1.1 vs 1.3 Radiator Cap
 

Debating whether or not to jump to a 1.3 rad cap. Read a few articles online to the advantages of 1.3 over 1.1
Any thoughts or concerns would be appreciated

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I think you would be fine with the 1.3bar, and it should not be too much more stress on the cooling components compared to stock. And I am sure you know if you have been researching it, but the higher the pressure you can run in the cooling system, the less likely your coolant is to boil. Many people don't understand how this helps the cooling in the car, and if you have never boiled the coolant than you will never see any gains from a higher pressure cap. Now if you have boiled the coolant before, these higher pressure caps can be very handy, not only to keep the coolant in the system, but also keeps it off the track and your tires if you get severe boiling for extended periods of time. So I say go for the 1.3 bar cap :)

Also just a late night fuzzy brained FYI for anyone who is interested. The boiling of a fluid is directly related to the pressure on that fluid. You can easily see this by placing a vial of water in a complete vacuum and even at room temperature it will boil. With no vacuum or added pressure, we know that water will boil at 212 Fahrenheit at 14.7psi(normal atmospheric pressure). Now start increasing the pressure above atmospheric pressure, and you can raise the temps above 212 without boiling the fluid. Pretty cool/fun science stuff!

Also just in case any one is Curious, F1 cars run their coolant systems around 150PSI, imagine how much heat it would take to boil the fluid in that system!!!

Sorry JPx if I got too off topic, but hope this helps you or anyone who reads it. :)
Thanks,
Rick

Very well said

the JDM TRD cap is 1.3 so I don't see why not

Just a note about F1 car cooling systems. The pressure max is set at 3.75 bar (about 55 psi) and this raises the boiling point to 150 deg. C. That is about 302 deg. F.

Thanks for the in depth comments ;)

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I wouldn't do it if you live in states that are more cold than hot. Texas = definitely. Colorado = prob not.

hmm i might consider this. ive had my cap pop off in my pontiac and all the fluid boiled out. it happened later in the afternoon so idk if it was due to the heat or not. i wonder if they will have a 1.3 STI cap.

"cost benefit analysis".

Q:
1: is there a need?
2: if there is a need, is this the right solution and the most cost effective one?

A:
1: I don't think there is a need until the car becomes modified in a manner that would affect or overly tax the cooling system, or the car will be driving in a manner and environment it was not designed for thus overburdening the system.
2: If your car does not meet the criteria of #1 and you find your 1.1 cap to be inadequate then you don't have a radiator cap issue, you have another issue that you should not be solving with a radiator cap.

I'm having trouble putting on my trd radiator cap.
Any one had trouble as well?
Any advice??

One more cool thing for you. Our nuclear power plant has coolant at 295C and pressurized to 10 MPa! How's that for temp and pressure...haha

Now that is some serious heat and pressure! Incredibly impressive to say the least. :cheers:

Thanks,
Rick

Raising the pressure capability of the cooling system won't strain anything unless and until the cooling system actually reaches that pressure. Adding a 1.3 Bar radiator cap will not change the actual pressure of the coolant until it gets hotter than the designed for temperature it reaches at 1.1 Bar.

That pressure number is the release pressure, not the pressure exerted by the cap. That 1.3 Bar is a maximum pressure before release of coolant. The pressure is exerted by the cooling system which, because the volume of the cooling system is fixed, depends entirely on the actual operating temperature.

Bottom line: changing the radiator cap won't change anything or Toyota would have fit the stronger cap in the first place.

Total. And. Complete. Waste. Of. Money. If you buy one, it is purely because you wanted to make your cap look different. Don't try to convince anyone otherwise.

I've tracked the car in 106F ambient temps and the coolant temps I logged NEVER never went above 200F. Coolant temps are not an issue in this car