Supercharged hp vs Webers+ported QV hp on dynos | FerrariChat

Supercharged hp vs Webers+ported QV hp on dynos

Discussion in '308/328' started by snj5, Jul 20, 2008.

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  1. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    Russ Turner
    #1 snj5, Jul 20, 2008
    Last edited by a moderator: Sep 7, 2017
    Just for the fun of it, since both Lou Gaudio and I both used Dyno -jet chassis dyno which are nominally comparable, I thought it might be fun to cross plot our dyno results. He has a superb bolt on supercharger kit as you all know and I went the old fashion way with ported heads and Weber carbs. The dyno I have is admittedly sub-optimal as it was just an initial (Mixtures were way rich) and the carb set up should pick up more as we get the jetting right, but it is fun to compare with the initial numbers.

    This is Lou's dynojet on his car with the results in colored lines showing the original run and two supercharged runs. I've plotted the hp of the Weber carb'd Mondial as red dots over the same graph. While Lou ultimately makes more hp at the top end above 6000rpm with the later pulley, the carbs keep up pretty well in the midrange where most street driving occurs. The Webers and ported heads may even end up stronger and torqueier down low once the Weber midrange A/F is above 10 - 11 after re-jetting.

    This was the target engine characteristics for the heavier Mondial in the street rpm range where it is most used. I'm very happy that careful tweaking of a few basics kept up with the Lou and Scott's great blower motors. While the Webers will not make the ultimate high end numbers, it will probably be a torqueier motor below 7000 rpm once tuned. How cool is that? And did I mention the sound?

    best to all
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  2. regisgtb4

    regisgtb4 Formula Junior
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    that steep curve is what horsepower feels like,and these Cars are about horsepower.
     
  3. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    Russ Turner
    #3 snj5, Jul 20, 2008
    Last edited by a moderator: Sep 7, 2017
  4. ctk

    ctk Karting

    Jul 2, 2001
    238
    Singapore
    Hi Russ,

    That's a beautiful engine! Tell me about the oil filler cap, how did you get it to fit onto your engine? I 've been planning a swap like that for sometime.

    ctk
     
  5. Modeler

    Modeler F1 Veteran

    May 19, 2008
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    a.n.other
    The naturally aspirated engine is certainly beautifully detailed.
    You are creating a nagging desire in me to finish jetting that motor though.
    Like straightening a slanting picture frame. Something you have to do.
     
  6. luckydynes

    luckydynes F1 Rookie

    Jan 25, 2004
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    #6 luckydynes, Jul 21, 2008
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  7. islandguy

    islandguy Formula 3
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    Jun 12, 2007
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    As much as I like the whine and huge tubes of a blown motor nothing can beat the look of those webers...
     
  8. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    You can get them from FChat sponsor Hill Engineering. They are very nice.
     
  9. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    #9 snj5, Jul 21, 2008
    Last edited by a moderator: Sep 7, 2017
    Not as much comparable as from different dyno, but here you go. Would be better if it was the FerrariChat standard Dyno-jet :)

    I'll be starting on the jetting optimizing next week. If I am able to correct the holes due to richmess it should approximate a more normal looking curve. Goal is 200 rwhp at 5000 rpm
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  10. RVIDRCI

    RVIDRCI Formula 3

    Dec 1, 2005
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    Luigi
    Russ, I'll venture to guess that motor sounds better than it looks. Impressive.
    The pure "drivability" of a carb motor with those kind of HP and torque #s must be fun

    As far as tuning goes, I have a little more to do in that dept (see other thread). Bolt on pure supercharged HP at redline is one thing, but there is really somthing to be said for nice steep and smooth torque curve. I'll get there.

    Cheers,
    -Lou
     
  11. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    #11 snj5, Jul 21, 2008
    Last edited by a moderator: Sep 7, 2017
    thanks, Lou

    I always believed one of the great things about Ferraris was how the engine looked and sounded, and I've tried to stick to Ferrari basics and general layout. I am very empathetic to your tuning challenges. If we fairly safely assume the dip in the Mondial's torque curve is the hyper richness of down 10 - 11 A/F, then normalizing the curve to the usual shape would yield the corrected curve, extrapolated below for a fairly serious midrange punch:
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  12. Lew L

    Lew L Formula Junior

    Jan 27, 2006
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    How do the set-ups compare in price?
     
  13. snj5

    snj5 F1 World Champ

    Feb 22, 2003
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    #13 snj5, Jul 22, 2008
    Last edited: Jul 22, 2008
    I can't speak for the final prices of the s/c gang, but the Webers are a bit of a bolt on deal, and the optional head/cam work is "to taste". In basic parts, best I remember:

    Phase 1. Webers alone, us. about a 20-30 hp pick-up and much improved throttle response:
    1. 4 Weber DCNFs, about $1000 for all
    2. Manifolds - about $1000 - 1500
    3. Air cleaner of choice - $100 and up
    4. Low pressure fuel pump and low pressure fuel line, filters - $120
    5. Gaskets - $100
    6. Linkage - $100

    Phase 2. Head porting, cams - can be done at the same time or later.
    Totally dependant on what you want done - prices from $2500 up + labor,gaskets and belts
    Cams -you can keep the stock cams, or replace; you really only need the intakes done and here again, a million flavors of cam: low end torque monster to screamer. Figure about $60 per lobe at Webcam

    Phase 3. Pistons - widely variable, many flavors.

    A nice exhaust also helps, and again that to taste; my favorite are the custom flow throughs: inexpensive, as effective as the higher priced brands and to my ear sound as good or better.

    YMMV
     

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