V8 Bike Riders Forums banner
1 - 20 of 26 Posts

·
Registered
Joined
·
8,619 Posts
Discussion Starter · #1 ·
I'm in the process of installing a radiator fan reverse switch and indicator light on my Boss and I have a question for those that already have them . When you reverse your fan when sitting in traffic or at a light , does the pulling of the air thru the radiator actually have a cooling effect that you can see on your water temp. gauge or can you just run it in reverse for short periods while you are sitting still ?
 

·
Registered
Joined
·
1,702 Posts
Jack,
In reverse (pulling) mode, the fan won't cool the radiator. It's pulling hot air from around the engine. I have one on mine, and I can only use it for short periods. It's only to keep the hot air on a hot day from blowing on YOU. But the temps will climb if you leave it reversed for too long. Just keep an eye on the gauge.
That's my experience. :capwin:
 

·
Registered
Joined
·
8,619 Posts
Discussion Starter · #3 ·
Thanks Don , that's what I thought , but I just wanted to hear what others have experienced. I reversed my fan while testing my switch and man I thought the bike was going to take off by the way the fan sounded running in reverse .
 

·
Registered
Joined
·
1,702 Posts
Yes Jack, definitely 2 different sounds. Also make sure the switch you use is rated high enough amps wise. Don't use anything less than a 15 amp rating, unless you're using relays. Yes it will work with a lesser amp switch, but in time the switch will start to melt. I assume you're using a double pole double throw (center position "off") toggle switch? That's what I use, and over time, I had to replace it due to melting. I went to a heavier rated switch. Lastly, when you change direction of rotation, wait for the fan to just about stop before reversing it. Big strain on the fan if you don't. Good luck! :wink:
 

·
Super Moderator
Joined
·
6,643 Posts
Jack

Mine will hold the temp fair for a while but it has saved my big butt from the heat. I started using mine in 2001 at Laughlin where it was so hot you couldn't breath, so the fan direction sure helped. One thing don't start driving it forward and forget the fan, (I have) because, it will over heat fast. Get the good switch like Don says if you don't have it already. Another nice thing is when the weather is cold you just turn the fan off and enjoy the quite time.

Adrian
 

·
Registered
Joined
·
616 Posts
I keep trying to figure this one out guys. Maybe I'm just used to the sweltering heat here and it doesn't bother me that bad.

When I had a problem with my fan at the fuseblock, my temperature went up as high as 30+ degrees without it running. When I'm at the track and the temp goes way high, I turn the fan on with the motor off and it cools lickety split.

My question to you guys running the switch...does it make that big a difference to you as the rider to warrant cutting it off? When it's that hot that it would make a difference, doesn't it make the radiator coolant temp really spike quickly and a lot without the fan running? If my temp was already 190 (as an example), I don't know that I'd want it jumping to 210 or more just to let me be a bit cooler while at a light.

Tell me what I don't know here please.

Elliot
 

·
Registered
Joined
·
1,702 Posts
:? Elliot,
It's a bit of a trade off actually. I only use the reverse "feature" to give myself a little break from the blast furnace at a stop light in the really hot weather. Yes, the engine temp will climb if the fan is left in reverse mode too long, which is usually just a few minutes. But then hopefully you're on your way, and, after reversing the fan back to normal rotation, things cool down again. If I'm in heavy stop and go traffic, I don't bother with the switch as the temp goes up too much and then the blast furnace is even worse! So it's a pick and choose kinda thing.
The really important thing is, (Jack, I hope you're reading this) make sure you don't accidently leave the switch in the center off position. I have and luckily I noticed the temps way up due to no fan! Live and learn!
 

·
Super Moderator
Joined
·
6,643 Posts
Elliot

Where I live and ride some of the time the temp is around 100 degrees. When I am in a stop and idle traffic deal with the fan in reverse it is worth every bit of the cost and time to install it. I have let my engine run in 100 degree weather with the fan in reverse for over 10 minutes and still didn't boil over. It gets hot maybe 220 but that is OK with me because I am not getting the heat off the radiator on my legs and belly. It will spike in a heart beat if you leave the fan off at those degrees. It will still cool the engine down pulling air from the radiator but not as good as pushing the air.

Adrian
 

·
Registered
Joined
·
616 Posts
Don & Adrian,

Thanks for the reply. There's one factor here that could make a difference but not discussed. The 502 is significantly hotter than the smallblock. I often see temps 20+ degrees lower than mine when riding with the 350 boys at both cruise and idle.

Another factor is the way you sit. You're just closer to motor on the bigblock. Hard to get the valve covers and headers/heat shield away from those legs and thighs.

Don's point could be quite valid. You're stopping the heat from blowing backward on you but at the same time you're increasing the motor temp and the heat coming off heads and headers are right there up close and personal. I wonder after all is said and done how much more comfortable it really is?

Adrian, if you see 220 on the gauge of your smallblock in those hot summer days, add at least 10 degrees for the bigblock. After your input and in spite of it being a good thing for you guys, I'm not yet convinced it's what I want to do. I especially wouldn't relish seeing the gauge start climbing at a light when it's already at 200 or so. Hmmm?

Elliot
 

·
Registered
Joined
·
1,702 Posts
Elliot,
The only reason I put a reverse switch in was for the brief, but welcome relief from the fan blowing that HOT air back on me, while stopped for a very short time (traffic light) and it really does make a difference to me. I only find it neccessary when the air temps are in the 90's here. Of course it doesn't do anything for the "radiant" heat from the motor, but I find it nice to have the option.
Maybe you might want to try a temporary set-up just to see if you like it. Really not that hard to do.
In addition, I also put a switch in to allow me to turn the fan ON , when the temps are nippy, and I'm stopped in traffic. Almost like having a car heater! But it doesn't sound like you would need it with your balmy Winter temps! 8)
Hope you're Christmas was good, and Happy New Year! :capwin: .........Don B
 

·
Registered
Joined
·
1,557 Posts
Fan switch

Elliot,
I just wanted to chime in here to give you my findings on the switch since I ride a 502 also. I only put an on/off fan switch on my bike, not the reverse switch, but I have run with it for over a year now and it has made a significant difference in my comfort level.

First, I run a Windvest brand windshield and I got tired of hearing the fan running constantly. The sound kind of reflects off of the inside of the windshield, right at me. This is what caused me to install the switch in the first place. I wanted the fan to not run in the winter/cooler months. I turn the fan off and back on constantly as I vary my speed! It has become as routine as using a turn signal.

Second, the reduction of heat on me in general, but especially on my crotch, has been surprising. I have made a point of leaving the fan on a few times just to remember how it used to be. I don't like it a bit. Depending on circumstances, I will turn the fan off when I hit 40 -55 MPH and it makes a difference that I don't want to understate, but I feel as if I CAN'T OVERSTATE!

All I can say is that you will be satisfied with your decision to take the time to install an on/off switch anyway...I have no idea about the reverse switch, but I may be interested in trying it in the future.

Bill Taylor
 

·
Registered
Joined
·
1,681 Posts
I do the same thing Bill. I turn my fan off most of the time and just watch my gage. As soon as I get around 180 I flip it on and it will drop pretty quick once it starts to pull air. I do this for a couple of reasons. One is I was having battery problems at the time and I didn't want the fan pulling juice when I went to start my hot bike. The other was the noise, I hate the sound of that fan running. I am surprized how little you really need to run that fan. Once you get underway you really don't need it.

Now that it is getting a little cold around here I will turn it on just to throw a little heat my way.
 

·
Registered
Joined
·
616 Posts
Thanks guys. Good info here. I really hadn't considered the fan noise thing Bill but as soon as I read it, I winced knowing the deal. I too dislike the fan noise a bunch.

I'm in the middle of some cooling issues with a couple of the other members. Heat will hopefully be less of an issue on the bigblock when done.

Will probably be adding a fan on/off switch to the "to do" list tomorrow. Best...

Elliot
 

·
Registered
Joined
·
543 Posts
south florida way

El- why don't just keep doing what you good old southern florida boys do and put a good piece old cardboard in front of your fan when you want it off.
 

·
Registered
Joined
·
616 Posts
Ed,

A great idea! That way we can paint the Stars & Bars on it or get us a BIG black magic marker and put something like; "if it's so great up north get your ass back up there" or maybe "will all you gray haired yankees in your white 4 door Buicks please steer that damn thing northbound I-75"? We'll of course reference they can stop as soon as they hit Jersey, hee hee :wink: .

Elliot 8)
 

·
Registered
Joined
·
544 Posts
Fan Switch Topic

Reading all your posts regarding reversing or stoping the rad. fan for verious reasons compells me to through in my two bits if I may please. What I have done is simple and by no way "my idea", got it from some of you , but didn't see it mentioned here! My Fan would run almost constantly above 85 - 90 deg. OSAT to try and maintain the 160 deg. set point of the thermo fan sw. I replaced the sw. with the FS-120 , on @ 195-205 & off @ 175 deg. (like the factory now uses I hear) then wired in parallel to that FS-120, a SPST on/off switch. My fan hardly ever runs now except in really hot weather or hot slow traffic. If I know that I am coming into hotter stop & go traffic I simply "flip the switch" to bring on the fan, before the coolant temp. gets up to the FS-120 "on point". If I forget to turn the sw. on, the FS-120 will do it, if I forget to turn it off, the lower temp. reading will remind me ! As forgerfull as I am getting, this set up works great for me !!
 

·
Super Moderator
Joined
·
6,643 Posts
Craig
The reasoning is good and does the job you want, however the reason I run the lower switch is to get my Engine down to the area that I need it to be for max out put with NOS. You need to run lower temps for NOS to put out max HP keeping the engine at 160 to 170 degrees. I can still turn off the fan when I need it to be quite and the weather is cool but when the weather is 100 degrees and you are dead stopped I need a break. The reverse switch does that.

Adrian
 

·
Registered
Joined
·
2,212 Posts
Another point no one has mentioned is the passengers comfort. Most of my heat seems to blow under me and up to my wife. I don't have the temperature switches hooked up yet, so I just turn the fan off at lights when the wife mentions the heat, works great.
 

·
Registered
Joined
·
616 Posts
Elvis,

Your hot wife's in heat and you don't like it, hee hee? :shock:

Elliot 8)
 

·
Registered
Joined
·
4 Posts
Hello my friends, Thanks for accepting a new wannabe. Hope to sell my Ultra and join you all someday soon. Have a little input on the heat issue. Would it be feasable to fabricate a rear shroud to mount behind the radiator to direct the hot air down toward the street or even under the bike? Just a thought...
Chaplain <><

[/b]
 
1 - 20 of 26 Posts
Top