Essential cooling mods?

[UFO CTR]

the angle of the hood with respect to the windshield is also critical. one more thing, if those streamers are that easily moved my the the engine fan, then it should also be easily move by the outside atmospheric wind conditions. To be accurate, this test should be conducted in a closed environment, such as a wind tunnel. then we will really see if the engine fan is really moving those streamers around that much.

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[Gansan]

so is there a local blockage that's creating this high pressure zone (i.e., a perpendicular wall)? I think it should work like a toilet (for lack of examples), right?...once you hit the flush, water from the tank rushes straight down the 4" drain, and thus dragging the waste water from the bowl down with the moving flush water? it should work the same, no? fast air moving above the hood, should drag air out from top of hood?

what you're saying right now is air actually blow in from the top of the hood; is that what you're saying?

"Louvers effect is when fast air passes over an opening thats filled with air that is not traveling as fast as the outside air. This causes a small vacuum at the opening sucking out the slower moving air." This is what I'm saying, and this does not occur at the trailing edge of the hood, regardless how small the suction/vacuum is?

If I grab my garden hose and shot a stream of water horizontally at my hood, you are telling me the water will not deflect upwards? Shouldn't water (similar to air) deflect perpendicular to the incoming angle?

Just a comment on thinking of this as a stream of water from a hose hitting the hood. It's not the same thing because the flow we are talking about is of being submerged in a sea of air. It's the interaction of all the layers of air that forms the behavior. You can use water to simulate it but you need to submerge the entire car in a tank of water and flow the water across the car at just the right speed. (You can calculate it based on the density and viscosity of the fluid so that water flows in approximately the same way as air.)

Regarding the toilet flush, the way most toilets flush is by initiating a siphon effect. Enough water gets going down the passageway that the weight and inertia of it sucks the rest of the water out, similar to a siphon.

 

[Harlaquin]

How could it not have a solution? What is so unique about the R that it can't be remedied?

I think what he is saying is that sure there are things. but you will spend 4 or 5 k to do it properly and end up with a result that is nowhere near the money spent. I fell into this trap myself. I bought a intake and intercooler and exhaust and front pipe and all the stuff that helps the engine breath and get air in and out and all i ended up with is a bunch of stuff to sell losing my butt on depreciation and shipping. Byt the time you buy the car and spend god awful amounts to mod it you could have just bought a track car that didn't have issues. BUT.. the overheating... I know several people who track theirs and they don't mention overheating. Like the other guy said if you dont drive it wide open for 40 mins straight there isn't an issue. I tracked my heat for a bit before and after mods and honestly felt like a fool for spending almost 4 k to save about 10 degrees.

Bottom line these companies are here to sell parts and make money. They are gonna tell you anything you want to hear to sell the parts period.

The other issue is buying one part does little. you really need all parts at same time. Throwing an intercooler into a car with no improved air in or out is sort of pointless. you need the whole ball of wax forit to all work properly. intake, front, down, intercooler, exhaust. or you end up with choke points and actually decrease performance as a friend of mine found out.

 

[Harlaquin]

Part of the "problem" is that not everyone has the "problem" so it isn't so easy to come up with a solution to an inconsistent issue.
I think the other is that only a small percentage of these cars end up on the track - and even less on the track under the conditions ripe for creating the problem.
Yes - we bought the car based on those amazing track times it was laying down around the world ---- but marketing is marketing!
(Never forget it is based on a family friendly 4-door hatchback)

In a way it is sad that so many feel it necessary to drop thousands and thousands of dollar and countless hours of work to try to fix something.
If we buy a race-biased car that we want to occasionally take to the track we should be spending thousands and thousands of dollars and countless hours on stuff to make it lighter, faster and handle better.

I love my R but if it shuts down into limp mode during a great track session - I suspect it will quickly become my ex-R.

To the post about that hood that is, "...in the works."
Prove it actually works and I'll buy it.
P-R-O-V-E it works!
I can't believe how much stuff has been thrown at this with not one company actually providing hard data to prove their solution has actual results.
I mean reading under hood temps shouldn't be that hard to do, right?
$100,000 on R&D but can't afford a few extra temp sensors for the data logger?

This, there are countless videos showing that Intakes do absolutely nothing. if anything they show the OEM intake is best. Yet these companies keep claiming gains form their products. Even in the Hondata tuning software you can check the box for intake but it says checking this box does nothing. LOL intakes dont do anything except make the car go woosh louder. The intercooler videos some will show oh look our intercooler is cooler. awesome great but where is the proof it actually does anything for performance or gains other then you say it does?

 

[UFO CTR]

Just a comment on thinking of this as a stream of water from a hose hitting the hood. It's not the same thing because the flow we are talking about is of being submerged in a sea of air. It's the interaction of all the layers of air that forms the behavior. You can use water to simulate it but you need to submerge the entire car in a tank of water and flow the water across the car at just the right speed. (You can calculate it based on the density and viscosity of the fluid so that water flows in approximately the same way as air.)

Regarding the toilet flush, the way most toilets flush is by initiating a siphon effect. Enough water gets going down the passageway that the weight and inertia of it sucks the rest of the water out, similar to a siphon.

what i was trying to convey was the angle between the hood and windshield should have something to say about the way fluid bounces of the windshield..the water hose analogy is just to say the water will result in a scatter pattern as it initially hits the windshield, but much of the water should deflect away perpendicular to the windshield (similar to momentum and billiard balls bouncing off each other),

 

[boosted180sx]

This, there are countless videos showing that Intakes do absolutely nothing. if anything they show the OEM intake is best. Yet these companies keep claiming gains form their products. Even in the Hondata tuning software you can check the box for intake but it says checking this box does nothing. LOL intakes dont do anything except make the car go woosh louder. The intercooler videos some will show oh look our intercooler is cooler. awesome great but where is the proof it actually does anything for performance or gains other then you say it does?

checking the box does nothing? That's actually a good thing considering the box is what you'd check to calibrate your maf and not to change your tuning parameters. Not needing to change anything means that the fuel trims will be just like stock without having to adjust the maf table.
There are all sorts of ways to manipulate like your product has gains without lying. Comparing a companies intake after a cooled down run vs a heatsoaked oem intake would show gains without them technically "lying".

As for the intercooler, If an intercooler is producing cooler air then yeah ... there are gains or consistent power. You might not be happy with the "gains" you see but I mean, i'm sure everyone here knows that cooler air entering the engine is better for engine performance.

Regarding the mods you mentioned like bolt ons, those are something most of us would do whether or not we bought a "track car" that didn't have issues so i don't really count that towards it. It's just part of the modding culture that we are in. Whether i bought a ctr or spent 20k more and bought a M2/supra, the mods i would have done will be the same.

The overheating on the other hand is a problem. Really hard to figure out what the problem is when everyones driving limit is not the same and live in different climates and driving on different tracks.

 

[lawl]

Honestly, if you are hardcore tracking, get a lightweight N/A car. less on consumables (tires, pads, rotors, all that stuff adds up FAST), less overheating, less headache.

I just think of it as a quick car I drive on the street but could spank a lot of cars on the track for a few laps if i really need to. But I don't need to. Nice to have it when I need it, but probably won't. I've probably veered into hard parker territory here, but my track instructor days are well behind me and I'm okay with that.

That said, if someone figures out how to fix it, that would be great! but here in socal there were days where every single turbo car on track was overheating, no matter how much they spent on cooling. For the cost of cooling mods for THIS particular car (and no guaranteed results, even) you could buy a miata and flog it around the track all day.

 

[Florence_NC]

Thought of something else...

Not that it can't also cause an issue of increased wear.. but what about simply over driving the water pump through using a smaller pulley?

If you raise flow rate... more heat exchanger will occur both out of the engine into the coolant and from the coolant to atmosphere via the radiator. I know it's not as sexy as bigger radiators or hoods... but it it's sort of one if those things that can't not work (thats a double negative right there).

Q=mc(Th-Tc) (can't make dots sorry...)

Raise mass flow rate and the delta T will collapse... and we're trying to get the Th down. Assume Q stays the same because the engine is still making the same heat.

BTW... since c is the specific heat capacity... going 30/70 or 40/60 would also effect the delta T as you're changing the heat capacity of the fluid by changing the ratio. (shrug) The math works.

While this formula is correct, as a full cooling system analysis, this formula alone doesn't properly convey the problem.

First thing: Where are you trying to apply the above equation? What is Q, is it the heat extracted from the engine (Q.e), or the heat rejected to the air passing across the radiator (Q.r)? Both terms exist in the problem:

Heat rejected by engine into cooling system fluid:
Q.e = mdot.e*Cp.coolant*(Th.e-Tc.e) ,
Where: mdot.e = mass rate flow of coolant system fluid

Heat rejected by cooling system fluid into air across radiator:
Q.r = mdot.r*Cp.air*(Th.r-Tc.r)
Where: mdot.r = mass flow rate of air across radiator
,
And in fact, when looking at the problem as a long-term steady state condition, both terms are equal:

Qc = Qr

Thus you can set the equations equal:

mdot.e(Th.e-Tc.e)Cp.coolant = mdot.r(Th.r-Tc.r)Cp.air

So now look at that equation and think about things again. Cp values are fixed, and mdot.r is fixed. So which Th are you suggesting should be the goal to lower, and does that look like it actually accomplishes the goal of improved cooling?

EDIT NOTE: I made a bunch of mistakes when I first posted this. So if you saw the earlier one before corrections, please ignore it. Also thermodynamics is not really my strong suit, if I made another mistake, please point it out.

PS: I saw in another post that you were in the Navy. You didn't specify where you used these equations, but typically they are used in naval applications to reject heat into seawater or the atmosphere. Both the ocean and the atmosphere are essentially infinitely-large heat sinks. They have infinite vloume and can absorb any amount of heat and never change their temperature. Neither of those is true in a car, the air available to cool the system is very finite, and thus the heat capacity is finite as well.

 

[charleswrivers]

While this formula is correct, as a full cooling system analysis, this formula alone doesn't properly convey the problem.

First thing: Where are you trying to apply the above equation? What is Q, is it the heat extracted from the engine (Q.e), or the heat rejected to the air passing across the radiator (Q.r)? Both terms exist in the problem:

Heat rejected by engine into cooling system fluid:
Q.e = mdot.e*Cp.coolant*(Th.e-Tc.e) ,
Where: mdot.e = mass rate flow of coolant system fluid

Heat rejected by cooling system fluid into air across radiator:
Q.r = mdot.r*Cp.air*(Th.r-Tc.r)
Where: mdot.r = mass flow rate of air across radiator
,
And in fact, when looking at the problem as a long-term steady state condition, both terms are equal:

Qc = Qr

Thus you can set the equations equal:

mdot.e(Th.e-Tc.e)Cp.coolant = mdot.r(Th.r-Tc.r)Cp.air

So now look at that equation and think about things again. Cp values are fixed, and mdot.r is fixed. So which Th are you suggesting should be the goal to lower, and does that look like it actually accomplishes the goal of improved cooling?

EDIT NOTE: I made a bunch of mistakes when I first posted this. So if you saw the earlier one before corrections, please ignore it. Also thermodynamics is not really my strong suit, if I made another mistake, please point it out.

PS: I saw in another post that you were in the Navy. You didn't specify where you used these equations, but typically they are used in naval applications to reject heat into seawater or the atmosphere. Both the ocean and the atmosphere are essentially infinitely-large heat sinks. They have infinite vloume and can absorb any amount of heat and never change their temperature. Neither of those is true in a car, the air available to cool the system is very finite, and thus the heat capacity is finite as well.

A good explanation… specific heat capacity would be a variable if you change the heat capacity of your coolant. This can be done by using a higher ratio of water to antifreeze. Mass flow rate can be raised by use of either a different pump (though, honestly... I doubt there's an aftermarket option) or raising the speed of the current one by using a overdrive pulley.

They're all bits and pieces of a larger system. Use of different grills... fans... radiators... caps to change system pressure... coolant to water percentages... and if you can swing it... coolant flow itself... they all play in. Still I figured things as cheap as adding a little more water vs the coolant and raising the flowrate of the pump might yield some untried benefits at a low cost, assuming of course the water pump can take it. I figure changing a whole radiator whose surface is mostly blocked would be a few steps down the line from trying to free up flow from the grill or improving it from a fan.

I was just throwing out ideas as people are spending thousands of dollars and are not achieving their desired results. Some of the best solutions are the cheap/simple ones.

 

[Florence_NC]

A good explanation… specific heat capacity would be a variable if you change the heat capacity of your coolant. This can be done by using a higher ratio of water to antifreeze. Mass flow rate can be raised by use of either a different pump (though, honestly... I doubt there's an aftermarket option) or raising the speed of the current one by using a overdrive pulley.

They're all bits and pieces of a larger system. Use of different grills... fans... radiators... caps to change system pressure... coolant to water percentages... and if you can swing it... coolant flow itself... they all play in. Still I figured things as cheap as adding a little more water vs the coolant and raising the flowrate of the pump might yield some untried benefits at a low cost, assuming of course the water pump can take it. I figure changing a whole radiator whose surface is mostly blocked would be a few steps down the line from trying to free up flow from the grill or improving it from a fan.

I was just throwing out ideas as people are spending thousands of dollars and are not achieving their desired results. Some of the best solutions are the cheap/simple ones.

Cp of the coolant can be raised by a small amount. Mdot of the coolant can be raised by theoretically any amount. But the system limitation is the Th of the air passing across the radiator. Th of the radiator air must always be less than Th of the engine coolant. If the coolant is not hotter than the radiator air, then no heat is transferred. So it doesn't much matter what you do on the coolant side of the equation, none of that gets around the limitations on the air flow side of the equation. Unless you do something to increase air flow across the radiator(s), nothing else is going to to do more than barely chip away at the problem.

 

[Florence_NC]

so is there a local blockage that's creating this high pressure zone (i.e., a perpendicular wall)? I think it should work like a toilet (for lack of examples), right?...once you hit the flush, water from the tank rushes straight down the 4" drain, and thus dragging the waste water from the bowl down with the moving flush water? it should work the same, no? fast air moving above the hood, should drag air out from top of hood?

what you're saying right now is air actually blow in from the top of the hood; is that what you're saying?

The high pressure zone at the cowl is created due to Bernoulli's Principle, and has nothing to do with any blockage or deflection of the air. The cross section of the flow region over the cowl increases, causing the velocity to decrease. By Bernoulli, when velocity decreases, pressure increases, thus the slower air over the cowl has a higher pressure.

Note that the diagram of the wing lift you posted is also an example of Bernoulli. The slower moving air under the wing has the relative higher pressure, and the faster moving air on top has the relative lower pressure, thus creating a push/pull effect to generate lift.

And your view of the toilet is missing the actual physics. The waste is not "dragged" down the pipe. Use of the term 'drag" implies that what is moving the waste is due to a force of attraction, like a magnet can be used to drag a piece of steel. While there is a force of attraction and friction due to viscosity that creates somewhat of a "dragging" effect, the primary force at work to move the waste is pressure differential. The flushing action causes a low pressure area under the waste, and the higher pressure atmospheric pressure "pushes" the waste down the pipe.

The water hose analogy is also not in line with the physics, but someone else already correctly pointed out the issue with that one.

 

[charleswrivers]

Cp of the coolant can be raised by a small amount. Mdot of the coolant can be raised by theoretically any amount. But the system limitation is the Th of the air passing across the radiator. Th of the radiator air must always be less than Th of the engine coolant. If the coolant is not hotter than the radiator air, then no heat is transferred. So it doesn't much matter what you do on the coolant side of the equation, none of that gets around the limitations on the air flow side of the equation. Unless you do something to increase air flow across the radiator(s), nothing else is going to to do more than barely chip away at the problem.

True… but if we're talking about 200F+ coolant... ambient air temperature force-fed by a fan is going to always be far-less than coolant temperature, though giant aftermarket intercoolers aren't going to help. I see how you can make improvements by allowing more air to pass across the radiator... but you're never going to have ambient temperature higher than coolant temperature. You can fight to improve convection though by passing more and more air across a larger portion of the radiator. There's a lot of room for improvement in the existing setup.

I would always go with a grill before a radiator. It 1) is cheaper and 2) would make the existing radiator more effective. Changing to a larger radiator with a stock grill would seem to be pretty ineffective and you wouldn't be getting your money's worth out of the current radiator. The grills in pretty much all modern cars are so blocked up to improve aerodynamics at the expense of outright cooling that it'd be one of the first things to go after. Our Civics have the giant plastic 'bar'. My Odyssey has fake vents even... most of it's grill looks functional but is not. There's a lot of cars that have grills that a great deal is totally non-functional and is for aesthetics alone. Anything to improve warm up and improve aerodynamics improve fuel economy for CAFE goals... but would hurt cooling when it's needed.

I think specific heat capacity and thermal conductivity is a larger benefit than many might think. While the difference in c between 50/50 and 30/70 may only get you about a ~10% improvement in capacity… the conductivity improvements to pull heat both out of the engine and let it get rejected back to atmosphere at the radiator amounts to around 20%. It also costs a buck or so of distilled to do.

 

[UFO CTR]

The high pressure zone at the cowl is created due to Bernoulli's Principle, and has nothing to do with any blockage or deflection of the air. The cross section of the flow region over the cowl increases, causing the velocity to decrease. By Bernoulli, when velocity decreases, pressure increases, thus the slower air over the cowl has a higher pressure.

Note that the diagram of the wing lift you posted is also an example of Bernoulli. The slower moving air under the wing has the relative higher pressure, and the faster moving air on top has the relative lower pressure, thus creating a push/pull effect to generate lift.

And your view of the toilet is missing the actual physics. The waste is not "dragged" down the pipe. Use of the term 'drag" implies that what is moving the waste is due to a force of attraction, like a magnet can be used to drag a piece of steel. While there is a force of attraction and friction due to viscosity that creates somewhat of a "dragging" effect, the primary force at work to move the waste is pressure differential. The flushing action causes a low pressure area under the waste, and the higher pressure atmospheric pressure "pushes" the waste down the pipe.

The water hose analogy is also not in line with the physics, but someone else already correctly pointed out the issue with that one.

yes, I also notice since faster air is on top of the wing, the lines on top of wing should actually be depicted closer together, and thus the diagram is incorrect, but the caption is correct...and yes, per bernoulli's initial must equal final, thus all mass must be conserved. And yes, high pressure does want to move towards low pressure, just like higher electrical potential wants to move towards lower, and water wants to flow down hill.

the water hose analogy is to say that water should bounce off perpendicular to the windshield. yes, there are a rushing gush of water molecules trailing behind the initial once to case a "scatter" pattern, but by and large, much of the water should deflect perpendicular to the windshield; otherwise, we be all F-ed when we wash our cars correct??

 

[Type-JZ]

They use to make a custom one for the grp downpipes, not sure if you can buy the blanket separately without buying the downpipe

you can. i have it. takes about 3-4 weeks to make.

 

[Florence_NC]

True… but if we're talking about 200F+ coolant... ambient air temperature force-fed by a fan is going to always be far-less than coolant temperature, though giant aftermarket intercoolers aren't going to help. I see how you can make improvements by allowing more air to pass across the radiator... but you're never going to have ambient temperature higher than coolant temperature. You can fight to improve convection though by passing more and more air across a larger portion of the radiator. There's a lot of room for improvement in the existing setup.

What you are not considering here is that the Th.air (I called it Th.r earlier, Th.air makes it easier to follow) is not fixed at the ambient air temp. The air enters the radiator matrix at ambient, but as it passes over the fins, it continually heats up. By the time it gets to the rear of the matrix it is far hotter, approaching coolant temp. THIS is the point that creates the system limit. This is why all these thicker radiators are not helping very much, adding extra fins and tubes that are positioned in the already heated air don't do much.

Also as the coolant passes through the tubes, it cools as it crosses the radiator, thus it approached ambient temp. Both of theses things close up the dT term (dT = Th-Tc), which in turn drops the final Q.air term. Thus your only option, with a fixed ambient temp, is to either raise Th.coolant or increase mdot.air. Raising Th.coolant is the exact opposite of what you said earlier would help the problem, that is why I went into all of this detail to explain why that wouldn't actually help.

I would always go with a grill before a radiator. It 1) is cheaper and 2) would make the existing radiator more effective. Changing to a larger radiator with a stock grill would seem to be pretty ineffective and you wouldn't be getting your money's worth out of the current radiator. The grills in pretty much all modern cars are so blocked up to improve aerodynamics at the expense of outright cooling that it'd be one of the first things to go after. Our Civics have the giant plastic 'bar'. My Odyssey has fake vents even... most of it's grill looks functional but is not. There's a lot of cars that have grills that a great deal is totally non-functional and is for aesthetics alone. Anything to improve warm up and improve aerodynamics improve fuel economy for CAFE goals... but would hurt cooling when it's needed.

This is exactly what I have said on other threads pertaining to this subject. I had "experts" argue with me.

I think specific heat capacity and thermal conductivity is a larger benefit than many might think. While the difference in c between 50/50 and 30/70 may only get you about a ~10% improvement in capacity… the conductivity improvements to pull heat both out of the engine and let it get rejected back to atmosphere at the radiator amounts to around 20%. It also costs a buck or so of distilled to do.

Again, the system limit is Th.air as it passes over the radiator and heats up. Conductivity improvements are worth only a fraction. An improvement in Cp of the coolant will allow the coolant temp to remain slightly higher as it passes through the radiator, which slightly helps the dT issue. But only slightly. A bigger mdot.air is the only significant solution to this issue.

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