock Ive found. Holleys have simple to change jets for tuning. If you need to, I am yet to see a daily driven engine that needed to be rejetted. No stupid metering rods or flapper to regulate fuel flow. The biggest downfall to Holleys is the power valve, but all new carbs have that problem fixed.
     
  6. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> I guess it all comes down to personal opinion. We had a Holley carb on my brother's old Nova and tried to get it tuned for over a year and it always gave us problems. Bolted on an Edelbrock Performer and the thing ran perfect after just basic adjustments. I've run them on my truck, a boat, and 4 of my friends have them on a total of 6 other cars and trucks, most were swapped in place of Q-jets or Holleys, and none of us would ever go back. The Edelbrock has some faults in off camber situations, but they can be fixed cheaply and easily. And there is NO OTHER carb that is as easy to tune as the Performer.</font color>
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    After pulling the top of my performer off (10 screws, 5 minutes) I have a hard time beleiving a holley could be easier. Actually I had a holley...it sucked, would not stay in tune for more than a day and didn't make as much power as the performer does. The Holley also heat soaked really bad...

    Rene
     
  8. Pure Insanity

    Pure Insanity 1/2 ton status

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    /forums/images/icons/grin.gif I knew I was gonna catch heat for that post! LOL!

    Changing jets on a Holley is incredibly easy. 4 screws and the bowl is off, and theres the jets. The gaskets suck though I do have to admit that. /forums/images/icons/mad.gif

    Ive had Qjets and Edelbocks before. The Edel could not be tuned to work on my motor, /forums/images/icons/mad.gif the Qjet burned my 1st Camaro down. /forums/images/icons/frown.gif I bolted a modified Holley 850 on my Jeep tuned it and drove the piss outta it for close to a decade. Bolted it on the Blazer and something happened to it while it was sitting up and would not tune in for nothing. One side of the carb just wouldnt lean out. The 850 was a bit too much for daily driving anyhow, but RIPPED on the top. /forums/images/icons/grin.gif So I got another Holley. This time its a 750. Bolted it on, tuned it and been running it everyday for 3-4 months now. No need to touch it.

    So yeah it is personal opinion. I will only run Holleys. I just love thowing Holleys in when people cant tune an Edelbrock. /forums/images/icons/wink.gif
     
  9. TX Mudder

    TX Mudder 1/2 ton status

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    I have a 1406 on my 350.
    All I did was run it straight out of the box and it was fine. I ended up putting the offroad kit just to see if it made a difference. To be honest, it didn't (that I could feel at least) but maybe I'm not the extreme rockcralwer a lot of guys are. More of a muddy trail/muddy pit type.
    -- Mike
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    You can pull the entire top off an Edelbrock carefully and not even need to replace the gasket.../forums/images/icons/cool.gif
    </font><blockquote><font class="small">In reply to:</font><hr />
    when people cant tune an Edelbrock.

    [/ QUOTE ]
    Usually when they can't be tuned they need a rebuild or at least a good cleaning...but that's true for any carb. On my old Holley the idle mixture screws were so loose they'd just walk out in a matter of days. I did get it used though so who knows what was done by the PO.

    Quadrajets i have no luck with...but I may cringe and try another one for some better off camber performnce.

    Rene
     
  11. Pure Insanity

    Pure Insanity 1/2 ton status

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    The idle mixture screws have a sort of packing around them that helps keep them put. They get hard over time and tend to let the screws walk out. /forums/images/icons/wink.gif
     
  12. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Typical Holley... /forums/images/icons/grin.gif

    Rene
     

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