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Overrevs

Discussion in 'Ferrari Discussion (not model specific)' started by Themaven, Jan 29, 2020.

  1. Themaven

    Themaven F1 Rookie
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    For anyone buying a Porsche of the modern/recent era, the overrev data is extremely significant. Porsche won’t warranty, and top independents won’t sell, cars showing ignitions in the top range of overrevs,as recorded by the car’s ECU. Cars which show significant overrevs, particularly in the recent past, are very hard or impossible to sell, or sell at a significant discount.

    This is particularly so for manual cars which can be accidentally shifted down from, say, 5th to 2nd at high speeds.

    So my question is: this is a Big Deal for any buyer of a used 911. Or a seller - try and sell a 997 GT3 RS 4.0 with too many ignitions in the wrong range, and you won’t. But in all the years I have been on this forum, I have never seen the subject mentioned in the context of Ferraris.

    It seems Ferraris don’t measure overrevs (or don’t do so in the same way). But if the issue is a potentially terminal deal breaker for Porsche buyers, how come it doesn’t even figure in the consciousness of Ferrari buyers? I know a lot of people here have both.

    a glib response would be that Ferrari engines are made to be revved, but I think no more so than a RS Porsche engine. So, either overrevs don’t actually matter, or Ferrari buyers are purchasing potentially terminal problems on a constant basis.

    any expert views like to weigh in?
     
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  3. technom3

    technom3 F1 Veteran
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    Porsche guys are the new Ferrari guy.

    Extremely nuanced buyers

    They aren't really big car guys. They are Porsche guys.

    The market is swayed by what people tell them is important. Not what is.

    Yes over revs can depending on the severity can be bad. But any are treated like an uncuttable disease. And all of this on the wonder highly coveted Metzger engines that are unbreakable and Motorsport derived blah blah blah. So the engine is designed to rev and be robust but God forbid anyone use the car the way it was intended.

    The Porsche market for the last 5 years has been fueled by speculators looking to make a quick buck. Most of them out of the financial services industry that went caput.

    They made nuance of things that never typically mattered to Porsche people as a reason to justify pricing.

    So now they are reaping what they showed. But... The speculators have left but their finger prints are still on the buyers checklists.

    Deviated stitching 12k for paint to sample... Leather air vents. These guys truly became worse than Ferrari guys.

    My favorite... Gotta have ceramic brakes... Yet... Anyone who uses their Porsche for track work changes then to steel brakes. Hilarious.

    And the main thing that is affecting sales all across the board in the car world...

    Any excuse to not buy it will suffice. Only one key... Nah don't want it. But wait I'll buy a replact... Nah only want original keys. Sir if I bought the key before you asked you'd never know... Hello? Sir? Sir? Did you hang up?


    Maybe I'm bitter.

    But the above is the bitter truth
     
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  4. ago car nut

    ago car nut F1 Rookie
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    Watch the u- tube video of Derek Bell running the 24 HRS Lemans at night, and the engineer Norbert asking him the revs he was pulling on Mulsane 3.7 mile straight? Bells says 8100, Norbert says good because it blows up 8200!
     
  5. Ianjoub

    Ianjoub Formula Junior

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    Overrevs don't happen with the DCT transmissions as the computer doesn't let it downshift to that point. Overrevs are stopped by rev limiters when on throttle. If you downshift a manual trans and cause an overrev, if you didn't float valves, you are ok!
     
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  6. Alex308qv

    Alex308qv Formula Junior

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    Pissed Off Rebuilding Six Cylinder High-strung Engines
     
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  8. vincep99

    vincep99 Formula 3
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    Lugging (underrevs if there is such a word) is just as bad because you don;t get the hydrodynamic lubrication in the main and rod bearings.
     
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  9. Alex308qv

    Alex308qv Formula Junior

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    That plus maximizing power at low RPMs places maximum forces on the bottom end. Think of riding a bicycle up a hill in fifth gear while standing and pulling up on the handlebars, versus going up seated in first gear.
     
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  10. italiafan

    italiafan F1 World Champ

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    I can't recall the last time I have heard of an engine blowing up, throwing a rod, etc.; unless there was some design flaw (Porsche 911 991.1 GT3).
    The thing that makes modern cars a PIA are failing sensors, chips, ECUs, PTUs, DCT, electronics....I suppose if you were a heartless careless SOB abusing a car on a regular basis it would be different...but an occasional accidental "overrev" Really"
     
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  11. Themaven

    Themaven F1 Rookie
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    Very interesting thank you! there are a lot of Ferrari owners who are also Porsche owners..I am just wondering if they switch attitude according to which car they buy. I’m not being glib. Over my years of Ferrari ownership I have owned 3 manual 911s, all of which had a overrevs check before I bought them. None of my Ferraris did because they can’t.
     
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  13. technom3

    technom3 F1 Veteran
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    They don't check because they can't and no one cares because well... There isn't really anything to worry about. Just like on a Porsche but now the buyers pool has been tainted with whadabout-isms. The ship has sailed.
     
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  14. technom3

    technom3 F1 Veteran
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    In theory that makes sense. But it's not right.

    It doesn't maximize force on the bottom end to make any great difference.

    In your example did you ever snap a leg? Crank set? Pedal?

    Nope.

    The stress exerted at lower rpms and on a gasoline engine is low because engines don't make much power down low.

    Rpm. Kills everything. RPM places far more stress then add in that you are making usually aboit double or triple the power at say 6k rpm.vs 2k rpm.

    You want to factor stress? How about taking a rotating assembly accelerating past 8k rpm rpm when you change gears it gets twisted back and slowed to 5500 rpm rpm you do that over and over and over and over.

    Bottom ends on cars are built extremely tough. Lugging an engine isn't going to hurt the bottom end on a modern car.

    Heck most modern cars bottom ends can support a minimum of double their factory hp output. (Except when you get over 600hp from the factory)
     
  15. Texas Forever

    Texas Forever Four Time F1 World Champ
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    Plus, don’t all modern cars have electronic rev limiters? When I raced my Miata, there would be times I’d bounce the car off the rev limiters because there wasn’t enough room to upshift, but it was too early to brake.


    Sent from my iPhone using FerrariChat.com mobile app
     
  16. technom3

    technom3 F1 Veteran
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    The over rev issues are mostly to look for "money shifts". Down shifting too early where the engine is forced to over speed and thsi so where some problems could occur.

    But with Porsche just hitting the rev limiter will cause an over speed.
     
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  17. Simon^2

    Simon^2 F1 World Champ
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    It's tough to over-rev a Ferrari when it's sitting in the garage on a battery tender determined not to accumulate miles before it is sold to the next owner.
     
  18. tomc

    tomc Two Time F1 World Champ

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    LMAO. Touché.
    T
     
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  19. technom3

    technom3 F1 Veteran
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    I tell you what. The 458 changed that. Lots of 458s and f12 with miles. Ffs too!
     
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  20. Carnut

    Carnut F1 Rookie
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    I am on Porsche #44 and I have not been without at least one for over 45 years. I have blown up engines (actually if you have ever taken a Porsche manual transmission apart you would know that it is the weak link), at least 5 transmissions, but I like to put things back together, usually better than they started out. You would think people would run from any car I have owned but it is the opposite. I often get asked to consider selling to them when I get bored of playing with a car. The overrev thing reminds me of chicken little, you don't have to overrev a car to cause problems, I have seen engines blow that were never driven over 4000 rpm.
     
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  21. Themaven

    Themaven F1 Rookie
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    I’m still not getting why for manual Porsches this is an end of the world dealbreaker that makes a car almost unsellable, and for manual Ferraris it doesn’t matter at all! One of these is wrong. Can anyone technical tell me which one?
     
  22. Andy348

    Andy348 Formula 3
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    Honestly if this type of information was readily available for manual Ferraris it would be a big deal and everyone would request it as part of a PPI.
     
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