I think insulation on top of the radiator would be sufficient. So no real need to close the U of the duct. Just for reference, with 75degF ambient temps, I measured 110-120degF radiator surface temp right at the stock airbox snorkel with highway driving. So where your carbon fiber duct also goes.

 

could you share the excel file you have made?

 

NEWS

I am still trying to understand why my physical results are so far from the theorical results based on the compressor pressure ratio.

Let's take it back from this point:
- as calculated in post #8, my SC pressure ratio should theorically be 2.28 at 8850rpm
- at this kind of rpm, I see 9 psi at the manifold

Now let's think about the whole system and find where the pressure loss comes from.

1. Atmospheric pressure is considered 14.7 psi in my location.
2. Let's assume 20°C (68°F) air temperature.
3. Intake filter and piping restriction: I should test it by running without filter. Let's suppose 0.5 psi (which seems typical for a boosted filter restriction).
4. SC inlet pressure is 14.7 - .5 = 14.2 psi (absolute pressure).
5. With a SC pressure ratio of 2.28, the SC outlet pressure is now 32.3psi (absolute), which means 17.7 psig (boost).
6. With an efficiency of about 70% for my SC, the outlet air temperature with 17,7psi of boost climbs from 20°C (68°F) to 123.8°C (254.8°F) !
   I used this calculator to estimate that: https://racingcalcs.com/supercharger...re-calculator/
7. Using this second calculator base on the "ideal gas law": https://www.omnicalculator.com/physics/ideal-gas-law
   We can see that 100L or air (as an example to make the numbers easy) at 17.7 psi and 123.8°C contains an amount of substance of 3.7 mol.
8. Now, let's assume that the intercooler system will get my air temp back to 40°C (104°F), which is a typical correct result (20°C above ambiant).
   Using the same calculator, we can see that 3.7 mol of substance, in the same 100L of volume and at 40°C results in a new pressure of 14 psi !!
   This is a "natural" 3.7 psi drop due to the cooling of the air !! and I think this is the major part of the equation that was not obvious for me at the beginning.
9. The last factor is the piping + intercooler pressure dop. And if we get back to my real results where I see 9 psi at the manifold, this would mean there is 5 psi of pressure drop in my system.
   This value would be a high/bad value for a FMIC system, but this may be reallistic as I have a quite small FMIC and TTS performance themselves told me that it was really restrictive (it was the supersport version and they made that choice to limit power, as they also offered the bigger race FMIC to get more power).

Now I think my math and my understanding of the whole process is quite close to reallity. I am really interested to here what you guys think about that !
I will work later on an updated excel sheet doing that math.

 

Wow, awesome! Bringing a more solid understanding to how all this works.

I have recently had a renewed interest in more thought on this, and was circling around something to do with before abd after temps and volume. Recent google searches were things like forced induction pressure ratio temp and volume, and air temp vs pressure. That is how I found the site with the detail on pressure loss on inlet side of of a compressor I sent you last night. Not sure if you even saw that email yet. Seems we are both looking at same things at same times. But you figured it all out first! Congrats!!

What I think what we can learn from this is how important compressor adiabatic efficiency is. The less air is heated, the less pressure lost to cooling it back down. The smaller ic you'd need, therefore less pressure lost there too. On top of all that, more of the added hp produced goes to wheels, less to heating air.

Since we can't control this efficiency on a forced induction system we already chose, next best thing we can control is air temp at filter intake. The cooler that air, the less the air temp going into ic, the less loss of psi once that air is cooled.

Locating a smaller than stock filter inside engine bay seems like a recipe for lost potential. Any restrictions on intake side are multiplied by pressure ratio (example, 1psi lost x 2.38 PR = 2.38psi lost). Any heat above outside ambient just raises temp into ic, resulting in more psi lost once its cooled (assuming ic has capacity to still cool it to same end temp).

So fit largest filter, shortest intake piping, least amount of bends, and don't leave filter exposed under hood.