I have a 4L65e transmission in my Vette controlled by a FAST/TCI controller. I am confused as to what I should set my accumulator pressure duty cycle. I can put in a percentage for each gear to gear shift at different throttle positions. I have lost 3rd gear in previous 2 trannies and was wondering if the tuning may be part of the problem. The trans was built by RPM transmissions and I am pushing about 700 rwhp. I know they won't hold up forever at that hp but I would like for it to last a while. I have the line pressure duty cycle going to 0 at WOT. Should accumulator pressure duty cycle be set to a large percentage at WOT? Right now the duty cycle goes to 90 percent at WOT. That is the reverse of what line pressure does.

 

I don't quite follow your question, perhaps because I am not familiar withe the FAST/TCI controller.
However the 4L60E only has one pressure control solenoid (PCS). It controls the line pressure. As you stated, you want the PCS duty cycle close to zero at WOT as that gives the highest line pressure. (HPT and others refer to the current/amperage going to the PCS, but it actually is a duty cyle at a fixed frequency of 292.5 Hz.)

There is accumulator pressure in the 4L60E, but it is regulated internally and cannot be changed externally. If may change with line pressure, but certainly cannot be independently controlled.

 

There is a table called "load vs accumulator pressure %". Right now it starts out at a low percentage duty cycle at low throttle and increases to a high duty cycle at WOT. So from what you are saying, I don't have to worry about this table. Thanks for the reply.

 

anyone else have any input?