[Mk2] [Turbo] Fan aluminium cowl issue on uprated IC

[oBladeo]

I've just been thinking about the spal fan and aluminium cowl on a uprated IC.

I can see it giving restiction issues at speed as it covers the whole IC

Am i right or wrong?

[jimGTS]

its probably a trade off tbh....
at low speeds, it helps pull in air to cool the unit down. and stop heatosak.

[oBladeo]

Yea which is like any other IC fan :S

The issue i have is that it covers the whole IC

If it was flat to the IC without the aluminium cowl. Then it should be better as it would allow air to flow around the fan as well as through it

[jimGTS]

but without a gap between the fan and the ic, it would only be pulling air through the fan area, not the other 30-40% around it....
that inch gap allows it to draw air through the whole ic surface (afaik)

[oBladeo]

hummm 30-40% i think you have that a little wrong

[jimGTS]

hummm 30-40% i think you have that a little wrong

Image Replaced With URL For Quote http://i343.photobucket.com/albums/o450 ... 01798a.jpg

why are you showing a pic of the shroud on?? that doesnt prove anything....
if anything, i can clearly see 30 odd % around the outside of the fan where there would be fins.....

[oBladeo]

The 30 odd % is the point that i'm making. That would allow the through from the otherside of the IC at speed to miss the fan to you have a better flow

[jimGTS]

i guess, in an ideal world, you could have the fan raised off of the ic, but not actually be contained in a shroud.....or even just have loads of holes in the shroud?

im pretty sure there designed the way they are for a reason. at standstill, it will be pulling air out of the whole unit..at standstill with just the fan against the side, its only pulling air through where its touching.

i dont think anyone has done any real test for this.

[oBladeo]

I only really picked up on this as a comment i heard on here a bit back about having the IC fan on all the time and it would restrict air flow. (i had the setup without the cowl and the fan flush to the IC and it cooled very very well)

I won't have this problem now as I’m fitting a huge CC but i thought it was worth mentioning for people with this setup out there

[jimGTS]

did you attach a spal to it, or just the old stock fan?

[oBladeo]

I had a spal on it as i only had to make a small bracket to hold it in place.

The spals moving to the oil cooler now tho and the IC will be up forsale soon

[jimGTS]

i may as well give it a go, because my shroud is breaking. so i either need a new one, or ditch it and do something else.
not to mention i have intake readings on my powerFC, so i can see the difference real time (if theres any in terms of temps)

[C50]

if the fan was directly flush on the ic, you can clearly see that no air would flow through that huge centre of the spal fan.

[jimGTS]

for now im going to position the fan on top of the ic....

but think i will try and copy something similar to this....

looks like a good medium???
raised, but no shroud.

[C50]

without the fan shroud.. it wont suck air through the intercooler effectively

[mattcambs]

I've often wondered about the amount of actual air that can flow through the Greddy style ICs with fan & fan shroud.

Surely the air flow via the side vent above 30mph is way better than anything a fan can achieve? But how much air can actually flow through the Greddy ICs from the side vent? The fan and shroud look like they'll block a lot.

It's a tricky one because there is so much heat in the engine bay. Do we just let the fan move air across the fins by having it on all the time, or do we go for worse heat soak when stationary, but have much better air-flow when driving?

[C50]

hmm.. i suppose it's not like you need boost when stationary or cruising <30mph, will heat soak really have a big effect?

the side vent would still channel the same volume of air as without the shroud on when on the move.. so the shrould and fan shouldn't be restrictive.

that raised design - to me it seems like drinking a glass of cola through a straw but with the straw hovering an inch away..

[oBladeo]

I think the raise fan would be good tbh. Maybe if the fan was 1/2 inch away that would be better. The fan would still suck a small amount of air through the ic being 1/2 a inch away. I know it's not as much as it would be with the shroud but if you think about it how often does your ic fan come on anyway? (what temp?)

We will only know when when someone has done the tests

[jimGTS]

anyone who does these mods genrally has the fan on 24/7...
i run mine all the time as soon as the car starts to get warmer.

it pulls a vast amount of air through that fan.

you can literally place a piece of paper at the "entry" of the sidevent (6inchs away from the fins on the ooutside), and it will suck it straight onto the ic...
now the fan is only going to be pulling air in at comparative low speeds, im guessing 20-30mph.
so anything below this, and its helping stop heatsoak.
this is an good advantage on the 1/4 when lining up. where theres lots of 0-5mph. and i guess if on a track, where theres lots of stops and starts, getting to pits or whatever.
either way, as soon as that engine is shut down the car will begin to heatsoak over the next 30-40mins, and get extremely hot. turning on and idling the car helps when that fan gets going (if you have it on a swtich)
then again i do have rogue lid fans to, they pull a stupid amount of heat out the bay.

refering to above 30 and to say 100 or whatever. yes the fan is made a bit redundant. but if on, i really dont think to restrictive. i guess the air blowing through the ic will outrun the fan, but the hole for the ic pipes are not behind it. they run in the middle (so before the fan), so that air from outside is running through the pipes before it exits the other side of the fins.

ive run with no fans at all over the last week and am seeing much higher temps than usual. 10C infact.

[mattcambs]

anyone who does these mods genrally has the fan on 24/7...
i run mine all the time as soon as the car starts to get warmer.

it pulls a vast amount of air through that fan.

you can literally place a piece of paper at the "entry" of the sidevent (6inchs away from the fins on the ooutside), and it will suck it straight onto the ic...
now the fan is only going to be pulling air in at comparative low speeds, im guessing 20-30mph.
so anything below this, and its helping stop heatsoak.
this is an good advantage on the 1/4 when lining up. where theres lots of 0-5mph. and i guess if on a track, where theres lots of stops and starts, getting to pits or whatever.
either way, as soon as that engine is shut down the car will begin to heatsoak over the next 30-40mins, and get extremely hot. turning on and idling the car helps when that fan gets going (if you have it on a swtich)
then again i do have rogue lid fans to, they pull a stupid amount of heat out the bay.

refering to above 30 and to say 100 or whatever. yes the fan is made a bit redundant. but if on, i really dont think to restrictive. i guess the air blowing through the ic will outrun the fan, but the hole for the ic pipes are not behind it. they run in the middle (so before the fan), so that air from outside is running through the pipes before it exits the other side of the fins.

ive run with no fans at all over the last week and am seeing much higher temps than usual. 10C infact.

Very good points, Jim

Plus using the Rogue lid fans has got to be a massive plus for anyone with a side mount IC.