HVAC Enhancements

[Verde]

Folks,
For some time I've been asked to show the mods that were built in to my car to illustrate the improved HVAC qualities that were designed in.
To repeat from an earlier post, the car was built by a master mechanic and SCCA top driver in Tampa Florida. For those who don't know about that part of the U.S., the (deg F) often hover around 95-100 degrees in the summer with a humidity in the 80% and higher. A very sunny, hot and muggy place. The builder realized that he would need to improve on the AC (having sampled another build in his area) if he was to be able to drive it at any day/time of the year.
So as he described, he made a few changes and they assuredly are very successful:
Modified plenum behind the center dash - with three large vents center panel. They are from a big Ford F150 and work perfectly though I have to swap them out with black ones;
Larger fans in the cabin to drive greater air flow
Twin condensers - one in each rear air grill
It's hard to see much of this, despite the photos taken but here we go:
http://richgreen.smugmug.com/Cars/Ultima/UltimaACF...
Slide 1 - left hand (drivers side in the U.S.) cooling sandwich - ac condenser, oil cooler and fan (the ac condenser is slightly visibile in the upper left corner)
Slide 6 - zoomed out of left hand side
Slide 5 - right hand side of ac condenser
Slide 4 - right hand side zoomed in
If other pics are desired, please let me know.
FWIW, the car has never overheated nor has the AC failed in 100 degree temps here in CA.
Thx,
Rich

[Steve_D]

Some questions if I may.
Has the evaporator been enlarged or just better fans?
Has the pump been enlarged?

Thanks
Steve

[Verde]

I'll have to do some research in the 10" of documentation that came with the car. Another delay on this I'm afraid but will look through it all. Happy to do it.
Rich

Steve_D said:

Some questions if I may.
Has the evaporator been enlarged or just better fans?
Has the pump been enlarged?

Thanks
Steve

[Storer]

With my standard Ultima air conditioning system (mostly) the car says bearable with no external air inlets.

The fans are noisy but not too powerful and I find I can get drips on my legs occasionally (despite drain tubes). This suggests I am cooling the evaporator efficiently (possibly some freezing) but maybe not pushing sufficient air through it (even with the fan on full chat and making lots of racket).....

My only non-standard addition is twin fans on the condenser. They are smaller than the original, but do pull slightly more air.

Wonder if I could supercharge the fan with a couple of extra fans. Not sure I could stand the extra noise though.

95% of the time though the car is cool enough in the UK. So I'll just drive it............


Paul

[anonymous-user]

In terms of noise, you want large areas of slowly moving air, rather than small areas of rapidly moving air. This means big ducts, fans etc, all of which are difficult to package under the dash of small cabins typical in kt cars! If you look at a modern production car, one of the reasons the dash frontage is so far from the windscreen is that there is probably 4 or 5 cubic feet of HVAC hiding under there! ;-)

The other issue of course is vent air. Modern cars use one way flappers (valves), usually that vent through the rear passenger space inner wings into the low pressure area beind the rear bumper. This allows the HVAC fan to move large volumes of air into (and out of) the cabin at low pressures, and hence quietly!

You can use a high percentage of re-circulation, but this does tend to seriously reduce the average air humidity, which can be very tiring / uncomfortable, especially for contact lens wearers.