Methanol/water injection pre-turbo
- Thread starter tekdeus
- Start date
I've seen setups like this on *lots* of drag cars, however, there are tradeoffs. FYI, most of these cars run straight meth or alcohol, and don't have an IC at all.
Consider that your BOV will now spray the same mixture into your engine bay.
Also consider that 48:52 mixture may not ignite under 1 atmosphere of pressure... but what happens when it's pressurized inside the intake tract? Combustion conditions change dramatically with pressure...
Furthermore, while lots of drag teams may use this, they also don't care as much about reliability. We're talking about guys who have entire spare motors. Something as piddly as replacing an intake manifold between runs isn't even considered real wrenching.
Lastly, basic chemistry says that the amount of heat energy a substance can absorb doesn't change based on where it's injected. I'd be rather surprised if injecting this pre-turbo would actually lower intake temps. Actually, I wouldn't be surprised if it actually increased intake temps! If the evaporation soaks up enough heat to drop the intake charge to below ambient, the intercooler will instantly become an interheater. Even if it doesn't take it that far, intercoolers are more efficient the larger the temperature difference is, so you want the air to be the hottest as it goes into the IC. Extra cooling measures should be added after the IC, not before it.
Consider that your BOV will now spray the same mixture into your engine bay.
Also consider that 48:52 mixture may not ignite under 1 atmosphere of pressure... but what happens when it's pressurized inside the intake tract? Combustion conditions change dramatically with pressure...
Furthermore, while lots of drag teams may use this, they also don't care as much about reliability. We're talking about guys who have entire spare motors. Something as piddly as replacing an intake manifold between runs isn't even considered real wrenching.
Lastly, basic chemistry says that the amount of heat energy a substance can absorb doesn't change based on where it's injected. I'd be rather surprised if injecting this pre-turbo would actually lower intake temps. Actually, I wouldn't be surprised if it actually increased intake temps! If the evaporation soaks up enough heat to drop the intake charge to below ambient, the intercooler will instantly become an interheater. Even if it doesn't take it that far, intercoolers are more efficient the larger the temperature difference is, so you want the air to be the hottest as it goes into the IC. Extra cooling measures should be added after the IC, not before it.
One more thing... if you're going to mix your own, measure each separately, then mix in another container.
Putting a litre of water in a container, then adding meth until it measures 2L will *not* get you a 50:50 mix. If you pour a litre of meth into a litre of water and mix it, you'll get substantially less than 2 litres. It's like pouring sand into gravel - the water molecules are small enough to fit in between the meth molecules.
Putting a litre of water in a container, then adding meth until it measures 2L will *not* get you a 50:50 mix. If you pour a litre of meth into a litre of water and mix it, you'll get substantially less than 2 litres. It's like pouring sand into gravel - the water molecules are small enough to fit in between the meth molecules.
GrimJack;1351079 said:
It gets quite warm when mixed as well. Chemical reaction?
All these important things to know. You'd think the suppliers like AEM and Snow would inform their customers about this stuff, maybe put warning pamphlets in with their product?
Seems that a few people are doing this without any harm to the compressor. One of my local shops is having success with it.
I found this handy pre-turbo nozzle holder pictured below here http://www.howertonengineering.com/custom_work.html I'm contemplating tapping a 2nd line into my existing AEM meth kit and running a solenoid to a small pre-turbo nozzle with a hobbs switch set to 15psi, so that it is instant on/off, and full pressure by the time my AEM kit ramps up to 15psi. Not sure if I have enough pressure to do this, and not sure if any drips would come off when it shuts off.
My car makes 435hp at 21psi and almost 500hp at 25psi, so I'm feeling greedy and wondering if this mod will get me that 500hp on pump gas :evil2:
Found this write up here: http://www.alcoholinjectionsystems....-My-Water-Injection-Nozzles/article_info.html
1. Pre-Turbocharger/Centrifugal Injection
By placing the water methanol injection nozzle or nozzles pre-turbocharger or centrifugal supercharger and injecting a fine precise amount of water methanol into the air inlet of the compressor can have a dramatic positive effect on compressor efficiency (particularly with turbocharger systems and high boost centrifugal applications) while substantially lowering discharge temperatures at the source of compression. On 8-25 psi applications, users can expect to see a 70-160+ degree drop in compressor discharge temperatures. While reductions of 160-240+degree's can be had on 25-60+ psi high boost applications such as diesels.
How is this possible?
When water methanol is first injected, we're able to begin slightly cooling the incoming air entering the compressor. This air is already relatively cool in relation to the ambient temperature of the day as it has yet to be compressed and heated. Depending on the temperature of the day and how the air inlet is plumped and where the air is being drawn in from, the incoming air entering into the inlet of the compressor commonly ranges between 5-20 degree's above ambient. Only minor cooling of the air charge occurs at this stage before it enters into the compressor. More importantly, we are about to dramatically cool the air that is being compressed and heated within the turbocharger.
It's important to understand it is here that the heat is being generated.
A turbochargers impeller can spin at an astonishing speed between 100,000- 150,000 rpms. While centrifugal supercharger impellers spin between 40,000-65,000+ rpm. Between each pair of blades on an impeller exists a wedge shaped open space which the air fills in. As the impeller is spinning, this wedge shaped air pocket is subjected to tremendous centrifugal forces and is forced outward away from the center of the impeller to the outer edges. It is here where the air begins to stack up and compress against the compressor housing forming the heat as it makes it way into the scroll.
As the compressed air heats up, it tries to further expand, making it now more difficult for the heated compressed air to pass through and exit the compressor thereby lowering the compressor efficiency. In addition, this compressed air is taking up more space within the compressor limiting new incoming air from being processed. Furthermore, the hot compressed air exiting the turbocharger is less dense as it has been heated significantly. Therefore, containing less power producing oxygen while making the engine considerably more prone to detonation.
By cooling the air as it's being compressed within the turbocharger or centrifugal supercharger, the compressed air is now substantially cooler, more dense, taking less space and moves more efficiently through the compressor allowing us to pack and process more air through the turbocharger or centrifugal supercharger. This leads us to our second benefit. Improved compressor efficiency.
All of this results in improved compressor efficiency. Because of this improved efficiency the compressor does not have to work as hard to produce the same amount of boost as without the water methanol injection. In turn it raises the maximum mass air flow of the compressor. Thereby, making a smaller turbocharger or centrifugal supercharger now perform like a larger turbocharger or centrifugal supercharger with the addition of the water methanol injection.
Lastly, as already mentioned above, pre-compressor injection substantially lowers the discharge temperatures exiting the compressor. The engine is now less prone to detonation through this reduction in air charge temperatures. Furthermore, the use of an intercooler is dramatically reduced and in some applications no longer needed as it may not offer substantial further cooling effects in return for the pressure drop caused by it. Removal of the intercooler could now offer a further increase in boost pressure at the engine as well as compressor efficiency.
While all of this sounds very exciting. To do this properly requires proper sizing of the nozzles in relation to the compressor size and output. Additionally, the type fluid being used also effects the size of the water injection nozzle selected. When done properly, very little of the water methanol mist injected into the inlet of the compressor survives the process. Thereby, discharging a much cooler air charge with a relativity high humidity with very little or no water methanol droplets present.
When injecting water, we can quickly over saturate the air charge and have an excess of fluid discharging the compressor. Water has a much higher latent heat of vaporization, nearly double that of methanol, and does not flash (instantly evaporate) like that of methanol or other alcohols when injected into a hot air stream. Therefore, a smaller nozzle must be used when spraying pure water.
A better choice for pre-compressor injection is a greater concentration of methanol vs. water or pure methanol. Methanol instantly flashes (evaporating) as soon as it enters into a hot compressor and meets the heat within it. By using an alcohol, this dramatically reduces the amount of actual fluid exiting the compressor due to it‘s fast evaporation. Additionally, methanol offers much greater cooling effect then water. Furthermore, methanol is also less dense then water thereby having a softer impact on the impeller. The specific gravity of pure methanol is .792 @ 68° F compared to water which is 1.00 @ 64° F.
One major concern associated with pre-compressor injection is erosion of the impeller. This is only likely to occur when injecting solid stream of water at the impeller of a turbocharger or using an excessively large nozzle. Impeller erosion is highly unlikely with centrifugal supercharger as they spin at a considerably slower speed then turbochargers. Impeller erosion is of little concern with centrifugal superchargers.
2. Pre-Intercooler Injection
While pre-intercooler injection may at first seem like a logical approach. Thereby, combining the effects of water methanol injection within the air-to-air intercooler for an increased synergistic effect. It is not so. Matter of fact, it's the opposite. The cooling effects and benefits offered by the water methanol injection are less when injected here then in all other locations. Further, more other issues arise such as puddling which can form in the bottom of the intercooler. Additionally, pour atomization will occur as the fluid will accumulate in the individual air to air intercooler core walls of the intercooler forming larger droplets which will eventually break away resulting in pour atomization. We do not recommend pre-intercooler injection.
I found this handy pre-turbo nozzle holder pictured below here http://www.howertonengineering.com/custom_work.html I'm contemplating tapping a 2nd line into my existing AEM meth kit and running a solenoid to a small pre-turbo nozzle with a hobbs switch set to 15psi, so that it is instant on/off, and full pressure by the time my AEM kit ramps up to 15psi. Not sure if I have enough pressure to do this, and not sure if any drips would come off when it shuts off.
My car makes 435hp at 21psi and almost 500hp at 25psi, so I'm feeling greedy and wondering if this mod will get me that 500hp on pump gas :evil2:
Found this write up here: http://www.alcoholinjectionsystems....-My-Water-Injection-Nozzles/article_info.html
1. Pre-Turbocharger/Centrifugal Injection
By placing the water methanol injection nozzle or nozzles pre-turbocharger or centrifugal supercharger and injecting a fine precise amount of water methanol into the air inlet of the compressor can have a dramatic positive effect on compressor efficiency (particularly with turbocharger systems and high boost centrifugal applications) while substantially lowering discharge temperatures at the source of compression. On 8-25 psi applications, users can expect to see a 70-160+ degree drop in compressor discharge temperatures. While reductions of 160-240+degree's can be had on 25-60+ psi high boost applications such as diesels.
How is this possible?
When water methanol is first injected, we're able to begin slightly cooling the incoming air entering the compressor. This air is already relatively cool in relation to the ambient temperature of the day as it has yet to be compressed and heated. Depending on the temperature of the day and how the air inlet is plumped and where the air is being drawn in from, the incoming air entering into the inlet of the compressor commonly ranges between 5-20 degree's above ambient. Only minor cooling of the air charge occurs at this stage before it enters into the compressor. More importantly, we are about to dramatically cool the air that is being compressed and heated within the turbocharger.
It's important to understand it is here that the heat is being generated.
A turbochargers impeller can spin at an astonishing speed between 100,000- 150,000 rpms. While centrifugal supercharger impellers spin between 40,000-65,000+ rpm. Between each pair of blades on an impeller exists a wedge shaped open space which the air fills in. As the impeller is spinning, this wedge shaped air pocket is subjected to tremendous centrifugal forces and is forced outward away from the center of the impeller to the outer edges. It is here where the air begins to stack up and compress against the compressor housing forming the heat as it makes it way into the scroll.
As the compressed air heats up, it tries to further expand, making it now more difficult for the heated compressed air to pass through and exit the compressor thereby lowering the compressor efficiency. In addition, this compressed air is taking up more space within the compressor limiting new incoming air from being processed. Furthermore, the hot compressed air exiting the turbocharger is less dense as it has been heated significantly. Therefore, containing less power producing oxygen while making the engine considerably more prone to detonation.
By cooling the air as it's being compressed within the turbocharger or centrifugal supercharger, the compressed air is now substantially cooler, more dense, taking less space and moves more efficiently through the compressor allowing us to pack and process more air through the turbocharger or centrifugal supercharger. This leads us to our second benefit. Improved compressor efficiency.
All of this results in improved compressor efficiency. Because of this improved efficiency the compressor does not have to work as hard to produce the same amount of boost as without the water methanol injection. In turn it raises the maximum mass air flow of the compressor. Thereby, making a smaller turbocharger or centrifugal supercharger now perform like a larger turbocharger or centrifugal supercharger with the addition of the water methanol injection.
Lastly, as already mentioned above, pre-compressor injection substantially lowers the discharge temperatures exiting the compressor. The engine is now less prone to detonation through this reduction in air charge temperatures. Furthermore, the use of an intercooler is dramatically reduced and in some applications no longer needed as it may not offer substantial further cooling effects in return for the pressure drop caused by it. Removal of the intercooler could now offer a further increase in boost pressure at the engine as well as compressor efficiency.
While all of this sounds very exciting. To do this properly requires proper sizing of the nozzles in relation to the compressor size and output. Additionally, the type fluid being used also effects the size of the water injection nozzle selected. When done properly, very little of the water methanol mist injected into the inlet of the compressor survives the process. Thereby, discharging a much cooler air charge with a relativity high humidity with very little or no water methanol droplets present.
When injecting water, we can quickly over saturate the air charge and have an excess of fluid discharging the compressor. Water has a much higher latent heat of vaporization, nearly double that of methanol, and does not flash (instantly evaporate) like that of methanol or other alcohols when injected into a hot air stream. Therefore, a smaller nozzle must be used when spraying pure water.
A better choice for pre-compressor injection is a greater concentration of methanol vs. water or pure methanol. Methanol instantly flashes (evaporating) as soon as it enters into a hot compressor and meets the heat within it. By using an alcohol, this dramatically reduces the amount of actual fluid exiting the compressor due to it‘s fast evaporation. Additionally, methanol offers much greater cooling effect then water. Furthermore, methanol is also less dense then water thereby having a softer impact on the impeller. The specific gravity of pure methanol is .792 @ 68° F compared to water which is 1.00 @ 64° F.
One major concern associated with pre-compressor injection is erosion of the impeller. This is only likely to occur when injecting solid stream of water at the impeller of a turbocharger or using an excessively large nozzle. Impeller erosion is highly unlikely with centrifugal supercharger as they spin at a considerably slower speed then turbochargers. Impeller erosion is of little concern with centrifugal superchargers.
2. Pre-Intercooler Injection
While pre-intercooler injection may at first seem like a logical approach. Thereby, combining the effects of water methanol injection within the air-to-air intercooler for an increased synergistic effect. It is not so. Matter of fact, it's the opposite. The cooling effects and benefits offered by the water methanol injection are less when injected here then in all other locations. Further, more other issues arise such as puddling which can form in the bottom of the intercooler. Additionally, pour atomization will occur as the fluid will accumulate in the individual air to air intercooler core walls of the intercooler forming larger droplets which will eventually break away resulting in pour atomization. We do not recommend pre-intercooler injection.
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