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Well, aftermarket intercooler might actually help.
Given that experiment, I hope the better IC has lower heatsoak point and brings the IAT to under 70c.
I have some reservation about that experiment, though. The hairdryer wasn't as hot as I hoped, no inlet temperature, and maybe there should have been a fan blowing through them. And measure with/without the fan. It does indicate that the aftermarket one cools better, though. Whether it's purely due to higher thermal mass, I'm not so sure, since higher thermal mass means it'll take longer to heatsoak, but it'll also remain at that temperature for longer too cool down as well.

If the hair dryer does indeed pump out 190F(87.8C), resulting heatsoaked temperatures 125F(51.7C) and 158(70C) show clear difference.
I've personally seen IAT reach 210F(99C) with the stock setup and float around 90C at a hot track day. Leaves a lot to be desired...

On a related note, I'll be running supplemental air duct to the IC as well soon.
 

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This is only a draft..... :eek:

4" = 101.6mm is very large :crazyeyes

Can you find 4" air dust?
Well, yeah. At 4", it ain't gonna fit.
I have a spare stock intercooler/shroud that I bought specifically to make a hole for side ducts sitting on my lap right now, and total shroud 'depth' is 3.5".

Stock intercooler's 'lip' that sticks out for the shroud attachment is about 3/4", and the shroud 'lip' that attaches to the bellow is another 3/4". If you're going to work with stock dimensions, you only have about 2" on the side to work with.

Of course if you're going to change the dimensions and come up with an original design, you can fit however big ducts you want. But if you're going to work with stock dimensions, 4" duct is going to take a lot of work....
 

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Yep!

4 inch piping is available in silicon and neoprene through specialised performance outlets on the net. If you want to be a cheap skate you can also use ally AC duct, 100mm. Available from a hardware store.

Lotus OEM will sell you a genuine 2-11 shroud and associated piping, but it is a pretty penny! The geniune shroud from lotus is made from ally and welded together, so it is pretty good quality.
If you replace the stock shroud to 211, I assume you won't be making use of the 'mail slot'? Not that it matters too much. It's barely adequate anyway...
 

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1. I will mod the OEM Shroud to fit with the 4" dust and also with the mail slot.

2. 2 Curve Seperators in the Shroud to smooth out the flow.

3. Need to make 2 Side Inner Scoops 4" X 7" open with 4" dia elbow outlet that can house the 4" dust.

What do you think?
Not entirely sure if there's enough space for 4" inlet in the side scoop...
I personally might like to keep and utilize stock side scoops(because I'm weird...

Looking forward to what you can come up with! :up:
 

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So when I start my car since there is no airflow to the IC it's heat soaked? Seriously, where do you get this nonsense?

San
Physics. -poke-

Given,
Zeroth law of thermo: if temp A = temp B and temp B = temp C, then temp A = temp C
where
temp A = Before IC
temp B = IC temp
temp C = After IC
things in a linked system will eventually reach thermal equilibrium, so [IC temp] reaches [before IC] -> [before IC] = [IC temp] -> [before IC] = [after IC].

Proof:
Specific Heat equation:
Q=cm*dT
where
Q = unit of heat(energy in transfer). [constant in our case]
c = object in particular's heat capacity(aluminum, air). [constant in our case]
m = mass. [constant in our case]
dt = final temp - initial temp. [variable]

in the case of 0 airflow at equilibrium, aka 0 cooling.
final temp IS initial temp,
then dt = final temp - initial temp = 0,
so Q = cm*0,
therefore Q = 0, aka no heat transfer, ergo heat soak.

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To take a step back to the original discussion:
Given Q = cm*dT and therefore Q/cm = dT, you may think doubling mass (2m) results in halved change in temp as in Q/(2cm) = dt/2
However, because all things reach equilibrium eventually, it just means it'll just take twice as long.

To put it simply:
If you place 1 pound of aluminum block and a 2 pound block on a heat plate(outputs energy at a constant rate), they'll both will reach the same temperature(equilibrium) as the heat plate. The difference is the 2 pound block will take twice as long. If you get a 100lbs block of aluminum on that heat plate, it'll also reach that thermal equilibrium. It'll just take that much longer.

In our case:
Say, if you hit 'heat soak' at lap 1 with 10lbs IC, you will have heat soaked at lap 2 with 20lbs IC.

To be fair, RLS IC could have better cooling efficiency due to larger surface area and/or bar&plate design when subjected through same amount of air.

IC is a device that depends on forced convection. The way to make it work better is by forcing more air through rather than adding mass. Besides, who'd want to add mass to the highest point away from the CoG?
On the other hand, A2W cooling would be more dependent on 'thermal mass', especially because water is has HUGE thermal capacity at ~4200J/kg*K. It takes a huge amount of energy to raise a kilo of water 1degreeC. It will stay at initial(ambient?) temperature for longer before it goes up in temp. Aluminum is comparatively tiny at ~900J/kg*K it'll go up in temp at the slightest chance.
Interesting thing is once the water in A2W heat soaks(eventually, preferably not before the race end), it'll just be as useless as heat soaked aluminum IC.

The point of my wall of text is not to bash RLS. I love their product. I'm just discussing science here.

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West oz loti, there's no 'camp'. It's true whether or not one believes in it.
Prove me otherwise, then I'll stand corrected.
 

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Ummmm last I recall it was around $7,000/day, not including set-up costs... :crazyeyes

Needless to say you understand why I haven't just done this myself!
Yeah, that's a little pricey. If it were under $1000 I might consider it. For science!
Uh.... Kickstarter/Gofundme? :crazyeyes
I'd rather spend that money on some other useful studies, though...

Heatsoak is not a term that has any strict engineering context. In fact after hearing it for so many years I can't even think of a sensible interpretation.

If you mean to say the material condition is carrying alot of heat, the term "hot" or "higher temperature" is pretty ubiquitous here

Perhaps the context is the IC is nearing some portion of steady state full load conditions

or perhaps it implies delta temperatures across the IC are below a certain threashold

Its not a term that makes sence to discuss in the context of thermal science without a rigorous definition.

I certainly agree the thermal capacitance is a negligible factor here.


I guess It has been too long since I have been @ school because for some reason I was thinking a joule was defined as the work required to raise 1 g of water 1 deg C @ STP. I guess that number is closer to 4 J. I guess it would be too much to ask for to coincide with 1 newton of force acting for 1 meter. Perhaps this is te first time the metric system has let me down!
Agreed. :cool:
 

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That is completely incorrect. The IC doesn't need to have air flowing across it to disperse the heat. It obviously helps tremendously when there is airflow, but it's not necessary. If the air temperature around the IC is lower than the air going through it, there will be heat transfer through the fins. You yourself pointed out in a subsequent post that the purpose of the fins is to increase the surface area for the heat transfer to occur. Unless the ambient air around the IC fins is hot enough to be essentially equivalent in temperature to the air going through it, heat transfer will occur. That heat transfer will be signficantly better with an IC than with a straight pipe, regardless of airflow, because of the enhanced surface area.
No one's going to argue that one. There will always be some heat transfer to the ambient air since ambient air will nearly always be at lower temperature than the output temperature of the compressor side.

Few assumptions had to be made in order to move the discussion forward. Such assumptions are useful, for example, in the case of whether mass has any significant effect on the final velocity of free falling objects. Assuming no air resistance,the equation ends up being like vf=sqrt(2gh) so you can see mass as no effect on objects in free fall. It's unlikely that such condition will exist, but it is a useful tool for understanding the physics behind it.

In the case of the thermal mass vs airflow discussion, cooling from passing convection is assumed to have negligible effect(in comparison to forced convection) especially since the car is assumed to be nearly always in motion getting airflow through the IC.
Plus, doubling mass doesn't double surface area when density is same due to square-cube law, therefore it is also unlikely that doubling mass also doubles passive cooling due to increased surface area.
 

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Just received 2-eleven shroud,

Boy it is light.

Just need to get the duct now :)
Weight?
I'd be curious about how it works out for you since I don't think there's enough space for the stock side ducts to accommodate 4" ducts/hoses, which probably means you'll be using aftermarket size scoops.
 

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Bumping this thread, cuz I have 'some' new data.
I added 2" ducts to my stock intercooler shroud recently and logged data.

Apples to Oranges because variables are different, but hopefully it's still somewhat usable.

Car: 2008 Lotus Exige S240. STOCK.
Date: March 26, 2015
Track: Laguna Seca
Ambient Temperature: 65F
Vmax: 111MPH


Car: 2008 Lotus Exige S240 +2" ducts.
Date: April 4, 2016
Track: Buttonwillow
Ambient Temperature: 72F
Vmax: 114MPH


Comments:
The ultimate goal is to keep the IAT under 70C(158F).
20C(36F) drop in IAT is decent, but the fact that I still went over 70C is a bummer.
The test conditions were obviously different. But, the Ambient Temperature at Buttonwillow was higher and the fact that stock supercharger is capable of shooting IAT up well past 80C by Lap 2 elsewhere still shows that additional airflow is a good thing as the IAT was kept under 80C with my ducts.
Larger ducts may be helpful. Better intercooler could be helpful. A2W Chargecooler could be the answer to high IAT, but it adds complexity and weight..

My original plan was actually to do a back-to-back session on a fair weather to reduce variables.
Run 1: Duct hoses disconnected around 1PM session.
Run 2: Duct hoses connected around 2PM session.
This would accentuate the effectiveness of the side ducts because ambient temperatures near my location typically peaks around 2~3PM. It would show that despite the Run 2 having marginally higher ambient temperatures, the side ducts should have decreased the IAT by however effective it is.
I couldn't do it this way because I've never been to Buttonwillow and we ran the other way around for afternoon session, forcing me to re-learn the track. And, I got tired.

I plan to do it this way on my next track day. Whenever that is.

==================
Here's what I did. Inspired by @cain-it http://www.lotustalk.com/forums/f157/my-new-exige-dubai-101782/index2.html#post1624410
I actually bought the parts about a year ago, but only just recently installed it because I had other things to take care of.







https://www.merlinmotorsport.co.uk/p/spun-aluminium-air-outlet-ao
https://www.merlinmotorsport.co.uk/p/revotec-black-single-layer-neoprene-ducting-per-metre-rev-blk
https://www.merlinmotorsport.co.uk/p/duct-joining-sleeve-70mm-id-pair-rev-js70
https://www.merlinmotorsport.co.uk/p/152mm-x-51mm-offset-air-duct-id152-51os
 

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Back to back test with a control just for good measure. I'm familiar with the track unlike the last time, so I was able to put down some consistent times.
Ambient Temperature was around 107F.
It definitely helps. I wish it did more. Upgrading the intercooler could help further, or going all out with A2W cooler is the way to go.





 
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