Thermal control for street, track, and motorsports - Type-A "Mini" Radiator Caps from Nuke Performance for 32mm radiator necks - 1.1 / 1.3 / 1.5 / 2.0 BAR.
Nuke Performance radiator caps are developed for demanding applications where cooling system stability is critical. Available in 1.1, 1.3, 1.5, and 2.0 BAR, each cap is precision-calibrated to maintain consistent system pressure and increase the boling margin of your coolant.
• Type-A "Mini" Radiator Caps, for 32mm radiator necks
• Fits all Nuke Performance Coolant Expansion Tanks
• Compatible with a wide range of OEM applications
• Stainless steel internals and body
• Silicon sealing is superior to OEM caps
By increasing system pressure, the coolant's boiling point rises, reducing the risk of localized boiling and maintaining heat transfer under load. Perfect match for the different available Coolant Expansion Tanks from Nuke Performance, as well as OEM replacement and custom installations.
• Available in different pressure ratings, ranging from 1.1 BAR to 2.0 BAR (16.0 PSI to 29.0 PSI). All with stainless steel internals and silicon sealing.
The Type-A Radiator Caps from Nuke Performance are manufactured from stainless steel for long-lasting performance and durability. The seal is made of silicon instead of natural rubber found in OEM radiator caps, ensuring a greater life span and durability.
The stated pressure rating represents the nominal release pressure and operates within a defined tolerance range. The illustration above shows the intended operating range for each Nuke Performance radiator cap.
Cooling system pressure directly affects the coolant boiling point. Always select the lowest pressure cap that provides sufficient boiling margin for your application, as higher pressure increases thermal stability but also places greater stress on system components.
Approximate boiling points :
| Radiator Cap Rating | Only Water | 50/50 Coolant / Water |
| 1.1 BAR (16.0 PSI) | ~121°C (~250°F) | ~129°C (~265°F) |
| 1.3 BAR (18.9 PSI) | ~124°C (~255°F) | ~131°C (~268°F) |
| 1.5 BAR (21.8 PSI) | ~127°C (~261°F) | ~135°C (~275°F) |
| 2.0 BAR (29.0 PSI) | ~134°C (~273°F) | ~142°C (~288°F) |
* Approximate values. Actual boiling point varies with coolant formulation and system conditions. Cap ratings are gauge pressure.
Higher pressure raises the boiling point, reduces the risk of localized vapor formation, and improves thermal stability under high load. However, increased pressure also places greater stress on hoses, radiator, expansion tank, and seals. Available in several different pressure ratings, make sure to select the preferred one when placing an order.
Type-A Radiator Cap, 1.1 BAR (16.0 PSI) Part # : 452-01-011
Type-A Radiator Cap, 1.3 BAR (18.9 PSI) Part # : 452-01-013
Type-A Radiator Cap, 1.5 BAR (21.8 PSI) Part # : 452-01-015
Type-A Radiator Cap, 2.0 BAR (29.0 PSI) Part # : 452-01-020
• Why radiator cap pressure and boiling point matter in high-performance engines.
In high-performance and turbocharged engines, the cooling system is exposed to extreme cylinder pressures, elevated exhaust gas temperatures, and sustained thermal load. Even when the average coolant temperature appears stable, localized hotspots inside the cylinder head can reach significantly higher temperatures.
When coolant reaches its local boiling point, micro-boiling occurs. Vapor pockets drastically reduce heat transfer efficiency, increase metal temperatures, and raise the risk of detonation, pre-ignition, and head gasket stress. Liquid coolant transfers heat efficiently — vapor does not.
Selecting a properly rated radiator cap increases system pressure, raises the coolant boiling point, and stabilizes cooling performance under high load. Nuke Performance Type-A radiator caps are engineered for precise pressure control and reliable operation in performance street builds and demanding motorsport environments.
• Nuke Performance Type-A Radiator Caps Specifications:
For more information about specifications, contact us directly.
| Available ratings | 1.10 / 1.30 / 1.50 / 2.00 BAR16.0 / 18.9 / 21.8 / 29.0 PSI |
| Part # 452-01-011 | |
| - Rated release pressure | 1.1 BAR (16.0 PSI) |
| - Verified opening range | 1.05 - 1.20 BAR (15.23 - 17.40 PSI) |
| Part # 452-01-013 | |
| - Rated release pressure | 1.3 BAR (18.9 PSI) |
| - Verified opening range | 1.25 - 1.40 BAR (18.10 - 20.30 PSI) |
| Part # 452-01-015 | |
| - Rated release pressure | 1.5 BAR (21.8 PSI) |
| - Verified opening range | 1.45 - 1.60 BAR (21.03 - 23.10 PSI) |
| Part # 452-01-020 | |
| - Rated release pressure | 2.0 BAR (29.0 PSI) |
| - Verified opening range | 1.90 - 2.10 BAR (27.55 - 30.45 PSI) |
| Radiator neck type | 32mm radiator neck (Type-A seal) |
| Material valve / cap | Stainless steel |
| Material seal | Silicon |
| Valve diameter | 29.2mm (1.15") |
| Cap diameter min. / max. | 45.5mm (1.79”) / 65.0mm (2.56”) |
| Height valve | 25.4mm (1.00") |
| Height overall | 27.0mm (1.06") |
| Weight | 38.5g (1.35oz) |
| For motorsports use | YES |
• Nuke Performance Type-A Radiator Caps fitment guide:
Fits all Nuke Performance Coolant expansion tanks, and widely used in Japanese performance engine platforms, including:
| Honda | B-, K-, and H-series |
| Nissan | SR, RB, and VR engines |
| Toyota | Celica, MR2, 1JZ and 2JZ engines |
| Subaru | EJ engines |
| Mazda | Rotary engines, and MX-5 |
| Mitsubishi | 4G63 engines |
Also compatible with select European vehicles and motorsport builds equipped with a Type-A (32mm) radiator neck. Always verify radiator neck specification before installation.
