Has anyone ever went with a VOV on a R-12 to R-134a conversion?
Did it improve A/C performance? Is it worth the extra money or should I just go with a standerd red R-134a orifice tube?

 

Yes and i think they help on a R-12 to 134A conversion here a link to a site you might want to look at.
http://www.imcool.com/articles/aircondition/VOV1.htm
also think they go for about 25.00 not a bad investment

 

I thought it was a rip-off when the parts guy tried to sell me one, but now I wish I had put one in.

 

Two years ago I researched the variable orfice tube for a conversion. The consensus opinion from several of the legitimate online a/c firms was the VOT produced only minimal improvement for the price. They were no longer recommending them for that reason. I went with the standard fixed style for the conversion and the results were excellent.

 

After doing some research myself, I decided to go with a fixed VOT. I had purchased a red one but after reading the retro-fitting procedure put out by Ford, talking to my parts guy and the mechanics down at "Fleet Maintenance" for the city, I decided to go with a fixed blue one.

This next question is for Steve83.
The FX-15 is such a dirty running compresser, why do you recomend putting in a red VOT on a retro-fit?
Wouldn't the finer screen make it clog up faster?
Man you should have seen my old one it was nasty!

 

The red tube is sized to give the correct head pressure for R-134a. The filter screen that protects the tube is probably the exact same size as the blue one, but I've never seen any specs on the screen - where did you see it?

 

I BOW TO YOUR FORD WISDOM!!!!!

When I did my retro I went with the blue one, BIG MISTAKE!
My head pressure was out the roof. Truck wasn't cooling worth a crap!
I read your reply. Vacuumed the R-134a out. Pulled the blue VOT and put in a red one. Pulled another vacuum and re-charged with 36oz of new R134a.
What a difference it made. Accum/Dryer and low pressure line is dripping with sweat. Cold air blowing out of vents and now even the old FX-15 doesn't sound like it's going to blow apart! Thanks

I'm still interested in hearing from someone who has done a retro and has tried both a fixed and variable VOT. The people who make them say they work better but of course they are going to say that!

 

Sorry, great conversation and good read from the link though.

I haven't seen more detailed discussion on the VOV versus FOT...

Steve83, have you tried a VOV in any of your trucks?

I'm in the process of swapping out the R12 system in my 91 F150... all new except for evaporator. Basically purchased new condenser, compressor, drier, hoses, LPCS, and adding HPCS. The compressor is brand new with clutch...came in a retro kit for 91. The kit included the drier/accumulator, o-rings, and a blue FOT. The condenser and hose assembly is new for a 94. I had the liquid line custom made.

I'm now ready to start replacing everything, but want to be sure about the orifice tube choice...should I go with blue, red, or VOV??

I basically drive short trips, stop and go traffic, and occasional highway trips no more than 20/30 minutes.

 

In case someone is doubting what to do as I did...go with the Red FOT for daily driver in stop and go traffic. I can't speak to the effects of going with Blue FOT or VOV...YMMV.

 

I'll be changing my '93 E150 to R134a next spring. I've read that a Hi-pressure cut out switch should be changed due to higher 134a pressures. I don't know the design pressure for the stock switch. Anyone have a suitable replacement part number?

 

A new hose will be compatible with 134A. Just buy a new HPCO switch when you do and it should be one for a 93/94 for 134A.

More Information for FOUR SEASONS 20916

 

I bought a Four Seasons Variable orifice tube and it howled and squealed on startup and shutdown of my AC when the system pressure was equalizing. Horrible sound eventually a week later I took it apart and found the thing came apart in 3 pieces. I replaced it with a red O tube that was standard for my 2001 ford ranger. I would stay away from them completely.