W2A system expansion

Surely a W2A IC setup will never get hot enough to warrant a radiator style expansion cap? 

Could it: Yes

Should it: No

For a more specific answer, we would need more specific details.

Its the first intercooler in a twin charge setup between turbo and supercharger.

Heat exchanger is a fluidyne from a cobra that is mounted under the car at the rear axle so decent capacity. 

I'm just T-ing into one of the lines and using some fittings as a filler with no expansion cap.

2nd intercooler after supercharger is an A2A fmic. 

Water changes volume when it changes temperature. I would have an expansion tank in a non-car application and the radiator cap is essentially a safety relief valve.

Say if you wanted a stand pipe with a pocket of air trapped in it:

For a system with 10 gallons of water, filled at atmospheric pressure with 50°F water and an expected high temp of 140°F with a 10 psi cap, you could use a stand pipe with of 0.37 gallons of air.

RossD said:

Water changes volume when it changes temperature. I would have an expansion tank in a non-car application and the radiator cap is essentially a safety relief valve.

Say if you wanted a stand pipe with a pocket of air trapped in it:

For a system with 10 gallons of water, filled at atmospheric pressure with 50°F water and an expected high temp of 140°F with a 10 psi cap, you could use a stand pipe with of 0.37 gallons of air.

 

So I leave a % of air (depending on coolant volume) in the system that will take up the coolant expansion?  

That calc is for straight water, but yes, a 'stand or capped vertical' pipe traps the air and will compress to take up the difference in water volume.

Now that I think about it, the radiator cap idea is probably the better way to do it however. It will puke out when over pressured due to change in volume, and will suck it back up when it goes cold and negative pressure.

do w2a systems reach boiling temperatures? if not couldn't the reservoir just be vented as to not hold any kind of pressure so it can just breath with expansion/contraction?

My Mercedes with WTA in a separate loop (AKA split cooling) with a big heat exchanger and 2.5 gallon trunk tank never got anything above "warm".  Maybe 110F tops.  This was with freeway pulls, drag racing, and long commutes.  That was a 600HP V8 car with a known heat-producing stock blower pulleyd to the moon.  Anything more efficient than that should be better.  

RossD said:

That calc is for straight water, but yes, a 'stand or capped vertical' pipe traps the air and will compress to take up the difference in water volume.

Now that I think about it, the radiator cap idea is probably the better way to do it however. It will puke out when over pressured due to change in volume, and will suck it back up when it goes cold and negative pressure.

Ill just not fill it up to the top! Running a cap and an expansion  tank is more stuff.. I have too much stuff already. 

edizzle89 said:

do w2a systems reach boiling temperatures? if not couldn't the reservoir just be vented as to not hold any kind of pressure so it can just breath with expansion/contraction?

I like that thought too.. Like a windshield washer bottle.. 

Oh yeah I left my WTA tank approx 1/2" below top, filled with a mix of water and green coolant around 50-50.  Not vented.  No probs.

What you may be thinking of is the little radiator cap surge tanks on things like Syclones. The Syclone had an intercooler as part of the regular cooling loop so it was pressurized.  Factory WTA has to have a radiator cap because it share a cooling loop with your regular cooling system.  Aftermarket WTA generally is a split system.  Of course you can in theory run engine coolant through a WTA, but all this is good for is keeping your intake air temp below 206 or whatever your cooling system runs at.  It would also add extra heat to your cooling system so you would need another radiator.

It'll be a stand alone system. I wouldn't consider using the engine coolant, it would be heating the charge up.