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F1 Superfast (599/8C/GTS/612OTO): slightly jerky downshifts...is it normal?

Discussion in 'Technical Q&A' started by Ferrarista3, Jan 7, 2010.

  1. Ferrarista3

    Ferrarista3 F1 Rookie

    Oct 30, 2007
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    Carlo
    #1 Ferrarista3, Jan 7, 2010
    Last edited: Jan 7, 2010
    I don't have a lot of experience with other F1-equipped cars other than our own 599 and I'm trying to figure out if this issue is normal.

    I absolutely love the F1 gearbox...except for the downshifts in the lower gears (3rd to 2nd and even more so from 2nd to 1st). When downshifting to lower gears, there is a noticeable jerk during the shift. It's as if the rev-matching isn't sufficient or maybe the clutch is released a little too late after the rev match (or a combination of both). With time I have learned to compensate by either braking a little harder during these downshifts (to "cover" the poor rev-match), giving a little more gas during the downshifts when possible to help the downshift or by simply shifting into neutral before a complete stop.

    Is this normal?

    Allow me to try create a simple scenario to (hopefully) help you understand the issue better. Lets say I'm at 20mph at around 2000rpm in 2nd gear when I see a red light up ahead. The road is perfectly flat and I decide to downshift into 1st whilst NEITHER acceleration nor braking. Should the downshift be smooth or jerky on well-functioning F1-equipped car?

    Thanks in advance for any info guys.

    Carlo
     
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  3. Napolis

    Napolis Three Time F1 World Champ
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    Jim Glickenhaus
    In the case you describe I'd shift into N at that point and stop the car with the brakes.

    When the light changes to green shift into 1 and you're off.
     
  4. Ferrarista3

    Ferrarista3 F1 Rookie

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    #3 Ferrarista3, Jan 7, 2010
    Last edited: Jan 7, 2010
    Yes, I usually do the same in that scenario.

    ...but it was just an example to help simplify the problem. In some cases you really need 1st gear and I'm just wondering if it's normal for the downshifts to be slightly jerky? Is it in the nature of the the F1 gearbox, or does our car have a problem?
     
  5. Napolis

    Napolis Three Time F1 World Champ
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    Hard to say without driving it. What does dealer's computer say about state of clutch adjustment of Box?
     
  6. Ferrarista3

    Ferrarista3 F1 Rookie

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    #5 Ferrarista3, Jan 7, 2010
    Last edited: Jan 7, 2010
    Roughly 2000 miles ago, 60% of the clutch was left.

    If you downshifted into 1st in the scenario I described above, how would your 8C behave? Would it downshift smoothly?

    The car was serviced in Modena a few months ago (12K mile service) and they test-drove the car before selling the "PowerCube" guarantee (ridiculously expensive!) and they didn't say anything concerning the gearbox and I therefore presumed it was fine. I now have some doubts :eek:
     
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  8. Napolis

    Napolis Three Time F1 World Champ
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    I don't downshift into 1 and rarely 2. Has it gotten worse? If so likely the clutch is wearing out or out of adjustment.

    If you do a lot of stop and go driving I'd bet clutch is going.

    P 4/5 ate it's clutch at 4K miles but 2K of those were track/hard miles. These clutches aren't like regular clutches. My TR clutch was fine at 100K miles.
     
  9. Ferrarista3

    Ferrarista3 F1 Rookie

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    #7 Ferrarista3, Jan 7, 2010
    Last edited: Jan 7, 2010
    I don't think it's getting worse. I hope it's just an adjustment... :eek:

    Yes, the car does see a fair bit of stop-and-go traffic (it's hard to avoid it over here).
    ...but it had 60% left 2K miles ago? It could be going already? :eek:

    I suppose the dealer should test-drive the car and check the gearbox. Lets see what they say.
     
  10. Napolis

    Napolis Three Time F1 World Champ
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    Good Luck with it!
     
  11. tazandjan

    tazandjan Three Time F1 World Champ
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    Carlo- Have him check PIS or point of initial slippage. If that is mis-set, it could give the symptoms you describe. On the late model manual clutch cars, the pedal tends to get harder/stiffer as the clutch wears due to the geometry of the linkage. Perhaps clutch wear makes the shifts jerkier on F1 systems. Same clutches except throw-out bearings and clutch position sensor for F1. Brian or Dave or one of the other pros should know for sure.

    I agree with Jim on how he drives. I use exactly the same technique. Get grief from the safety mavens, but it just does not take long to pull a paddle if you need power. I am hoping to get a fairly long life out of my clutch, but no guarantees. My car does not have the torque of you two's monsters, but 434 ft lbs is still pretty stout, even by Corvette standards.

    Taz
    Terry Phillips
     
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  13. Ferrarista3

    Ferrarista3 F1 Rookie

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    #10 Ferrarista3, Jan 7, 2010
    Last edited: Jan 7, 2010
    Thanks!

    Thanks for the info the Terry. I will definitely ask about the PIS. I hope it's just something like that.

    ...but from your experience with your 575 F1, would you say that the rev-matching is perfect? I often read posts here on Fchat stating how F1 gearboxes rev-match perfectly...but this doesn't correspond to my experience. I'm guessing something is wrong with our gearbox?

    The up-shifts are fine. It took me some to learn how to consistently make smooth shifts. Correctly feathering the throttle results in perfectly smooth up-shifts, whilst keeping it to the floor results in beautifully fast ones. It's just the downshifts which annoy me a bit at times.

    The car has been driven 9000 miles (shared between my father and I) in 5 months and it has truly been a blast. The poor lower-gear downshifts and the only thing which I can complain about. Hopefully that will be sorted.


    I try to do the same when I know for certain that the car will come to a complete stop. However, there are a lot of situation where I have to downshift into 2nd or 1st and in those situation, the insufficient rev-matching (or late release of the clutch?) can get annoying.
     
  14. tazandjan

    tazandjan Three Time F1 World Champ
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    Carlo- There is a small bump when I downshift in normal (your Sport), but virtually none for downshifts in Sport (your Race). Try Race and see how it works. Too bad your 599 does not have Michael's 458 shock switch, which allows control of the shocks and shock ECU independently of the Manettino setting. Like Jim, I rarely downshift to 1st, but do use downshifts to 2nd relatively frequently in city driving.

    Like you, I feather the throttle for normal upshifts and let her rip for Sport upshifts. People and the Owner's Manual disagree, but it makes for smoother shifts whatever they say. Jim is going so bloody fast in his car most of the time, it does not make much difference.

    Incidentally, if you are approaching a line of traffic, and select Neutral and the traffic starts moving, selecting the Down paddle will give you at least one gear lower than the Up paddle will. You probably already knew that.

    Taz
    Terry Phillips
     
  15. Ferrarista3

    Ferrarista3 F1 Rookie

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    #12 Ferrarista3, Jan 8, 2010
    Last edited: Jan 8, 2010
    The 599's gearbox works exactly the same both in Sport and Race mode as far as I know. The "Superfast" shifting strategy starts once in Sport mode.

    If I remember correctly the 575 only rev-matches once in sport mode?

    I'm glad that you say that the 575 downshifts nicely in sport. Hopefully that means that our car requires some adjustment.

    I sometimes put the car in "Rain" mode when in the city to soften-up the suspensions when the roads are in poor conditions. However, the 599 rev-matches in all modes and I don't really see a difference in the smoothness of downshifts when driving in the city.

    Yes, I noticed the owner's manual says to keep the gas constants in all circumstances. Which makes sense for fast up-shifts, but not for normal driving. By feathering the throttle correctly, the up shifts are absolutely perfect. I also noticed that when going down-hill shifts are smooth even if you keep the gas as it was, but when going on a flat or up-hill road, throttle modulation is required.
     
  16. North East Auto Doctors

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    Checking the pis is right but the procedure for that car is a kisspoint adjustment that is the procedure I would request be performed and is the best way to set the pis
     
  17. Ferrarista3

    Ferrarista3 F1 Rookie

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    #14 Ferrarista3, Jan 11, 2010
    Last edited: Jan 11, 2010
    Update:

    The car went to the shop and the "self-learning" feature of the gearbox was reset. It took around 15 minutes.

    The downshifts are now very "clean" and even the upshifts feel better. So far the gearbox seems perfect :)
     

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