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The S4 and the S4s is probably not the same. Sport300 used an SE chargecooler, but have a different part bumber, because it's grey and more importantly, it's been modified to suit the bigger turbo, by sawing 10mm off the outlet. If not, it wouldn't fit under the also modified S4 engine cover (extra tubing).
So, the chargecooler is dimentially the same back to the SE.
I'll measure mine tomorrow.
What type of engine cover do you use? SE, S4 or?
Cheers,
Redfox
 

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I am looking forward to your charge cooler build. Will you be fabricating your self?

If you dont get the measurement soon I will re-install the engine cover and try to get the measurement.

If you feel like welding up two at once I would be happy to pay for your trouble!
 

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Integrator
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Discussion Starter #5
Yep, I'm thinking that dual pass 4"Hx6"(8"?)Wx9"L divided core will be much more effective than the stock Behr part. Slightly larger, but not as monstrously big and heavy like Alunox.
I found bar&plate cores 3.7"H and 4.1"H. Looking at the OEM part (4x4x9" core), I hope to be able to package 4.1H there.

This modification should implemented together with increasing c/c plumbing to 3/4" diameter all the way. Current 5/8" plumbing has 12mm ID and is too restrictive. 3/4" plumbing opens up ID to 16mm reducing the pressure drop from 0.74 psi/ft to 0.12 psi/ft at 30 l/min.
Here is a handy-dandy calculator:

 

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Great so you will build two then! Let me know where to send the check! Seriously though, if you want to build a prototype and then a nice one, I will take the prototype !!

One thing I have wondered about.

If the line size up to the CC radiator in the front is increased, the speed that the coolant travels increases too. Assuming that the lines are the bottleneck and not the CC radiator, or CC heat exchanger.

Will that result in less time in the radiator, there fore reduced cooling?

If the lines up and back are not the restriction. Is there a point to larger lines

I suspect some one checked this and verified larger lines = lower intake temps but I dont recall reading that.
 

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Integrator
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Discussion Starter #7
Lowering the intake temp by 1F gives you +0.5 HP increase.
Time the coolant spend in the radiator has nothing to do with the efficiency of heat transfer.
More coolant mass flowing faster = higher heat extraction and higher efficiency.
 

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Thinking some more on this - the volume of coolant in the system goes up a decent amount which must be good. Kind of like a dry sump oil system that has that big tank full of oil.

Maybe we should add a coolant sump for the CC system? :cool: too much weight!
 

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Integrator
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Discussion Starter #9
Higher flow will certainly result in a lower coolant temperature change, but that is actually desirable, as it's associated with a lower thermal resistance of that heat exchanger. At a system level, that is what you want to achieve. The lower coolant temperature change is compensated by the higher coolant flow rate, and the reduction in the latter is greater than the decrease in the former.

The equations cited in this paper 6.21.1 Radiator Equations
show the only time dependent element,
=fluid mass flow rate (kg/s), is in the numerator, hence the heat flux q increases proportionally with fluid mass flow rate. In another words, bigger the pump trough-put results in a higher heat transfer and efficiency.




The same is true for the heat transfer coefficient,
,


Heat flux does increase with coolant flow, but it's non-linear. It does plateau at very high rates, so you do get to diminishing returns. You have to have a high pressure to get there, and the pump would have to be very big and powerful. The increase in pumping power required becomes very high compared to the increase in cooling capacity. In normal automotive IC's operating around 0.5 bar, a better pump is a big win.

Careful with upgrading the pump though, you can't simply buy a pump with a higher flow figure. High pressure is more likely to increase cooling than high flow.
_
Yes, sump, of course.
Some folks are adding a "cold reserve tank" to cc system.
How big? Depends on how many seconds of full boost would you need ?
If you have a 30l/min cc pump, you'll need only 2 gal reserve for 15 second blast.
 

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I have NO space lift under my engine cover (nut higging slightly on engine cover), but that is the odl type SE one. Not the newer version you have. SO cannot really say how much space there may be for a bigger chargecooler.
Cheers,
Redfox.
 
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