High Pressure Radiator Cap
 

I need an 18+ psi radiator cap that fits a stock miata radiator. So far, I've heard a Ford Explorer 20psi oem replacement will fit but I'm not sure from which year. Anyone know? Thanks in advance

Why exactly?

Stock Ls1 powered camaros come with 18 psi caps

stock powered camaros didnt come with dinky miata shitiators.

My miata doesn't have a dinky miata shitiator either it has a much larger aluminum shitiator that came with and accepts stock miata caps.

well, the most I've seen is the 16psi cap sold in most part stores. Probably more than sufficient considering the airflow in camaros suck...

I would be curious to know what insufficiency exists in the cooling system which is causing the OP to experience boil-over using (presumably) a new, tested-to-spec OEM-style 13 PSI cap.

If the engine is overheating such that coolant is boiling out of the system, welding the radiator cap shut will do nothing to ameliorate this. The engine will still be overheating, it'll simply be doing so at a higher pressure.

Higher pressure caps are standard issue on track cars, Joe. I'm kind of surprised you don't know this.

I sincerely hope we can avoid a stupid thread about "who in the world would need a high-pressure radiator cap".

Simple curiosity as to the application. This ain't the Race Prep section, and I'd expect a track car to not be using the stock radiator as the OP is. If he's trying to solve an overhating problem in a DD this way, it merits discussion.

I thought he said he had an aftermarket aluminum radiator. I would presume it would allow more pressure than the plastic factory style. No idea when the rubber hoses explode though. When silicone ones explode I'd assume the pressure is high enough to cause damage elsewhere.

True this. I was going from the very first sentence of his first post: "I need an 18+ psi radiator cap that fits a stock miata radiator."


I don't have a dog in this fight, I was just curious as to what problem, if any, the OP was experiencing.

If you folks want, next week when I get around to firing it back up and putting on the new 22-24psi flyin miata cap I was recently informed of that I ended up purchasing I'll post my results. I expect operating temp at cruising rpms to be 175-180. Currently, as soon as it reaches 175 or so the radiator cap starts allowing coolant to flow out. My temp gauge is in the cylinder head btw I believe it's accurate.

I phrased it this way to keep it simple. Maybe I should have posted "I need an 18+ psi radiator cap to fit an aftermarket larger then stock aluminum radiator that accepts stock miata radiator caps." Seems like my original post kept it more simple than that but I guess not.

My 2000 Trans Am with LS1 operates at about 210 degrees according to the gauge, not sure how accurate the gauge is on either vehicle but the gauge on my 5.3 Chevy pickup reads pretty close to the same.

Over on ls1tech they say on some models they're dummy gauges but 210-220 is the normal operating temp range for ls1's. Don't ask me how but it supposedly helps with emissions reduction. I put a 160 thermostat on mine so it should stay around 175~ I'm hoping

Why do you want such a low temp?

You do know that ca cooler block will wear faster, plus you are also giving up thermal efficiency of the fuel you burn.

Some basic math.

Water boils at 212* at sea level.

For every pound of pressure a rad cap holds, you can go 3* over boil point.

so a 13 lb cap is worth 39*
212* + 39* = 251* boil point

18lb x 3* = 54*
212* + 54*=266* boil point


22lb x 3* = 66*
212* + 66* = 278*

Also most late model cars are engineered to run 210*-220*

The 160* thermostat you have installed will be fully open at 160*, but your temp should still go to the 210* range, it will just take longer to get there.
This will not hold true if you have a oversized/more efficient rad installed

Also depending where the coolant temp sensor is installed, can give in accurate readings.
closer to the front of the engine/water pump will give cooler readings, at the back, hotter readings.

If the cap is opening at 175*, something is wrong. Bad sensor, bad gauge, bad rad cap.

Rad caps are supposed to be tested/replaced every other year.

The rated temp of various t-stats I've boiled in a pot, *start* opening at their rated temp. They're fully open about 7-10*C later.

Slick, well-produced video with amusing soundtrack or it didn't happen.


:D

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