For those that have been following the progress of our car you know that we experienced a similar issue that others have seen where the clutch pedal sticks to the floor after high rpm shifts. We only experienced this once the stock rev limiter was raised and we started shifting the car at 7000+rpm's. What happened was during the 1-2 as we as the 2nd-3rd gear shift the clutch pedal seemed to want to stay at the floor preventing the clutch from re-engaging. Definitely not a good thing for drag racing. Shifting the car itself wasn't the issue as the transmission is smooth as can be and the shifter is really easy to use but again it was the issue of the clutch pedal sticking to the floor keeping the clutch from re-engaging.
After speaking to a few others that had experienced the same thing we finally started hearing what the issue was. Supposedly it was the clutch box pedal assembly. A TSB to this date has not been made for it but there was a control number issued. The word was that the clutch box pedal assembly needed to be replaced with one from a GT500. We obtained the part number from our friends at Lamotta Performance (Thanks Jake!!) and ordered one up.
As we waited for the assembly to show up we put a Mcleod RXT twin disc clutch kit in the car compliments of our good friends at Mcleod. After the install which went great the clutch pedal seemed even lighter than stock. However I believe that the installation of the clutch made it easier to feel the problem in the stock clutch pedal assembly. The best way to describe it was that the clutch pedal just felt lazy coming back off the floor. It was weird though as it seemed there was a point just a few inches off the floor that it was binding and then it would finally spring back. I knew this wasn't the clutch and it really became apparent that there was definitely an issue with the pedal assembly. At this point we had not received the replacement pedal assembly so I started thinking of another fix. If we were to use a pedal stop to prevent the pedal from passing the point to where it was binding when pressed in it would eliminate the bind in the pedal when the clutch was depressed. Just as we were speaking about this in the office guess what? The new clutch pedal assembly arrived.
So we had Derek go right to work on the car and pulled the stock pedal assembly out to compare to the one off of the GT500. Here's a few pictures with a few notes which should hopefully help others to see what's going on.
GT500 assembly is on the Left. Stock 2011 GT assembly is on the right.
Stock 2011 GT assembly- Take a look at the spring mechanism. It's a completely new design than the GT500 has. The rebound spring is separate from the main pivot shaft that the clutch and brake pedal work off of.
Stock GT500 assembly-Now take a close look at the way the spring is used on main shaft in this assembly where both the clutch and brake pedals pivot on. Even outside of the car when you press in the clutch pedal on the GT500 assembly the clutch is smooth all the way in and released smooth all the way out. What happens on the 2011 GT assembly is after it's pressed in and starts being released you can feel a bind in the pedal as it tries to pivot with the new spring setup. It seems to be the spring itself but also how it pivots in it's new location. After installing the new GT500 assembly in the car you can press the clutch in and let go of it and it springs right back. There's no binding at all and doesn't feel lazy to come back off of the floor. At this point we're pretty confident that the pedal issue is fixed. The clutch pedal now feels just as smooth as it did on our 2010 GT500 which felt awesome. We'll be taking the car to the track on Friday just to be sure but from what we can see it looks like the 2011 clutch box pedal assembly has some issues that definitely caused problems us shifting in the higher rpm's.
Hope that helps some of the guys out there that experienced the same thing we did.
Jared
