jct

crazy idea... would it work if i put one in front of the a/c condenser (like a flex-a-lite) to help give me a colder output in my car for my already weak a/c system???

DarkSide_xB

that would be like taking a page out of the Honda Book. i dont see why you couldnt alot of there cars have an axtra fan behind the condensor pulling air thru. so go for it, let us know how it works out for you.

Reactor

I want to to that especially since i have a nice low profile SPAL that would fit between the bumper and condenser. The only thing i have not decided is how to activate it - its only needed with AC on when not moving, Any ideas other than a crude switch on the dash?

jct

i had a few ideas on how to hook it up with the a/c switch/button

or maybe a 3 way switch (off, low, and high)

i'm just trying to get ideas

Metro273

The extra fan would also block some much needed air to the radiator to cool down the hot coolant too.

Reactor

By a neglegable amount, i think.

jct

i'm just glad i'm still at the idea stage of things so it can get knocked down and i don't have to spend any money :D haha

Cinderblock

look up the wiring diagram, find out where the power wire for the ac condensors clutch is, and tap into it, so when you turn the a/c on, itll kick on the fan, then you can have a manual over ride switch on the ground side of the wire, so if need be you can turn the fan off, bam your done lol. and a fan wont block much air. try having your a/c system recharged too. what year is the car?

Reactor

I think if the fan shows through the lower grille opening,- it'd look niiiice.
I might throw gauges on the AC lines to see if it even makes any sense to have the add-on fan ON before the factory one kicks in. Bacause the one thats allready in the car is operated by the high-side line pressure switch.

jct

its an '05

Cinderblock

really? my fan kicks on when the my oil temp hits 180, dont have water temp. is their more than one fan, cuz ive only seen one, and it runs off engine temp, not a/c line temp. and better evaporator is waht would make a cooler a/c anyway, not a cooler condensor, itll help but not as much. the evap is what actually cools the air down, if you want your a/c to work better for the moment, dont put the blower fan on high, the faster the air passes through the evaporator, the less it gets cooled down ya know.

jct

haha yeah i noticed that as well about the fan speed setting

Reactor

Here is what i know : xB uses 1 fan but 2 control circuits. ECM can activate both fan relays based on either the coolant temp sensor reading (FAN1 relay circuit), or the AC high side line pressure switch (FAN2 relay is activated and the radiator fan turns at lower speed because there is a resistor in that circuit). So even if the coolant temp is low, but the pressure in the AC high side gets high, the fan should come on.
Here is what i think i know: Late in production Toyota addressed the poor AC performance by increasing the size of the condenser. Look at yours. If its the same size as radiator, then you have the latest version. If the condenser on your car is about the half the size of the radiator, then its the earlier version. I admit, i am not 100% sure about that though.
As someone who worked with AC systems for years, i must say that the size of the condenser makes a difference, especially in hot climates like SoCal. When back in the 90's we first started retrofitting old R-12 systems to run on R-134 refrigerant, we would always try to add extra fan in front of the condenser if possible, because R-134 does not cool as good as R-12 and one of the ways to compensate for it was to cool the condenser as much as possible.

Cinderblock

ill have to look at my condensor, im not sying changing the condensor size doesnt help, i just thought the evap did more? if not now i know, i know how R12 cools better than 134. didnt know about the second fan relay, becuase i llike never use my a/c lol. it works ok but i dont like how sluggsih the car is with it on lol. thanks man i now know something new

Black_Sheep_xB

The fan comes on with the compressor.. the safety switches shut down the compressor if pressure is too high/low
Once you hit that A/C buton the fan comes on via a relay..
Stays on with the compressor as it cycles.. if the compressor cycles off, but the temp rises then that system comands the fan
A second fan would work, because as long as you use the same signal, the power to the OEM fan, the fan would come on for a/c and over heat command (so if it did block some airflow, it would then make up for it, and in theory cool everything quicker) .. helping both.. the factory doesnt see the need for a second fan, but they also didnt see the need to change the a/c system any for the xB vs the xA..
Also, electrical pull is something to consider.. a fan on high draws less amps.. and I don't see the need for a low/med/high switch any way.. just high
If you use a relay to power the aux. fan directly from a added power source (batt. or add a fuse circuit), and use the power wire to the OEM fan to signal the relay.. everything should work out

We built a 75 stingray up for a guy, and he wanted an ice cold a/c.. we ended up adding 2 fans and everythinbg worked great

cobb

The benz I had had horrible ac performance. I would rig the electric fan that only came on when it reach 230 degrees to stay on with the switch by using a paper clip in the high temp switch. It made a world of diference.

My condensor is the same width as the front of the car from head light to head light and the radiator is rather small. I too want to do the fan mod, but am rather stuck on how to work it short of just using the acc fuse as a trigger so its on with the key, then disconnect it in a few months when it cools out. I would stick the fan on the passenger side on the condensor only and on the front side right behind the grill.

Reactor

Here is a test i did today:
06.5 xB parked in the shop. Outside temp 95F.
At idle the temp out of the center vents, recirculation ON, AC Max - 48-50F
With the industrial 2ft diameter fan directly in front of the car - 45-48F
Raising the PRM didn't do any difference other than making AC cycle with higher frequency.
So the improvement is very slight- adding more airflow does not make the AC run cooler than by may be 3F.
As i said before, my 06.5 came with the bigger condensor than the earlier models- its the full width of the radiator grill opening.

cobb

3 degrees? SOLD!!!!!! I just find it strange that of many cars, trucks, suvs, vans, etc, this little car just has a fan for the engine radiator, not a secondary fan on the remainder of the condensor. Thats my next mod.

jct

i have a full size condenser on my 2000+5

just remember there is the fan shroud so that helps way bunch too...

cobb

I puttered around in stop and go traffic in 80 degree weather with outside air ac on bluest setting and fan speed 3. When I finally got to 40 mph I felt the air start to feel colder.

Also earlier today went out for lunch. No sooner I started the car within 3 second I got cold air. Then teh fan outside on the radiator reved up into high gear. The ac was cool, but not really cold. For the most part the fan stayed on til after I left the fast food place drive up and again one I got to rolling it startd to cool down.

Going to go for the fan next month when I get this over time done. Going for the 10-12 inch one as it takes least amps and can power using my old aftermarket fog light harness kit and just turn it off and on as needed and hook the trigger wire to the acc fuse so it cuts on/off with the key.