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As coryf says, dip the clutch proactively before the downshift.
Specific to T11, don't d/s too early...
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"Combining the Art and Science of Driving Fast!"
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When I first bought my cup, I was told push VERY aggressively. What does that mean? Push hard and quick. Sorry to be some simplistic, but if you were sitting at your desk with a gallon of milk, push it so quick and hard as to have it fly for 10 feet. And your left clutch leg should "just" release the clutch at the same time. The g forces you experience in turns will cause you to push slower if you are just learning. Sounds weird I know, but alot is going on for a first time driver. Once you get your shifting habits engrained, it will become natural.
Don't know for the 2006 997, but for the 2008, the so-called Motec cable is a simple standard USB cable that you can get virtually at any shop that sells IT goods. Same one that most printers use.
With that, you will, at least, be able to read the potentiometer voltage. According to the 08 manual, it should be 3,85V in 6th. You can adjust the potentiometer manually until it read the correct voltage.
To shift your car to 6th without running the engine : Lift the car and have someone help by moving the rear wheels during shifting with the lever.
The potentiometer can affect upshifts in my experience. As far as the downshifts are concerned, as long as you are unloading the gears with the clutch before you get to the downshift it should slot right into gear assuming that you are using enough force on the shift lever. As others have mentioned you have to be very quick and precise with the shift action, any half effort on the downshift can cause it to get stuck between gears which as mentioned is very catastrophic. Maybe try hitting the stick with an open palm rather than actually grabbing it. I go to that method on occasion when I need to get the shifting done quickly during a race.
-Id also recommend bleeding the clutch if you haven't already. I do this every race weekend because air will get into the system after every couple hours of use, which obviously affects the systems ability to fully disengage.
The motec data will also be the place to go to see exactly what is happening with your clutch pressure in relation to the shift, where and when your missing the shift etc.
Also I would verify that the shift cable was replaced when your gearbox was replaced (im sure it was) but on the off chance it wasn't, those cables stretch over time and are rated for just 25 hours.
The car takes a bit of getting used to but once your really on it you'll adore the thing! I never want to sell mine! goodluck im sure its something simple
That is VERY dangerous, just doing that ONCE (stuck between gears) can grenade the tranny.
Originally I wanted a paddle shifter just to extend my gearbox rebuild interval. Then I heard the good news about the software preventing over revs on down shifts. Now this.
Talk about an expensive trap just waiting to be sprung. As a new guy to Cup cars and bump shifters, I wonder how many gearboxes I would have blown up before I got the
"feel" of it.
The paddle shift conversion is looking like a better and better investment all the time.
1. Operate the shifter HARD AND FAST like others said. Hands on the shifter ONLY when you have to shift to avoid triggering the hall sensor inside the shifter. This gets harder and harder as your stint continues--I often run into problems you describe towards the end of a stint--fatigue being the main culprit for me. I have programmed my Motec shift light to go "Green" every time I shift with sufficient force to "condition" my right input.
2. The previous talk about the gear potentiometer is confusing and not entirely accurate. There is a rotary potentiometer at your gearbox that is mostly responsible for the gear indicator on your dash. It doesn't do much other than that. Now to configure that properly, you need to be in 6th gear, make sure the gear is actually engaged, and then read out the potentiometer value. Make sure it reads 3.85V and if not, rotate potentiometer until you get 3.85V.
Now you may not need either the Motec or MODAS cable to read this value. Some dashes are configured to show a G_POT (or something similar) in the "Warmup" page. But if you're serious about maintaining and learning this car, at the minimum you need to get a USB cable and learn to use/configure the Motec dash.
You can get a USB-A cable like this online for dollars:
Now to be clear, a completely messed up potentiometer--or none at all--will not cause the shifting problem you described. This info is just a matter of maintenance and won't solve your 4D3 issue whatsoever.
3. Try to do (1) right and if the problem persists you'll probably need to take further actions with the box itself. But from the sound of things I suspect it's just a matter of getting used to it.
11-08-2016, 10:27 AM
