Kevin Doe
July 14th, 2019, 02:27 PM
I just switched clutch setups from an already light setup using a Fidanza aluminum flywheel and Spec 3+ clutch (40 lb assembly), to a Quartermaster 7.25" twin plate on a button flywheel and flex plate (20 lb assembly). I'm having a lot of stalling issues that I've been unsuccessful in resolving on my own.
Background: My car is a 1993 Mazda RX-7 with a 2004 GTO engine/trans/PCM. The car is more or less a race car at this point. I've been racing it now for 10 years with more or less the same tune. The tune felt very dialed in, and had great manners (while racing, driving in the paddocks, and the occasional street cruise if the event called for it). Between the old and now, here is a list of everything that changed on the car: Clutch assembly (-20 lbs), ATI Super Damper (-2 lbs), Faceplated transmission.
I've been playing with the throttle cracker, throttle follower, idle underspeed error timing, desired airflow, desired idle speed, etc with no success. My primary issues are stalling in two scenarios. Comparing the two attached tune files will show a complete list of things I've changed.
When coming to a stop while driving. Sometimes, but not all the time, when I push in the clutch while coming to a stop (~20 mph and under) it just goes to 0 rpm. Doesn't even seem like it tries to catch itself.
While stopped, and reving it up. This often results in a stall when I'm attempting to get the car rolling to back out of the garage. I give it some gas, and when the RPM comes back down it undershoots. Sometimes it recovers, sometimes not.
I've attached a few things:
22935 - This is tune for the old clutch, which was my baseline.
22934 - This is the most recent tune I've tried with the lightweight clutch.
22933 - The log file goes with FD_190713_0010_QuarterMaster.ctz tune file. It is a ~15-20 minute drive.
In the log there are several stalls in each of the categories I'm having issues with. Any help would be appreciated.
Background: My car is a 1993 Mazda RX-7 with a 2004 GTO engine/trans/PCM. The car is more or less a race car at this point. I've been racing it now for 10 years with more or less the same tune. The tune felt very dialed in, and had great manners (while racing, driving in the paddocks, and the occasional street cruise if the event called for it). Between the old and now, here is a list of everything that changed on the car: Clutch assembly (-20 lbs), ATI Super Damper (-2 lbs), Faceplated transmission.
I've been playing with the throttle cracker, throttle follower, idle underspeed error timing, desired airflow, desired idle speed, etc with no success. My primary issues are stalling in two scenarios. Comparing the two attached tune files will show a complete list of things I've changed.
When coming to a stop while driving. Sometimes, but not all the time, when I push in the clutch while coming to a stop (~20 mph and under) it just goes to 0 rpm. Doesn't even seem like it tries to catch itself.
While stopped, and reving it up. This often results in a stall when I'm attempting to get the car rolling to back out of the garage. I give it some gas, and when the RPM comes back down it undershoots. Sometimes it recovers, sometimes not.
I've attached a few things:
22935 - This is tune for the old clutch, which was my baseline.
22934 - This is the most recent tune I've tried with the lightweight clutch.
22933 - The log file goes with FD_190713_0010_QuarterMaster.ctz tune file. It is a ~15-20 minute drive.
In the log there are several stalls in each of the categories I'm having issues with. Any help would be appreciated.