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Post by nitro on May 30, 2013 12:33:06 GMT
Water injector before compressor? I often saw an injector (or two) before compressor on some drag bikes. I was always wondering what it is, may be that it was water injector. But does it gives really benefits? Thought water cools down the charged but (when it is already charged).
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Post by nomex on May 31, 2013 7:15:47 GMT
Properly placed injector before compressorwheel should cool the compressorhousing a bit. It might also seal the compressor wheel and make turbo more efficient. I would like to test if one injector before compressorwheel adds more boost without changing anything else at the same time. Will be seen...
There seems to be also a risk to corrupt the blades, if injector is badly positioned.
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Post by nomex on Jul 10, 2013 20:17:20 GMT
Well.. the fun lasted 2079km this summer. 1st conrod (Hayabusa) snapped for some reason. Turbo is ok, but atleast start, engine blocks, 1 conrod should be replaced. Tomorrow I will dissamble the whole motor. Intresting to see if there's some oiling problem or some other reason. Afterwards I have to say, that before last stint it did have a strange clonking sound. Actually I was about to change the startmotor, but not in this way
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bamihapper
Velociraptor
Posts: 36
Bikes: gsxr 750, katana gsxr 1100 turbo project
Reg: May 9, 2013 15:48:45 GMT
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Post by bamihapper on Jul 10, 2013 21:09:07 GMT
Ouch, and i was waiting for an update. Good luck with the rebuild.
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Post by nitro on Jul 11, 2013 13:52:36 GMT
Sorry, to hear mate. How much boost you drive the last km?
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Post by nomex on Jul 14, 2013 21:01:46 GMT
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Post by nitro on Jul 16, 2013 15:04:40 GMT
Uuups! Heard, always take new ones. But I didn´t :X Still keeps - knocking on wood.
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weegaz22
Oviraptor
Posts: 11
Reg: Aug 21, 2013 18:25:49 GMT
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Post by weegaz22 on Aug 24, 2013 7:39:32 GMT
Water injector before compressor? I often saw an injector (or two) before compressor on some drag bikes. I was always wondering what it is, may be that it was water injector. But does it gives really benefits? Thought water cools down the charged but (when it is already charged). If you inject before the compressor you will change/alter the compressor map(shifts slightly to the right iirc), say you run a small turbo, if you add pre compressor injection you will have still have all the throttle response and minimal lag but you will also get a slight increase in power at the end of the effeciency range because you are adding water before the compressor charge, when it enters the compressor housing the water gets turned to steam absorbing some of the latent heat in the charge, this stops the air charge getting as hot all over the range which in turn gives more power. if you inject after the compressor you aren't changing/affecting the turbo's map as all you are trying to do is now cool intake air after its already been compressed and heated up cons of it are you will get slightly more wear/damage on the compressor wheel if you don't properly atomize the charge, ie imagine a large water droplet hitting the edge of a blade that is spinning faster than the speed of sound, it will eventually end up looking like someones sandblasted your compressor wheel, but thats not really an issue here as most guys here are not looking to attempt to get 80k miles out of a turbo
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Deleted
Posts: 0
Reg: Apr 25, 2024 12:22:51 GMT
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Post by Deleted on Aug 24, 2013 12:23:05 GMT
ouch that's not pretty. steel conrod and tool steel pins time I think..
phil
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Post by nitro on Aug 26, 2013 9:05:01 GMT
Cheers, weegaz!
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Post by Devilman on Aug 27, 2013 8:08:32 GMT
Water injector before compressor? I often saw an injector (or two) before compressor on some drag bikes. I was always wondering what it is, may be that it was water injector. But does it gives really benefits? Thought water cools down the charged but (when it is already charged). If you inject before the compressor you will change/alter the compressor map(shifts slightly to the right iirc), say you run a small turbo, if you add pre compressor injection you will have still have all the throttle response and minimal lag but you will also get a slight increase in power at the end of the efficiency range because you are adding water before the compressor charge, when it enters the compressor housing the water gets turned to steam absorbing some of the latent heat in the charge, this stops the air charge getting as hot all over the range which in turn gives more power. if you inject after the compressor you aren't changing/affecting the turbo's map as all you are trying to do is now cool intake air after its already been compressed and heated up cons of it are you will get slightly more wear/damage on the compressor wheel if you don't properly atomize the charge, ie imagine a large water droplet hitting the edge of a blade that is spinning faster than the speed of sound, it will eventually end up looking like someones sandblasted your compressor wheel, but that's not really an issue here as most guys here are not looking to attempt to get 80k miles out of a turbo converted to steam? is that confirmed? seems highly unlikely that level of heat is generated, hell intake temps don't rise enough to suggest this is likely to happen? I can see the water / denser charge could improve the compressor efficiency slightly, but I have always been concerned about the incompressabilty (is that even a word? ) of water, you may just be robbing yourself of extra air you could be compressing into that space which is being taken up by incompressable water? Utimately the limiting factor for power is airflow, we can always force in extra water and fuel after the compressor, but anything that isn't air going through the compressor is just reducing the total airflow through the engine as far as I can tell, which should result in a net power-loss. It would sure be interesting to run several side-by-side comparisons on a dyno and monitor things like inlet temps, exhaust temps, boost pressures, fuel usage and air consumption aswell as the HP figures, as it may suggest that one setup is more efficient at making power, even if it makes slightly less total power.
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weegaz22
Oviraptor
Posts: 11
Reg: Aug 21, 2013 18:25:49 GMT
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Post by weegaz22 on Aug 27, 2013 19:09:28 GMT
If you inject before the compressor you will change/alter the compressor map(shifts slightly to the right iirc), say you run a small turbo, if you add pre compressor injection you will have still have all the throttle response and minimal lag but you will also get a slight increase in power at the end of the efficiency range because you are adding water before the compressor charge, when it enters the compressor housing the water gets turned to steam absorbing some of the latent heat in the charge, this stops the air charge getting as hot all over the range which in turn gives more power. if you inject after the compressor you aren't changing/affecting the turbo's map as all you are trying to do is now cool intake air after its already been compressed and heated up cons of it are you will get slightly more wear/damage on the compressor wheel if you don't properly atomize the charge, IE imagine a large water droplet hitting the edge of a blade that is spinning faster than the speed of sound, it will eventually end up looking like someones sandblasted your compressor wheel, but that's not really an issue here as most guys here are not looking to attempt to get 80k miles out of a turbo converted to steam? is that confirmed? seems highly unlikely that level of heat is generated, hell intake temps don't rise enough to suggest this is likely to happen? I can see the water / denser charge could improve the compressor efficiency slightly, but I have always been concerned about the incompressabilty (is that even a word? ) of water, you may just be robbing yourself of extra air you could be compressing into that space which is being taken up by incompressible water? Ultimately the limiting factor for power is airflow, we can always force in extra water and fuel after the compressor, but anything that isn't air going through the compressor is just reducing the total airflow through the engine as far as I can tell, which should result in a net power-loss. It would sure be interesting to run several side-by-side comparisons on a dyno and monitor things like inlet temps, exhaust temps, boost pressures, fuel usage and air consumption aswell as the HP figures, as it may suggest that one setup is more efficient at making power, even if it makes slightly less total power. On a street turbo bike it may not because that may depend on the size of your balls, It will depend on the turbo and the boost level used in reality, but i would imagine it hard to be able to keep the throttle open for prolonged full boost(unlike in a car which is a lot slower and heavier), for example with an outside air temp of 60f @ atmospheric pressure running a turbo @ 7psi would roughly have an outlet temp of 148F, running at 16 psi would be 234F @ 70% comp efficiency, so yes, there is enough heat to turn a tiny amount of water into steam, google "adiabatic processes" for some light reading in reality the amount of water you are atomizing into the motors intake is only a tiny amount per revolution, that will have a much greater affect of preventing intake temps rising too high in the first place than another few CC's of extremley heat laden air.
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Post by Devilman on Aug 27, 2013 21:25:00 GMT
converted to steam? is that confirmed? seems highly unlikely that level of heat is generated, hell intake temps don't rise enough to suggest this is likely to happen? I can see the water / denser charge could improve the compressor efficiency slightly, but I have always been concerned about the incompressabilty (is that even a word? ) of water, you may just be robbing yourself of extra air you could be compressing into that space which is being taken up by incompressible water? Ultimately the limiting factor for power is airflow, we can always force in extra water and fuel after the compressor, but anything that isn't air going through the compressor is just reducing the total airflow through the engine as far as I can tell, which should result in a net power-loss. It would sure be interesting to run several side-by-side comparisons on a dyno and monitor things like inlet temps, exhaust temps, boost pressures, fuel usage and air consumption aswell as the HP figures, as it may suggest that one setup is more efficient at making power, even if it makes slightly less total power. On a street turbo bike it may not because that may depend on the size of your balls, It will depend on the turbo and the boost level used in reality, but i would imagine it hard to be able to keep the throttle open for prolonged full boost(unlike in a car which is a lot slower and heavier), for example with an outside air temp of 60f @ atmospheric pressure running a turbo @ 7psi would roughly have an outlet temp of 148F, running at 16 psi would be 234F @ 70% comp efficiency, so yes, there is enough heat to turn a tiny amount of water into steam, google "adiabatic processes" for some light reading in reality the amount of water you are atomizing into the motors intake is only a tiny amount per revolution, that will have a much greater affect of preventing intake temps rising too high in the first place than another few CC's of extremley heat laden air. As you rightly said... on a street bike, with limited boost and never being able to keep the throttle pinned open for more than a few seconds, which unless I am mistaken, is very much the situation here and in 99% of "turbo bike" cases on this forum, thus I still feel its completely pointless and does nothing except to rob the turbo of more air it could instead be squeezing into the cylinders, reducing your power output.. And with regard to the last comment... you seem to think that its water before the compressor or nothing... you can shove the water injection in downstream of the compressor, still have the same cooling effect on the inlet charge and completely negate the issue of a few extra cc's of extremely heat-laden air", while actually adding a few extra cc's of air.. since THAT is utimately what gives us power. This is not a case of "one or the other", we can STILL have the same water injection cooling the inlet charge, but have MORE air, cus we are not wasting space inside the compressor housing with incompressible water... More air = More fuel = More bang = More power. I fail to see how shoving any amount of an incompressible substance through the compressor is going to aid the situation, if its something that can be crammed into the system downstream of the compressor, thereby not reducing the mass airflow through the system. But the real proof would come from side-by-side dyno runs, not people throwing around theory like its fact and saying that what may affect a dragster engine (or a car engine which can maintain high loads for far longer) would have any merit when used on a street bike, or even a drag bike tbh... Less than 10 seconds of full throttle, in a single 1/4mile run from start-up is highly unlikely to create the kind of heating effects required.
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weegaz22
Oviraptor
Posts: 11
Reg: Aug 21, 2013 18:25:49 GMT
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Post by weegaz22 on Aug 27, 2013 22:55:51 GMT
On a street turbo bike it may not because that may depend on the size of your balls, It will depend on the turbo and the boost level used in reality, but i would imagine it hard to be able to keep the throttle open for prolonged full boost(unlike in a car which is a lot slower and heavier), for example with an outside air temp of 60f @ atmospheric pressure running a turbo @ 7psi would roughly have an outlet temp of 148F, running at 16 psi would be 234F @ 70% comp efficiency, so yes, there is enough heat to turn a tiny amount of water into steam, google "adiabatic processes" for some light reading in reality the amount of water you are atomizing into the motors intake is only a tiny amount per revolution, that will have a much greater affect of preventing intake temps rising too high in the first place than another few CC's of extremley heat laden air. As you rightly said... on a street bike, with limited boost and never being able to keep the throttle pinned open for more than a few seconds, which unless I am mistaken, is very much the situation here and in 99% of "turbo bike" cases on this forum, thus I still feel its completely pointless and does nothing except to rob the turbo of more air it could instead be squeezing into the cylinders, reducing your power output.. And with regard to the last comment... you seem to think that its water before the compressor or nothing... you can shove the water injection in downstream of the compressor, still have the same cooling effect on the inlet charge and completely negate the issue of a few extra cc's of extremely heat-laden air", while actually adding a few extra cc's of air.. since THAT is utimately what gives us power. This is not a case of "one or the other", we can STILL have the same water injection cooling the inlet charge, but have MORE air, cus we are not wasting space inside the compressor housing with incompressible water... More air = More fuel = More bang = More power. I fail to see how shoving any amount of an incompressible substance through the compressor is going to aid the situation, if its something that can be crammed into the system downstream of the compressor, thereby not reducing the mass airflow through the system. But the real proof would come from side-by-side dyno runs, not people throwing around theory like its fact and saying that what may affect a dragster engine (or a car engine which can maintain high loads for far longer) would have any merit when used on a street bike, or even a drag bike tbh... Less than 10 seconds of full throttle, in a single 1/4mile run from start-up is highly unlikely to create the kind of heating effects required. I dont want to clog up the Op's build thread with a debate on water injection pre and post compressor, if you want to start a thread on it i'd be happy to contribute, but there's plenty of info out there with plenty of evidence/proof on how to get the best from pre comp injection works. and as for the "pre comp water injection or nothing" comment that is not what i meant, pre compressor WI setups are typically used inconjunction with WI thats further downstream (which also have less contact time with the air), the purpose is to prevent iAT getting to the example of 234f in 1st place, if you added pre comp WI the IAT's will be down to say 175f out comp housing as water is "boiled" off, then your WI downstream only has to cool 175F air instead of 234f, in short its more effective preventing it getting to 234f and then trying to cool it, i didnt mention anything about you should only run pre comp or nothing And are you forgetting that 1 third of H2O contains Oxygen?
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Post by Devilman on Aug 28, 2013 9:05:55 GMT
Fair point about clogging up his thread Would be interested to see the documented evidence that shows the gains from pre-compressor WI. I still have doubts (especially in a streetbike) that we could ever push inlet temps high enough to gain anything either, as we couldn't keep the throttle open that long And true H2O is 1 part oxygen but c'mon, we both know that's not the reason its used, the amounts are fractionally small, if we wanted to do that, we would use NO2 instead. That brings up an interesting point also... based upon the refrigeration effects of releasing a gas (or liquid) under pressure, I wonder how good small shots of NO2 are at cooling the inlet charge, compared to water? ... and what differences there may be in pre / post compressor usage. Perhaps something for another thread Apologies to nomex on clogging up your thread, and bad news about the conrod snapping, any hints as to the cause?
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