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Discussion Starter · #1 ·
I have a 2006 CS and perhaps I'm just not used to it yet but I find that when I turn on sports chrono, ,my shifting is a bit rough? When I don't have it on, my shifts are pretty smooth shifting at 3000rpm. When I turn sports chrono on, for example shifting at 3000rpm going from 2nd to 3rd gear, it feels like the car kind of "shakes" when I step on the clutch before throwing it into 3rd gear? What am I doing wrong? Am I shifting too slowly or something?
 

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Slow shifting should not have caused any "shakes". Most likely not a tranny issue since you can't reproduce the problem with the Sport Chrono disabled. May be you let the gas out a bit too early before stepping on the clutch. Try not letting the gas pedal out all the way and depress the clutch pedal to see if you can reproduce the problem. If you can't then work on the timing of the clutch/gas pedals when you shift and see if the problem would go away.
 

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One of the features of SC is increased throttle mapping. In this situation, this feature is actually working against you with respect to shooth shifting, because at 3,000 rpm in second gear, you are in the range of having a very touch gas pedal. For instance, to get 20% of throttle with SC on you must push the gas 20% of the way down, whereas with SC off to get 20% throttle, you push the gas 40% of the way down.

So you either need to turn SC off, or modulate the throttle pedal much more carefully when shifting at low rpm with it on.

When shifting at high rpm and driving the car hard, the features of SC start to work together (increased throttle mapping, hard rev limiter, and higher threshold of PSM intervention) to make the car more lively. There is really no point having SC on if you are shifting at 3,000 rpm.
 

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Discussion Starter · #4 ·
What should I be shifting at with SC on? I actually like the extra throttle response even when I'm not driving the car hard. I'll try to not let go of the gas so soon before I step on the clutch and see if that smooths out. So using an example with shifting from 2nd to 3rd, I keep on the gas and then right before I let go of the throttle, I step on the gas and shift to 3rd? Does that sound right?
 

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My Cayman has SC and, as noted by others here, it's like two cars. There have been several other recent threads about making smooth shifts. One of the consensus is to try not to over concentrate and just let it happen. I'll drink to that. I've been driving a clutch on my cars for the past 23 years straight and learned on one. When I got the Cayman this past December, it was like learning again. I can't get smooth. I think it is trying too hard and I'll bet it's some or all the same with you.

That said, I think it's easier with SC on. In normal, with the "switch" you'll read about here, it hesitates a bit. It does it much less with SC.

I think it's a matter of relaxing and instinct. Sound easy? Yeah, I know..I still feel like a ham fist (or foot). But, I just love the car.;)
 

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Driver needs to "re-map" learning smooth shifting with sport chrono on. My first two track sessions (over four years ago) with it on were disappointingly rough; it was affecting my driving beyond just the shifting part. By the third session I had apparently re-mapped everything in muscle memory and was back to my usual crummy driving.
 

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Somewhere on this site there is considerable discussion on the merits of disabling the clutch delay valve. I have not tried it yet, but understand it may make clutch action more linear.
 

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I almost always drive my CS with SC on, so I must be numb because I have never detected any difference in the smoothness of the shifts.
 

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Discussion Starter · #9 ·
Perhaps I'm just over thinking my shifting and just have to learn how to drive with SC on. I'm not sure if I'm explaining it properly. It's when I'm around 3000 rpm and in 2nd, I step depress the clutch in while and not on the gas, I feel like there's a stutter or shake? I don't get that when SC is off?
 

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I almost always drive with SC on. In my opinion, I get better shifting action with SC on. You probably just need to log more hours behind the wheel with SC on to get used to the throttle response.
 

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Seating position plays a more important role than you might think. I recently moved my seat forward one notch and my shifts are noticeably smoother. I think ideally you want a slight bend in your left leg when the clutch is fully depressed. My leg was fully extended, and moving the seat forward a notch fixed that. The new position will take some getting used to, as now my right foot seems a bit too close, but I think not having my left leg fully extended is the better compromise.
 

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Something similar here. I usually drive with SC-off while cruising, so I'm more used to the "lazy" throttle mapping. Although my shifts with SC-on are smooth, I've met the rev limiter 3 or 4 times :). I also believe that it's just a matter of experience to get everything running smoothly.
 

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What should I be shifting at with SC on? I actually like the extra throttle response even when I'm not driving the car hard. I'll try to not let go of the gas so soon before I step on the clutch and see if that smooths out. So using an example with shifting from 2nd to 3rd, I keep on the gas and then right before I let go of the throttle, I step on the gas and shift to 3rd? Does that sound right?
Crikee, man. Shift wherever you like! You can shift at 2,000 if want to save gas and you're just going for red light to red light. Learn to do that with SC on or off. It just takes a little practice.

Also, there is a button under the dash that the clutch lever pushes in when your foot is off the clutch. When you push on the clutch, the button comes out. If you tape that button down, it's easier to pull away from a stop and not stall the car. There is an article on this. Guys have done a lot of involved things to push the button down, but a piece of strong tape works fine.

You have to get on your hands and knees and lay in the floor with the seat pushed fully back to see this button, but after you know where it is, you can find it without looking.
 

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Also, there is a button under the dash that the clutch lever pushes in when your foot is off the clutch. When you push on the clutch, the button comes out. If you tape that button down, it's easier to pull away from a stop and not stall the car. There is an article on this. Guys have done a lot of involved things to push the button down, but a piece of strong tape works fine.

I may be wrong about this, but I think just the opposite is true with respect to this "button"

I have taped it down and the car is much easier to stall. In fact, the first thing I did after this mod while backing the car out of the garage was stall it!

The consensus has been that this switch retards the ignition timing so that the car is less easy to stall. It also times out. Push the clutch in and hold it for a long time and the timing retardation goes away.

The main advantage of this mod is better throttle response, ie. less delay when you blip the throttle.
 

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AJK,

Did you have this button taped down when we were on the Dragon Run? I ask because when I rode in your car you blipped the throttle a couple times and I wondered how the engine responded so quickly. Just wondering if this was perhaps the reason (besides your mad skillz behind the wheel).

Bret
 

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AJK,

Did you have this button taped down when we were on the Dragon Run? I ask because when I rode in your car you blipped the throttle a couple times and I wondered how the engine responded so quickly. Just wondering if this was perhaps the reason (besides your mad skillz behind the wheel).

Bret
Hi Bret,

The button was not taped down, I just had to give the throttle a really hard push when doing the heel/toe thing.

However that is a thing in the past since I just finished (like 1/2 hr. ago)hooking up the adjustable Sprint Booster. This is the new model that has a button to push which gives three choices; no boost, low boost, high boost. Having little experience with it so far it is hard to be comprehensive in an evaluation, but so far my conclusion is that this device is about equal to the sport shifter in improving the driving experience.

The low boost mode is a noticeable improvement and the high boost is easily drivable, not too harsh at all.

Just before I got back from the test drive I decided to go to the off position. It felt like one cylinder was deactivated.

It's a keeper.

Art
 

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Whenever I turn SC on it gets very jerky, mainly because I'm accelerating so quickly and then stop to press clutch, but I don't think you can do anything to avoid that.

The shifts themselves are fairly smooth, but it's really just about getting used to doing it differently than with SC off. I find 3-2 downshift at higher speeds much easier with SC on.
 
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