Cooling fan operation, Removing 1 of 2 fans? Options

[94bird]

Each fan weighs 5.5 lbs., with the total assy of 2 fans and shroud weighing 13 lbs.

BTW, it looks like 2 12" fans would be the most we could fit behind our radiators. However, I did find these fans that flow some serious air: http://www.alamomotorsports.com/pmc/Cat_page16.html . Check out the 14" & 16" versions. Just one of these would do quite well I would think. Possibly use one of them as a puller and then mount a 10" pusher on the front of my oil cooler and I would expect my situation would be well improved.

[ESPCamaro]

Really?!!

They feel much heavier. Or did last I removed one.



Anyone know if the V6 system was different and how. Was the radiator smaller?

[Soma07]

I believe the V6 cars had a single fan but the same radiator.

[#07]

By adding a third relay, low speed can be achieved by running the power to the fans in series. This way, each fan does not get full voltage and runs at a slower speed.

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/unsure.gif) Mike is this saying that this can be done to an earlier set-up(just looked mine only 2 relays) to achieve the later 94 fans operation? And thats all?

[94bird]

I believe the wiring would also have to be updated. Here's a link to a comparison. The wiring looks totally different to me.

http://shbox.com/1/fan_schematic_1995.jpg

[#07]

I believe the V6 cars had a single fan but the same radiator.

And for 98+ far as I can tell looking between them (in the garage) they are close(diff. p/n) to same radiator and same dual fan set-up. radiator pn for 99 ls1= 52473159, 98 3.8= 52471356 but looking dimensions/hoses size all seem same.

[#07]

I believe the wiring would also have to be updated. Here's a link to a comparison. The wiring looks totally different to me.

http://shbox.com/1/fan_schematic_1995.jpg

Uhh huh (IMG:http://www.frrax.com/rrforum/style_emoticons/default/dry.gif) IC

[rmackintosh]

Mike...

My front breather opening is 3 1/2 tall by 38 wide.....

All completely ducted and in a dual plane, so 1/2 the air goes to the top of the rad and 1/2 goes to the bottom.

A thought on fans....

I don't think fans do much while running on the track....now cool off laps, pit time, etc. yes, but they should have MINIMAL impact during racing....

[CMC#5]

See, that was my impression also, that fans don't do a whole lot at speed. Still, if the issue is the stock setup doesn't naturally flow enough air into the radiator, then maybe forcing it helps.

By the way, since you guys are comparing ambient temps and car temps, wouldn't humidity affect this quite a bit? 90F in Houston isn't the same as 90F in Bakersfield as far as that air's ability to transfer heat, right? I don't know, I would think the more humid places would provide more cooling due to the moisture in the air.

[Jon A]

Interesting, guys. I didn't know they made the switch that early.

I hope you can find some info on those flow rates, Mike. They would be good to know.

I'm not sure how needed the fans are on the track--that's why I'm experimenting. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif) One would think that once you're over 35 MPH or so the fans wouldn't be doing much. But in the past I've been in "rolling traffic jams" traveling in the 30-50 MPH range in hot weather and the car will get hot without the fans programmed to come on soon. On one such day I saw temps over 215--with the fans on low speed. This makes me think these cars might depend on them a bit more than you'd think. It could be the way the air is taken in just isn't all that efficient--being scooped off the ground, redirected upward, then it needs to turn again to go down through the radiator....

When studying some fan tech I found many interesting things (Google is cool). A system like this would likely be classified as a "high resistance" system, especially with the condenser in front of the radiator. Here's what that means: In a system with low or even figure zero resistance, two fans in series won't flow any more than one fan. One could consider the atmosphere as the first fan. If you remove the radiator and the speed at which the free airflow matches the CFM of the fan then the fan isn't helping you at all. But put a big resistor in there and this is where fans in a series can flow a lot more than one fan alone--or the atmosphere and the fans work together to flow more air than either would alone. This is why you see "pusher" and "puller" fans working together in some applications. The radiator obviously causes a pressure buildup in front of it as it slows down the air. When this happens less air is going to want to go into the radiator opening so maybe figuring that vs vehicle speed isn't an accurate way to come up with a CFM figure--that assumes the radiator has zero resistance to flow.

Who knows. One thing to consider as we all think of tracks as such high speed driving, I consider PR a pretty "high speed track" but my average speed is only 80 MPH there. There are tons of tighter tracks where I'd average slower. So there is quite a bit of time spent at speeds that aren't all that high.

But like I said, I'm still experimenting. One of these track days I'll try to just shut off my fans completely and see what happens.

[Sam Strano]

I am LUCKY with all the NEW STUFF, to see 220 degrees...

Course that is at 95-100 degree weather!

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/unsure.gif)

Um, do you think it could be because all the air you are getting to cool the car is coming only through the grill opening? That airdam you have isn't letting any air in from under the bumper like a stock car does. Hell my Camaro's bumper cover is even curved like a diffuser to help, along with the plastic airdam to force air up and nowhere but the radiator...........

[rmackintosh]

I am LUCKY with all the NEW STUFF, to see 220 degrees...

Course that is at 95-100 degree weather!

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/unsure.gif)

Um, do you think it could be because all the air you are getting to cool the car is coming only through the grill opening? That airdam you have isn't letting any air in from under the bumper like a stock car does. Hell my Camaro's bumper cover is even curved like a diffuser to help, along with the plastic airdam to force air up and nowhere but the radiator...........

I doubt it....by going to front breather, and all the ducting I have done.....MORE AIR is getting in there and at a BETTER angle than ever before....

If there is a flaw in my system, I put the big Mocal Oil cooler right in the center/front of the radiator....it is spaced 4-5 inches in front of the rad, but it may be a big blocking force that must be moved...

....I had planned to move it to a headlight bucket, but car prep/repair is taking 200% of my time lately....

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/rolleyes.gif)

[94bird]

Jon, your last post is right along the lines of what I was thinking. I suspect our stock air routing is very inadequate for what we're doing. Your ideas about pusher/puller fans is precisely the reason I had planned on putting a 10" pusher on my oil cooler and a 14" puller on the back of the radiator. I know that would have less restriction at speed and if I can find a good place for my oil cooler afterwards I can use the 10" pusher to be the primary cooling air flow for it. BTW Randy, my Long oil cooler is also centered in front of the radiator, about 2" space between. It's about 11x11.

However, the first experiment will still be to run with no fans and see what happens. I think there's a test session at Waterford in the next week or so and I'll try to make it. I should have my oil temperature gauge installed by then too so I'll have one more data point about whether everything is running really hot or just primarily my coolant.

Still waiting on the Blackstone oil analysis lab kit so I can get a 2nd opinion before I pull the engine.

[94bird]

Well, I got myself motivated and am making my car a front breather. I've cut out the foglight holes in the front fascia and extended them towards the center of the fascia. The front bumper is temporarily gone until I can get a rollbar-type made up like Randy. I've sealed up the sides of the radiator with foam and now just need to block off the side of the cavernous openings in the fascia. That may be a bit trickier. Randy, I know you built aluminum ducting, but I'm thinking dense foam attached to the fascia may be easier for me and would allow me to remove and install my bumper without problems.

Man, it's cool looking into the 2 of 13x4 holes I now have in my fascia and seeing nothing but oil cooler and radiator.

Should do some more sealing up tomorrow and thread in my oil temp sender. Gauge is in the dash and the cable is routed to the pan.

I was looking on the fascia at the front turn signals and thinking with a little mods that area would be a great place for brake cooling ducts using a duct like Jon has. When I remove my radiator diverter under the car and put on a front air dam I can see that being part of the project.

Got my Blackstone oil analysis kit today so I'll try to get that off to them this weekend also. Anyone know about how long it takes to get results back? I'm going to use them as a doublecheck.

Waterford session on Monday if I'm ready. Gonna bolt up my 315s again and go have some fun hopefully.

[#07]

Sounds really cool,Makes me want to do this too. Let us know how it does. That is if the sample came back alright? I guess.

But Randys does look cool,but does it keep cool (IMG:http://www.frrax.com/rrforum/style_emoticons/default/tongue.gif) I imagine it does. But one thought with this front breather if I was to do this...maybe I would put some(3to4) horizontal diverters spreading the air path up-high, center mid-low & mid-high,and down-low.
But then I think if the stock air gathering(air dam) is still in place/operational.This would cause a problem/disruption? So maybe the front air dam removal test would have to be done after the front breather upgrade to determine this. So if better w/o stock air dam and a front breather just extend bumper like Randys (IMG:http://www.frrax.com/rrforum/style_emoticons/default/cool.gif) .But if the 2 coexsist and work together for optimal cooling well... leave it alone of coarse.

Tony

[94bird]

I've blocked off the air flow from the black plastic diverter up into the radiator. It's more likely air would come in through my fascia and try to escape down than for more air to come in through the stock path.

Almost done, but just taking a little break. Also mounted my oil cooler better and relocated my transponder while I'm in there.