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Great work!

Question, would it be possible to hook up the bypass back at the engine instead of at the heater core? That way the hot water associated with the core loop wouldn't circulate thru the framework.
 

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Tonywa28 said:
2) Bypass in the engine compartment rather than up front to have cooler sills. Likely wouldn't help too much as the main radiator pipes still go from back to front to the radiator.
I may be making a bad assumption, but if the water in the heater core loop is as hot as the water in the radiator loop, wouldn't you be cutting the amount of hoses running hot water by half?

Or is the amount of heat generated by the engine now fully transferred to the radiator loop, and the net dissipation from hose to chassis hardly changed?

Tonywa28 said:
It would also take a larger amount of the available coolant out of circulation. It also bugged me a bit that when the bypass was switched off a fair amount of cooler water would hit the system. But I'm over analyzing....always. It would probably work great.
I think Tim made that point too. One might have to be careful not to shunt unheated water into a hot engine.
 

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Tonywa28 said:
The only open item I know of is the switch in the cockpit. This is very personal on what switch you want and where you mount it.
Would a Lotus hazard switch work? Just thinking how to preserve the look and feel.
 

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Tony, instead of a push/pull, would it be more likely to find a pot with detents that had a on/off position at the far range of travel?
 

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I found something on digikey but I can't tell how the switch works. :shrug:

Doh. Here's the datasheet.



Out of curiousity, can you tell who the manufacturer is of the OEM switch? Is there a part number to x-reference? Maybe they have some additional varieties.
 

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lucksta said:
Another alternative to a push-pull switch (and one I think I'll try) is to add a SPDT relay to the standard rotory pot-switch combo which will activate the bypass when the switch is turned off (fully counter-clockwise to coldest).
Definately post pics once you get it together. :up:
 

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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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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
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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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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Strange, mine was a complete transformation. Low 90's outside 45' at the vents, the tip of my nose nearly froze.
Cheers,
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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