Fowler F-11 Help

Discussion in 'InsideTopAlcohol.com Tech Questions' started by Dirty Deeds, Feb 10, 2019.

  1. Dirty Deeds

    Dirty Deeds New Member

    Joined:
    Nov 27, 2016
    Messages:
    12
    Likes Received:
    1
    Can you please give me some guidance. Running in RED with 526 hemi running Veney fuel heads approx. 10.4 compression

    I have just changed my blower from 14-71 standard to a Fowler F-11 Plus. It has the high RPM shoe (as off a boat) in it and I'm not sure what OD I should run? Thinking of starting at 28% or should I go higher with the shoe its got?

    Also I'm using Alky Pro and not sure what gallon requirement I should enter - with the old blower I was using 10 gallons?

    Thank you for your assistance
     
    #1
  2. Policy Peddler

    Joined:
    Oct 12, 2005
    Messages:
    199
    Likes Received:
    1
    Try calling Jeff Fowler, I am sure he can steer you in the correct direction.
     
    #2
  3. Dirty Deeds

    Dirty Deeds New Member

    Joined:
    Nov 27, 2016
    Messages:
    12
    Likes Received:
    1
    Thanks, I have had a couple of PMs that I will be following up on
     
    #3
  4. promodracer

    promodracer Member

    Joined:
    Jan 8, 2008
    Messages:
    343
    Likes Received:
    0
    I was told 35% over is max wo shoe, then blower stalls. I run 35% and makes 34 lbs wo mods
     
    #4
  5. Soldierboy0098

    Soldierboy0098 Active Member

    Joined:
    Feb 17, 2006
    Messages:
    1,222
    Likes Received:
    11
    The method Bob Newberry taught me is to take your boost and divide it by your flow number. On a roots blown alky deal the lower the number the safer you are. I like to start at 2.8-3.0 and creep up on it. Typically 3.6 Seems to be a sweet spot. Example 35 lbs of boost by 10 gallons is 3.5 and would be right there but you have to make sure your pump is big enough to give you room and still maintain pressure. 25 lbs of boost and 12 gallons would be 2.91 and should be safe. This is all assuming timing, fuel distribution, ect...is correct. A modified F-11 is best at 25-29 percent but if yours is set up for more o.d. you may want to start at 25 and creep up watching the mph and boost numbers, you will know when it falls off. Mike Canter can tell you the exact number but if I remember correctly the tips go supersonic on a roots at 12,300 or 12,700 rpm. So if you run to 9800 rpm and 30 over that puts rotor rpm at 12,740 rpm, less rpm and you might be able to go a little higher on the blower. May be best to just get a 25-29 shoe which is where they make the best power.

    Calling Fowler with the serial numbers and shoe size is a great idea as well.

    Hope this helps some,
    Trevor Sherwood
     
    #5
  6. Dirty Deeds

    Dirty Deeds New Member

    Joined:
    Nov 27, 2016
    Messages:
    12
    Likes Received:
    1
    Thanks Trevor very informative. Using your maths we are running at 3.5
     
    #6
  7. Bjs344

    Bjs344 Member

    Joined:
    Sep 10, 2013
    Messages:
    224
    Likes Received:
    11
    Those rotor speeds speeds sound pretty low for a hh roots in general. I was told by the previous owner that my SSI F3 is set up to go 13+. I’ve talked to SSI briefly about it and don’t remember them telling me anything different.
     
    #7
  8. nitrowannabe

    nitrowannabe Member

    Joined:
    Oct 9, 2006
    Messages:
    354
    Likes Received:
    9
    I wouldn't compare your Fowler to an SSI. I wouldnt start a new combination at 29 over. Search rotor speed here. Much of this has been discussed before.
     
    #8
  9. Soldierboy0098

    Soldierboy0098 Active Member

    Joined:
    Feb 17, 2006
    Messages:
    1,222
    Likes Received:
    11
    I would double check with Mike Canter but when I had my SSI F3 HH I planned around the same rotor rpm's we were going to run the blower at 38 over and turn less engine rpm. SSI rotors are a different design than the Kobelco/Fowler but I can tell you when I owned Phil Esz F11 World record holding 3.60 blower and spoke with Critchley who did the mods 25-29 percent was where I was told it's most efficient.
     
    #9
  10. Soldierboy0098

    Soldierboy0098 Active Member

    Joined:
    Feb 17, 2006
    Messages:
    1,222
    Likes Received:
    11
    3.5 is great, 3.7 is usually on the verge of hurting parts, If it bumps 3.7 for a tiny bit during the run I wouldn't panic but once you find where your combination has issues those numbers will help you with tuning. They are all slightly different.
     
    #10

Share This Page