EARZ

[marcher]

Sure you have all seen these Earz before

http://www.ebay.co.uk/itm/131766520239?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT" onclick="window.open(this.href);return false;

Anyone use them??? anyone got any views/reports on them??? Do they really work???

Seem a little bit on the "rich" side for me until I have some concrete advice that there worth the £££

New bigger engine coming soon and trip to Europe in the middle of August planed, so any cooling help would be ideal.

 

[Graham L]

Hi Matt

Christophe from Vintage Autohaus uses them and reckons he gets a 10 degree reduction in engine temp on long runs, they easily unclip when left parked as people tend to catch them as they cant see them.

They are not new and worth checking the price with JK as I know they sell them as well,

 

[marcher]

There getting some proper f*cked up replies on the LB forum about the Earz. Bit of marmite I think

 

[Bluesnailman]

i dont see how they would help.

For me the cooling is generated by the fan, which picks up on underside, and is function of your oil reservoir size and whether it goes through a cooler.

i think the vents are there to provide positive air pressure at 'speed'. this would stop hot air from the underside leaching (through any holes in the tinware) into the upper part of engine, allowing air to the carbs and helping heat dissipate when you turn the engine off. (personal opinion - not fact). what i dont understand is how tying to force more air in would work. Given that we make sure our engine tinware is well sealed - where's this air going?

lm not a fan...but happy to be given a great explanation

 

[who?1]

I second the above.

Where does all the air go? The fan can only cope with so much I suppose.

Another theory is that they create more drag and make the engine work just that little bit harder too.

A 10 degree difference in running temperatures would, however, make me sit up and think.

All the pics and films I have seen of Vans crossing Africa and Australia and I can't remember seeing any EARS fitted (could be wrong though).

Where's the boffins? I wanna know what they think.

 

[Trikky2]

At speed they can create slightly more positive air pressure in the engine compartment but you would need a sensitive piece of equipment to measure the difference. The test would have to be conducted in wholly wind still conditions, since the slightest breeze would change the results significantly.

The usefulness of these scoops can be judged by the change made to the design on late bays, where the early scoop design was changed to much less aggressive grills.

 

[Rikki James]

I use them.... installed them ready for my new performance motor which is imminent, which will need all the cooling it can get!

 

[gas1man]

I thought in my naivety that the fan used the air forced in from outside through the top slats and entered the fan at the rear in the engine compartment. So now finally been put right can someone please tell me where the fan gets its air from? Been wrong all this time and never new. This is a genuine question and not a p...ss take guys.

J & P

 

[paul_q]

 

[Trikky2]

I thought in my naivety that the fan used the air forced in from outside through the top slats and entered the fan at the rear in the engine compartment. So now finally been put right can someone please tell me where the fan gets its air from? Been wrong all this time and never new. This is a genuine question and not a p...ss take guys.

J & P

Yes - pretty much - except it's drawn rather than forced - helped a bit at speed but there's too much turbulence and the vents are too small to force air to any significant degree.

 

[Graham L]

Air is definitely drawn from the side vents and not from the bottom of the engine where the air is hot, as I said Christophe from VA reckoned he got a 10 degree reduction is engine temp on a long run, (his unit to EBI last year which is 900km). I would have thought that the ability to draw in a greater volume of 'cold' air would be an advantage.

 

[Trikky2]

I would have thought that the ability to draw in a greater volume of 'cold' air would be an advantage.

Think of it like a pump. The fan propels a given quantity of air. Making the reservoir larger doesent make it pump faster.

 

[chad]

I guess from this ^^^^ the question is the fan supplied with the maximum air that it can 'pump' by the normal intakes?

 

[paul_q]

I guess it all depends on the bigger engines rpm and fan speed if the extra air can be used.

 

[paul_q]

Would probably help if you have big carbs aswell taking extra air.

 

[monkeyvanwestybike]

When driving on long summer runs
Fully laden with camping gear
They do get quite hot
And when you do occasionally end up
In stationary traffic
They do seem to cool down nicely on tick over
I find
so I wouldn't of thought
The earry things really help that much
When you are driving at any speed
But then I have a crossover
And it has big ears anyway

 

[rlepecha]

I'm sure a simple calc can solve this, albeit without taking into account losses.

At about 4000rpm the fan can pull 1350cfm.

Say 4000 rpm is 65mph, thats 5720ft/minute.

An approximate area of one vent is 11.75in^2. We are talking actually frontal area not the area of the vent at an angle.
That's 0.0815ft^2 each

So 5720*0.163=932.4cfm

Take the amount of air the engine uses for burning, 85.5mm dia barrel (1600) is 3.366in, PI*r^2=8.89in^2

69mm stroke is 2.717 in, so 8.89*2.717=24.15in^3. Which is 0.014ft^3
1 rev is two cylinders firing so 0.014*2=0.028ft^3.

0.028*4000rpm=112cfm required to feed the engine at wide open throttle and assuming 100% cylinder filled with air which is not correct.

112+1350=1462cfm minimum required air flow into the engine bay to meet the requirements of the engine at 4000rpm.

Thus 932.4 cfm provided by the vents would not be adequate to provide positive air pressure.



Sent from my Siswoo C55 using Tapatalk

 

[gas1man]

:shock: :shock: :shock: ^^^^^^^^^^^^^ :lol: 8)
WOW well done that man. Impressed.

J & P

 

[marcher]

WOW - what a debate.....love it.

 

[chad]

I'm impressed that you did the calculation and put a solid base under the discussion