Brentis

Just installed a SPAL 6.5 fan on the back of my greddy smic. To test it out, while out of the car, I ran a hair dryer on hot & high for 15 minutes. The temperature of the direct heat 2 " from the hair dryer was 154 degrees. When put through the IC for 15 min the IC outlet reached a 138 max. The IC was pretty much heat soaked and the temperature didn't change the last 5 min of the 15 minute application. When I turned my IC fan on after 2 minutes the temperature dropped to 131 degrees. After another 7 or 8 minutes the temperature dropped to 113 degrees.

The ambient temperature is about 81 degrees. My take is that is quite a reduction.

While this simulates driving conditions, I think it also illustrates the benefit of drastically reducing heat soak in stoplight traffic.

Thoughts??

T88NosRx7

iTrader: (1)

Thats interesting, do you have any pics? I take it that you have temp probes at the IC inlet and outlets.

BoOsTin FD

Got any pics?
Where do you mount a fan on the ic, i was always wondering that. Also do you pull the air through the Ic or push it?

How much was the fan?

FormerPorscheGuy

Yes, how much was the fan and where did you get it from?

Brentis

I can take a few pics... I haven't installed it yet. I just mounted the fan.

I toiled for a month on the best way to install a fan w/ circuit and decided on using the ignition wire coming out of my turbo timer as a relay trigger. This way my IC fan helps cool my engine a bit and prevent some heatsoak from occuring (not a lot I'm sure but every bit helps).

I also just saw a wireless switch with relay made by Pilot at Autozone. It would work perfectly to remotely activate the fan without having to install an ugly switch.

I wound up buying the fan from Jaycorp Technologies http://www.jaycorptech.com/shop/shop...v+Cooling+Fans

They had the best prices. I also didn't buy the fan mount - I just used tie wraps (a total of 8) 1 acted as the pull through connector (bolt) and the other I trimmed to used just the connector (and it acted as the "nut")

The fan was about $65. And a "pull" design (mounted on the back of the IC) is more effective - apparently if a fan is mounted on the front it is only 80% as efficient.

Here's an interesting link as well on various fans. http://www.jcna.com/library/tech/tech0008.html I couldn't find the Davis Craig one in the US so I bought a SPAL (those Davis Craig fan's move some air!)

As far as temp probes - I used a wireless home thermostat and inserted it into the IC outlet. (measures in tenths of degrees fwiw).

I'll post some pics later today or tomorrow.

ech

I've done a similar project - here are the details for any that are interrested (somewhat long)

Summit racing has 8" fans (two brands) that fit perfectly on many ICs. I have one on a PFS IC, but it might not fit if you still have your AST at the "stock" location.

I've seen both push and pull installs, nd the "push" is the cleanest if you can swing it. You mount the fan inside the intake duct for the IC. Depending on the IC you have this may or may not be possible. WIth the PFS IC, I would not have the clearance to get the parts in place.

After I decided to get an IC fan - mostly to control temps at city driving - the control circuitry became the next big question for me as well.

Here are the options I came up with:
1) whenever the Rad fans are on.
2) with a manual switch
3) with an air pressure switch that can sense when you are below a certain speed.
4) with a thermoswitch on the IC or in the engine bay.
5) other...

I chose a combination of 1,2, and 4.

The next question is whether the temp relay should be on ingnition switched power, or shoudl run after the car is off. I've chosen to let it run until the engine bay is cool, but this creates a tradeoff between heat soak in traffic, and keilling my battery on blistering summer days.

You can buy variable temp thermo switches for radiator fans, but they usually have a temp range for radiators, which is too high. I ended up ordering a gas-filled thermo switch from Omega electronics.

I ordered more relays from Jemco, along with a 3-position switch, and a few diodes.

Sensing the radiator fans is a pain, because they run on 3 different leads off 3 different relays. I spliced into all 3 and then used diodes to isolate the 3 lines. I ran them all into one relay.

I mounted the thermoswitch at the top of the IC, and behind it, so that it would be cooled if the car was running fast, and ran that into another relay.

I jammed all the electronics into a small box, with the 3-way switch mounted, and some watertight connectors. and mounted the box onto the IC duct.

The switch will turn off the fan completeley on one position, turn it on for good in the second position, and listen to the temp and rad fan relays in the third position.

I made small wiring harnesses for the IC, and the engine bay, so I could take the IC and duct out without cutting wires.

It seems to work pretty well. The 8" fan is a bit noisy, and high-pitched, like a hair dryer - you can defineteley hear it. If I could have mounted it in the duct it would probably have been a bit better.

And last summer it did work. It would run for about 15 minutes to drag the temps inside the engine bay down from over 180 down below 135 or so. One thing that was a bit dissapointing was that in gridlock the fan is not enough to prevent heat soak. The intake temps still climb, but defineteley slower than they do without an IC fan.

Overall I think this is a good modification, but it sure was a bunch of work.

Brentis

Good feedback- I agree with most of what you said minus the placement of the duct in front of the IC. SPAL and other sites say that it is 20% less efficient.

What type of air intake temps were you getting?

Kento

I would have to agree with Brentis and the SPAL site (which I should've checked before letting Mark at Tripoint talk me into getting a push-type fan). It appears that there is some bleed-off around the edges from the IC fan; there's not a whole lot of air being moved when I put my hand on the other side, and when I stick my hand into the IC duct, I can feel a small amount of air being bled back, like the fan assembly can't force all the airflow through the cooler. However, there's not a whole lot of room on the engine side of the IC, so it may have been a wash anyways. Regardless, better than nothing at all and heatsoaking to death...

I had to get them to weld some tabs onto the IC in order to mount the SPAL fan, but it's a clean assembly. I may look into another fan later that can handle more CFM (while also remaining thin enough to fit on the engine side of the IC; might not be possible).

I'm thinking of putting heat insulation tape on the outer portions of the IC and the duct, since their location means that much of the heat soak results from heat rising up from the radiator. Even though the fan is cooling the fin area of the IC, the IC body is absorbing heat as well, so the less hot air that comes in contact with the IC body, the better. And no, let's leave the FMIC vs. SMIC debate out of this thread, please.

ech

Oh, by "cleanest" I meant that the push mount is cleanest visually - since the fan would "disapear". I'll try to get some pics of my install up here.

I didn't record my air temps and can't remember them exactly. Picture being stuck in trafic for 30 mins in one messy intersection after pulling hard on the highway, under direct sun, with a black car. gack - hot.

Brentis

Rather than use insulation I'm likely going to cut an aluminum shield to direct the air from the duct to under the support brace that the IC sits. Currently following the duct the IC is directly exposed. The shield should provide a redirection + 1/2" of clearance where the IC doesn't hit the shield.

I'm a wanabe enginyr but it sounds good to me

Kento

My thinking (although theoretical at best ) is that any way you can insulate the portions of the IC body that can absorb underhood heat could only help matters. Perhaps even the IC piping (although if you're pushing big boost, intake temps at the pre-IC stage could be higher than the underhood temps). Nonetheless, your shield will surely help matters a great deal. I'll probably do the same when I pull everything to upgrade the radiator and replace the driver's side fan motor soon.

Zoomspeed

wouldn't a fan on the IC creat a bottle neck while your at speed though?

cavellm

The fan is on the engine side of the IC. You're still gonna get unrestricted flow coming from the front of the car. And the fan on the back will suck the hotter air from the rear of the IC.

LUV94RX7

iTrader: (3)

I'm going to order the SPAL 30100291 pull fan. 295CFM and it's 6"x6" and only uses 2.5 amps. I just need them to let me know what mounting kit I need.

Zoomspeed

even on the engine side wouldn't it be a bottle neck? If the velocity of the incoming air is less then what the fan can flow then then the air would pass threough the IC then hit the blades of the fan slowing the air down, then the mass of air behind that has to slow down to right? Since the air that has already slowed down is in it way.

LUV94RX7

iTrader: (3)

I think a better test would be running the car for awhile on a warm day and then stop and idle the car and wait till the temps on the IC go up with the fan off. Then turn on the fan and see what it drops to.

I have temp probes installed in my K&N filter, after the single turbo and after the IC. When I get my fan I'll run this test and see what the temps are at all locations during real world heat soak situations. I'm predicting a 20 F degree drop. I hope I'm wrong and the numbers are better than that.

Ken

Radical Rotary Avantgard

I have the SMIC M2 large with 2 Permacool 8 inches each.
They are mounted in a pull air rather than push.
This has been proven to be more efficient.
People still think that fans in any location might create a bottleneck for the air but it is not that significant.
IMHO, the function of the fans is for when your SMIC is heat soaked after you park the car for a little while to bring down the temps quickly.
If you are on a stop and go situation they won't help much because they will pull the hot air from your radiator and heat up your IC core.
Trust me when I tell you this.
It was happening to me and I was stumped.
I read it here and can't remember who but he posted the same thing and the explanation for it.
If you drive mostly on the highway then you don't need the fans.
The air flow is good enough to cool the core and with the fans ON it is only quicker.
If you do stop and go, I would get them just to bring down quickly the temps, but remember you can't keep them ON, ALL the time.
These Permacool fans move each about 800 CFM for a total 1600 CFM and that is alot of air for small fans.
They are on the Permacool web site with other sizes, dimensions and how much electrical amp draw.
The amount of air being pulled by the fans has to be greater than the air coming in at low speed in order for them to be effective if not, then don't bother.
At higher speed (over 30 mph don't qoute me on this, I can't remember) the air speed will beat the highest CFM fan you can place there, so don't need them on over that speed.
My next step, is to try to block the air that exits the radiator fans with some aluminum shield, so that it doesn't heat up the base of the IC.
LUV94 RX7, I wouldn't even waist time or money for only 295 CFM of air with that 6x6 fan, unless it is a typo.
Brentis, haven't met you yet, only know about you from 7racer (Dr.Bob) lets get together and compare notes.
PM me or post here, I work in the Plano area.
WOW!!!.
This is my longest post ever!!
Sorry.
PS. if you see the table on the Jaguar site the Permacool is probably the best overall size with the highest CFM and least amp draw.
I am happy with mine, YO!!

LUV94RX7

iTrader: (3)

[QUOTE]Originally posted by Radical Rotary Avantgard [B]IMHO, the function of the fans is for when your SMIC is heat soaked after you park the car for a little while to bring down the temps quickly.If you are on a stop and go situation they won't help much because they will pull the hot air from your radiator and heat up your IC core.

My GReddy has ducting that eliminates the radiator heat and just brings in air from the outside.

LUV94 RX7, I would even waist time or money for only 295 CFM of air with that 6x6 fan, unless it is a typo.

Thanx for the advice. I already ordered it so we will see how much it helps under different conditions. My IC is only 375 cu in and your ASP medium is more like 500 cu in.

Ken

airborne

i actually just ordered the 7.5" (440cfm) from jaycorptech ($60). they recommend their pin style mounting. i don't like the idea of sticking pins through the IC (pettit cc2) but for $8 i thought i'd see how it looked. also for the heck of it i ordered the harness and relay kit which "includes wiring harness, relay and socket, fuse holder, and instructions. "

i also think luv's idea for a test (let idle until heatsoak sets in, turn on fans and watch temp) is a good one. that is the main problem i'm trying to combat. it seems like if you just let the car sit and idle it would darn near overheat itself. even on coolish days my intake temps see 60c (by pfc) if i let it just sit long enough.

everything should be in today/tomorrow, hope to post pics/review.

Radical Rotary Avantgard

Airborn, not trying to down you, but for the size, price and CFM of that fan you are getting short changed.
I don't work for Permacool nor have any vested interest in the company but check out their web site.
www.permacool.com
They have all the hardware and harness that you might want or need.
Just trying to help.
You don't have to let the car idle until it heat soaks, all you have to do, is ride it until normal temp then park it for 20 minutes, come back and read out your PFC.
I'll guarrantee you your IC will be heat soaked for sure.
Now turn your fans on and see the temp go down.

airborne

i did look at those but unfortunately i think this is the biggest i can fit w/my IC. the pettit cc2 uses the stock pipes and the actual fin area is only 9x9. and some of that is unusable due to the ic pipes runnin with 1.5" of the ic surface. still twice as big as stock

here's a pic if you care:

Radical Rotary Avantgard

I see the problem now then never mind what I said then.

airborne

the problem being that its the bottom rung on the ladder of aftermarket ICs

as far as FD mods go an IC fan of any kind is relatively affordable and if it can lower intake temps by say an average of 10C in stop go traffic/between runs at the strip/between autox runs its worthwhile.

also agree with how you measure effectiveness. i plan to set it up initially to run just on a regular ol' switch to hopefully see the effect.

Brentis

very good posts. I agree on many fronts. I got the 330cfm spal - 6amp though. It blows like mad and I read that amperage is almost a better indicator of pull than CFM - based on different mfgs. as fan blade architecture is highly refined and the testing is very different.

One other thought about the fan vs. 30mph speeds is that I recall, the IC god Corky Bell stating that the 1st inch is where most of the fan cooling occurs. I speculate that this is for a couple of reasons. 1) The heat transfer from the IC to the air has made the air temp reductions negligible past the 1st inch 2) (more likely) the air pressure cannot effectively penetrate the 1st inch of the IC. The reason I think 2 is more likely is b/c when I ran my "test" the air coming from the back of the fan albeit warm, was not as hot as the IC temp (guessing). I may be wrong but we'll see.

Another consideration is that the back pressure from a closed hood may prevent the air from efficiently passing through the IC - something which the fan passes through.

airborne

random thing i thought of from reading that jaguar site. say you have an IC fan. its agreed that its not necessary when at speed where airflow is good. so if you do have a fan do you

A) leave it on so that the airflow is not slowed by the fan

or

B) turn it off so airflow is not limited by the top speed of the fan