i possibly do. ZisLuv, do you think there is risk of hydrolock if you drive through water deep enough to flood the air box? how wet can the air box get?do you think the high volume air box after market systems are more vulnerable to flood water conditions than oem air box?have i got this right? air intake circuit; airbox to turbo air suction side to turbo air pressure side to intercooler to plenum. seems like a long way for the water to travel 200ml from the air box probably wouldn't wet all of the inside of the piping.
You just need to reread whats already been written and have a think about it. 200ml is just an imaginary volume to demonstrate the difference RPMS and combustion temps make in terms of hydrolocking an engine.
Thanks for the unwanted Chemistry lesson, however> the subject being discussed was "Hydrolocking" or to be more accurate "Hydraulicing", which is the act of a piston trying to compress a liquid (in this case water)inside a cylinder. It can't, and won't, succeed, but it does happen, regardless of whether you're a Science Graduate or not. It does break engines, as any Motor Engineer will tell you. Your theory about steam coming out of a turbo exhaust fan, is valid, but not relavent in this instance. Cheers
Glad I could teach you something And the thread you happen to be posting in and commenting on was in regards to this statement: Hence my discussion on steam is both valid and relevant as it explains why the above is the case, which you and Ben originally disagreed with.
You obviously have some different understanding of the > term "Hydrolocking/Hydraulicing". I'm not sure what that might be, as you have not elaborated that information. Using your "imaginary" 200ml theory , what RPM does the engine need to achieve if the volume of water is, lets say 2-3 litres?(This amount of water can easily be ingested, if driving into a deep puddle.)
A slight tangent here.....>> But how high is the airbox from the ground? How high is the door opening from the ground? How high is the ECU in relation to the door opening? If the water is so deep that you are worried about imersing your intake then spare a thought for all the other items that require air to live. How about the breather hole on the gearbox? Any serious off roader will tell you that you need to water proof (or fit extensions) to the breathers on the diffs and gearboxes to prevent water from being sucked in (thermal shock causes an inrush of air as the hot item is imersed in cold water). My simple solution is not to drive through deep water, and by that I mean water deeper then about 10". My car is worth too much to me to risk it.
ok, i need to start again. and i would like to get it right. 1, i am toying with the idea of installing a twin pop system, are they relatively lower than the oem system? at the point of opening. 2 hydraulic lock / hydrolock i have considered to mean the same thing in this discussion, and that is the entrapment of water in the combustion chamber,locking the engine..bulk modulus of air is different to water. 3 a z is what? less than 100mm of the road at the front bar. that is not deep enough to come in the door. but is deep enough to create a bow wave as you drive through the water. 4 i do not know how much water can be sucked in before you are likely to get problems, but, don't you think that a z is somewhat vulnerable to this scenario.
You are perfectly correct in your logic and concerns. Yes, a Zed is more vunerable under these conditions than most other vehicles, simply because of the low placement of the air intake. For this reason it would be advisable to avoid potentialy deep water situations, if at all possible. Making sure that the under body plastic covers are intact, and secure, will help to some extent, but they won't stop the water that enters via the grill. Perhaps a small deflector, placed in front of the aircleaner, might be some added precaution, but it would not want to restrict airflow to the radiator, or you will have a different problem. All the scientific explanations, whilst interesting, were in relation to an entirely different situation, and didn't really apply to the questions that you raised. That happens on here sometimes, because people are anxious to help, and may mis-read or misunderstand the query.
The front of your zed.....>> Should be higher then 100mm, your air intake shoud definately be much higher. The only member of this forum who I am aware of having experienced this problem had it caused by a car coming the other way at a much higher speed. It was the bow wave of the other car that caused the problem, although driving through any deep standing water probably isn't a good idea. As far as dual intakes go.... that is an old picture, and they have since been raised up by about 60 to 100mm, they definatly protrude lower then the stock intake, which actually draws its air from just in front of the wheel arches on either side.
Only injesting 80mL increases CR up to 10.5:1 which at high boost would make the engine go bang clunk then nothing as it would hydrolock. At high rpm a shitload more water would be injested then at lower rpm as the suction effect at the filters would be much greater at high rpm due to the significantly higher CFM flow rate.
As Wykked says, there was a Z in WA which hydrauliced through a 4WD created bow wave. There is also an NA in the Z Shop at the moment which suffered the same problem when the owner drove into deep standing water.
Good point I think this would depend on the situation as to if this makes it better or worse. With something like a bow wave like the WA incident, I think the filter would actually block the majority of water, with the filter getting instantly soaked and letting water through. Now water is in the system but the bow wave has passed so there is no further water coming in. Also unless completely submerged air would still be passing into the filter at a faster rate than water. So I think even though there is a lot more suction, proportionately there is more air volume to water than you would get at low speeds. This would make it easier to vapourise. This is just talking out of my ass though, as there are so many factors happening there I dont have a clue what would really happen. I imagine the only way to tell for sure would be some experimentation. If the filter was completely submerged then youd be stuffed regardless Im sure.
Agreed, but even more so! Chewy, I assume that calc. refers to even spreading of the 80mL across all cylinders? That will not be the case, as if just a small amount of the ingested water hangs together or reforms (which water tends to like to do) instead of breaking up, then it will be sucked into the next available cylinder on the induction cycle, and it's instant banana time for the conrod. :sick: Af few other general comments - no-one has mentioned in this post (or I haven't seen it), but combustion compressions are FAR FAR higher than static compressions - yes, you have in the order of 10:1 or 150 psi when the piston squeezes the inducted mixture, but as soon as it detonates, the combustion pressure skyrockets up to many thousands of PSI - it is theoretically possible to recombine vapours such as water and petrol into solids, even if only in small areas. Top fuellers constantly run on the edge of hydrolocking with just the massive amount of fuel that is being pumped in, especially at lower revs, where burn is less efficient. Also, just because the water that may make it into the combustion chamber turns to steam, it doesn't change its mass, or volume of solids. Whatever water makes it into a commbustion chamber will still increase the effective compression ratio by some amount whether it is steam or liquid. The rapidly vibrating water molecules will take up some of the volume that the fuel/air mixture would normally use, so the end result is a much higher effective compression ratio, higher combustion pressure, and much more resistance to compression, leading to a greater risk of busted pistons and bent conrods. Nathan, running a car through a water puddle at higher revs will probably cause more damage, as the engine is running at a much higher volumetric efficiency that at lower revs - especially a turbo car. This does two things. Firstly, it will attempt to suck in more water due to the higher volumetric efficiency, and secondly, its combustion pressure will be far greater at high revs/high boost (more fuel, more air, bigger squeeze), leading to much greater probability of 'hydrolocking'. An engine running at much lower revs gets less cylinder filling and less fuel, leaving more 'safety margin' for water molecules to be present inside the combustion chamber without necessarily causing damage.
gotta disagree on some points If water is changed into steam, its compressible. There is no way it increases the effective compression ratio the same as liquid water because water isnt compressible. Gas can be happily compressed to many thousands of psi but liquid cant. Your right, enough steam can be enough to cause high load on the rods but not failure as surely as liquid. As to the higher combustion pressures, as I said before, as long as the water present is heated above 373 degrees (where it takes 3200psi to compress to liquid) it cannot be compressed back to liquid form at any pressure, its not possible. Fuel is different. As for the last part, thats where Im uncertain. I dont know if in real life how much more water will be sucked in the intake from a passing wave. I just have a feeling that the filter will act as a limiting factor depsite the extra suction as more air than water will be sucked in if not fully submerged. Try half dipping a straw into a drink so it has room to suck in air. When you suck harder you just get a lot more air rather than a lot more water. If this is so then the higher temps from more revs will allow greater volumes of fluid to pass safely through the engine. I guess the whole thing depends on how much more water can be sucked in at high revs against how much more water can be vaporised at that point. At low revs however, even sucking in a small amount of water I would see doing damage, however high revs if a small amount entered it wouldnt.
Like you, I have to disagree on some points of yours. Turning liquid water into steam does not create or destroy any particles. All it does is to increase the volume for a given pressure that the water as steam likes to occupy. Raise the pressure, and the given volume decreases (PV=nRT). Raise the temperature, and the given volume will try to increase, depending on the suprounding pressure. Sure, steam is compressible, but it's only compressible to the level which it becomes liquid again, or with variations of temperature and pressure, to the equivalent volume, even if it is still in a gaseous state. From your discussion, it appears that you are assuming that steam is infinitaly compressible, or at least compressible past the state where it would normally turn back into liquid. This is a false assumption. The long and the short of that is, if water gets into a combustion chamber, it will occupy volume, no matter whether it is a liquid or a gas. Occupying volume in the combustion chamber increases the effective compression ratio, and if there is enough H20 in the combustion chamber, it will destroy the piston and/or rod, irrespective of whether it exists as steam or liquid. Your statement "There is no way it increases the effective compression ratio the same as liquid water because water isnt compressible. " is false on two levels; firstly, itm is incorrect unless you are referring to volumes of steam vs water, not mass. Secondly, water is compressible (you can compress water just by melting ice, as the ice takes up 4% more volume that liquid water at 0C), but it takes more pressure than most pistons and rods can exert before failure to compress by any significant amounts. Also, your statement "it cannot be compressed back to liquid form at any pressure, its not possible. " is false. Boltzmanns equation and empirical testing shows that just about anything can be forced to change state by varying the pressure. A simple example is your car's cooling system. Leave the radiator cap off, at (let's assume just water as cooling medium here for simplicity) 100C it will start to boil, ie change state froma solid to a gas. Put a 15 PSI cap on the radiator, and the water will return to a liquid state and stay that way up to eg 120C, just by changing the pressure. Increase the pressure, and you force a change of state. It's not impossible. It's physics. Car air conditioners work on the same principle. Increase the pressure to form a liquid, cool it down, decrease the pressure to allow it to become a gas, at which time it becomes much colder as a result, recompress it into a liquid, cool it down again, etc. All just by using pressure. Your last point - don't forget that air is far more compressible than water, so only a fraction of the ingested mixture has to be water to cause damage once the pressure starts to rise. Vaporising the water once it's in the combustion chamber doesn't change the minimum volume that it likes to take up, whether it's steam or liquid. It will still cause problems. As I said, at low revs, you typically have much less volumetric efficiency, so more water can be ingested before compression pressures reach a level where something will break. Think for example about operating at low revs, eg at 50 or less VE. That's 50% less air taken in to the combustion chamber, so it will need to be compressed twice as much before causing the same static compression level (which obviously won't happen), and it will result in far less combustion pressure, so there's 'room' for a bit of water to hang around and not want to compress. Also, the conrod will be subjected to peak pressures over a longer time as the revs are less, so there is at least a possibility that you will be operating in the elastic phase of the metal of the rod, not the plastic phase, and no long term damage will be done. Lucky last, at much lower revs, the engine is simply likely to stop without permanent damage, as the hydraulic lock of one or more cylinders will outweigh the lower inertia of the slower rotating mass and stop it without bending anything. It would have to be at fairly low revs though, but it's still feasible.
