991 GT2RS
01-02-2018, 02:29 AM
#4546
Engineer hat on: average tap water is 150-400 parts per million total dissolved solids. If you boil a pot of water too long on a stove you’ll see those solids as the white stuff that’s left behind when the pot is dry. With time they build up to form a hard scale which is both unsightly and cuts heat transfer. Boil you pot dry 100 times and with very hard water and in theory you could have 4% less pot volume left due to a nice, thick, rock hard coating on the bottom.
Your intercooler is functioning to evaporate water very much like that pot, so using hard tap water will cause it to scale up over time. That would be bad, because unfortunately the chemicals you’d normally use to attack and remove the scale will also attack the aluminum, so once it’s on it’s likely to stay. Of course it will happen slowly: 400 ppm is a pretty small number, so while you might visually be able to see some white stuff on the intercooler after running a couple tanks through it probably won’t hurt anything. If you want to keep it clean, on the other hand, distilled water is one ppm, so 150-400 times less white crap.
Personally while I might use tap or bottled water once or twice if I was in a pinch (ideally “purified” bottled water, never “mineral water”) I’d try to stick with distilled water, as the white stuff would probably bug me. Not to mention a future owner if I ever sold.
01-02-2018, 05:09 AM
#4547
Rennlist Member
01-02-2018, 06:58 AM
#4548
I'd want to only use distilled water for sure.
just wondering how often it will need topped up, given it's literally not on tap!
i know the claims, but wonder about reality and also the effect on the 700hp if tank is dry.
just wondering how often it will need topped up, given it's literally not on tap!
i know the claims, but wonder about reality and also the effect on the 700hp if tank is dry.
01-02-2018, 08:06 AM
#4549
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Rennlist Member
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The legendary aerospace developed Secan intercooler which Porsche commissioned for the 993GT2 EVO cars was capable of maintaining IAT at within 15 DegC of ambient (the 993 turbo Motors had a much lower critical IAT as the heads got hot and broke) the Secan intercooler was massive and the units they are using on the 991GT2RS have a much smaller surface area. Obviously there is better overall tech in the new car to assist in keeping the IATs down, turbo efficiency, new expansion manifold but tracking extensively at full load in 30+degC ambient will have that water sprayer squirting away - will be interesting to hear real life experiences, as AP said they were amazed at how much better the I/C sprayer worked in practice compared to theory !
01-02-2018, 08:44 AM
#4550
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Re: Distilled water - Guess Porsche will have a product we can buy to make sure we have some "rated" water ready after spirited driving and/or track days. Otherwise you might hear: "Sorry that your GT2 engine expired coming out of Eau Rouge. Unfortunately Porsche HQ has declined the warranty claim citing that IC tank was partially filled with non-rated water."
When will the US cars start arriving for customers? First UK cars will be here early February, my car is estimated to arrive week 8 (w/c 19 Feb). Very very excited.
When will the US cars start arriving for customers? First UK cars will be here early February, my car is estimated to arrive week 8 (w/c 19 Feb). Very very excited.
01-02-2018, 01:25 PM
#4551
The critical IAT is about 55 degC over this the ECU tables will start adjusting timing and boost to try to stop it from rising further this reduces the power from the optimum 700PS, I wouldn't imagine the power will drop lower than around 640PS without sprayer..
The legendary aerospace developed Secan intercooler which Porsche commissioned for the 993GT2 EVO cars was capable of maintaining IAT at within 15 DegC of ambient (the 993 turbo Motors had a much lower critical IAT as the heads got hot and broke) the Secan intercooler was massive and the units they are using on the 991GT2RS have a much smaller surface area. Obviously there is better overall tech in the new car to assist in keeping the IATs down, turbo efficiency, new expansion manifold but tracking extensively at full load in 30+degC ambient will have that water sprayer squirting away - will be interesting to hear real life experiences, as AP said they were amazed at how much better the I/C sprayer worked in practice compared to theory !
The legendary aerospace developed Secan intercooler which Porsche commissioned for the 993GT2 EVO cars was capable of maintaining IAT at within 15 DegC of ambient (the 993 turbo Motors had a much lower critical IAT as the heads got hot and broke) the Secan intercooler was massive and the units they are using on the 991GT2RS have a much smaller surface area. Obviously there is better overall tech in the new car to assist in keeping the IATs down, turbo efficiency, new expansion manifold but tracking extensively at full load in 30+degC ambient will have that water sprayer squirting away - will be interesting to hear real life experiences, as AP said they were amazed at how much better the I/C sprayer worked in practice compared to theory !
will stock up on some when the time comes, and report back on how it goes!
01-02-2018, 01:27 PM
#4552
Re: Distilled water - Guess Porsche will have a product we can buy to make sure we have some "rated" water ready after spirited driving and/or track days. Otherwise you might hear: "Sorry that your GT2 engine expired coming out of Eau Rouge. Unfortunately Porsche HQ has declined the warranty claim citing that IC tank was partially filled with non-rated water."
When will the US cars start arriving for customers? First UK cars will be here early February, my car is estimated to arrive week 8 (w/c 19 Feb). Very very excited.
When will the US cars start arriving for customers? First UK cars will be here early February, my car is estimated to arrive week 8 (w/c 19 Feb). Very very excited.
Last edited by Footsoldier; 01-02-2018 at 04:19 PM.
01-02-2018, 02:28 PM
#4553
I have to finalise the spec on my car in the next few weeks.
I have heard all UK cars coming in the next 3 months or so, may not be any more,
What have you gone for?
I am currently split black or white, red indoors? definitely upgrade pack
I have heard all UK cars coming in the next 3 months or so, may not be any more,
What have you gone for?
I am currently split black or white, red indoors? definitely upgrade pack
01-02-2018, 02:58 PM
#4554
Rennlist Member
Originally Posted by Petevb
Engineer hat on: average tap water is 150-400 parts per million total dissolved solids. If you boil a pot of water too long on a stove you’ll see those solids as the white stuff that’s left behind when the pot is dry. With time they build up to form a hard scale which is both unsightly and cuts heat transfer. Boil you pot dry 100 times and with very hard water and in theory you could have 4% less pot volume left due to a nice, thick, rock hard coating on the bottom.
Your intercooler is functioning to evaporate water very much like that pot, so using hard tap water will cause it to scale up over time. That would be bad, because unfortunately the chemicals you’d normally use to attack and remove the scale will also attack the aluminum, so once it’s on it’s likely to stay. Of course it will happen slowly: 400 ppm is a pretty small number, so while you might visually be able to see some white stuff on the intercooler after running a couple tanks through it probably won’t hurt anything. If you want to keep it clean, on the other hand, distilled water is one ppm, so 150-400 times less white crap.
Personally while I might use tap or bottled water once or twice if I was in a pinch (ideally “purified” bottled water, never “mineral water”) I’d try to stick with distilled water, as the white stuff would probably bug me. Not to mention a future owner if I ever sold.
Your intercooler is functioning to evaporate water very much like that pot, so using hard tap water will cause it to scale up over time. That would be bad, because unfortunately the chemicals you’d normally use to attack and remove the scale will also attack the aluminum, so once it’s on it’s likely to stay. Of course it will happen slowly: 400 ppm is a pretty small number, so while you might visually be able to see some white stuff on the intercooler after running a couple tanks through it probably won’t hurt anything. If you want to keep it clean, on the other hand, distilled water is one ppm, so 150-400 times less white crap.
Personally while I might use tap or bottled water once or twice if I was in a pinch (ideally “purified” bottled water, never “mineral water”) I’d try to stick with distilled water, as the white stuff would probably bug me. Not to mention a future owner if I ever sold.
01-02-2018, 03:51 PM
#4555
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Rennlist Member
Rennlist Member
01-02-2018, 04:18 PM
#4556
Engineer hat on: average tap water is 150-400 parts per million total dissolved solids. If you boil a pot of water too long on a stove you’ll see those solids as the white stuff that’s left behind when the pot is dry. With time they build up to form a hard scale which is both unsightly and cuts heat transfer. Boil you pot dry 100 times and with very hard water and in theory you could have 4% less pot volume left due to a nice, thick, rock hard coating on the bottom.
Your intercooler is functioning to evaporate water very much like that pot, so using hard tap water will cause it to scale up over time. That would be bad, because unfortunately the chemicals you’d normally use to attack and remove the scale will also attack the aluminum, so once it’s on it’s likely to stay. Of course it will happen slowly: 400 ppm is a pretty small number, so while you might visually be able to see some white stuff on the intercooler after running a couple tanks through it probably won’t hurt anything. If you want to keep it clean, on the other hand, distilled water is one ppm, so 150-400 times less white crap.
Personally while I might use tap or bottled water once or twice if I was in a pinch (ideally “purified” bottled water, never “mineral water”) I’d try to stick with distilled water, as the white stuff would probably bug me. Not to mention a future owner if I ever sold.
01-02-2018, 05:03 PM
#4557
The specific heat of water is also almost double that of ethanol, while the heat of vaporization 2.7 times higher. In other words you'd need to carry and pump well over twice the weight of alcohol to remove the same amount of heat, so water's the better choice even before we consider flammability. Water's actually very tough to beat as a heat transfer fluid.
01-02-2018, 05:23 PM
#4558
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Rennlist Member
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The specific heat of water is also almost double that of ethanol, while the heat of vaporization 2.7 times higher. In other words you'd need to carry and pump well over twice the weight of alcohol to remove the same amount of heat, so water's the better choice even before we consider flammability. Water's actually very tough to beat as a heat transfer fluid.
01-02-2018, 05:23 PM
#4559
7th Gear
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I have been a regular reader of Rennlist but not posted until now.
I have a GT2RS coming in March I believe.
I plan a few European trips and to use the car as Porsche intended. I am happy that the residual values of the cars is strong would I still be buying the car if they weren’t, you bettcha I would.
The time the car set around the ‘ring’ is simply stunning, to be 10sec quicker than the 918 is unreal and those laps that BOTH drivers did within a few tenths of each other is testament to how strong this car is.
I look forward to meeting up with other owners to hear some of their ‘experiences’ near misses or whatever
I have a GT2RS coming in March I believe.
I plan a few European trips and to use the car as Porsche intended. I am happy that the residual values of the cars is strong would I still be buying the car if they weren’t, you bettcha I would.
The time the car set around the ‘ring’ is simply stunning, to be 10sec quicker than the 918 is unreal and those laps that BOTH drivers did within a few tenths of each other is testament to how strong this car is.
I look forward to meeting up with other owners to hear some of their ‘experiences’ near misses or whatever
01-02-2018, 05:56 PM
#4560
Drifting
If money is no object, (based on what i have read, it's not for some of you), if you do not want the solvents in distilled water, do some reading on Honeywell (DuPont (Vertrel) , 3M has some as well) and their alternatives to water. Solstice, Genesolv and theirs a few more. I have worked w/ a particular solvent of theirs in the past. I'm having a brain malfunctioning moment (can't recall the name). I'm not sure in their thermal cooling efficiency (+/-) over water in being used in a combustion engine, as that has never crossed my mind at $40 bucks a gallon (however likely that Porsche will charge that price for distilled water anyways, and some of you can it eat that with your cake too)
Last edited by F1CrazyDriver; 01-02-2018 at 07:21 PM.