PRODUCT DETAILS
SpeedFactory 1.9 Bar High Pressure Radiator Cap
If your car's running hot at the track or you live somewhere the summer doesn't let up, a higher pressure radiator cap is one of the cheapest ways to buy yourself some headroom. This is SpeedFactory's 1.9 Bar cap, and it does something simple but important: it raises the pressure in your cooling system, which pushes your coolant's boiling point up by roughly 35°F. That's 35 degrees of extra margin before things start to boil over, and when you're leaning on the car hard, that margin is exactly what keeps you out of trouble. It fits standard 42mm radiator filler necks and every SpeedFactory Race Cooling System fill pot, and it cleans up the look of your engine bay while it's at it.
Why More Pressure Means A Cooler Head
Here's the physics, quick and painless: the more pressure you put on a cooling system, the higher the temperature your coolant can hit before it boils. Bump the pressure up to 1.9 bar with this cap and your coolant can climb about 35°F higher than it could before it turns to vapor. That matters because once coolant starts boiling, you get cavitation, little vapor pockets that stop pulling heat out of the engine, and that's when temps spike on you fast. Keeping the coolant liquid longer means it keeps doing its job, absorbing and carrying heat away, right when the engine's making the most of it. In a hot climate or under race conditions, that's the difference between a car that holds temp and one that's creeping toward the danger zone every session.
Built For 42mm Necks And SpeedFactory Fill Pots
This is where you've got to pay attention before you order. This cap is made for standard 42mm radiator filler necks and SpeedFactory's Race Cooling System fill pots, and the plunger on it is a good bit larger than the plunger-style caps you'll find on a lot of Honda and Acura chassis from the factory. So this isn't a universal swap for any Honda cap, it's built specifically for the 42mm setup. If you're running a SpeedFactory race fill pot, it's a guaranteed fit. If you're putting it on a radiator neck, make sure that neck is the 42mm size before you buy, because the wrong neck size and the cap won't seal the way it needs to.
Who This Is For
If you're tracking the car, autocrossing it, or just daily driving somewhere that gets brutally hot, this cap is cheap insurance for your cooling system. It's especially worth it if you've already done cooling upgrades like a bigger radiator or a race fill pot, since the higher pressure lets the rest of that system work to its potential. Just know going in that 1.9 bar is a lot of pressure, so your hoses, clamps, and radiator all need to be in good shape to handle it. On a tired old cooling system, sort the weak links out first, then add the cap.
What You Get
- SpeedFactory 1.9 Bar high pressure radiator cap
- Raises coolant boiling point by roughly 35°F
- Larger plunger than factory Honda/Acura plunger-style caps
- Fits standard 42mm radiator filler necks
- Fits all SpeedFactory Race Cooling System fill pots
- Helps prevent cavitation under high heat and race conditions
Note: SpeedFactory 1.9 Bar high pressure radiator cap for standard 42mm radiator filler necks and all SpeedFactory Race Cooling System fill pots. Increases cooling system pressure to raise the coolant boiling point by roughly 35°F, helping the system absorb and dissipate more heat and preventing cavitation under high temperatures and race conditions. Features a larger plunger than the factory plunger-style caps used on some Honda and Acura chassis, and is designed specifically for 42mm necks and SpeedFactory race cooling setups, not as a universal replacement. Confirm your filler neck is 42mm before ordering. One radiator cap per order.