The Lotus Cars Community banner
1 - 5 of 5 Posts

·
Premium Member
Joined
·
2,847 Posts
I have always thought the air flow was too weak on my car so I took a look through the grille on my '05 (late production) and only two of the intake plenums were opened and covered with the mesh. The middle plenum was uncut and totally sealed while the two open plenums were completely plugged with bugs, leaves and road crud. I cleaned all the crud off the mesh with a stick and a wet rag, but I need to pull the grille and clean everything thoroughly when I have more time. This looks like another cleaning chore that I will need to add to my list on a yearly basis. When I pull the grille should I cut open the center plenum or did the factory leave it uncut for some reason?

Tonywa28 said:
The ribs form three plenums that feed the intake to the climate control system. The openings to those plenums (at least on my very early car) were considerably smaller than the plenums themselves. The holes just weren't cut with much care. One other sort of jungle math bit - I'm pretty sure the vent hose on the output side of the climate control is 4" diameter yielding 12.5 square inches of area. For my car (the only example I have:) ) the inlets in the ribs probably had more like 8 or 9 square inches (approx. 1.5 *2* 3) of total area. Again the cut-outs did not "port match" to the plenums very well. Imagine a big carb vs. small carb. Bigger venturi gives more CFM or try drinking coffee through a coffee stirrer. I think I'm on solid ground here, but am open to opinions.
 

·
Premium Member
Joined
·
2,847 Posts
Arno said:
Correct. Part of it, yes.
I had the same thought when I looked at the structure. I wouldn't open up the plenums on the top, but I can't see why enlarging the existing holes to their edges would be any different than the crude holes Lotus cut into the face of the plenum structure. I am mainly curious as to why the photo on this thread shows three open plenums while my car has only the two outer plenums open and the center plenum uncut.
 

·
Premium Member
Joined
·
2,847 Posts
Thanks for the info. Tony and sorry to hear about the blood letting. I can't see how cutting into the face of the plenum structure would have any effect on crashworthiness so I agree with you. The only downside I can see from adding the center hole would be possibly less air flow to the radiator, but it couldn't be that much considering you have been driving your Elise around Florida without cooling system problems. Keep us updated on the heater bypass kits and thanks again for all your efforts.
 

·
Premium Member
Joined
·
2,847 Posts
The parts list was in the first post of this thread, and later updated in post #69. I didn't see a part number or source for the potentiometer switch, although there was a lot of discussion about it in various posts between 46 and 69. Everything else that didn't have a part number in his list were just generic parts.
Tony sent me the potentiometer seperate from the kit and I still have it in my parts collection. I don't remember it having any numbers or identification on it, however I will take a good look at it tonight when I get home from work and report back any I.D. markings I might find on it.
 

·
Premium Member
Joined
·
2,847 Posts
Tony sent me the potentiometer seperate from the kit and I still have it in my parts collection. I don't remember it having any numbers or identification on it, however I will take a good look at it tonight when I get home from work and report back any I.D. markings I might find on it.
The potentiometer from Tony has the marking CTS (the manufacturer's name) on the front and R1378550 as well as 37-2022 on the back side. It looks like one of their 270 series potentiometers, but I can't tell for sure. Hope this information is of some use to you guys.
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top