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Sorry I should have been clearer. I don’t have any issues with gear selection. The box only has around 12 hours on it since refresh. Gearbox oil is fresh and changed every 2-3 hours. Gear engagement is nice and smooth. The issue I feel I’m having is timing the throttle application when releasing the clutch, meaning clutch operation is not as smooth as I’d like it to be. I suspect 2-3 may be more noticeable with this because it takes slightly longer than 3-4 and the revs are dropping more between changes? May need driver mod haha.
From watching the video your timing is off. You are shifting too slow and the rpm has dropped too low for the next higher gear before you complete the shift. It also sounds a but like you are back on the gas prior to fully releasing the clutch pedal and slightly slipping the clutch as you release the left pedal and get back on the gas in the higher gear.
The light clutches drop revs very quickly and a 996 cup has very close ratios. You need to sbift very quickly to not let the rpms drop too far between gears.
From watching the video your timing is off. You are shifting too slow and the rpm has dropped too low for the next higher gear before you complete the shift. It also sounds a but like you are back on the gas prior to fully releasing the clutch pedal and slightly slipping the clutch as you release the left pedal and get back on the gas in the higher gear.
The light clutches drop revs very quickly and a 996 cup has very close ratios. You need to sbift very quickly to not let the rpms drop too far between gears.
Appreciate the insights, everything you are saying makes sense. I feel I am being too hesitant with the shifting as a mis-shift worries me. I’m quite comfortable with the h pattern even considering I’m doing things with the wrong hand - Australian, used to sitting on the right side of the car. I guess my next question is, how can I increase my shift speed? Is it a matter of physically moving the shifter more quickly or is it also to do with the footwork needing to be faster? Also should the technique of timing the clutch release require significant adjustment as the clutch wears? In my mind I didn’t have as much difficulty with it when I first got the car and wonder if the uptake point on the clutch has changed which has also partly thrown off the timing?
At this point I am considering changing back to an OEM cup clutch. But, I hate throwing in the towel and the responsiveness of the twin plate really is wonderful when it comes to rev matching. Is there a performance disadvantage by going back to an OEM clutch when one cannot shift fast enough to take advantage of the light weight assembly in the first instance?
Hard to say for sure from the video but I think its a little bit of both hands and feet. Maybe more feet. You are done with the shift with your hand but then have a split second pause before releasing the clutch. When done properly and with properly setup gearbox in a cup, the clutch action should literally be a stab in and release and you have to get the hands done within that time. Should take about 300ms if you have data. I would also take care not to get back on the gas until you are fully off the clutch. It sounds like you are slipping the clutch a little on each upshift as you release the pedal.
I would also check the pedal stop adjustment. It does change the timing a bit. You can find the pedal stop setup procedure on Tiltons website.
Hard to say for sure from the video but I think its a little bit of both hands and feet. Maybe more feet. You are done with the shift with your hand but then have a split second pause before releasing the clutch. When done properly and with properly setup gearbox in a cup, the clutch action should literally be a stab in and release and you have to get the hands done within that time. Should take about 300ms if you have data. I would also take care not to get back on the gas until you are fully off the clutch. It sounds like you are slipping the clutch a little on each upshift as you release the pedal.
I would also check the pedal stop adjustment. It does change the timing a bit. You can find the pedal stop setup procedure on Tiltons website.
Thanks for that explanation. I think you are right about the slipping too....I smelt the clutch a little after one of my sessions on the weekend. Whilst I need to be more committed with the shifting, the bite point of the clutch is too high which is slowing down the process for me (and leading to jumping back on the gas before the clutch is fully engaged). Perhaps the friction discs are at the point of needing replacement. When else do you know it’s time for a clutch service? Great videos and driving by the way, I’ve spent quite a bit of time on your YouTube channel in the past!
Originally Posted by MarcD147
do you have a data trace? eg motec?
Yes I do have motec. I’ll take a screenshot tomorrow and post it up.
Thanks for that explanation. I think you are right about the slipping too....I smelt the clutch a little after one of my sessions on the weekend. Whilst I need to be more committed with the shifting, the bite point of the clutch is too high which is slowing down the process for me (and leading to jumping back on the gas before the clutch is fully engaged). Perhaps the friction discs are at the point of needing replacement.
You might try a clutch stop to limit the amount of pedal travel. I use one and it helps tremendously as my clutch engages in the top of the pedal stroke. I use the OEM 6Cup flywheel and disc along with a bolted Sachs Motorsport 487 pressure plate. Great clutch if you are not looking for the lightning fast shifts of a 5.5 multi disc. Very user friendly when used with a clutch stop.
You might try a clutch stop to limit the amount of pedal travel. I use one and it helps tremendously as my clutch engages in the top of the pedal stroke. I use the OEM 6Cup flywheel and disc along with a bolted Sachs Motorsport 487 pressure plate. Great clutch if you are not looking for the lightning fast shifts of a 5.5 multi disc. Very user friendly when used with a clutch stop.
Do you have any pics of your clutch stop set up? OEM style set up is sounding like a go to but if there is a simpler option like I clutch stop that I can try first before giving up on the small diameter I’d like to give it a go.
Do you have any pics of your clutch stop set up? OEM style set up is sounding like a go to but if there is a simpler option like I clutch stop that I can try first before giving up on the small diameter I’d like to give it a go.
Bringing this one back up again. Since the RSS clutch stop above is no longer being produced, I am having a custom one fabricated by my shop.
When removing my car from storage today, I had to back it down a longish driveway (could not push as the pavement was too rough). I slipped the clutch at idle down the driveway and by the time I went to grab 1st, I could not get any gears. By shutting down the engine, I was able to engage first, restart the engine and take off. Shifting 1-2 seemed ok at road speeds right after this. I have always tried to be careful not to slip the clutch but this was a brain fart moment. Just curious to know what has happened to the clutch in this situation and whether this would have damaged it. I assume the friction disc became overheated. Do they come back from these types of events?
Hi Simon, based on your description it sounds like a spigot bearing problem. Likely sized and turning the input shift. I would check the hydraulics to make sure everything is good first to make sure there is no clutch drag before pulling the box out.
Hi Simon, based on your description it sounds like a spigot bearing problem. Likely sized and turning the input shift. I would check the hydraulics to make sure everything is good first to make sure there is no clutch drag before pulling the box out.
Hi Andy, now that you mention this, occasionally I have had difficulty engaging first gear. Having said that, once the box is up to temp the shifts always feel smooth when out on track, no crunching or resistance. This is the first time I’ve not been able to select a gear. Thanks for the heads up, I will get them to check this.
07-26-2020, 07:44 PM
