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Interestingly enough, the wiring diagram definitely shows the headlight and parking light switches as maintained (on/off). However, what is not shown, is the logic circuitry in the switch pack module, that could very well mean that these switches are momentary.
 

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I am simply saying that the wiring diagram shows them as being maintained, there is no latching circuit shown. Lotus admit that what goes on in the Switch Pack module is not shown. What is shown is that the parking light relay contact controls the two headlight relay coils, which is why the headlights can only be on with the parking lights.
 

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There is one possible disadvantage of bypassing in the engine bay which has never been mentioned as far as I know. Because the heater, coolant and oil lines run parallel, very close to each other in the sills, we don't know how much heat would be transferred from the coolant and oil lines to the bypassed heater lines. There could still be significant heat ending up in the heater core even though it has been bypassed. Now, I really don't know if this would happen, but it is a possibility to be considered until it is proven otherwise. The other issue that has been mentioned is that if there is a switched bypass, cold coolant would suddenly flow into a hot engine, which is not a good idea. However, if the 3 lines transfer heat to each other, this is a moot point.
Dumb question. The heater bypass you are are describing is mounted up front, bypassing just the heater matrix, dropping the vent temps about 5 deg.

Looking at the diagram, and not the car, it seems like it would not be that difficult to move the bypass back to the engine bay, and not run hot water through the side pods and/or the heater core.

What am I overlooking?
 

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Doug,
I guess the answer is to try to insulate the duct and take before and after temperature testing under similar condition.
Michael
Michael,

I agree. Its just that I found, on my car anyway, a BIG place where the hot radiator air can heat soak the top of the heater box and the fount of the peddle box.

There was a 4 1/2 by 6 inch hole for the hot air from the radiator to blow directly on the big hose that connects the heater box to the dash board.

Doug
 

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Doug,
Done, thanks. After I insulate I will take vent temperature readings to compare to "before" readings and post the results. I know that after driving for 10 miles approx. the vent temps. increase about 8' which I know are cooling system heat soak related.
Michael
You bet you can add it. Glad I could give back something.
Score now Doug 1 LotusTalk 999,223
 

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Tom,
Thanks for the offer, however because I have been monitoring the vents temps for over a year now I know exactly where it settles. It always starts out after a few miles in the low high 40's (low 40's in the winter) and after about 10-15 miles settles at approx. 52'. If the insulation works, the temperatures will not go up to 52'. BTW,I have my hardtop on during the summer.
Michael
Michael:

Let me know if you want to use my car for a side by side comparison if you want to do a test. I will be free Sunday after 1 PM.

We could put the cars in my garage and run the tests so that heat soak from the sun wouldn't be a factor or meet at the Blue Anchor and park underneath the covered area. Both roofs should be off so that the difference between a hard top, insulated top, and non-insulated top wouldn't factor into the equation. Granted, temperatures wouldn't decrease by 38 degrees because the cold air wouldn't be recirculated, but it would just affect the vent temperatures, which is what you are trying to determine.

Also with the roofs off, the changes to the sill insulations wouldnt have any effect either.

Later on we could do a road test with the softtops on to determine the vent temperature differences that occur with a car that had the insulation, tinted windows, etc. (yours) vs. mine that only has the floor covers removed and the heater bypass installed.

I almost forgot- Tony put insulation around the black corrugated plastic dryer type tube on my car that leads into the vent area. This helps keep the air going into the vents cool too.
 

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My only comment is that the access panels should not be insulated because you want heat to escape.
Michael
UNBELIEVABLE! Doug has broken the code. I had the same results as Viper, I went for a three hour drive yesterday in 100+ deg. temps mixed highway and slow moving traffic........amazing. Makes me wonder, was this a manufacturing misstep or did lotus have a reason for leaving that open to the outside? I think this may also lessen the amount of grime present in that area. I noticed the top surface of the access panels also became very hot so they both got a thin layer of insulation as well......couldnt hurt. Im going out again at 1pm.....just because I can :cool:
 

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If you are referring to the center spline, it does not have to fit perfectly. A little larger and fold the sides around which improves the seal. The radiator cowl, just form the insulation over it.
Michael
Request: Once you've narrowed down a decent fit, can you post a template in pdf format? Would like to have something to print out and use to mark where to cut the insulation for a tight fit.
 

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Actually, where you circled is not a gap that needs sealing, after you get everything back you will be able to see any gaps. Incidentally, just came back from a drive, outside temp. 90', vent temps around 46', 7' lower than before the mod :coolnana::coolnana::coolnana:
Cheers,
Michael
Gotcha. Thanks!

For the two radiator cowls, don't I also need to fill in the gaps on the ends? I circled where I'm talking about from your original pix, in green.
 

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Leave the original block in place and insulate over it, extending down to cover the gap. See my link below.
michael
Ok so the insulation goes in those spots or are you removing stock insulation to let it breathe more?

I apologize for the dumb questions, I'm just trying to understand it all.

Thanks!
 

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Strange, mine was a complete transformation. Low 90's outside 45' at the vents, the tip of my nose nearly froze.
Cheers,
Michael
I did the mod last night. Perhaps went a bit overkill with the two black cover panels: I did them in two sections, the bottom section I made deliberately longer to fold onto itself and thus try to block some of the air that might escape thru the bottom edge. However this bit is touching the radiator and might be working against me, by directly conducting heat to the aluminum sheathing.

I can definitely feel an improvement as it can keep cold air flowing longer, but on a 93 degree day like today it seems it still reaches a point where the system feels overwhelmed. I'd say it's moved from "mediocre" to "acceptable" with occasional bits of "great". ;) Whereas before, it would only stay between "mediocre" and "acceptable". I think with some anti-IR window tint, and perhaps removing the blocking panels in the footwells, this might work quite well.

The painted access panels are certainly quite hot to the touch, almost to the point where I can't rest my hand on it for too long. It might be good as to not insulate the back edge of the black panels as that might transfer heat to where it slides onto the painted panel. Also while I tried to fill in as much seams near the center spar as I could, I'm a bit concerned that the insulation may redirect the rain channels on either side of the spar to not drain properly. I might go back in and remove some insulation.

Of course I only found my a/c thermometer after the mod, but I'll try to measure some duct temps soon.
 

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Jared, any improvement is a wonderful thing :)
Michael
I didn't say it's not working! :bow: It's a significant improvement. And your car is a bit better insulated than most. ;) I'm on a base trim car.

Just did a couple of 15 mile stints. WC says the outside temp is 95... i'm measuring 99.9 in the sun with the digital thermometer (not certain if it goes more than that).

Cabin temp at start: 88 (garaged)
Vent temps with recirc on, fan speed 2: 45 to 50 degrees*
Vent temps with recirc off, fan speed 3: 48 to 53 degrees*
Cabin temp at end: 77 degrees

*range is due to when the electronic temp control cycles on and off. These were measured with an analog needle hvac thermometer. I see a difference with the hvac thermometer vs. two indoor digital thermometers with the digital being higher: might need to add 3 degrees to the above vent temps.

I could feel a significant improvement when the sun was behind me, and I realize my test conditions weren't consistent or scientific, but the ability to cool the interior by 11 degrees in 100 degree sunlight is a significant leap forward.

Cheers,
Jared
 
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