A/C intercooling
#41
TECH Junkie
iTrader: (4)
what if you dont have ice? What if you get to the track and you forgot to pick some up? What if the track is out? What if you wanna race someone in Mexico? Do you tell them to pull over at the gas station so you can get some ice? I have this odd feeling about doing things that are extra steps or extra trouble. If you already have ac on the car, an inter chiller adds how much weight? 30lbs? 50lbs? But you have it ALL THE TIME. the ac doesn’t kill but maybe 5hp down low. As soon as your foot is to the floor, basically the ac cuts off. You lose nothing. If you have a 13 second or 14 second car, you might see a negative difference, but I doubt because it kicks the clutch off past like 3500rpm, and or full throttle. If I had the $$, interchiller is what I’d do. Adding ice to make runs sounds cheesy to me. I laughed at people that used to ice their intake. That’s just silly to me.
What does icing the intake (it does work by the way) have to do with ice in a reservoir ?
#42
TECH Veteran
iTrader: (1)
But you don't have it all the time, It will warm that water faster than you could imagine, My 5 gallon bed mounted intercooler (Over 8 gallon total volume) goes from ambient (80*) to over 130 with one good hit. With the interchiller it still takes quite a bit of time to bring the temp according to what I found online. Plus the last thing I would want to is to run the AC for 10 minutes or more in the staging lanes trying to get the intercooler temp down to a level that will actually help. The what if you don't have ice argument is lame, That's like saying what if you forgot to get fuel and the track didn't have any lol. If you stop at a gas station/grocery store they are going to have plenty of ice. If you're not smart enough to remember to pick some up you don't belong behind the wheel of a fast car.
What does icing the intake (it does work by the way) have to do with ice in a reservoir ?
What does icing the intake (it does work by the way) have to do with ice in a reservoir ?
it’s not that i can’t remember to pick up ice, it’s just another hassle I wouldn’t want to deal with. I don’t want to remember to fool with that. Regardless of any opinion, the interchiller is a far superior choice. It’s odd you’d think it would slow the car down, you should contact dodge and tell them they made a mistake by doing that with the demon. Let them know that ice is better. Funny thing is that’s one of the fastest production cars, doesn’t seem to slow it down by having the ac on.
#43
TECH Junkie
iTrader: (4)
i relate the icing an intake to using ice in an intercooler. It’s silliness. Extra trouble. If your iat rises that much, something isn’t right. Mine may rise 20 degrees with my air to air and it comes right back down.
it’s not that i can’t remember to pick up ice, it’s just another hassle I wouldn’t want to deal with. I don’t want to remember to fool with that. Regardless of any opinion, the interchiller is a far superior choice. It’s odd you’d think it would slow the car down, you should contact dodge and tell them they made a mistake by doing that with the demon. Let them know that ice is better. Funny thing is that’s one of the fastest production cars, doesn’t seem to slow it down by having the ac on.
it’s not that i can’t remember to pick up ice, it’s just another hassle I wouldn’t want to deal with. I don’t want to remember to fool with that. Regardless of any opinion, the interchiller is a far superior choice. It’s odd you’d think it would slow the car down, you should contact dodge and tell them they made a mistake by doing that with the demon. Let them know that ice is better. Funny thing is that’s one of the fastest production cars, doesn’t seem to slow it down by having the ac on.
Tell me what will make more power... A heat soaked engine with an intercooler full of cool water or cool engine with ice cold water?
By the way, Watch some serious drag races like no prep and such and see how many are running AC units versus ice or dry ice, I've haven't seen a single ac compressor on any of them.
#44
There is math that can be done to figure out this argument.
How many BTUs can a car AC compressor put out? 5,000 BTUs maybe? How many BTUs does it take to lower 5 gallons of 90* water to 45 degrees?
How many BTUs can a car AC compressor put out? 5,000 BTUs maybe? How many BTUs does it take to lower 5 gallons of 90* water to 45 degrees?
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The BallSS (08-02-2022)
#46
TECH Apprentice
Definitely following along as well. I'd love to do this some day. I will probably need something like this AND meth to keep things safe here in AZ. Dealing with 110 temps all summer with no e85 and only 91 octane available will be a challenge.
#49
8 Second Club
iTrader: (13)
#50
#51
TECH Senior Member
iTrader: (17)
it easier to "maintain" cold than it is to ask for it instantly. always having the intercooler brick cooled is much more efficient than having 90* intake air and 90* intercooler brick, going WOT and then flooding the brick with cooled water. the hot air is going to win. these chiller kits use an expansion valve, once the fluid is cold the demand for refrigerant drops and valve closes. youd be better off targeting a certain air temp and letting the pwm ramp up or down the coolant flow to meet it.
chiller doesnt do any better of a job than icing the tank for a 1/4 mile run, if your intake temps jump up 50* on a pull then its going to do the same exact thing with the chiller - given the storage, pump, etc are all the same. mine could be a whole lot better set up, but form was more important than fuction.
this is shearer fab A2W hi ram intercooler, 10gal reservoir, cwa400 (on manual pwm controller), about 25' of 16an hoses front to back, not sure which turbo but old log -cleanest one i could find. probably older 92/110 turbo. with this set up, the IATs are about 20* higher than the chiller coolant temp. ex- IAT of 59*, chiller temp is around 40*
a clip of a log on mine, all pulls done in a 3 minute window, light blue top row is intake temp ....
temp start at 59*>104* 35-125mph ,
next pull 68*>122* 80-135
next 81*>122*, 80-125
84*>111* 78-115
then (not shown) takes a little less than 5 minutes to get intake temps back down to about 60*
chiller doesnt do any better of a job than icing the tank for a 1/4 mile run, if your intake temps jump up 50* on a pull then its going to do the same exact thing with the chiller - given the storage, pump, etc are all the same. mine could be a whole lot better set up, but form was more important than fuction.
this is shearer fab A2W hi ram intercooler, 10gal reservoir, cwa400 (on manual pwm controller), about 25' of 16an hoses front to back, not sure which turbo but old log -cleanest one i could find. probably older 92/110 turbo. with this set up, the IATs are about 20* higher than the chiller coolant temp. ex- IAT of 59*, chiller temp is around 40*
a clip of a log on mine, all pulls done in a 3 minute window, light blue top row is intake temp ....
temp start at 59*>104* 35-125mph ,
next pull 68*>122* 80-135
next 81*>122*, 80-125
84*>111* 78-115
then (not shown) takes a little less than 5 minutes to get intake temps back down to about 60*
I agree with you that thermal mass is a thing and it is more beneficial to your immediate IAT to have it pre-chilled. But you don't really need it at the beginning of the pull...its the back half of the track that suffers if you've used all of your heatsink/thermal reserve in the first half of the track when you probably weren't knock limited anyway. I want the chilling effort ramping in harder, but later, so that you keep below the knock threshold when temps start building. Of course you can't do this with manual PWM control unless you want to turn the **** while you drive lol. I used similar load-dependent control with the CWA400 as my primary water pump and was able to manage ECT better than the stock cooling system, all without a thermostat.
I think your temp rise is more than it should be during a pull. I see charge temp performance pretty close to that from mid-range A2A intercoolers on builds with similar mods. With a bit of plumbing reconfiguration, some insulation and maybe a variable pump speed controller...you could likely cut those temps down by 30 degrees or more.
#52
TECH Fanatic
Thread Starter
I am told the the BMW water pump has a PWM input to control the flow. Gotta look into that.
No reason why the compressor and water pump can't be controlled by closed loop setup. Another cool arduino project.
#53
TECH Senior Member
iTrader: (17)
This is on line with what I'm thinking about. Evaporator in tank.
Everything in my car is PWMd based on what driving mode the car is in. I like your idea of increasing the flow at top of the track. In my car, along with turning the compressor off, I can see increasing flow based on MPH, in drag mode, or closed loop with the IATs.
I am told the the BMW water pump has a PWM input to control the flow. Gotta look into that.
No reason why the compressor and water pump can't be controlled by closed loop setup. Another cool arduino project.
Everything in my car is PWMd based on what driving mode the car is in. I like your idea of increasing the flow at top of the track. In my car, along with turning the compressor off, I can see increasing flow based on MPH, in drag mode, or closed loop with the IATs.
I am told the the BMW water pump has a PWM input to control the flow. Gotta look into that.
No reason why the compressor and water pump can't be controlled by closed loop setup. Another cool arduino project.
#54
TECH Fanatic
Thread Starter
#55
1BTU = energy to raise the temperature of 1 pound (pint) of water 1 degree F. 5 gallons = 40 pints (pounds), * 45 degrees F = 1,800 BTU. But AC is rated in BTU/Hour, so the question is how quickly do you want to chill that water. If you want to chill it in 5 minutes, then that would be 21,600 BTU/hour to do it in 5 minutes.
That's way more than your "guess" at capacity for automotive AC systems. Good thing you were way off on that estimate. Most modern (R134 or newer) automobile AC systems (compressor, evaporator, condenser) operate at between 18,000 BTU/hr and 24,000 BTU/hr (aka 1.5 to 2 ton). Dual evaporator units may be slightly larger than that.
So that goal is not too far out of reach for an average car AC system, if you don't have refrigerant flowing to the evaporator in the HVAC system, and only use the refrigerant to cool the intercooler water.
That may not happen at idle, and the heat load into the condenser (and into the radiator, engine coolant, etc) would be pretty high while the water is chilling. Wich means you'll start the next run with the engine already operating at the high end of your target temperature range.
For the drag strip, ice (with salt if you want it even colder) is a better choice.
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Jwooky (03-04-2022)
#56
For comparison, if you put a chill coil like this one in a cooler or box shaped tank, put a block of ice in the middle and added salt and water to fill the tank, the brine in the tank would be at 0°F, how cool the solution in the pipes would be would depend on the flow rate and the material of the tubing.
A run that would bring your hypthetical 5 gallons of working fluid from 45°F to 90°F would put 1800 BTU into the tank, melting 12.5 pounds of ice. Assuming you started with more than 12.5 pounds, the fluid in the tank/cooler would still be at 0°F (or 32°F if you didn't put any salt in the tank). The temperature of your working fluid that you pump through the coils and through the intercooler would always depend on the heat transfer in the coil in the cooler, but if you had enough tubing in the cooler tank, you could maintain the temperature of the fluid entering the intercooler at close to the tank temperature. If you wanted to keep the intercooler core cool, you could PWM based on a coolant loop temp sensor at the outlet from the intercooler core, running low flow untill the temp starts rising, and going to full flow as soon as the temp increases.
A run that would bring your hypthetical 5 gallons of working fluid from 45°F to 90°F would put 1800 BTU into the tank, melting 12.5 pounds of ice. Assuming you started with more than 12.5 pounds, the fluid in the tank/cooler would still be at 0°F (or 32°F if you didn't put any salt in the tank). The temperature of your working fluid that you pump through the coils and through the intercooler would always depend on the heat transfer in the coil in the cooler, but if you had enough tubing in the cooler tank, you could maintain the temperature of the fluid entering the intercooler at close to the tank temperature. If you wanted to keep the intercooler core cool, you could PWM based on a coolant loop temp sensor at the outlet from the intercooler core, running low flow untill the temp starts rising, and going to full flow as soon as the temp increases.
#57
TECH Apprentice
Suppose I should have elaborated on the idea more. I've always had it in my mind that the evaporator needs to be inside the reservoir, not simply elsewhere in the loop. So when it is in recovery following a pull, it doesn't just work on removing heat from the small volume that is being pushed through the chiller brick - its working as hard as possible on the bulk of the intercooler water in the tank itself. Not only that, but if you slow pump speed down...it doesn't pick up 'parasitic' heat from the loop as well as trying to cool the IATs when not needed. Then upon some input, like TPS for example, you'd ramp the pump speed in accordingly to flood the IC with cold fluid. Granted in your case with the chiller external to the tank, you have to cycle the fluid to get the reservoir volume chilled. But with the evaporator in the tank this would be possible. Three6GMC actually did the tank-enclosed evaporator and had some awesome results. Fixed pump speed though I believe. This is his tank build.