Post your meth injection setup

[Kingtal0n]

Originally Posted by 1988montecarloss

sorry to hijack, but are there gains to be had with a meth injection setup where youre already running the turbo at the top of its efficiency range? say im running my s14 t28 at 17-18psi and want to go higher, could i run 21-22psi safely and gain power without changing the tune in the car?

car is currently running an rs-enthalpy modded stock ecu so i cant just go in and change it on the fly

It depends on the ambient temperature, how far away from the engine you inject the methanol/water (you can use 100% distilled water), and how hot the air is coming off the compressor to begin with.

When you inject liquid water, it may now move to gas state, carrying away energy (temperature) when it changes phase. If it changes phase in the plumbing (pre-engine) it can make the air cooler, thus improving compressor efficiency (just like intercooling). Keep in mind we cannot achieve lower temperature than ambient, since our intercooler would then work in reverse, heating our air as it passes through (you would be better off without an intercooler at that point). So there is an optimal position for the water injection site as well as intercooler use/size, and it should be located using several IAT sensors and combinations if the car is serious competition level. Otherwise, many people simply inject it pre-turbo for simplicity and proven benefit to improving compressor mass flow (although whether or not to intercool using it in that location is up for debate) and others opt to inject it near the throttle body, which does not give the water ample opportunity to change phase in the plumbing (not much compressor mass gain) but still helps to lower combustion temperatures, which I discuss in the next paragraph


Next, there is a whole other aspect of injecting water/methanol, that has nothing to do with improving turbo-compressor mass flow (which phase changes in the plumbing achieve, to nearly ambient temp, as we already discussed) And that is phase changes once the valve is closed. A phase change from liquid to gas when the valve is closed (inside the combustion chamber) cannot improve turbocharger mass flow because the charge no longer has access to additional air molecules (because the valve is closed). However, the phase change still carrys away a large amount of energy as the water/meth moves from liquid to gas, thereby lowering combustion chamber temperatures (we see this as reduced EGT) and helping to prevent damaging pressure spikes which occur with increased temperature (detonation, explosive unwanted behavior). The reduced EGT allows us more flexibility with ignition timing and we can get away with using a lower octane fuel (a fuel which would normally be too high of a temperature to behave itself at that point(without the water the reaction moves too quickly and proceeds suddenly with an explosive character) is now losing enough of its energy to phase changing water/meth molecules, so the fuel is safer to use).

Water/meth injection has many benefits and could be used in any turbo/boost application successfully, and even naturally aspirated applications.
Water also tends to clean the combustion chambers up so I regularly spray 100% distilled into all my engines just for that effect.

[KAT-PWR]

Originally Posted by Kingtal0n

It depends on the ambient temperature, how far away from the engine you inject the methanol/water (you can use 100% distilled water), and how hot the air is coming off the compressor to begin with.

When you inject liquid water, it may now move to gas state, carrying away energy (temperature) when it changes phase. If it changes phase in the plumbing (pre-engine) it can make the air cooler, thus improving compressor efficiency (just like intercooling). Keep in mind we cannot achieve lower temperature than ambient, since our intercooler would then work in reverse, heating our air as it passes through (you would be better off without an intercooler at that point). So there is an optimal position for the water injection site as well as intercooler use/size, and it should be located using several IAT sensors and combinations if the car is serious competition level. Otherwise, many people simply inject it pre-turbo for simplicity and proven benefit to improving compressor mass flow (although whether or not to intercool using it in that location is up for debate) and others opt to inject it near the throttle body, which does not give the water ample opportunity to change phase in the plumbing (not much compressor mass gain) but still helps to lower combustion temperatures, which I discuss in the next paragraph


Next, there is a whole other aspect of injecting water/methanol, that has nothing to do with improving turbo-compressor mass flow (which phase changes in the plumbing achieve, to nearly ambient temp, as we already discussed) And that is phase changes once the valve is closed. A phase change from liquid to gas when the valve is closed (inside the combustion chamber) cannot improve turbocharger mass flow because the charge no longer has access to additional air molecules (because the valve is closed). However, the phase change still carrys away a large amount of energy as the water/meth moves from liquid to gas, thereby lowering combustion chamber temperatures (we see this as reduced EGT) and helping to prevent damaging pressure spikes which occur with increased temperature (detonation, explosive unwanted behavior). The reduced EGT allows us more flexibility with ignition timing and we can get away with using a lower octane fuel (a fuel which would normally be too high of a temperature to behave itself at that point(without the water the reaction moves too quickly and proceeds suddenly with an explosive character) is now losing enough of its energy to phase changing water/meth molecules, so the fuel is safer to use).

Water/meth injection has many benefits and could be used in any turbo/boost application successfully, and even naturally aspirated applications.
Water also tends to clean the combustion chambers up so I regularly spray 100% distilled into all my engines just for that effect.

[Kingtal0n]

Originally Posted by KAT-PWR

fun pictures thread