The cooler I used was designed for a car ac. No doubt it was highly restrictive. In my hookup I had used flexible stainless steel natural gas lines to plumb the cooler in. The flare fittings didn’t match up so I simply soldered them allowing me to keep the 1/2 gas flex line from compressor head to tank. I believe the corrugations may help with heat dissipation although they may also be restrictive in their own right due to the corrugations. That would be an interesting flow problem out of my capacity but right up @TinWhisperer level! Anybody know whether 16 inches of 3/8 copper or 1/2 corrugated stainless steel has more back pressure at 90psi flowing at 17cfm? I’m interested to know about ur runtimes. I am also curious if creating a longer circuit is the culprit for the decrease pump efficiency??? Could the circuit length between head exit and check valve to tank cause issue with the efficiency of the pulses and valve timing of compressor heads??
Maybe? it really depends on the specs ( Height and Spacing ) of the corrugations in the stainless tubing.
This question is a huge rabbit hole.
In HVAC at low pressure a rule of thumb is a lets say a 6" flex duct moves about the same amount of Air as a 5" solid pipe. This is kinda of but not really comparable result .
It subjects the air to the resistants’ of the pipe for longer so yes it does.
Think if you added a 100’ feet of exhaust pipe to your car; What would be the result ?
" Increased back pressure levels can cause increased emissions, increased fuel consumption, and can negatively affect engine performance ."
While not totally comparable the effect on a air pump would be similar
Another good argument for open headers!!! 
If this goes on any longer I’m going to ask Mark Rober to see if he can help us.
Howdy, I removed my air to air cooler/dryer from between the head of my compressor and the tank due to extended cycle times. I built a refrigerated cooler. I found a 35 dollar used mini bar fridge. I took about 70 feet of 1/2 pex and made two coils going down a 18 inch long 5 inch diameter steel pipe. i places aluminum tape between the two layers of pex. essentially just wrapping the first layer prior to wrapping the second layer. I turned the refridgerator to 33 degrees. Prior with the air to air dryer. my compressor charge time was 5 minutes. I would capture a ton of water before it went into the tank. Tank was staying essentially dry however I was still having to dry my desiccant every 30 to 45 mins of cut and the beads would be significantly saturate along with some indication of moisture having passed thru my consumables based on discoloration of nozzle and electrode. I removed the air to air dryer. My charge time dropped to 2min 55 seconds. I am getting some water in my compressor tank that purges ever cycle with the auto drain. I think I am going to just plumb an easily accessible quarter turn valve off the bottom of my compressor and make that a nightly routine to empty it. Today I ran for a little over an hour non stop cutting with just over 900 pierces on brand new consummables. I have a machine torch on a everlast 52i. The consummable i was using was a 45 amp version of nozzle that harbor freight sells for the titanium 45 amp plasma torch. I had zero cut issues. Nozzle is still cutting well. There is absolutely no indication of any water contamination on the inside of the nozzle/tip. My I opened and emptied my fire extinguisher converted desiccant holder just to see if i had any discoloration of my beads. I could not detect any but put them in oven to dry anyway. I am not getting any water in my water trap immediatedly post refrigerator however when i disconnect on the inlet side of the fridge i get a ton of water ejected back out. so currently to purge it of water i simply connect and disconnect it a few times. the air lines exiting the the fridge are are cool enough from the cooled air they are carrying to condense water on on the outside of the lines for a couple feet beyond the unit, and the temp of my desiccant holder 5 feet away is noticeably cooler than the ambient air temp. Over all I am very happy with this concept so far. attached is a little video of the setup and images of the consumables.
$50 diy refrigerated air dryer
A Brave New World
I am going to leave this historical Document Here
I’ll update my original post to say we’ve pretty much debunked the benefits
I agree I must say I gained some interesting information from this thread.
The cycle times are longer, but you’re putting MORE air into the tank (PV=nRT), since the charge air at the tank is far cooler than it would be (200+°F) straight from the compressor, and you’re dropping a lot of mass in terms of water vapor out of the charge as well. So, while it might seem like the compressor is doing more work, it’s filling your tank with MORE (and cooler) air mass.
How are you mitigating water condensing and collecting in the bottom turns of that cooler?
That is correct but my tank output temp isn’t that much higher. I have a after cooler post tank that takes care of that. Even on long runs my refrigerated air dryer very sees inlet temp above the mid 70s.
I used values posted by @Phillipw related to his experiment with and without the aftercooler pre-tank.
Given/Assumed
P = 145psi (assumed)
V = 140 gal (see above)
n = mols of compressed air
R = 8.314 (kgm^2)/(s^2K*mol)
T1 = 265 deg (compressor head temp see above)
T2 = 90 deg (aftercooler discharge temp - assumed didn’t see if he posted it)
No Aftercooler:
n = 158 mol / 2 min = 79 mol per min
Aftercooler pre tank:
n = 209 mol / 4 min = 52 mol per min
As you point out you can store more air in a cool tank. But when you consider the longer cycle times the increased gas storage does not overcome the longer cycle times.
This is an overly simplified calculation as the tank temperature would not be equal to the compressor head output temperature.
Also, I did not consider the air volume lost from the cooler each compressor cycle.
I believe if these variables were included it would show even more benefit to eliminating the aftercooler pre-tank.
I also used the True Gas Law and the change in results were negligible.
Values were entered in MATHCAD which allows the use of mixed units and converts the units internally for calculation.
Edit: I mixed up the results in my original post… its correct now. 
I will add this as a rule of thumb my compressor has a 80 % duty cycle . I would always let it catch up when blasting… since I removed the aftercooler I can blast between 80 and 100 psi and I don’t have to stop the compressor will stay ahead of me. I do still give it a break from time to time.
totally. also we should use the tank output temp considering the tank is a heat exchanger rejecting heat while its filling.
The tank is not at 200f , The mix air temperature of the tank will never be 200f . so you cant use 200f for the temperature of the air in the tank.
Also when using the ideal gas law to calculate air its is only a approximation because air is a mixture of gases and water vapour.
I firmly believe that short comings of the pre tank after cooler ( on a standard house hold compressor ) far exceeds any benefits.
I ve done it in the past but let us make a pro con list and see what it really ends up looking like .
the RH of the air being compressed is one of the main wild cards when using the ideal gas law
" the density of air decreases with increasing humidity."
More water vapour = less dense air
So winter vs summer numbers will be very different
@72Pony thanks for posting. I was writing a very long winded ( pun intend ) response now, i dont need to .
I am only concerned with the system operating in flow over time of use. So, that is not relevant.
I can’t speak to the science of it, but I deal with extremely large and long pneumatic systems in a steel mill. After cooling is critical and it is Amazing how many miles of pipe moisture will travel and build up to the point air valves are pouring water out when cycling and when it gets to freezing temps the nightmares that develop. We dealt with this for two years after our air dryer broke and it took a few months for the new one to show up and have it not be a broken unit.
In my home shop, I run a Eastwood scroll compressor, to 6 vertical runs of 3/4” steel pipe( so 3 upside down u runs) and have a drain valve at the bottom of each, to a standard filte, then a harbor freight air dryer. The pipes get a vast majority of the moisture and any blow by oil. I have nearly 0 moisture to be found after the air dryer. I say this because I have multiple automatic condensate drains as a precaution and I’ve never heard one go off. Only the one on the tank and the ac dryer but it’s not often on the dryer.
My shop is climate controlled though so humidity stays between 40-50% usually. Occasionally 55-60 during long rain stretches
I’m not very smart and I will not argue the science that folks have worked out on cycle times etc. I will say that I catch a metric s**tload of water after the cooler and before the tank. I have a fraction of water in the tank that I used to. My Motorguard stays bone dry and the desiccant beads stay blue for a very long time, ( as opposed to a day in Oklahoma). If this is causing problems with my bought used compressor, I haven’t noticed. So for my usage, the after cooler brings enough benefit, I will accept the loss of efficiency.
But y’all are truly some smart folks! 
One thing to think about if you put the after cooler post tank it will do the exact same thing without the extra load on your compressor.
I say that because you are not getting all the moisture out before it goes into your tank. It doesn’t matter in you have a tablespoon or a gallon of moisture the inside of your tank is still wet.
Then if you can’t tell a difference in cycle times you are probably getting a massive amount of blow by before installing a after cooler.
First off, please understand that I am coming from a position of ignorance. Not arguing, just trying to squeeze all this into my brain, ( it’s rather clogged with hops, barley and bong resin). But if my objective is dry air and my air is SIGNIFICANTLY drier, with hardly any water making it to the tank, it would seem that I have met the objective, unnecessary wear and stress on the compressor aside. Also, if the aftercooler works by virtue of dropping the air temp from 300 to 90 to get the water to condense out, it would seem that, placing the aftercooler after the tank would not be dropping the temp at all, (ambient being 90 degrees. So, again, break out the crayons and tell me what I am missing.