Front mount V.S. Charge cooler

Re: Front mount V.S. Charge cooler (Weaver)

You can do a search on intercooler efficiency and find the math. What you will find is that Air to Air is the most efficient (one vs two heat exchangers). I don't have the formulas in front of me, but remember every time you try to move energy from one place to another, there is some amount that will never transfer. But in brief:
Air to Air:
How:
1. Hot air from the SC enters the IC tubes, flowing from high to lower pressure - accomplished by having a larger outlet than inlet, and of course pressure from the SC
2. Cooler air surrounds the hot tubes, absorbing heat in the process
3. Process repeats
Requirements:
1. Cold airflow must have a high pressure to low pressure path, or air will not pass through the IC - This generally means that it has to be out front with vanes directing air to it with no other escape path
2. Long tubes to enable a FMIC on a G60 Corrado (with stock radiator / AC)
Pros:
1. Simple - no moving parts
2. High efficiency if mounted correctly
Cons:
1. Tubing is long
A. Causes a small amount of boost lag
B. Added air drag
C. Heat gains from engine in IC to TB tubes (usually there is enough air flow for the SC to IC tube to lose heat energy)

Air to Water IC Setup
1. Hot air from the SC enters the IC tubes, flowing from high to lower pressure - accomplished by having a larger outlet than inlet, and of course pressure from the SC
2. Cooler water surrounds the hot tubes, absorbing heat in the process
3. The heated water is sent to an air to water radiator, usually separate from the main engine radiator - but not always so, cooling the water back down
4. The water is pumped back to the IC for step 1 to start over
Requirements:
1. Large additional radiator
2. Additional plumbing and pump with water or other absorbing substance
2. Electrical or mechanical energy to power the pump
Pros:
1. Short IC to TB path
A. Minimal boost lag
B. Minimal heat gain in tubes
C. Low air drag
2. Easy placement of IC
Cons:
1. More complicated with moving parts and liquids
2. Heavier as there are additional parts
3. Less efficient.
A. Fist the outside air has to cool the water radiator at some inefficiency
B. The water then has to cool the hot SC air at some inefficiency
C. A + B inefficiencies are always more than an air-to-air IC's inefficiencies using the same frontal area
Hope that answers a few questions

Re: Front mount V.S. Charge cooler (Weaver)

BTW, what I am doing... after saying all that....
Air to Water. Why? It's so darn hard to get the plumbing from the G60 or any other SC up front to a FMIC and then back to the TB. And then on the C, finding a place to put a large enough IC that is not blocked by the bumper or other things is tough. The radiator I'm using can easily be mounted under the bumper, and the neat thing about Air/Water is that you can easily add additional radiators for more surface area if the first doesn't do the trick.
To start with, I bought a like new Fluidyne oil cooler from Gary Trout (DB-30816, http://www.fluidyne.com/race_std_products.html) on Ebay for $90. I am looking for a spearco air/water heat exchanger to connect it to. In addition, I may add a freon cooling rig in-line for those times when you want to go fast after sitting in traffic (Florida), which is something else that is very easy to do with an air/water rig.
The old OEM IC will come out and be replaced with an oil cooler at that location. Should be cool (pun intended)...

Re: Front mount V.S. Charge cooler (Fast_bunny)

Granted, if this were on a boat and cool water was available all the time, this would hold true. But a C is not a boat (even if it feels that way sometimes down here in the rain)
There are many heat gain/loss issues involved here (these are simplified calculations). The sizes of frontal area, and velocity of air drastically change the base formulas. But for normal <100MPH driving assuming the same frontal cooling areas, they are close.
Assumptions:
Ambient Air: 100deg F (Florida - hot day)
Altitude: Sea Level
G60 Efficiency: 75% (not exactly sure about this – but does not change comparison much)
Compression: 15 PSI
Air-Air IC Efficiency: 80%
Air-Water IC Efficiency: 90% (does not matter as much, as the radiator is what kills this energy transfer)
Water-Air Radiator Efficiency: 60%
ICE Box Efficiency: 90%
Air-Air cooling
1. Air to G60: 100F
2. Air leaving G60: 266F (see http://www.3si.org/member-home/jlucius/2-turbotemp.htm for nice calculator)
3. Metal pipe heat gain: 20F (now 286F)
4. IC cooling outlet temp: (286-.8*(286-100))= 137F
5. Metal pipe heat gain: 20F
6. TB inlet: About 157F
Air-Water-Air cooling (ambient air)
1. Air to G60: 100F
2. Air leaving G60: 266F
3. Metal pipe heat gain: 10F (now 276F) – much shorter pipe!
4.Air-Water IC outlet temp
1.Water temp coming from radiator: (276-.6*(276-100)) = 170F
2.Air-Water IC outlet: (276-.90*(276-170)) = 180F
5.Metal pipe heat gain: 10F – short pipe!
6.TB inlet: About 190F
Air-Water-Air cooling (ice setup for short-term racing)
1. Air to G60: 100F
2. Air leaving G60: 266F
3. Metal pipe heat gain: 10F (now 276F) – much shorter pipe!
7.Air-Water IC outlet temp
1.Water temp coming from ice box: (276-.9*(276-32)) = 56F
2.Air-Water IC outlet: (276-.9*(276-56)) = 78F
8.Metal pipe heat gain: 10F – short pipe!
9.TB inlet: About 88F – 12F BELOW ambient air temp!
I like the Air to Air best. It is more efficient due to no compound heat exchangers. It is simple as there are no pumps involved (or to fail, power, etc.).
But, where to put the charger without lots of piping, blocking the radiator and A/C condenser coils, or cutting up the bumper? Relocating the headlights was VW's answer, placing the I/C in the battery compartment. This works, but looks weird. Removing the A/C is not an option here.
Either way I do it, I will have cooler air than the stock IC, or an oil cooler that never lets the oil above the thermostatic value