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Running Velocity stacks on a Daytona

Discussion in 'Vintage (thru 365 GTC4)' started by ag512bbi, Jul 2, 2021.

  1. ag512bbi

    ag512bbi F1 Veteran
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    Nov 8, 2003
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    Anyone running velocity stacks on a Daytona. Educate me.
    Maybe looking to buy a set.
    Please give me your views. Pros and Cons.
    And a direction to look into buying them. I believe I need the "filter" or "screens" to go with it, correct?
    During service on my Daytona I had a chance to drive it around the block without the air cleaner. I LOVED the sound and I felt more power. Photos would be appreciated.
    Let me know... Thank you
     
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  3. 1monza

    1monza Karting
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    Jan 11, 2005
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    Norbert Hofer
    When you change to velocity stacks, you'll have to change the carburator tops and the jetting. I have the correct carb tops and velocity stacks but I don't believe an entire set.
     
  4. TTR

    TTR F1 Rookie
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    I did such conversion last year and the owner appeared pleased with the results.
    Discovered at least 2-3 different ways to do it, each presenting its own set of technical challenges…
     
  5. miurasv

    miurasv F1 Veteran

    Nov 19, 2008
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    There is good reason why road cars use carburettor air filters.

    As well as not being original specification, running a car without the carburettor air filter causes premature engine wear, and greatly reduced longevity due to the engine ingesting debris like dust, water, dirt, sand, insects etc.

    Valves, valve guides, cylinder bores, pistons and piston rings get scratched and wear out much quicker. Debris also ends up in the engine oil causing more wear around all the internal bearings in the engine. The carburettors themselves get damaged too.

    The Daytona uses an air filter with a snorkel, that actually draws air in directly from the front of the car, and distributes the air more effectively and evenly around the surface area of the carburettor intakes, resulting in cleaner and better carburation

    It may be beneficial for cars like a 250 GTO and certain racing cars (but not all), that are rebuilt often, to run without filters, where every single horse power counts, but not for a road car where any potential power increase would be very marginal, if anything at all.

    Yes, velocity stacks look nice, and sound great, but using them is not respecting the internals of the engine.

    Just my opinion.
     
  6. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
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    I agree with your writing steven. but how many miles you will drive each year? if you would have a "normal" daily street driving car I never would go without airfilter, but for may be max. 1000 km a year I would not be afraid going with open snorkels. have this also on my BB, only on the snorkels/"intake funnel" some "fly screen material" that no insects can come in
     
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  8. daytonaman

    daytonaman Formula Junior

    May 1, 2007
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    howard pigdon
    I have a set ,inc correct 3 stud tops
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  9. TTR

    TTR F1 Rookie
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    I pretty much agree with above and did forewarn my aforementioned client/car owner with similar lecture about the very potential pitfalls associated when running a road car without air filter(s).
    One just has to weigh benefits of looking and sounding cool vs. (very real) potential for problems conversion/modification like this may bring.
    There appears to be a small increase of bell HP associated with elimination of air filter assembly, but like any other high HP increase or rating on any (modern or vintage) car, nothing noticeable unless it’s actually being put to use near or above 80% the car’s performance capabilities.
    Large/huge HP ratings on road/street cars are usually just paper tigers (i.e. easy marketing gimmicks) and bragging rights, but rarely, if ever used or useful.
     
  10. daytonaman

    daytonaman Formula Junior

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  11. ag512bbi

    ag512bbi F1 Veteran
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    Great information. I appreciate the education.
     
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  13. Ianjoub

    Ianjoub Formula Junior

    Dec 22, 2019
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    Ian Joubert
    What do velocity stacks do?

    Air is sucked into the combustion chamber. Pressure waves occur in the intake tract. Varying the length (height) of the velocity stack optimizes the engine's ability to fill the cylinders at a certain RPM (which will have a specific wavelength). Velocity stacks are used to create more power at certain RPMs. At what RPM are you wanting more HP? In most racing scenarios, people optimized high RPM power. This may be counterproductive for street use.

    Many modern sportbikes use varying length stacks directed by the ECM and moved with a small servo motor. This creates the ideal length at all RPMs. Of course, this is done in the filtered area of the air box.

    <iframe width="560" height="315" src="" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
     
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  14. Edward 96GTS

    Edward 96GTS F1 Rookie
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    no actual hp gain will be seen on the road as the engine will be sucking in hot air whereas the stock setup breathes cold air thru the snorkel tube.
    bad idea.
    even the racing daytonas had an air box to source cold air.
     
  15. Jack-the-lad

    Jack-the-lad Four Time F1 World Champ
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    I look at these matters through a fairly simple lens: The factory engineers could have designed and specified the desired modification (velocity stacks being just one of many) but they did not. They must have had a good reason.
     
  16. AllTwelve

    AllTwelve Rookie

    Apr 6, 2009
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    Hi Monza, I have been looking for a carb top for one of these. Is it possible to PM me?
     
  17. Ed Niles

    Ed Niles Formula 3
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    I agree with Miura SV, and will add that I seriously doubt that there is much, if any, actual HP increase. I admit it could sound better, but is that worth the extra wear and tear?
     
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  18. ag512bbi

    ag512bbi F1 Veteran
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    After reading all these posts, I am really leaning on NOT installing the Stacks. I really didn't know there were more cons than pros. I appreciate all the opinions.
     
  19. rossodino

    rossodino Formula Junior

    Dec 16, 2007
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    bruce sansone
    That is the right thing to do Armen good decision.
     
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  20. llink

    llink Karting

    Nov 18, 2013
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  21. ag512bbi

    ag512bbi F1 Veteran
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    Man, that looks Good!
     
  22. Dogdish

    Dogdish Formula Junior

    Dec 27, 2005
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  23. TTR

    TTR F1 Rookie
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    Did you by chance do any before/after (chassis ?) dyno testing to gauge power improvements ?
    Is the engine otherwise stock or … ?
     
  24. Dogdish

    Dogdish Formula Junior

    Dec 27, 2005
    359
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    I didn't do any "before" dyno runs. I first put on some poorly made euro style equal length headers and those really woke the car up. Later I installed the velocity stacks and an airbox. We dyno'd the car here in Colorado without the airbox and with open side pipes.....not much exhaust restriction. 293HP. I installed bolt on parts to let the engine breathe better that can easily be removed by a future owner. Very loud at 7000 RPM
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  25. TTR

    TTR F1 Rookie
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    :cool:

    “HP” at the rear wheel or a Typo ?

    The “conversions” (stacks & muffler delete) I recently did I designed and made to be easily reversible back to stock components, all which were saved and stored away.
     
  26. Dogdish

    Dogdish Formula Junior

    Dec 27, 2005
    359
    Denver
    Yes, at the rear wheels. Dynojet chassis dyno. I didn't and don't care about HP or torque figures, just trying to get a nice safe fuel/air ratio up here at Denver altitude. At sea level, the car is demonstrable more alive.
     
  27. bighitter2

    bighitter2 Formula Junior

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    #24 bighitter2, Jul 22, 2021 at 7:47 AM
    Last edited: Jul 22, 2021 at 7:55 AM
    Velocity stocks were on my car when purchased in 1999..engine is built to “ Lemans specs with symetrical 8500 rpm P6’s , comp distributors , high compression pistons and due to euro car tube headers …had it dynoed when first bought and out of respect for for the motor i instructed them to only take it to 6500 which showed 365 hp on a steep upward curve …since i show and display more than drive i installed the red micro screen booties over the metal screens and clean regularly…never had a problem..runs like a scared rabbit and looks and sounds awesome ( especially running thru the tunnel at fisherman's warf in Monterey :). First Pic Concorso about 2003.. 2nd pic Newport Concours about 2004 , with screens and red micro filters 2012 Kingsmill Ferrari event Williamsburg Va.
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