SpecTuned - JZ Thermostat Delete Kits

SpecTuned JZ Thermostat Delete Kit

This product serves as an effective solution for mitigating cooling challenges associated with JZ-powered configurations, particularly in high-performance racing applications. Frequently, in instances where the thermostat is removed, it is common to still retain the OEM bypass tube. This tube facilitates the direct return of heated water from the cylinder head to the water pump via the OEM 1-inch tube. Consequently, the radiator is bypassed, as water follows the path of least resistance. As a result, a substantial volume of water may bypass the radiator if this tube is retained. 

 We provide a variety of kit options, available in FOUR distinct sizes to accommodate all JZ engine combinations and will work with both OEM and Aftermarket water necks. 

(VVTi and Non-VVTi) (ChaseBays upper water necks will need the 1.5JZ height even if you have a 2JZ)

-  1JZGTE 

-  1.5JZGTE**

-  2JZGTE

-  2JZGE

**1.5JZ customers: Please verify your tube height needed as different water neck combinations can use the tall 1.5JZ or the medium 2JZGTE size.

Designed and Made in the United States. 

What's Included

- (1) Bypass Tube with O-Rings (6061 Aluminum CNC Lathe)

- (1) Thermostat Delete Ring with Gasket (304 Stainless)

- (1) OEM Upper Water Neck Gasket OR OEM O-Ring for NA 

- (1) Tube of Super Lube for O-Rings

Testing

We conducted a series of dyno testing in an 8 hour duration, during which a variety of distinct water flow configurations were meticulously examined. These configurations included the utilization of the OEM thermostat, deleted thermostat retaining the OEM bypass tube, solid bypass tube with water restrictor, and solid bypass tube with no water restrictor. The testing was performed on an IS300 with an OEM+ 1JZ engine swap. All testing was conducted with the vehicle's hood closed, and measures were taken to maintain a consistent dyno cell temperature. Following the testing, we have arrived at the conclusion that our solution stands as the most effective cooling remedy available.

The Spectuned Thermostat Delete Kit is an advanced solution designed to optimize the cooling efficiency within your system. Throughout our testing, we observed temperatures as low as 145°F, even while maintaining the cooling fans at their maximum operational power, during idle conditions. While achieving an idle temperature of 145°F might seem advantageous, it's important to note that such conditions can lead to deviations from optimal engine clearances, potentially resulting in suboptimal engine operation. Additionally, excessively cool oil temperatures could have unintended consequences on overall engine performance.

To harness the full benefits of this kit, we recommend use of your ECU to regulate the cooling fan operation. Specifically, configuring the fans to deactivate at a minimum temperature threshold, such as 175°F, is advised. This approach to fan control ensures that your engine maintains a suitable operating temperature. Lowering the initial temperature at which the cooling fans activate provides a valuable performance buffer during racing scenarios, enhancing overall endurance. Our kit's design ensures gradual warming of the cooling system, further elevating the performance headroom available to you.

We take great pride in offering a kit that excels not only in functional performance but also in its aesthetic contribution to the engine bay's visual appeal.