I live in Texas and as the heat of summer approaches I would love me some colder A/C.
Proper refrigerant capacity is a hot-button thing to DIY. So I asked around and pretty much all sources I ask say to just go by PSI. The online pros I see writing on forums say to go by weight. IE, kia specs say 2010 kia rio LX has 17oz or so 134a refrigerant. That's less than 2 cans of 12oz. Which cost ten bucks around here.
So I decided to try this theory out. Warmed up engine for 15 minutes running ac on max, pulled over and measured low-side pressure. 30psi 80f out(just after dusk). Various charts I consulted specify that is too low. So I added more and more 134a and checked my pressure in stages as I went. Coming in close to 40psi I was out of 134a in a new can. So I put in 11.5oz or so and saw 10psi bump. A/C feels colder, but no means of using thermometers was conclusive.(many varying readings)
If I had to guess the A/C is barely colder. But 11.5oz more sounds too much. I am watching the pressure carefully.
Another subject I want to touch on is insulating the aluminum piping for low-side. Some say they see some difference, some say they see a big difference. I can't find any down-side to spending some cash on foam and zip-ties. So I will report my findings once my car cools down and I wrap it. It looks like I might have to take a tire off to get to all the low-side pipe.
Proper refrigerant capacity is a hot-button thing to DIY. So I asked around and pretty much all sources I ask say to just go by PSI. The online pros I see writing on forums say to go by weight. IE, kia specs say 2010 kia rio LX has 17oz or so 134a refrigerant. That's less than 2 cans of 12oz. Which cost ten bucks around here.
So I decided to try this theory out. Warmed up engine for 15 minutes running ac on max, pulled over and measured low-side pressure. 30psi 80f out(just after dusk). Various charts I consulted specify that is too low. So I added more and more 134a and checked my pressure in stages as I went. Coming in close to 40psi I was out of 134a in a new can. So I put in 11.5oz or so and saw 10psi bump. A/C feels colder, but no means of using thermometers was conclusive.(many varying readings)
If I had to guess the A/C is barely colder. But 11.5oz more sounds too much. I am watching the pressure carefully.
Another subject I want to touch on is insulating the aluminum piping for low-side. Some say they see some difference, some say they see a big difference. I can't find any down-side to spending some cash on foam and zip-ties. So I will report my findings once my car cools down and I wrap it. It looks like I might have to take a tire off to get to all the low-side pipe.