air air intercooler
Into the water and sent through a cooler or soe sort of radiator mounted externally to cool it. Just like a radiator, but for your intake system. Todds right, the proper size tank shouldnt have problems keeping the temps where you neeed it. If you are really going to be pushing it hard like at a track, drop some ice in the tank
ok but how does the water cooler suck out heat faster than it's put in? doesn't the cooling unit need to be pretty big to do this? If it can be that big, why wouldn't you just run A/A ?
I mean, the advantage of water is it takes a lot of heat to load it up with heat. But that also means it takes a lot of cool to unload the heat. The water cooling unit needs to be at least as efficient as the aftercooler itself to dissapate the heat put into the water, right? Otherwise, you have a steady temp rise of the water.
To be clear - i don't build or design turbo systems, I am not a physicist, and I don't doubt that A/W systems can work great in practice.
What I want to understand is the"steady-state" effectiveness of an A/W system. To me, it seems that eventually you're going to heat soak the thing. If you're at WOT for 30 minutes on a dyno, with no moving air, you'd obviously heat soak the thing. (and your engines cooling system, for that matter).
Working backwards from that, it seems that there is some combination of track conditions and load conditions such that you'll eventually heat soak. So when you say a/W sytems that are well designed don't heat soak, are you really saying "for any possible track environment", or "for typical track environments" ? What are the qualifiers on the statement?
When you watch F1 coverage they tell you what the on-throttle percentage is for a given circuit - many of them are 70% or better. If you're at WOT and boosting 70% of the time, you're putting a huge amount of heat into that water, right? Seems to me you'd need a tremendous amount of water cooler effectiveness to not heat soak in those conditions.
I mean, the advantage of water is it takes a lot of heat to load it up with heat. But that also means it takes a lot of cool to unload the heat. The water cooling unit needs to be at least as efficient as the aftercooler itself to dissapate the heat put into the water, right? Otherwise, you have a steady temp rise of the water.
To be clear - i don't build or design turbo systems, I am not a physicist, and I don't doubt that A/W systems can work great in practice.
What I want to understand is the"steady-state" effectiveness of an A/W system. To me, it seems that eventually you're going to heat soak the thing. If you're at WOT for 30 minutes on a dyno, with no moving air, you'd obviously heat soak the thing. (and your engines cooling system, for that matter).
Working backwards from that, it seems that there is some combination of track conditions and load conditions such that you'll eventually heat soak. So when you say a/W sytems that are well designed don't heat soak, are you really saying "for any possible track environment", or "for typical track environments" ? What are the qualifiers on the statement?
When you watch F1 coverage they tell you what the on-throttle percentage is for a given circuit - many of them are 70% or better. If you're at WOT and boosting 70% of the time, you're putting a huge amount of heat into that water, right? Seems to me you'd need a tremendous amount of water cooler effectiveness to not heat soak in those conditions.
Matt,
You are thinking too much. Keep it simple. The water is being coolled all the time. 100% of the time. In situations (like braking) the intercooler is also acting like a heat exchanger to cool the water.
At least in my 130 miles at Mid Ohio, the system was able to remove the heat as fast as the intercooler could absorb it. That said the system was designed for 400hp and the car was only making 275hp.
Todd
You are thinking too much. Keep it simple. The water is being coolled all the time. 100% of the time. In situations (like braking) the intercooler is also acting like a heat exchanger to cool the water.
At least in my 130 miles at Mid Ohio, the system was able to remove the heat as fast as the intercooler could absorb it. That said the system was designed for 400hp and the car was only making 275hp.
Todd
Matt, a couple things... the heat transfer between water and aluminum is 14 times that of air and aluminum. So, the intercooler transfers heat to the water pretty efficiently. On the radiator side, the water transfers the heat to the aluminum radiator pretty efficiently resulting in the aluminum radiator getting hot. This creates a larger heat gradient (best for more efficient heat transfer) than an A/A system where the radiator/intercooler does not become as hot.
Also realize that the turbo is pumping heat into the system for far shorter periods of time than the system is radiating the heat out to the atmosphere.
Also realize that the turbo is pumping heat into the system for far shorter periods of time than the system is radiating the heat out to the atmosphere.
Matt, one of the advantages of A/W, is that due to the high specific heat capacity of water, a small(er) core can be used as the intercooler element resulting in less pressure drop between the turbocharger outlet and the intake valve. Once the water is "loaded" with heat, you have the luxury of using as large a radiator, or multiple radiators if you like to get rid of that heat without adversely affecting the efficiency of the intercoolerMatt wrote:ok but how does the water cooler suck out heat faster than it's put in? doesn't the cooling unit need to be pretty big to do this? If it can be that big, why wouldn't you just run A/A ?
I mean, the advantage of water is it takes a lot of heat to load it up with heat. But that also means it takes a lot of cool to unload the heat. The water cooling unit needs to be at least as efficient as the aftercooler itself to dissapate the heat put into the water, right? Otherwise, you have a steady temp rise of the water.
To be clear - i don't build or design turbo systems, I am not a physicist, and I don't doubt that A/W systems can work great in practice.
What I want to understand is the"steady-state" effectiveness of an A/W system. To me, it seems that eventually you're going to heat soak the thing. If you're at WOT for 30 minutes on a dyno, with no moving air, you'd obviously heat soak the thing. (and your engines cooling system, for that matter).
Working backwards from that, it seems that there is some combination of track conditions and load conditions such that you'll eventually heat soak. So when you say a/W sytems that are well designed don't heat soak, are you really saying "for any possible track environment", or "for typical track environments" ? What are the qualifiers on the statement?
When you watch F1 coverage they tell you what the on-throttle percentage is for a given circuit - many of them are 70% or better. If you're at WOT and boosting 70% of the time, you're putting a huge amount of heat into that water, right? Seems to me you'd need a tremendous amount of water cooler effectiveness to not heat soak in those conditions.
In an A/A system, a larger intercooler core must be used to compensate for the lower specific heat capacity of air. This larger intercooler results in a larger pressure drop between the turbocharger outlet and the intake valve, as well as greater heat build up in the turbo. The advantages of A/A is low cost, reliability and light weight.
In formula 1, where weight is everything, using an A/A intercooler is no brainer because of the available supply of high speed air (200mph+) to cool the intercooler core. Remember, intercooler efficiency is a function of heat rejection and heat rejection is a function of air flow.
M635CSi wrote:Matt, one of the advantages of A/W, is that due to the high specific heat capacity of water, a small(er) core can be used as the intercooler element resulting in less pressure drop between the turbocharger outlet and the intake valve. Once the water is "loaded" with heat, you have the luxury of using as large a radiator, or multiple radiators if you like to get rid of that heat without adversely affecting the efficiency of the intercoolerMatt wrote:ok but how does the water cooler suck out heat faster than it's put in? doesn't the cooling unit need to be pretty big to do this? If it can be that big, why wouldn't you just run A/A ?
I mean, the advantage of water is it takes a lot of heat to load it up with heat. But that also means it takes a lot of cool to unload the heat. The water cooling unit needs to be at least as efficient as the aftercooler itself to dissapate the heat put into the water, right? Otherwise, you have a steady temp rise of the water.
To be clear - i don't build or design turbo systems, I am not a physicist, and I don't doubt that A/W systems can work great in practice.
What I want to understand is the"steady-state" effectiveness of an A/W system. To me, it seems that eventually you're going to heat soak the thing. If you're at WOT for 30 minutes on a dyno, with no moving air, you'd obviously heat soak the thing. (and your engines cooling system, for that matter).
Working backwards from that, it seems that there is some combination of track conditions and load conditions such that you'll eventually heat soak. So when you say a/W sytems that are well designed don't heat soak, are you really saying "for any possible track environment", or "for typical track environments" ? What are the qualifiers on the statement?
When you watch F1 coverage they tell you what the on-throttle percentage is for a given circuit - many of them are 70% or better. If you're at WOT and boosting 70% of the time, you're putting a huge amount of heat into that water, right? Seems to me you'd need a tremendous amount of water cooler effectiveness to not heat soak in those conditions.
In an A/A system, a larger intercooler core must be used to compensate for the lower specific heat capacity of air. This larger intercooler results in a larger pressure drop between the turbocharger outlet and the intake valve, as well as greater heat build up in the turbo (to compensate for intercooler pressure drop). The advantages of A/A is low cost, reliability and light weight.
In formula 1, where weight is everything, using an A/A intercooler is no brainer because of the available supply of high speed air (200mph+) to cool the intercooler core. Remember, intercooler efficiency is a function of heat rejection and heat rejection is a function of air flow.
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Bill in MN
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rundatrack
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Over in sweden they get 600+ rwhp outta stock internal m20'sBill in MN wrote:The thing can't be all that radical. Looking through his list of mods it states that he's using a stock head gasket and a b34 motor with stock internals.
Nice car and nice work,though.
I dont know how but I know they do...so I guess "radical" is relative
gol10dr1 wrote:how tall is that intercooler? it doesn't look like the majority of it gets a whole lot of direct air exposure............
r
There is a lot of air that rushes the front of your car, so even if it isn't getting direct exposure, it is still seeing a lot of air. Look at your radiator. Lot of parts are blocking it, but air is still able to rush through all the holes, slits, and cracks in the front of your car.
With an intake temp of about 15-20 degrees celsius, my charge temp gets to about 35-40 with my water injection turned off. With water injection I'm seeing about 32-38 degrees.
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rundatrack
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