Need more output from A/C fan

[netcsk]

My R-134a conversion works very well on the interstate, but leaves much to be desired when sitting still or moving slowly.

I've heard of people switching the fan so that it runs full speed when the A/C is on. What's the easiest way to do this and does it provide enough of a boost to be worth it? Also, does the fan hold up running full speed?

Another option is finding another fan that fits and mounts up to the same place as the stock fan. Anyone know of a fan here?

Also, does anyone know the spec on the fan when running on low and high speeds? That way I can compare to something that I may be able to put in.

Thanks guys!

[Coco Savage]

interesting...

[nando]

a 16" pusher fan fits in there just barely - flexalite sells a 2100cfm fan that will work well with the stock wiring, it's quieter and lighter than the stock fan as well. I got my fan from summit racing for around $150-200 (way cheaper than a new stock fan).

another option is to bypass the low speed setting, basically jumper the thermoswitch so it only goes on high speed and/or bypass the resistor - you'll probably have to put a bigger fuse in the low speed circuit though.

[Sean]

a 16" pusher fan fits in there just barely - flexalite sells a 2100cfm fan that will work well with the stock wiring, it's quieter and lighter than the stock fan as well. I got my fan from summit racing for around $150-200 (way cheaper than a new stock fan).

another option is to bypass the low speed setting, basically jumper the thermoswitch so it only goes on high speed and/or bypass the resistor - you'll probably have to put a bigger fuse in the low speed circuit though.

Yea, I was gonna say you could cut out the resisiter and replace it with a wire. But, most definitely you'll need to upgrade the fuse - it'll need a 30a, and I think lowe speed has a 15a by default.

[netcsk]

What did you do to mount up the replacement fan? Does it push a good bit more than the stock fan on low speed?

a 16" pusher fan fits in there just barely - flexalite sells a 2100cfm fan that will work well with the stock wiring, it's quieter and lighter than the stock fan as well. I got my fan from summit racing for around $150-200 (way cheaper than a new stock fan).

another option is to bypass the low speed setting, basically jumper the thermoswitch so it only goes on high speed and/or bypass the resistor - you'll probably have to put a bigger fuse in the low speed circuit though.

[Sean]

What did you do to mount up the replacement fan? Does it push a good bit more than the stock fan on low speed?

Here's how I mounted mine:


Bottom is held in by the robber thing cut enough to fit the fan. however, the one thing I need to make is a fan shroud - hopefully workin on that soon!

[netcsk]

Very cool. Thanks for the pictures and explanation.

I decided to try the fan on high speed. Wow. It is very loud.

I looked at the diagram and decided that K1 and K6 connected via terminal 87 would kick the high speed fan on via the A/C and the thermo switch. I just had to remove fuse 3 (only for the aux. fan low speed) so that I wouldn't be running the circuit for no reason.

Feels like much more output from the fan. Hopefully that will do the trick. Even more so, I hope the fan was designed to run full speed continuously. I guess I will find out.

[nando]

that's why I reccomended an S-blade fan - much more efficient and less noise than the stock fan. mine is mounted with the kit it came with - basically some zip-tie like clamps that go through the radiator core.

[Sean]

Mine is really loud at full speed too, but not as much as the stocker. AND it moves TONS of air! If I put my hand in front of my car, I can feel all the air gettin sucked in.

I would have done the ziptie method right on the radiator - but my fan didn't have a big enough gap, and it would have rubbed. But, i only spent like $50 on mine...so, you get what you pay for. ;)

[netcsk]

I'll have to get a better fan if I wind up not being happy with this method. Maybe wait till the next timing belt to put it in.

[Coco Savage]

id like to see some pics of install process when you do!

[jlevie]

The big problem here is that the condensor, evaporator, and compressor aren't sized for R134a. I don't know that increasing aux fan performance is going to do all that much. A better solution to the R12 problem is one of the Freon replacements (Freeze12, etc).

[netcsk]

I'd rather not use a mix freon as they are usually simply R134a with a small portion of organic fuel added to increase efficiency. Nothing wrong with them, but I'd rather keep all the equipment I own clean.

Also, lower the temperature will help drastically. The main problem is that the condenser is not large enough to remove enough heat from the freon. This can be helped with a higher velocity of air. It is by far the biggest problem with converting.

[emi325i]

Ha.. I was just thinking the same thing... the system can't get rid of the heat fast enough, so temperature and pressure builds up.