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I'm wanting to fit a fan to the underside of my intercooler.
I'm pretty OK with all of it, but 1 thing I don't know about is how I can turn the fan on? I want the fan to automatically turn on when a certain temperature is reached in the engine bay. What can I use for that???
Rather than engine bay temp, I use a little Jaycar 50C temp sensor fitted onto the intercooler itself closer to the cold side. It switches a relay earth to activate the fan.
I have another wire in parallel to a dash switch to override it but never use it. Also use a small LED to tell me when it's working.
They're cheap as chips at Jaycar and quite reliable. I know several who use them.
Found a pic of mine..
...Attachment 74294
Wot he said X 2 ^^^^
Fantabulous, thanks jff45, that is exactly what I was hoping someone would tell me, many thanks.Quote:
Originally Posted by jff45
What fans are you fellas using?
I used one of these as a Puller on my CRD I/C due to needing slim body because of clearance issues http://www.ebay.com.au/itm/HIGH-PERF...cAAOSwVL1WCjie
The advert says it comes with a temp control, but there's no details. You got any info on it ET??
Mine is a Davies Craig 250mm under a 450x300 core.
It was on my CRD for a while but I took it off and threw it in with the vehicle when I sold it about 4 years ago.Quote:
Originally Posted by 10G
It shifted some serious air as I recall.
The temp control is the thermo switch in the piccy, mine didn't have that in the "deal" but I wouldn't have used it anyway as the Jaycar Thermo Switch on the I/C like jff45 piccy is the way to go, easy to change the thermo for different value as well if needs be.
This has all been a great help, thanks guys.
I'm hoping once I put a fan on, it will help alot in high temperatures, well temps over 30c anyway. My old girl really dies in the heat, so I'm hoping getting some cooler air through the intercooler may help get up to the performance I get when the temps are in the high teens to low 20s.
Having said that, I've been thinking about bonnet scoops.
From what I've read, you don't seem to get much improvement with a larger bonnet scoop when you're doing highway speeds, well that's OK coz I reckon when you're up to highway speeds you're able to maintain that speed easily. I've read that you get more benefit from a larger scoop at lower speeds, such as in sand etc and also creeping through city traffic.
At lower speeds the tunneling effect of a scoop will be much less than at high speed so I'm thinking that maybe we just need to let more air in to the intercooler, I guess this is where a front mounted intercooler comes into it's own??
If I had the resources I'd make a vented bonnet scoop, this would be more open to the air and when at low speeds the fan could suck in more fresh air. It would also allow for more heat to escape possibly reducing the heat soak problems??
I absolutely disagree with this.Quote:
Originally Posted by 10G
Larger scoop will Always be more beneficial than the little bonnet pocket that comes standard with the GUs. Especially at highway speeds.
You get the air ram effect at higher speeds. And you can only cram so much air into the little Nissan scoop. The larger the scoop , the higher the speeds , the more air will be "scooped" in and shoved through the IC.
At lower speeds is where the fan comes in and can help a lot.
But yeah as you said front mount is the much preferred method.
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STD scoop starts to works up to 60kph and the larger scoop works up to 80kph,
Thats what I was told when I brought my larger scoop.
Swapped it back once to see if it really did make a difference,
Big difference so big scoop went back on,
The larger scoop has vanes so the front of the IC gets air flow not just the rear of the IC
I'm with Hodge and 3D
Fan - works below about 30 to 40 KPH then gradually becomes an impediment to flow the faster you go above that
Bigger scoop - works at higher speeds and is more efficient at directing airflow.
Not wanting to get involved in a huge discussion about aerodynamics but basically... a given scoop cross section at given ram air speed into a given flow restriction (the Intercooler in this case) results in a given flow and deltaP (pressure change)
Add a fan and you get a better flow at low speed as you have dropped pressure at the I/C low pressure side (puller) or increased pressure on the inlet side (pusher) and now have a greater deltaP.
This holds true until the ram air capacity (CFM) exceeds the fan air capacity (CFM) at which time the fan starts to become an obstruction and draw energy from the airflow raising pressure and lowering deltaP
Add a scoop and you get better flow as you go faster as you are raising the inlet pressure for a given speed and increasing deltaP.
deltaP is not linear to speed increase because air compresses so this holds true until other factors like air compression and/or the vehicle aero affects the flow into the scoop and that happens to the bigger scoops at higher speeds than the factory jobbie so the advantage diminishes with speed.
Bottom line for Scoop V Fan is... low speed slogging (below 30 KPH or so) fan is better, high speed cruising/towing (above 60 KPH) bigger scoop is better
That's all valued input, thanks everyone.
My truck is a daily driver and all my driving is 100km/h stuff. I wonder what affect a fan will have with a standard scoop?? I reckon I'll be able to tell.
I'd get an ARE scoop but I don't know about the price of them, seems pretty steep. My plan is to keep the OEM scoop & IC. Fit a fan, see what happens. Need more change, fit a new IC, need more change fit a new scoop.
I ran a fan for over 100,000 K's with full instrumentation IE EGT, Scangauge etc etc on a CRD with factory scoop.
I can pretty much guarantee they do absolutely bugger all over 40 or maybe 50 KPH.
Mine was set up as IE as a puller, flush under the I/C with some thin hi-density foam added as strips for ducting wherever the fan housing had a gap.
Having said that, the fans aren't all that expensive and nothing beats having a crack.
Who knows, your setup may well get acceptable results
[QUOTE=the evil twin;751553I can pretty much guarantee they do absolutely bugger all over 40 or maybe 50 KPH.
[/QUOTE]
Yep, that's what I'm expecting. I'm hoping for improvements in power in the heat at around 20-40 kmh. If I do I'll be happy. If I don't, yep I've not wasted much money.
Thanks for your input ET.
Hey @the evil twin did that intercooler fan fit OK onto your intercooler? Did you mount it via holes drilled into the side 'wings' of the stock IC? That's how I'm hoping to mount one.Quote:
Originally Posted by the evil twin
Yep, mine was almost a perfect fit using 'slotted' holes as there wasn't quite enough meat on the wings.Quote:
Originally Posted by 10G
I toyed with the idea of some thin strap to effectively widen the wings but that would have been a fair bit of extra ginning around for not much gain in mounting strength.
Finally got around to fitting my IC fan.
It was a pretty good fit, but had to cut out some of the cowal so it would fit flush on the IC:
Attachment 74656
It sat flat once those cuts were made:
Attachment 74657
That thing with the 2 black leads to it is a 50 degrees C nomally open switch.
I put a simple toggle switch in the power line so I can turn it off manually:
Attachment 74658
It all works pretty well. You can easily feel it sucking in air when stopped via the IC bonnet scoop.
My bad... forgot to menetion I had to do the same mod to the cowling on mine as well.
No biggee as only took a few secs on a linisher belt.
I didn't do the 'placcy mounting thingy thru the core' method.
I was concerned the vibration over time would either wear thru the mounts, wear thru the I/C core or both.
I rotated mine 90 deg to the pics and mounted it on slots in the wings (as prev mentioned)
Yep, I expect those plastic strips to become useless sooner rather than later, I'll switch to cable ties then.
Please do be careful 10G mate as ET kindly mentions the usually supplied placcy things or also sometimes ‘allthread rods’ on most thermo fan kits can be disastrous. I personally destroyed a new radiator on one of my old FJ’s years ago from vibrations cutting the cores. Thermo fans on radiators are of course mounted vertically which is a worse case scenario although I honestly would never trust them buggers of things anywhere ever again for me!
Twin 16” Davies Craig jobbies on my Patrol ute now ‘bolted’ via an external frame with millimeters fan shroud clearance to radiator happy results now mate!
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