IMPROVED A/C & HEATING SYSTEM

[xxxotic]

I just checked and I dont have the foam piece on the spline.

I think I might have thrown it out when I did the heater bypass. Good thing is that I insulated my black plastic duct with foil insulation when I did the bypass. This is the black dryer vent like tube that goes into the ducts.

It looks like this is the area that we want to keep cool since if the duct intake tube gets hot it transfers the heat into the ducts. Guess My ac problem wasn't that bad since the tube was insulated, but now I an going to insulate the whole area.

Michael, what is the foil that you got,and where do you get it- Home Depot-Lowes, or at an AC supply house?

[TheViper]

Here we go Tom,
Thermwell 12 In. x 15 Ft. x 1/8 In. Self-adhesive Foil/foam Duct Insulation - FV516 at The Home Depot
Michael

Originally Posted by xxxotic

I just checked and I dont have the foam piece on the spline.

I think I might have thrown it out when I did the heater bypass. Good thing is that I insulated my black plastic duct with foil insulation when I did the bypass. This is the black dryer vent like tube that goes into the ducts.

It looks like this is the area that we want to keep cool since if the duct intake tube gets hot it transfers the heat into the ducts. Guess My ac problem wasn't that bad since the tube was insulated, but now I an going to insulate the whole area.

Michael, what is the foil that you got,and where do you get it- Home Depot-Lowes, or at an AC supply house?

[xxxotic]

Thanks, Michael
Found a roll of it at Lowes.

[mrcarcrazy]

Just wanted to post regarding blocking the intakes in the mouth of the Elise. Blocking those off significantly decreased the temp of my a/c. I wish I would have run a before and after, but I can definitely say it was a few degrees...sustained degrees (seems that the a/c got heatsoaked before). (this is on a 96 degree day).

I went to my local home depot, with no luck, they didn't have any thermwell - or if they did, they had no clue where it was. I'll try lowes.

[TheViper]

That's great news, however to conquer heat soak, the center hood spline and radiator cowls need to be insulated.
Michael

[xxxotic]

Just went for a 20 mile drive down a highway at 60-70 mph the entire way.

The vent temperatures were between 45-48 all the time even at the end.

I started out from a garage that was about 97 degrees and the outside temperature was about 86 degrees.

There was no major increase in temperatures even when stopped at a light for a few minutes. Except my temperature increased when some idiot ran the light and almost t-boned me!

Just wondering. If shutting off the intake vents and using Recirculate causes the system to draw in air from the cabin by the footwells, would it be better to keep the selector dial turned so that air comes out of the footwells instead of the vent for the first few minutes, so that it is sucking in cold air instead of the normally hot air that is there?

[ZAMMY1]

i don't know if it was mentioned, the heater/AC must be set to recirc if the vents sre taped off.
mine works very well.
good luck.
sam

[TheViper]

Actually, the system does not need to be set to recirculating. All that feature does is shut off outside air from the nose intakes which is being done already by taping them. It is just duplicating the taping and has no effect. The "Recirculating" switch in the Lotus actually means shutting off outside air so that 100% is being drawn from the footwells, (air is always being drawing from the footwells )
Michael

Originally Posted by ZAMMY1

i don't know if it was mentioned, the heater/AC must be set to recirc if the vents sre taped off.
mine works very well.
good luck.
sam

[skelliott2]

Michael,

While I was removing the pieces in order to do your heat soak fix, I noticed that there is a line for hot water that runs through the bottom of the area where the cabin air tube runs (inside of the cowlings and your new center insulation over the foam block). I had driven the car and so the hose was VERY HOT. I am going to wrap the entire cabin air tube and see if maybe that prevents the hose that is actually inside of the area from transferring heat to the tube as well. You may have already found this, but I figured that I would share just in case you had not.


This has to be one of the most useful threads in all of Lotus Talk. Thanks for keeping us up to date on your findings. I look forward to dramatically cooler air temps. I might have to actually turn down the AC if this works well!!!

Scott

[xxxotic]

Originally Posted by skelliott2

I am going to wrap the entire cabin air tube and see if maybe that prevents the hose that is actually inside of the area from transferring heat to the tube as well. You may have already found this, but I figured that I would share just in case you had not.

This stuff looks like it could either fit over the tube or replace it. It also comes in 6 inch diameter. I dont know the diameter of theBroan at Lowe's: Flex Duct, 4", Insulated (25') tube on our cars.

[TheViper]

Remember, the objective is to not only keep hot air away from the inlet duct, but also other components such as the evaporator enclosure, etc. I will try to additionally insulate the duct too and see if there is any additional benefit. I am not sure if the other end of the duct is accessible for removal and replacement.
Thanks for all your inputs.
Michael

[ZAMMY1]

thanks, viper, more good info.
sam

[407Driver]

I insulated the AC trunking tube with a 16x16" square of thin foil/neoprene foam cut from a windshield shade by stuffing it in and around as best I could. The trunking is easily removable, however it is difficult to re-install with anything attached to it. While the AC works very well now with the Doug mod I have insulated the back side of both black heat shields and the access panels as they are also exposed to heat from the radiator. I noticed for the first time my car leaves a real puddle of condensate under it..... just like a big car

[skelliott2]

I just finished wrapping the flexible air hose. It is a tight fit, but you can detach the two screws from the wiper motor cover (black cover with the fuse box on it) to help with making room to get it back in once wrapped. While the cover will not come off due to a zip tie holding it on, it gives enough clearance to get the covered tube back in. I also think the covering of the tube will have the added benefit of acting as a further barrier to heat from the master cylinder and other brake parts on that side of the car.

Michael, can you tell me some of the specific additional areas that your insulated? While I have it cracked apart, I want to get it all done at once. You mentioned that the goal is to prevent heat soak in the evaporator enclosure, where is that located? Is it the part that the lower cabin air tube connects into?

Now I just need to experience the fruits of my labors!! Cooler air here I come!!

PS. - Thanks for the corrections Michael. I am an auto guy in driving mostly as was evident from my post!!

[TheViper]

Take a look back where all this started at my post #1, it is ALL documented there. BTW I think you are referring to the wiper motor cover. Also, it's heat soak into the evaporator enclosure.
Michael

Originally Posted by skelliott2

I just finished wrapping the flexible air hose. It is a tight fit, but you can detach the two screws from the blower motor cover (black cover with the fuse box on it) to help with making room to get it back in once wrapped. While the cover will not come off due to a zip tie holding it on, it gives enough clearance to get the covered tube back in. I also think the covering of the tube will have the added benefit of acting as a further barrier to heat from the master cylinder and other brake parts on that side of the car.

Michael, can you tell me some of the specific additional areas that your insulated? While I have it cracked apart, I want to get it all done at once. You mentioned that the goal is to prevent heat soak in the heater matrix, where is that located? Is it the part that the lower cabin air tube connects into?

Now I just need to experience the fruits of my labors!! Cooler air here I come!!

[xxxotic]

I noticed that the R value on the peel and stick insulation is 3, and saw on home insulation sites that doubling it up doesnt necessary double the insulation value.

Different materials have higher r values, so i was wondering is using something like a ceramic paint coating or other type of insulation would make a significant difference?

Thermal Insulating Sound Control Coating

Would using a r6 insulation value instead of an r3 value make a significant difference or is it only minimal?

[stinkyonion]

so what is the effect of a passenger footwell sub on the A/C and heating? Thinking about getting one but curious if it will seriously effect cabin comfort because of blocking passenger footwell vent.

[TheViper]

If you totally block it, there will be a 50% reduction in air volume. Just leave a gap large enough for air to be drawn into the return.
Michael

Originally Posted by stinkyonion

so what is the effect of a passenger footwell sub on the A/C and heating? Thinking about getting one but curious if it will seriously effect cabin comfort because of blocking passenger footwell vent.

[RWLott]

Originally Posted by TheViper

Revised in post #1 (highlighted in blue with photo's 6 - 8) to include simple modifications to drastically reduce the engine cooling system heat soak, which reduces vent temperatures by an impressive 8'F.
Cheers,
Michael

I purchased a roll of Frost King (12"w x 1/8" thick x 15' long) self adhesive foil & foam from Lowes. So far all I have done are the Heat Soak mods parts 1) and 2) (photos 6, 7, & 8). The interior of the car remained noticeably cooler on a recent 80 degree day trip. Normally the Elise is a warm ride even in cooler weather.

Today the outside temp was a humid 86. It was the first time the car was too cold while running the A/C.

This is an excellent mod!

Thanks much.

[TheViper]

Too cold in a Lotus, great news, I am so happy it worked for you. BTW, I just added part 3)
Michael

Originally Posted by RWLott

I purchased a roll of Frost King (12"w x 1/8" thick x 15' long) self adhesive foil & foam from Lowes. So far all I have done are the Heat Soak mods parts 1) and 2) (photos 6, 7, & 8). The interior of the car remained noticeably cooler on a recent 80 degree day trip. Normally the Elise is a warm ride even in cooler weather.

Today the outside temp was a humid 86. It was the first time the car was too cold while running the A/C.

This is an excellent mod!

Thanks much.