Your CTS-V's stock intercooler tank is... non-existent. With nothing more than the hoses, bricks and heat exchanger holding fluid the CTS-V's (and ZL1's) exhaust all cooling capacity of the coolant almost instantly on pulls. The fluid volume on the stock setup simply isn't enough to absorb and reject heat. When your intake air temperature (IAT) reaches 140 degrees or so your ECU starts pulling timing (power) from your setup.
Our CTS-V fender water tank was designed specifically for the V3 CTS-V and fits hidden on the driver's side fender. More importantly it adds a full 1.5 gallons of water capacity to the stock system.
Pre-made lines with fittings attached make for a quick and easy install directly into the stock system's coolant connector points.
Capacity: 1.5 gallons