[Dwain]

A pusher fan is going to restrict airflow while driving. A 3 core radiator is not helping either. 3 cores will have more restriction than a 2 core of the same thickness simple because of the fin breaks between cores. You get turbulence and air slows more each gap between fins A 2 core with 1 inch tubes would be better than a 3 core and give you more than enough cooling.

Have you put gauges on it? Gauges will tell you if your pressures are good. Low refrigerant will cause the vent temps to be higher than normal too.

 

[Dwain]

205 is the normal temp it should be running at with ac on. That's the normal operating temp for a SBF. When cruising down the highway your car gets most of it's cooling from the bottom of the radiator/condenser which is the part getting fresh air. With a shrouded fan over the condenser it is going to block that area off. You would be better off investing in a quality 2 core radiator and getting a less restrictive condenser available for your car. When cruising above 35mph youre getting a lot more air into the radiator than a fan can push which is why the fans turn off above 35mph. It becomes a restriction. In my car, i'm upgrading to a 97 condenser because my giant fmic + standard condenser blocks too much flow at low speeds causing my car to hit 225 on hot days. If i remove the condenser, it runs at normal temps.

 

[Dwain]

It won’t be a shrouded pusher fan otherwise I’d agree with being too much of a restriction. I’m considering biting The bullet and replacing the evaporator core as well. I compared the ac to my buddies 95 and his vents seem to blow much harder than mine in every setting. I replaced the blower motor and resistor so I think the evaporator could be clogged up with crap which isn’t helping my situation. The ac never worked fantastic when I bought the car with an HCI 302. I really wanna get it dialed in because it’s brutal in the summer.

I hear you. I live in Colorado which normally is 100+days often although this year it's been cooler and rainy this whole summer. It rains almost every day for the last few months which is how it was in the 90s with i moved here. The biggest upgrade you could do is to put a 97-98 condenser in it. It will help allow your radiator to pull more fresh air through it. My ac blows really cold when it was installed but the problems i listed above have forced me to upgrade to condenser. For now i am running without a condenser. I verified with LMR 2 days ago, their condenser for 96-98 is the less dense 97+style. They sent me pictures of the fins so u know for sure it's the better sn95 version. It's worth doing if you're serious about having ac.

 

[Dwain]

According to @fasterthangas it's a direct swap. Pictures look the same. Fasterthangas said he did it on a couple sbf sn95s. I'm ordering mine here in the next coupe days.

 

[Dwain]

Before you replace it, check your pressure levels. Fyi, you have to cut the ducting on sn cars to get the evaporator out. It's not removable like the fox. I did mine 2 years ago because mine was full of metal shavings because someone cut the metal hose instead of removing it at the coupler.

 

[Dwain]

some loss over time occurs if im not mistaken. it permeates through the hose very slowly from what i remember. im not 100% sure on that though so Im sure someone will correct me if I am wrong.

 

[Dwain]

I’ve read about it too, I just see people boasting vent temps in the mid 40s to 50s and my car struggles to reach those temperatures at any given day which is frustrating hence why I feel like it’s an airflow issue or clogged evaporator.

low refrigerant will cause that and if your on an AC charge from 7-10 years ago, my bet is its low. Gauges will tell you everything you need to know.

 

[Dwain]

I agree with @Ilusivefox and @Mustang5L5. I will add that the few trained AC technicians I know typically use the weights as a guideline but often adjust the amount added based on pressure readings vs ambient temp and based on temp coming from the vents. My car has custom AC lines that are longer than stock so when mine was filled, the weight was just a guideline to get us close, then pressures and temp were used to fine tune the amount of refrigerant in the system.

 

[Dwain]

If it's 93 outside your low side should be between 45 and 55 psi, high side around 270ish . That tells me your refrigerant levels are low but you need to verify high side first.

 

[Dwain]

R-134a System Pressure Chart - AC Pro

A/C PRO is the easy DIY car A/C repair that saves time & money. This simple fix recharges the R-134a (freon), stop leaks & gets your car A/C cold again.

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[Dwain]

so would I forgo the addition of freon by weight and rely entirely on pressure alone? I saw someone mention that above but wasn't sure

You need to verify both high and low side to make sure both are reading low. If both are reading low you would add more refrigerant. I know you said your replaced the orifice tube. Anything else replaced and was your system leaking before you replaced parts? Did you add oil to the system?

 

[Dwain]

new compressor, accumulator is less than a year old, condenser less than a year old. only items I haven't replaced are the lines (minus the liquid line containing the orifice tube) and the evaporator. we couldn't find any leaks with the dye in the bay so if there is a leak its gotta be the evaporator. I can verify pressures in a couple days I have some extra R134 I can add to the system

How much oil did you add? The new compressor usually comes with some oil but not enough for the whole system. Sometimes they have no oil. Do you know if yours had oil?

 

[Dwain]

Also when you replaced the compressor did you drain the old compressor to see how much oil was in it? That determines how much oil you add when replacing it.

 

[Dwain]

I don't think you need to add much more, but do agree with Dwain that you need a little bit more. However it's possible that's because you didn't have the proper level of oil in the system.

Yep that's what i was getting at.

 

[Dwain]

It came with oil I didn’t need to add any

Compressors never have enough oil for the whole system. Mine came with 3 ounces. The system needs 7.

 

[Dwain]

Depending on how much was in the evaporator and condenser you may be ok. You should check to make sure how much it came with.

 

[Dwain]

For future reference, two hours really isn’t enough time, especially if you’ve opened the system up and replaced parts and have fresh oil. Often times the oil traps air bubbles.

I Know most DIYers don’t have this sort of equipment (and I don’t blame them because it’s spendy), but I use a micron gauge and pull down to 500-1000 micron before charge. On systems that I replace parts like orifice tube and condenser, I find I have to run about 24 hours to get to that level and my pump is a big 7 CFM vacuum pump with fresh oil. Once I do that initial pull, any subsequent pull only takes 15 min or so to get down to 500 micron.

next time, I’d just run it overnight at least. My number below is a bit overkill, but overnight should be adequate unless the system is extremely saturated.

Man, those gauges are expensive. I was going to get one since I need to pull mine down after swapping the condenser and drier. I think Ill just run it for 12 hours and call it good. The system has stayed sealed this whole time and I live in a low humidity environment so I would think 12 hours should be sufficient.

 

[Dwain]

I have some gauges on the car. It’s about 95° outside at the moment with 60% humidity. Low side pressure is reading 30 psi, high side sitting at 275 psi

you should be seeing 50-55 on the low side and 275-300 on the high side. I think you should add a little more refrigerant.

 

[Dwain]

Since your high side is on the low side of the range and the low side is low, I would add some refrigerant. If your high side was already at 300 or higher I would suspect airflow being too low to the point its causing an issue.. I believe spraying water on it will always lower the high side some as its going to pull heat of the condenser. @Mustang5L5 seems to be more experienced than me with AC so you can wait for him if you want a 2nd opinion. You arent going to need to add much more. I would think 1 or 2 ounces would probably do it.

 

[Dwain]

I got the high side to 300 and left it alone. Vent temps still aren’t where they should be so I’m gonna go ahead and add an auxiliary fan

What was the low side when you brought it up to 300 on the high side?