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I took my car apart (and cut myself nicely) to try and see if I could determine whether there were two holes originally or three. I couldn't tell, but I'm very much leaning toward the idea there were two original holes and I added the center one. Old age is tough on the ego..... I did verify that the center hole does draw air, so I guess I not only increased the area in the existing hole, I added a third hole which raises the input area by 50% even if you don't go into the top of the rib. Also checked the thickness of the fiberglass of the rib.....it was less than 1/8 inch...... Measured the area of the one original hole and it was right at 3 square inches.
So back to my observation about the stock set-up:
The vent pipe from the climate system to the car is around 4" in diameter yielding 12.5+ square inches of area. The original openings for climate control intake were close to 6 square inches (2 openings * 3 square inches)....
So for those folks who don't want to cut on top, you could still add a third center hole with screen just on the front of the rib.....unless folks think that compromises the "crash" structure.....-poke-
It's all about the opinions!!! and we all are the absolute undeniable authority on our own!
As always, no warranty or liabilty is accepted for changes you make to your own car, I'm just posting what I did as an idea....
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.
A bit off topic but sort of relevant...Chapman recognized this way back in the early cars. I can remember updating my Elan with nice shiny big tubular a-arms over the original stamped steel channels because I thought strong and heavy was always good. Then a revered Lotus tuner pointed out that now any curb impact that I had was going to send the shot straight to the stressed skin frame rather than the orignal a-arms sacrificing themselves.....much more expensive proposition to replace a frame than replace a-arms...Chapman was a genius because everything was sized correctly for the job, no more, no less and he tried to get multiple uses out of parts (frame sections carrying vacuum is an example). He seemed to more get more performance (at least the kind of performance I like) from the sum of the parts than other manufacturers.
I did the same thing on my Elan, Some sort of polished nickel chrome tubular A arm because my stock ones were looking rusty if I recollect. A few years after I was driving in Boston and one of the A-arms failed as I went down one of the streets there that might just validate ownership of an all-terrain vehicle in an urban environment. The A arm sheared completely... Nice job of plating the outside to prevent corrosion.... erm... but water inside did a lovely job and ate it from the insde out... Glad I was not on an interstate doing highway speed at the time. So I bought Chapman's stock parts and replaced the shiny stuff all the way around
My very late 05 only has 2 inlets. Is there a way to get into the plenum without removing the screens? I was thinking of just swiss cheesing the center plate with a drill for a bit more air until I get around to all three screens.
These are the ones I have (in nickel which flaked off within a year) since 1985. pg3 Spy tubular wishbone
Bought these, space frame with sill tubes and rollbar, half shafts all from the same outfit. My opinion looking back was that it was all a bit.....agricultural.
I also had a dual wishbone rear suspension conversion from these same guys. It had a problem where if you lowered the car any at all the rear brake discs would try to saw thorugh the new lower a-arms...I junked it.
I don't think you can get at the existing openings without removing the screens and they are really gooped on there. I used a single edge razor blade and it was sort of a pain. As far as the swiss cheese idea for the center rib, that might be a really good alternative. Might make some of the other ETers a bit less apprehensive about the mod (structural integrity concerns) Are you planning on using the smaller holes in lieu of a screen?
If you want to go for the bigger cutout you might want to use a hole saw and cut a hole at the top and bottom of the panel and use a hacksaw to connect the holes (rather than a cutoff tool like I used). Of course this would get you into needing to make a screen...
I can remember updating my Elan with nice shiny big tubular a-arms over the original stamped steel channels because I thought strong and heavy was always good. Then a revered Lotus tuner pointed out that now any curb impact that I had was going to send the shot straight to the stressed skin frame rather than the original a-arms sacrificing themselves.....much more expensive proposition to replace a frame than replace a-arms...Chapman was a genius
As another Elan owner, but one that had an idiot pull out in front of me from a stop sign and take off the left front corner of my Elan, I can attest to the wisdom of this. My front tire/wheel was pushed back, and a couple of a-arms buckled, but my frame was completely undamaged. The a-arms were cheap to replace...
I finally got around to doing the kit install this afternoon/evening. Clearly I have put more than 3 hours into the process. The installation is a snap, but my problem is the bleeding. The engine is definitely heating up quickly. The fans are coming on and I can hear the heat soak pump running after turning off the engine. I have not bothered to drive the car, just running it at idle.
Apparently, I have no water flowing through the valve. I have triple checked the plumbing and believe that I have the hoses in the correct pairings. Water is flowing out of both bleed valves. I tried bleeding the valve inlet hose.
I will have to wait until tomorrow when I can get more water wetter for the reservoir.
Anyone have experiences that I may have missed a step?
I did mine this week also...when u say the engine is heating up rapidly...how hot is yours getting? Mine with get to 192-194 and the fans kick in...she just sits around 190. I though this was the regular operating temp. I had trouble with the bleeding also...I could never find the front bleed valve so I just gave up on it...figured I would just keep an eye on the temp. I just drove her about 40 miles today on the highway...with the wetter water she stayed around 184 and the temp from the vents was between 45-50.
Am I supposed to turn off the bypass when I shut off the car?..I figured the vacumn line would lose pressure and it would turn off by itself enabling the heat pump to circulate if it needed.
I did mine this week also...when u say the engine is heating up rapidly...how hot is yours getting? Mine with get to 192-194 and the fans kick in...she just sits around 190.
I was seeing temps over 200 before I would shut it down. Radiator fans would come on high.
madguppy said:
I had trouble with the bleeding also...I could never find the front bleed valve so I just gave up on it...figured I would just keep an eye on the temp. I just drove her about 40 miles today on the highway...with the wetter water she stayed around 184 and the temp from the vents was between 45-50.
I was afraid to drive it so I was just running it idle in the garage. I found the front bleeder valve reachable without removing the front wheel liner. Had to use an offset screwdriver to loosen it the first time but then with a little bit uncomfortable manuevering I could open and close it from above.
madguppy said:
Am I supposed to turn off the bypass when I shut off the car?..I figured the vacumn line would lose pressure and it would turn off by itself enabling the heat pump to circulate if it needed.
Coolant is finally flowing through the valve and thus the heater. Don't know what I did other than going throught the bleeding process 4 times this morning besides twice last night.
I'm very glad the mod is working out for you. So far I've heard nothing but good stuff except for one wiring snafu that was corrected, so I'm keeping my fingers crossed.
FYI - my temp always stays between 188 and 194, typically 192. I've seen it go a BIT higher but nothing near 200...except when I first modified my car with the bypass. I forgot to put more fluid in the overflow before I bled :wallbang:, so the first time I drove it, it was a little hotter than normal (maybe 205 tops) as it was low on coolant.....added fluid, bled, and I'm back to normal..
Oh yeah, this is all with Water Wetter.
Helpful pic for that radiator bleed screw!
For John (madguppy): You are correct about the vacuum bleeding down and the heater coolant circuit returning to normal flow on it's own as soon as the engine stops.
CALtd,
I've updated the kit instructions using your idea for top access to the radiator bleed screw....swiped your picture too! Thanks for the update, that's a time saver.
I've gotten enough feedback to feel comfortable in saying there are only TWO original intake passages to the climate control system (I just couldn't recall it if was two or three...). That being said, by far the biggest fan flow improvement is obtained by just opening a similar one in the front of the center rib and silcone on a screen like the two Lotus ones on the outer ribs. Don't bother with cleaning up the other two intakes, it's likely just making work...
Just a quick note. Bypassing the heater core, works for me well enough in Texas. And the recirculation system still works, it just doesn't go through the core, but keep in mind the pipes/tubes are so long they've gotta be helping keep the car cool if and when it gets that hot on shutdown. The only downside I see its cold in the winter, but I don't drive the car during the winter so OK there.
Got this by-pass kit from Tony Last fall and never installed it....Now it is getting hot down here in TX. Installed the bypass valve push-pull switch and
cut out the center HVAC intake vent .This is truly a beautifully mod.....now the AC blows cold enough that I have to turn the fan down. If you have about 6 hours and like working in tight places this cures the "AC blowing warm"
problem for good.
Mike
Bleeding the system is the easy part, just takes a few times repeating the process...run, bleed, cool, repeat. You will know when all the air is out just
make sure the coolant tank is topped up and you should be fine
Mike
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