Welcome to Club Hot Rod!  The premier site for everything to do with Hot Rod, Customs, Low Riders, Rat Rods, and more. 

  •  » Members from all over the US and the world!
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and hundreds of thousands of posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

 

Thread: Vac secondary test?
          
   
   

Reply To Thread
Results 1 to 5 of 5
  1. #1
    Kevyd is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2005
    Location
    Winnipeg
    Car Year, Make, Model: 64 Chevelle
    Posts
    43

    Vac secondary test?

     



    What can I do to check if my secondaries are opening??? Carb is holley 750vac model 4160. Thanks.

  2. #2
    Kevyd is offline CHR Member Visit my Photo Gallery
    Join Date
    May 2005
    Location
    Winnipeg
    Car Year, Make, Model: 64 Chevelle
    Posts
    43

    vac sec

     



    That sounds good. I already have a lighter spring in there. I'm just not sure if they're opening at all! After a WOT run, the plugs are clean and white, showing a lean condition. I don't really feel a power surge, more of just a gradual increase of RPM. I've tried bigger jets-no dice. Plugs always come back the same. Is there anyway to ensure the secondaries are opening other than strapping it to a dyno and watching?????

    Thanks for the help guys/gals.

    -KevD

  3. #3
    BigTruckDriver is offline CHR Member/Contributor Visit my Photo Gallery
    Join Date
    Dec 2004
    Location
    TX
    Car Year, Make, Model: hotrod
    Posts
    1,830

    Go down the road about 10-20 mph then floor it!Be safe about it though!come up to speed and,let completly off of the gas as fast as you can.When you do this you will hear a big "woosh". This will be the secondaries closing.The best way to really adjust it,is to take it to the track and pay attention to your times,and MPH.I started with a weak spring and changed springs until ,my et,mph got it best.When my mph and et started to fall after peaking,I went back to the spring I put in just before.They sell a kit of a few springs(color coated) for I think less then ten dollars.Theres also a little red book holley sells.This thing is a Holley " bible" .Theres another that has more ibfo and tricks ,but I forget the writer.There is also plenty of pics. to help get a better idea of tuning your holley.
    Last edited by BigTruckDriver; 06-15-2006 at 06:52 PM.

  4. #4
    timothale's Avatar
    timothale is offline CHR Member Visit my Photo Gallery
    Join Date
    Mar 2005
    Location
    castroville
    Car Year, Make, Model: 16 t buckethotrod 17 horsless carriaget
    Posts
    170

    I used to modify the linkage, bend 16 d nails weld them on the linckage so I had a mechinical kick in.
    timothale

  5. #5
    NTFDAY's Avatar
    NTFDAY is offline CHR Member Visit my Photo Gallery
    Join Date
    Aug 2003
    Location
    Springfield
    Car Year, Make, Model: '66 Mustang, 76 Corvette
    Posts
    5,353

    This book is a good source of information
    Last edited by NTFDAY; 02-04-2008 at 10:04 AM.
    Ken Thomas
    NoT FaDe AwaY and the music didn't die
    The simplest road is usually the last one sought
    Wild Willie & AA/FA's The greatest show in drag racing

Reply To Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Links monetized by VigLink