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Old Jan 11, 2008 | 05:11 PM
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HDDP
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Joined: May 2004
Posts: 4,094
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From: Charleston, SC
Default Re: Very Confused About Overflow Tank

Steve, I obviously misundersttod your original posts... I thought you were going to isolate the charge air cooling system from the engine cooling system by adding the new tank to be for IC coolant only... Forgive my poor reading comprehension

Now that I understand your thoughts, I think adding an extra coolant tank for the engine is not necessary... The ECT's (engine coolant temps) never really get that high unless you are sitting at idle in rush hour traffic with your air conditioning on during a hot summer day...

What needs to be cooled more is the charge air coolant that runs thru the intercooler to reduce your IAT's (air intake temps), that will help increase engine performance (HP).

Originally Posted by svo
Just an idea...

Wouldn't it be easier to add a second overflor for the cooling system versus one for the supercharger?
I hope this answers your question as well... The intercooler has coolant flowing thru it to reduce the IAT since the compression from the SC heats the intake air more. The charge air cooling system shares coolant with the engine cooling system via the overflow tank. But the engine cooling system really never circulates it's coolant back into the overflow tank, unless it reaches a boiling point (which is higher than normal water in a pot because of the ethylene glycol that is under pressure in the system raises the boiling point) and then it spits out the boiling coolant and steam from the radiator into the overflow tank.

The boiling point of water is 212 degrees and the boiling point of glycols mixed with water are

219° F at 40 percent concentration
222° F at 50 percent
225° F at 60 percent
increase by 40° to 45° F if a 15 psi radiator cap is used

All of the data logs I have done on the ECT's of the engine during race conditions never showed any temperatures near the boiling point of plain water, let alone with the antifreeze (glycol). This means that the coolant in the overflow tank is not being circulated with the engine coolant, except during overheating.

Just a bit of info... The coolant system capacity is:
NA Crossfire 11.8 qts
SC Crossfire 15.3 qts

This would mean that between the IC / HE and plumbing they have an added capacity of 3.5 qts.

All of my research has shown that the IC coolant temps only run about 15 degrees lower than the ECT's. This is robbing power... So if you can reduce the coolant temps running thru the IC, it will deliver denser intake air and you can increase engine performance (HP). That is why I thought we were discussing seperate cooling systems for the engine and IC.

This is a good article to read... http://jalopnik.com/cars/custom-cars...ics-122019.php
 
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