Whatever happened to that ultra-cold Ford truck?

[tony1963]

I remember someone coming here and saying that their R134a converted Ford truck blew AC at 38 degrees out the vents with the fan on high, both doors open, on a 100 degree day. I don't see how that is possible, but I'd like to know more.

[tbirdtbird]

Our 1931 Model A Ford with 134 does just that. 134 can work better than ppl think.
Selection of the largest parallel condenser you can fit along with sufficient air movement such as adding an electric fan or better yet installing a shroud on the mechanical fan. If you install a fan shroud recall that long ago the racers determined the best position for the fan blades is for the trailing edge to protrude outward (backward) from the shroud by 1/2"

[tony1963]

Several years ago, I obtained the design specs from the dealer on a 1984 Ford F-series. I ran the calculations on the air flow through the HVAC box, fan speeds, etc.

There was no way at the CFM that results from a blower on HIGH that you can have a 38 degree output when the air temperature coming in is 120 degrees. According to my math, the evaporator temperature would have to be 30 degrees below zero to achieve that temperature output.

[tbirdtbird]

If the evap is 30 degrees below zero then the vent temp will be 30 degrees below zero, which will freeze the evap into a solid block of ice.
dealers and specs have been wrong before.
You are welcome to swing by and check my Model A Ford out next summer The aluminum evap helps, too

[tony1963]

I know that. My point was that the individual obviously stretched the story. The only way that I could run the calculations to have 38 degree air with 120 degree air comining in at the CFM of the high blower speed was to use 30 degrees below zero as an evap core temperature, which we know can't occur.

Why do people come here and make up stuff?

[tony1963]

Is there any evidence to support the claims?

[tbirdtbird]

FWIW, (probably nothing) I have re-read your post.
Drivers do not have 120° ambient air rushing into their cabins. They choose recirculate, and the longer the AC blows the colder the interior gets.
Any driver on the road with the air source set to 'fresh air' in 120° ambient such as in AZ is living in the wrong state.

[JohnHere]

I know that. My point was that the individual obviously stretched the story. The only way that I could run the calculations to have 38 degree air with 120 degree air comining in at the CFM of the high blower speed was to use 30 degrees below zero as an evap core temperature, which we know can't occur.
Why do people come here and make up stuff?

I have been reading this Forum for more than 20 years, and I don't recall a discussion about "that ultra-cold Ford truck." However, we respect and value everyone's knowledge and contributions. If you would like to research and reopen such a topic from the archives to correct something or to provide additional information, please do so in a civil manner. Spitefully unpleasant comments, such as yours above, will not be tolerated.

[Tim]

Tony, you've been coming to this site for years stirring the pot. So, in my book, you're the only one intentionally coming here to make stuff up.

[swampy 6x6]

hi
A good working auto air can achieve low vent temps in hot weather .
My 2007 diesel Ford Ranger I finally fixed properly in approx 2015 . Done at approx 65,000miles
new evap core
new txv
new desiccant bag
added 2nd condenser with e fan

Performance in the record setting hottest day 46 deg cel 114f high humidity greater tan 70%
high side 150psi idle 1500rpm 160psi
low side idle or 1500rpm 22psi to 35psi cycles up/down as txv opens closes
doors open
max cooling / recirculation
vent temps cycles compressor at 40 f off ,,,, On 45 f pulls these temps at idle