Stock F40 Dyno Numbers | FerrariChat

Stock F40 Dyno Numbers

Discussion in 'Technical Q&A' started by zsnnf, Dec 6, 2003.

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  1. zsnnf

    zsnnf Formula 3

    Sep 11, 2003
    We finally got the F40 back on the DynoJet. This is what we found. I think the Numbers are a little low. The Air/fuel ratio is good up until about 4500rpm, then it goes rich gradually, to about 10 to 1.
    All number are rear wheel H.P.
    Any Thoughts? Rob?

    350 Base run. 91 Octane (I don't think Cal. gas is very good)
    368 5 gallons of 100 octane added to the 15 gallons of 91 in the tank
    414 We removed the stoct muffler
    400 We installed a Tubi Muffler

    We drove the car a while and came back to the dyno a month later.

    413 Test pipes (No cats) and Tubi on 91 octane
    420 8 gallons 100 octane added to the 24 gallons of 91 in the tank

    We gained 2+ psi of boost when we removed the stock muffler and another 2+ when we removed the Cats. Boost is about 19-20 psi now.

  2. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn

    Looks like you're cranking out about 520 hp at the flywheel with your modifications. I'd expect more.


    Did we talk about leakdown test results? I had a customer F40 years ago with a broken piston ring and 80% leak.

    I'll do a little more digging for information this week.

    You're wise to invest in 100 unleaded, which is fine at the pressure your running. Is it fresh from a 55 gal. barrel, or local pump fuel? I'd recommend Phillips B35 100 RON+MON/2 unleaded by the 55 gal drum.

    Best regards,

    Rob Schermerhorn
  3. F40

    F40 F1 Rookie

    Apr 16, 2003
    24=8=32. How big is the tank?
  4. ferrarifixer

    ferrarifixer F1 Veteran

    Jul 22, 2003
    Full Name:
    Phil Hughes
    I'd question the efficiency of your boost control valve.....

    Changing exhaust system shouldn't really effect the boost on most cars, certainly when the start point for a std F40 is 0.8 Bar Max....Do you have many mods to the boost system??

    The biggest bolt on gain I've found is in intercooler size. Going just 20mm thicker will give up to 10% BHP increase. The LM and GTE cars I see regularly only run approx 1.85 BAR with Wills rings head gaskets and other boost system mods.
  5. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    I'll politely disagree here, typically, reduction of exhaust pressure increases boost, in spite of wastegate settings. The turbo spools quicker. Of course, each application is different.
    1.1 bar by design, and injector cut-off is about 1.5 bar.
    OE intercooler is not a restriction of great concern until over 1.8 bar (26.5 psi!), and is a justified modification for LM/GTE. Bang for the buck on stock F40 is boost with proper A/F ratios (add fuel where necessary).

    I'll look for my intercooler flow numbers :)

    Best regards,

    Rob Schermerhorn

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