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I didn't expect much from the A/C on a car like the Elise, but after driving 100 miles in 100°F heat, I'm starting to think mine is not working properly.

I've heard that it's possible for it to freeze up when kept on the coldest setting. Is this true? The AC feels reasonable when I first embark, but it seems to get worse the longer I drive (decreased air volume, warmer air). I'm not sure if this is due to the evaporator freezing or the A/C just not being able to keep up with the heat from the radiator lines and the hot ambient.
 

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I didn't expect much from the A/C on a car like the Elise, but after driving 100 miles in 100°F heat, I'm starting to think mine is not working properly.

I've heard that it's possible for it to freeze up when kept on the coldest setting. Is this true? The AC feels reasonable when I first embark, but it seems to get worse the longer I drive (decreased air volume, warmer air). I'm not sure if this is due to the evaporator freezing or the A/C just not being able to keep up with the heat from the radiator lines and the hot ambient.
http://www.lotustalk.com/forums/f313/improved-c-heating-system-71031/
Michael
 

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S2K: Follow the instructions SirLotus posted. At a minimum, remove the covers on over the perf panels at your footwell. It makes a big difference. I'm actually looking forward to the ride home today. It will be the first time since doing the mod that I'll be in the car at about 105. My expectation is it will be "acceptable". Prior to this, it wouldn't have been.

If the volume is actually reducing over time, you may have another issue.
 

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Texas can be hard on the Elise a/c. If that system were R12, I think we'd be in good shape. Drilling out the foot panels will dramatically increase your airflow. Do this one first as it's the easiest, and you get the most bang for your buck. This should also be done with closing off the fresh air vents, otherwise, your extra airflow will be mixed in with hot concrete air.

I also did the air duct insulation as well as the access panel insulation. Again, day and night difference. The temperature dramatically went down at the vent. However, both of these SirLotus mods only make the a/c marginally adequate, not comfortable.

What part of Texas are you in?
 

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I didn't expect much from the A/C on a car like the Elise, but after driving 100 miles in 100°F heat, I'm starting to think mine is not working properly.

I've heard that it's possible for it to freeze up when kept on the coldest setting. Is this true? The AC feels reasonable when I first embark, but it seems to get worse the longer I drive (decreased air volume, warmer air). I'm not sure if this is due to the evaporator freezing or the A/C just not being able to keep up with the heat from the radiator lines and the hot ambient.
If you are new to the car first check the system is serviced properly then find out what Mods or updates have been performed by a PO. In my personal experience the trifecta of mods most likely to improve the AC performance is:

1. Insulation of the center spine to prevent heat soaking of the HVAC and footwell area as shown in photo 6. very significant discovery by Doug----Porsche.
2. Install updated electronic thermostat if not already done, will cure the freezing up issue early cars have (part #A120P0149S)
3.Open up the return air vents by removing or modifying the plates in the driver and or passenger footwell. greatly increases air flow.
:cool:
 

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The real problem is, the car was designed in England.

It never gets really cold (winter temps are 45 ish) , and it never gets really hot (summer temps are 70 ish) in England.
Lotus did a great job on sizing the HVAC for this temp range.
The heater has never left me cold at 50 deg. (but outside temps in the 20s, well, lets just give the heater a nice participation ribbon!)
The A/C has kept the interior temps very pleasant when its 75 deg out side. (at triple digit temp, the A/C will make it very easy to keep too much sweet from running into your eyes, and your shirt probably needed to go to the laundry anyway.)

Just like the suspension, you have to optimize everything on HVAC because, well lets face it. ... at best, the fan is run by a "four pack of cigarets a day gerbil", the floor vent has one outlet, on the passenger side of the car. The dash ducting was built with the understanding that forcing air to turn as many 90deg bends as often as possible is best for NVH and airflow.

The wife drives a Corvette. The A/C can give you frostbite, and the heater is capable of giving you heatstroke. Now if they could just make the car smaller, lighter, better driver feedback.....
 

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Putting carpet in the car (like the touring pack) reduces head radiating from the side sills. The Sills have hot oil and water lines ran through them. Tinting the windows reduces the amount of solar heat baking the interior. The less heat which is introduced to the cab make the AC work less hard to keep a decent temperature. These two final steps make a difference when all of the updates provided by SirLotus are performed.
 
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