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Hot Rods Repro Scot blower can't make real boost

Discussion in 'The Hokey Ass Message Board' started by CheatersPete, Jul 24, 2018.

  1. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,600

    Johnny Gee
    Member
    from Downey, Ca

    Then this means you will do the carbs and tune them before the can swap? I ask because never change more than one thing at a time or one may never know what made things better or worse when changing everything at once.
     
    porkshop and belair like this.
  2. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    Hi all, it is morning In Switzerland beautiful country, (7.78 am) , I m arriving at work, driving the roadster with the Stromberg BIG 97, I can tell you, what a change ! boost is now coming up to 4 PSI at 5000rpm. engine is smoother at every rpm. my conclusion as off today is, that 500cfm vs 330 cfm is way better, my blower case-lobes clearance is not Ideal but I should get more boost. I order the same cam as I have now but with 112 overlap instead of 108.

    Just to recall, on my ex coupe, I had the french flathead 255ci, full stock rotating, porting, max 1 cam, 4/71, dual holley 94 (2110), chevy ignition and capable of making 234 hp at 6 pasi/5000rpm.

     
  3. HotRodMicky
    Joined: Oct 14, 2001
    Posts: 1,783

    HotRodMicky
    Member

    Much better!
    The 112 LSA may help a little , but i am still not sure it makes so little boost with the small 255ci engine
     
    loudbang likes this.
  4. continentaljohn
    Joined: Jul 24, 2002
    Posts: 5,504

    continentaljohn
    Member

    Awesome video and great to hear it’s running stronger..
     
    loudbang likes this.
  5. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    Ok, tuning is almost done, still too fat but I have ordered adjustable jets.
     
  6. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    driving to work this morning
     
  7. Almost makes me want to build a flathead! :cool:
     
    loudbang likes this.
  8. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    I talked with Pete about having a cam ground for a blower motor last year when I had my 1007b ground. I tossed an extra core into the box and asked him to come up with something for a hot flathead that would work well with a blower. He came back with a grind I never really heard too much about. It's a harmon Collins 6372 grind. I was a little dubious at first given its .408 lift and big duration. Then I ran the numbers! It's got a 113.5 LSA. I can't wait to build this motor and see how she runs!

    Sent from my SM-G965U using The H.A.M.B. mobile app
     
    loudbang likes this.
  9. Measuring the vacuum under the carb at WOT, will tell you if the carbs are too small.
     
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  10. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    I just realized something about the carbs you were running. You said you had 94's... but called them 2110s. 2110 carbs were not 165cfm. If you had 94/100 venturis.. you had 165. Most 2110 carbs were bigger than that. I couldn't tell in your picture what you had. 2110's with manual chokes usually came off early y-blocks with a boss for something off the rear of the base. Forget what it was for now. You may not have gained much as those carbs are around d 210cfm

    Sent from my SM-G965U using The H.A.M.B. mobile app
     
    gimpyshotrods and loudbang like this.
  11. haileyp1014
    Joined: Feb 15, 2006
    Posts: 933

    haileyp1014
    Member
    from so cal

    Makes a nice $8000 paperweight or something to talk about on the workbench. Why isn't H&H taking care of this?
     
  12. lumpy 63
    Joined: Aug 2, 2010
    Posts: 2,603

    lumpy 63
    Member

    So if a person was to take a poll on the people who buy SCOT blowers ...how many do you think actually hammer on em, or just use em for car show cred? I'm not talking crap about CheatersPete by any means, and I'm glad he got it to work better. IMHO I would say 90% couldn't give a shit wether it made boost or not . But Damn it looks good at the show;)
     
    loudbang likes this.
  13. Brand Apart
    Joined: Jan 22, 2011
    Posts: 808

    Brand Apart
    Member
    from Roswell GA

    Glad you seem to be on right path. Beautiful car and looks like a beautiful place to drive based on video. Curious though, is this a year round daily driver? Seems like winter in Switzerland can be harsh based on what we see on TV movies etc. Unfortunaly I can't speak from experience .
     
    loudbang likes this.
  14. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    No sign from HandH since a month or so, I don’t know how their business can continue like this as so many disappointed people , maybe many people only want show parts ?
    To answer concerning the Swiss weather , summer is usually good and hot , spring and autumn can be nice with decent temperatures and weather but can also be terrible and cold , I drive 2000 to 5000 per year , driving to work and bringing the kids to school
     
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  15. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    I would think the Scot blower is more a show piece than anything. much less efficient than other roots style blowers. guys who run them typically aren't looking for much boost. hell, most guys who supercharge them period aren't looking for much boost. it's a flathead with three mains... you get up into the 6psi range things start to get expensive on the the main cap end.
     
  16. x77matt
    Joined: Mar 2, 2004
    Posts: 812

    x77matt
    ALLIANCE MEMBER

    Thanks for the follow-up Pete! I love your videos. When you get it tuned in, can you tell us what jetting you ended up with in your carbs?
     
    loudbang likes this.
  17. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    Man, that almost makes me wish I still had to drive to work in the morning.




    Sent from my iPad using The H.A.M.B. mobile app
     
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  18. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    I use adjustable jets on my 97's, hard to tell... but the original jets are too big for sure. I have my O2 sensor set at 13.5 at idle and 13 at WOT, my engine like to be rich.
     
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  19. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    Of course they do. Any wet blower will make more power with a rich mixture than optimal. The extra fuel cools the charge.

    Sent from my SM-G965U using The H.A.M.B. mobile app
     
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  20. G-son
    Joined: Dec 19, 2012
    Posts: 1,275

    G-son
    Member
    from Sweden

    ...and helps sealing between the blower rotors/housing, slightly increasing boost.
     
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  21. Kiwi 4d
    Joined: Sep 16, 2006
    Posts: 3,564

    Kiwi 4d
    ALLIANCE MEMBER

  22. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    Past 5 month were really really busy building engines and hot-rods, spring is coming and I will have to get my roadster from my parents house... will continue working on the jetting and asap dynoed. Will let you know where it stand soon.
     
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  23. 41rodderz
    Joined: Sep 27, 2010
    Posts: 6,540

    41rodderz
    Member
    from Oregon

    Boy to have a rich mans problems . :D
     
  24. scrubby2009
    Joined: Jan 9, 2011
    Posts: 204

    scrubby2009
    Member

    Awesome, for you and your kids. I will never forget being 11 years old and seeing my pops slide into the school parking lot in out mintgreen '57 BelAir. I was the proudest happiest kid. Hope your kiddos are too.
     
    Montana1 likes this.
  25. Hey Pierre, good to see its running better ;)

    FYI - I ran an L100 4-71blown combo in my old 258 cube engine, and it ran like a raped ape. The current combo is a 289 ci deal with a custom Tatom blower cam on a 112 LSA.

    I run 2x Stromberg WW large cfm carbs.so there is no restriction on the blower inlet side. The tune is great, plugs look great and at WOT I'm close to 8lbs ;)

    As others have said , a wider LSA will help - but a way to eliminate the blower as the issue would be to remove the Scot blower and swap the 4-71 onto your current mill with the same carbs and test to see what boost you are generating.

    Do you still have the 4-71 amigo ?
     
  26. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    HEY RATY, good to read you , nope I sold the 4/71 blower while ago. the scot blower is smaller and look better to IMO but perform not as well as the 4/71. the repro scot blower have to run twice the speed of a 4/71 for the same boost.
     
  27. Kiwi 4d
    Joined: Sep 16, 2006
    Posts: 3,564

    Kiwi 4d
    ALLIANCE MEMBER

    As we know higher speed generally generates more heat, I dont think A Scot at 172 cu.in. will make the boost the bigger 471 does at 280 cu.in., be nice if it did though.
    Did you use the factory H&H top and bottom pulleys?
     
    Last edited: Mar 25, 2019
  28. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    I agree, the small scot will never match the 4/71, I use a lower home pulley and a HH top pulley
     
  29. Kiwi 4d
    Joined: Sep 16, 2006
    Posts: 3,564

    Kiwi 4d
    ALLIANCE MEMBER

    Apologies for all the questions @CheatersPete but am I correct in assuming you have a larger lower pulley to overdrive the blower to make it spin faster and increase boost.
    Agreed the Scot does look cool , but in this case we spent a lot. So it does matter how fast you look and how you look going fast. I very much appreciate your replies.
     
  30. CheatersPete
    Joined: Sep 25, 2002
    Posts: 1,290

    CheatersPete
    Member

    Kiwi4d, indeed, I did a couple of blown flathead with 4/71, IMO they look gook as well, but not as good as the scot, running 6 psi on a street flathead is more than I need... but more power is always a good feeling
     
    soonrodder likes this.

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