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probably a dumb question about high revs at start-up

Discussion in 'Ferrari Discussion (not model specific)' started by Husker, Sep 8, 2020.

  1. Husker

    Husker F1 Veteran
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    This isn't necessarily a Ferrari-specific question, but I am noticing with many late model sporty-type cars, at start-up, the revs quickly spike up to around red line and then go back down. My wife's Range Rover Sport was programmed to do this. I assume it is all for show and effect. However, I was thinking that a rev at start-up is precisely the worst thing you can do to an engine, as the oil has not adequately warmed and/or circulated.

    Any thoughts on this?
     
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  3. vraa

    vraa Formula 3
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    Is it actually revving or the needle just bounces to max and back?

    edit: Kinda makes sense why Range is always ranked so poorly on reliability if they are automatically revving a cold engine haha
     
  4. Alex308qv

    Alex308qv Formula Junior

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    It's done for emissions purposes, getting things up to temperature and such (like getting the catalyst "fired up" to handle those raw hydrocarbons), and with today's thin multi-viscosity oils I'm sure there is no concern for the motor even in winter. In older cars with fast-idle settings I personally don't like how it feels but likewise think there is no harm done. You'll probably end up using your right foot to keep it running and warming up if the car didn't do it itself.
     
  5. flat_plane_eddie

    flat_plane_eddie F1 Rookie
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    I don’t know of a single car that will actually rev to redline when started up. The rev counter might go all the way but not the engine itself.
     
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  6. Husker

    Husker F1 Veteran
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    that may be what is happening.
     
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  8. flat_plane_eddie

    flat_plane_eddie F1 Rookie
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    They definitely rev 2,000 to 3k but if a car actually revs to redline that's news to me. They always idle a bit higher too until warmed up but that's common knowledge.
     
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  9. Jb-Slow

    Jb-Slow Karting

    May 11, 2020
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    The needle sweep is just for show, the high idle is strictly for emissions and getting the cat up to temp faster, it's usually dumping fuel in at the same time. You can turn all that nonsense off with a tune if you've gone the catless route. I always turn the cold start high idle off on my cars once the exhaust is done, it keeps the neighbors happy early in the morning and saves a little bit of gas.
     
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  10. Husker

    Husker F1 Veteran
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    that's kind of what I was thinking.

    I'll never forget a number of years ago, I put together a fundraiser car show at my kids' school. We had one guy bring a Bugatti Veyron to the show. It sat for like 3 hours and someone wanted to hear it rev. The owner got in it, started it, and was basically almost redlining the thing from cold. Cute.

    As a side note, he also scraped the front spoiler pretty good driving into the parking lot - the crowd gasped. :D
     
  11. Redneck Slim

    Redneck Slim Formula 3
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    At one point the 308s were set up to run at something like 2500-3000 rpm when cold to meet emissions standards . The engines didn't last as long. I recall reading that it was easy to disable that fast idle mechanism.
     
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  13. spirot

    spirot F1 World Champ
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    yes - the 308's especially the early Injected cars would catch and go up to about 3K,, then come down to 2K and eventually bounce down to 1500 rpm and then hunt for idle around 900 -1K... basically you dont even want to try to drive the car when its in fast idle... the check valve and relays would go crazy... and the car would jerk when accelerating until it got about 150F... ( thermotime switch started to lower idle. I think most guys just disconnected the o2 sensor and then connected it up for passing emissions.
     
  14. Husker

    Husker F1 Veteran
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    I recall my 308 did precisely this, and I did disable the fast idle mechanism, though I have slept a few thousands times since then.
     
  15. Redneck Slim

    Redneck Slim Formula 3
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    I have here a 308 GTSi road test from the March 1981 Road & Track. The writer says that "one can't help but cringe" at the "2500-rpm cold idle".
     
  16. Solid State

    Solid State F1 Veteran
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    No stock ICE engine is programmed to hit redline at startup. That would be terrible for a cold engine especially a performance engine with solid lifters.
     

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