86 Air Conditioning

[PandaSPUR]

Originally Posted by bkharmony

90% of the time I'm in start/stop traffic or inching along. Probably not the best conditions for an AC system.

Yep, theres the problem. Compressor runs off the engine and relies on airflow created by movement of your car. No movement = no airflow = hotter compressor = less cooling inside.

[bkharmony]

Originally Posted by strat61caster

The Scion TC weighs >3,000 lbs, what you get with that extra 250+ lbs is a better HVAC system for the passengers (more powerful A/C, better routing and insulation of the ducting), it's all about sacrifices when you build a car on a price point.

I swear I get significantly more engine heat through the vents when the system is completely off. And like you said, I've been wondering if that's simply an effect of the engineering focus on low weight, compact design, and performance. If that's the case, I'm good with that. I knew I'd ben making sacrifices. I just want to be sure I'm not crazy, ill, or my brand new AC system is already on the fritz.

Thanks for your help.

[bkharmony]

Originally Posted by PandaSPUR

Yep, theres the problem. Compressor runs off the engine and relies on airflow created by movement of your car. No movement = no airflow = hotter compressor = less cooling inside.

I get that's how AC systems work. I'm just comparing two vehicles in exactly the same conditions (my commute hasn't changed in 5 years, and neither has Texas heat), and seeing two different results. I mean, if the 86's AC just isn't as good as a more "comfort-focused" vehicle, I can live with that. I just want to be sure it's not faulty.

[humfrz]

Originally Posted by PandaSPUR

Yep, theres the problem. Compressor runs off the engine and relies on airflow created by movement of your car. No movement = no airflow = hotter compressor = less cooling inside.

.....

You wanna re-think that..??

An A/C system is a "closed" system .....


humfrz

[PandaSPUR]

Originally Posted by humfrz

.....

You wanna re-think that..??

An A/C system is a "closed" system .....


humfrz

?

Yea, the refrigerant never comes in direct contact with air, but the condenser has to be cooled somehow. If the heat never escapes, the system just keeps getting less and less efficient at cooling.

[PandaSPUR]

Originally Posted by bkharmony

I get that's how AC systems work. I'm just comparing two vehicles in exactly the same conditions (my commute hasn't changed in 5 years, and neither has Texas heat), and seeing two different results. I mean, if the 86's AC just isn't as good as a more "comfort-focused" vehicle, I can live with that. I just want to be sure it's not faulty.

Yea I get what you mean, but its the best explanation I can think of.

Every passenger I've had comments that the AC in my BRZ is freezing cold, even on the hottest of NYC days. I also tend to drive above 3k RPM even in the city.

[VIP BRZ]

Not to be this guy.. but are you large in stature?

my AC gets unbearably cold.. even at the lowest fan setting.

[humfrz]

Originally Posted by PandaSPUR

?

Yea, the refrigerant never comes in direct contact with air, but the condenser has to be cooled somehow. If the heat never escapes, the system just keeps getting less and less efficient at cooling.

That's what the fan does when it blows air across the radiator/coils ......

If you put your car in your garage on a hot day (the car is not moving) and run the engine and A/C, it will still cool......

DAMMMNNNNNN ....... I've been hanging with ol @Tcoat for too long .......


humfrz

[extrashaky]

I've had mine since 2014 through stints in Louisiana, Texas and now Florida. I have never had a problem with the A/C, even in the horrible traffic in shithole Houston in August.

HOWEVER, I have Llumar ceramic window tint and the OEM shade I usually put in the windshield whenever I'm going to be out of the car more than a few minutes. The UV and infrared blocking properties of the film made a significant, noticeable difference in comfort inside the car. The shade keeps the dash and steering wheel from heating up while it's parked and protects them from UV damage we've seen on some of these cars. Cooling the volume of air inside the cabin is only half the battle.

[Tcoat]

Originally Posted by humfrz

That's what the fan does when it blows air across the radiator/coils ......

If you put your car in your garage on a hot day (the car is not moving) and run the engine and A/C, it will still cool......

DAMMMNNNNNN ....... I've been hanging with ol @Tcoat for too long .......


humfrz

Yes you have and as a result the moments of lucidity have been becoming more common!

[PandaSPUR]

Originally Posted by humfrz

That's what the fan does when it blows air across the radiator/coils ......

If you put your car in your garage on a hot day (the car is not moving) and run the engine and A/C, it will still cool......

DAMMMNNNNNN ....... I've been hanging with ol @Tcoat for too long .......


humfrz

But @Tcoat is usually right in what he says... and doesn't suggest death by carbon monoxide

[humfrz]

Originally Posted by PandaSPUR

But @Tcoat is usually right in what he says... and doesn't suggest death by carbon monoxide

....... you DON'T shut the garage door .....

......and @Tcoat isn't even usually right ...... just ask mrs Tcoat ......


humfrz

Besides carbon monoxide isn't all that bad for you ....... as a kid, I spent countless hours on a tractor that the muffler had long since rusted away ..... and you can see how I turned out, so .......

[Ultramaroon]

Originally Posted by bkharmony

I get that's how AC systems work. I'm just comparing two vehicles in exactly the same conditions (my commute hasn't changed in 5 years, and neither has Texas heat), and seeing two different results. I mean, if the 86's AC just isn't as good as a more "comfort-focused" vehicle, I can live with that. I just want to be sure it's not faulty.

It's just how it performs. Your and strat's experience matches mine. In heavy traffic my temperature control is a choice between recirc or fresh. :|

It does great once I get moving. The compressor doesn't really keep up with the evaporator below 2K RPM

[Tcoat]

Originally Posted by PandaSPUR

Yep, theres the problem. Compressor runs off the engine and relies on airflow created by movement of your car. No movement = no airflow = hotter compressor = less cooling inside.

Doesn't really matter how hot the compressor runs. That isn't where the cooling happens.
Heat is removed at the condenser which is downstream of the compressor. Hum is correct in saying the fan removes the heat at that point. You are also correct though since a moving car sheds heat better than a stationary one. The more efficiently heat is removed from the condenser the more efficient the system works. As mentioned the engine bay is packed pretty solid so our AC isn't the most efficient out there.

Originally Posted by Ultramaroon

It's just how it performs. Your and strat's experience matches mine. In heavy traffic my temperature control is a choice between recirc or fresh. :|

It does great once I get moving. The compressor doesn't really keep up with the evaporator below 2K RPM

Yep. This is where the compressor comes in. At low RPMs it just isn't moving enough gas to the condenser too turn it to liquid. Not enough liquid at the condenser means not enough is turning back to gas at the evaporator to remove the heat from the passenger compartment. Poor cooling at idle is not unusual for small displacement engines since a larger compressor that would move more gas would rob too much power. Combine this with the hot engine bay and you have an AC system that is happiest when moving with higher RPMs.

Now what is "cold" is subjective to individuals so when one guys says his is freezing and another says his is still warm it could very likely be exactly the same temperature in the car.