Note: Each Unit Takes (5) Pistons!
Billet Steel Project Carbon® High Pressure Pistons
The Aisin Seiki AS66RC manages oil pressure through accumulation in an extremely similar manner to it's older brother, the AS68RC. This is nothing new, accumulation dates back to the 50's! Accumulation systems simply provide a "shock absorption" effect to oil on it's way to the clutch pack, enabling smoother shifts. As a result, it's one of the first places to look when seeking to improve the shift quality of a transmission. The AS66RC is notoriously a horrible shifting transmission with dismal self control, and for this problem in specific, our Project Carbon® Accumulator & Dampener Piston Set is absolutely imperative!
To begin, we remove the factory pistons and springs entirely, they will become trash during the installation of our kit. The factory pistons are smooth-bore, featuring no O-Rings, PTFE Seals or otherwise to prevent billowing volumes of crossleakage. Additionally, the springs behind these pistons are insufficiently weak to ensure progressive and safe application of line pressure. These springs have been found broken but more frequently, do not hold the adequate pressure to prevent fully bottoming out during the gearshift; a prime cause of "banging" shift complaints in this transmission.
Our accumulator set was engineered and is manufactured entirely in-house to directly assert this specific issue. They feature 2 high temperature O-Rings per piston, one on each end, to suffice 2 purposes. One purpose served is to prevent oil from exiting the accumulator bore, much like to avoid compression from exiting a cylinder during the compression stroke of a motor by using piston rings. The factory pistons in this "motor" (transmission) have no piston rings.. how smart?
There beyond, the second ring is to provide axial support that prevents the steel piston from making physical contact with the bore at any point. This permanently and indefinitely resolves bore wear as the piston never actually touches the bore. The ring protrudes and cannot be compressed enough to make the piston to cause physical contact. Translation? Longevity, longevity, longevity!
Recalibrated Project Carbon® Accumulator Spring Set
As mentioned in the previous section, the springs often crush completely inside the well depth of the piston, enabling the pistons to bottom out against their retainers causing a "banging" shift, or in some cases are even broken when this occurs. Our Project Carbon® accumulator springs across various transmissions have a reputation for being unbreakable due to their immense cross-section diameters and commanding seat-pressures.
How does this solve your problems as an AS66RC owner? One of the biggest complaints we found in market data amongst the driving behavior of the AS66RC was that consumers feel the shifts are unpredictable, erratic, too soft, too harsh and simply never "just right." As instrumental as our pistons are for resolving this miasma of maladaptive behavior, so are our accumulator springs.
These drop-in springs slide into our pistons, push rod in tappet style, and stay arrow straight. They are designed to be in excess of nose pressure to any line pressure figure the AS66RC can produce under any circumstances, rendering it mathematically impossible for you to bottom these pistons out against their retainer. Further, their staunch pressure figures and double-spring feature amongst the dampener pistons ensures progressive and controlled shifts that are never aggressive. Simply a firm and concise shift oriented towards daily driving, practicality and durability!
