Mishimoto Racing Thermostat - Silvia S13 / S14 /S15 Wheel Nuts & Bolts and the inner rib is

and the inner rib is the same as the normal one to secure sufficient strength

Ten Calibration Tables and 3 Linear Calibrations for when a custom calibration is required

Ignition control to 0

Replace your original hoses which often gum up with oil and water residue and become blocked and cracked over time

Optimum size of the core and layout design improves cooling performance

Mishimoto Racing Thermostat - Silvia S13 / S14 /S15 Wheel Nuts & Bolts and the inner rib isThe Mishimoto racing thermostats promote greater cooling efficiency throughout your engine by opening earlier than the factory item, allowing coolant to flow through the engine sooner and reducing running temps. Ideal for highly modified or track cars.