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flywheel mod not for wimps Ernie U there?

Discussion in 'Technical Q&A' started by fatbillybob, Mar 21, 2004.

  1. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,830
    socal
    This is a FW mod for those who are interested. It is not for wimps. This will change the charator of the drive and the the compromise would be toward track use. So Ernie, remember when we talked about this experiment? I have had very little time but here is what I have done to the 348 FW assembly. You can see I cut the grey spider looking things off. I lathe cut off the surround of the center splined hub to minimize its size and weight so i could weld it to the cake platter. This was not easy or cheap. The center hub is supper hard. I destroyed several colbalt and M series tools to cut this thing off. I almost gave up but my last tool finished the cut. I have to find the right tool to make this cut easy. The way I did it took way too long and can't be good for my lathe either. Anyway, I'll weld it up Tomorrow. Then I can put it together with the old spacers but my plan is to make a more robust spacer system that can't rattle and find someone who can spin balance the assembly. I'm not sure who can do that. If someone knows please chime in. There are many pounds off the assembly. I estimate 5-7 lbs so far, no spiders, no center hub guts, no plastic things, no springs, no rattling metal guts. When I do my test and pull the OEM assembly I'll weigh it. So the result will be a solid FW assembly using all stock componants. This is not for the street but for perhaps track use or overly aggressive street users.
     
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  3. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
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    The Bad Guy
    BILLYBOB!!!!!!!!!!!!!!!!!!!! You ROCK! Try giving CDI a call, they are in Vista. They may be able to balance it. I had a windshield repair business quite a while back and I did a replair of one of the workers cars there. Anyway we walked around back to the garage and what do I see, but four GTP cars sitting in garage. You know the Nissan's and Toyota's. Yup the real deal. They were building an engine for Pikes Peak. A little turbo charged four banger that was pumping out 850 hp!!!! I'm not sure if they are still there but give it a try. I'll also ask an aquaitance of mine, who has a SW Busch NASCAR team, if he knows anyone local that can spin it. If you need my old flywheel for any parts let me know. I have it put away in the garage. Have you tried any diamond tip bits? I'll ask a friend were he gets his. Dude If this works, man oh man.
     
  4. GrigioGuy

    GrigioGuy Splenda Daddy
    Global Moderator Owner

    Nov 26, 2001
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    Dindu Nuffin
    For those of us who haven't driven a 348, would you mind explaining the goal and advantages of this mod?

    thanks
     
  5. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,046
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    The Bad Guy
    There are two goals. The first is getting rid of the leaky flywheel seal. The flywheel is packed with grease. When the seal goes bad that grease gets flung on the clutch, resulting in the clutch buring up. It can also cause the plastic guides inside the flywheel to get melted, as what happened to mine. Well the flywheels are $3,000- $3,500 a pop, and the twin plate AP Racing clutch runs about $1,500. Now for the second reason. Less weight = faster revs. The quicker you can get your engine to rev the quicker it will be around the track. The power in Ferrari engine is at the higher end of the rpm range. So the faster the engine gets there, the sooner you can put that power to use. You also get a little bit more power because the engine has less weight to push. The down side of a light flywheel is the car can stall easier. That is why you see race cars burning rubber out of the pit lane, and why you see these guys stall in the pits. There isn't any weight to keep the momentum of the crank shaft moving, so when the clutch is realesed the engine bogs down.
     
  6. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,830
    socal
    Tillman,

    Ernie got it right. Also, when the grease gets wet from the crappy seal design of gearbox oil leaking into the grease pack the plastic and metal flywheel parts rattle. This throws of the TDC sensors and the car has a difficult time starting. This is evidenced by hard hot starting. The downside potentially is as Ernie mentioned bogging off the line possibly and the big banana of whether the 348 engine is desinged so bad that the dampned FW assembly really handles destructive harmonics. IMO Ferrari could not have designed a car that badly. Many other cars use this type of system for driver street comfort and hotrod streeters routinely remove them for all the performance reasons Ernie sited. If you are going to make a change you might as well make an improvement that hopes to allow the car to rocket out of turns. See an earlier post on Dave Helms IMSA 348 Flywheel on this board. That is the ultimate evolution of FW's. That is even too extreme for me...for now.
     
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  8. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
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    chris morse
    Fatbillybob,

    I very much agree.

    Light flywheels and or clutches are the single biggest improvement you can make for a quick, responsive throttle/engine.

    The very esence and purpose of the flywheel is to store energy, to dampen the power strokes and essentially, to make it easier to get started from a stop.

    All of this is fine if you are going to get groceries, (or BEER), in a hum drum auto. Ferrari does this, (significant flywheel mass or should I say inertia), to make the car easier to drive.

    There is a BIG improvement in responsiveness to be had for a very little extra attention on your, (the drivers), part.

    I have some experience with this: going from the easiest to drive,
    a 1400 pound porsche speedster with a race engine and a 8.5 pound flywheel,
    a 2000 pound auto cross/street 175 hp 914 porsche with a 9 pound flywheel and an aluminum 911S pressure plate, Very light rotating mass - but what the heck, just slip the clutch a bit and you are off. RIGHT NOW throttle response, (from a volkswagen engine no less - it wasn't cheap but it did go).

    My daily driver is a pumped, Weber carbed 85 toyota 2.5 litre truck, a lot of suspension work AND a 11 pound steel billet flywheel.

    My point here is that I can haul 1000 pounds of concrete or wood in my 3100 pound, empty truck with my 4 cylinder engine and light flywheel - BUT, it is fun to drive with the light flywheel. Sure, I occasionally stal it but very infrequently.

    Go for the light rotating mass, especially in a Ferrari.

    rev it up -

    chris
     

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