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F355 piston weight vs other brands

Discussion in 'Technical Q&A' started by MD355, Aug 20, 2019.

  1. MD355

    MD355 Formula Junior

    Mar 8, 2004
    778
    Europe
    Full Name:
    MD
    I found this photo of an F355 engine rebuild and it was interesting to see the weight of the OEM F355 piston : 292 grams.
    I recently purchased a set of CP Carrillo forged Pistons for my 2001 Lotus Esprit V8 and the weight turned out 315 grams.
    An interesting comparison because both cars are V8 with exactly 3.5 liters.
    The F355 revs to 8250 rpm for max power (I think 8500rpm is fuel cut off) whereas the Lotus Esprit V8 only goes up go 6500 rpm (7000 rpm fuel cut off)
    The CP are upgraded pistons.
    I guess the lower weight of the F355 helps go up to higher rpms
     
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  3. MD355

    MD355 Formula Junior

    Mar 8, 2004
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    MD
    Qavion likes this.
  4. Ferrari Tech

    Ferrari Tech Formula Junior

    Mar 5, 2010
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    Wade Williams
    That is correct. The light pistons and titanium rods make for a very quick and high revving engine. Mahle makes extremely nice pistons and they are usually very light. I have used them in Chevy stroker engine as well and again, they were very light. The 355 crank is also extremely light compared to other V8 engines. Being a flat crank design helps as the need for counter weight is eliminated. Unlike a 90 degree crank where the counter weight must be balanced to the weight of the rod and piston assembly. I think 355 cranks are about 37 lbs, in comparison, a small block chevy crank is 55-57 lbs.
     
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  5. slide9595

    slide9595 Rookie

    Mar 24, 2019
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    slide
    Piston weight isn't so much the issue as how far you are willing to go to balance your rotating/reciprocating parts. You get a good balancing service and it almost doesn't matter what the piston weights are because they become part of a matched assembly. Purchase a good quality set of pistons, get parts balanced and make sure that you have the right piston/bore clearance and go worry about something else...
     
  6. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    33,076
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    Terry H Phillips
    Bore size (piston diameter) has a big effect on weight, too. The F355 is a short stroke revver with a large bore. The Esprit V8 is an undersquare torquer with a small bore and long stroke. Hence the difference in redlines. Logically, with similar skirt lengths, the Lotus piston would have been lighter weight.
     
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  8. jcurry

    jcurry F1 World Champ
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    Jan 16, 2012
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    Jim
    Close to 6% difference in stroke, which I agree would have an impact on max revs.
     
  9. slide9595

    slide9595 Rookie

    Mar 24, 2019
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    slide
    You get a good balancing service and it almost doesn't matter what the piston weights are because they become part of a matched assembly.










    Tutuapp 9apps Showbox
     
  10. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    33,076
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    Terry H Phillips
    Of course it matters what they weigh or we would all still be using steel pistons like they did in the early WW-I period. Even when the LeRhone rotary went from steel pistons to aluminum pistons, hp went up from 110 to 120, and that was in 1917.
     
  11. BMW.SauberF1Team

    BMW.SauberF1Team F1 World Champ

    Dec 4, 2004
    13,221
    Yes, bore/stroke ratios are important for how high an engine can rev. F1 cars have bore/stroke over 2/1.
     
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  13. Ferrari Tech

    Ferrari Tech Formula Junior

    Mar 5, 2010
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    Wade Williams
    NHRA Pro Stock push rod V8 engines are 500 Cubic Inches, limited by the rules. A few years ago they limited the RPM to 10,500. That is a huge bore but a pretty short stroke to make that happen. I know, they only run hard for 7-8 seconds, but with valve lift at close to 1 inch, that is impressive. Engines just fascinate me. I think they are all cool.
     
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