Safety factor is an extra margin that manufacturers put into their designs to prevent problems near the maximum ratings of products. Basically the manufacturer doesn't want a failure at 1.300001 MPa, so they make sure that the maximum pressure the cap sustain is greater than the rated pressure on the top of the cap. So a 20% safety factor means the cap can withstand a sustained pressure 20% above the rated pressure on the cap. This adds .26 MPa in this example, so the total pressure the cap can withstand would be a little above 1.5 MPa.

Sorry about any confusion there and for nerding up the thread, but as an engineer, I have a pretty good familiarity with this kind of stuff.

 

I'm afraid you may have misread the specifications of the caps. The caps are rated at .13 MPa, not 1.3 MPa, which is the only way for you to get those numbers. Once again, this leads to .15 MPa, with a 20% safety factor, which is about 1.5 atm.

 

Oh, good call. Looks like I missed that . So I guess we're still at the same point of whether .13 MPa is enough when the cap in our G's is .137 MPa.

 

It shouldn't be a big deal, it may even be that the Nismo cap is .137 MPa but didn't write it out to enough decimal places, but yeah, your earlier findings of 2 atm are a bit high for these caps...

 

LOL you guys take radiator cap science pretty serious huh?

My thought process, "Oh look a cool Nismo cap! Its only $10! But really who is going to see it? IDK I am getting it anyway." purchased and installed.

 

Lol I'm a mechanical engineering student so I was curious to see how he got his numbers.

 

Kidcane, you have no idea, lol.

I guess this proved that my engineering degree doesn't guarantee the ability to read.