this is the concept behind meth mouth. We are aware that the filter element is in front of the injection point.
The purpose of injection into the turbo, pre-compressor has benefits for intake charge cooling and overall turbocharger efficiency.
When you cool the air entering the compressor, you reduce the compressor outlet temps because your T_inlet has a bigger effect on T_outlet rather then T_outlet alone having meth injection, all else being equal. The reason is isentropic efficiency of the compressor being governed strongly by T_inlet. Cooling inlet temps to the compressor has the effect of reducing overall turbine speed, increasing turbo efficiency on both the hot side and cold side. The turbine does not have to spin as fast to produce the same boost, since you reduced the inlet temp and you are island hopping around the compressor map, shifting downward on your Nr RPM bands as well. It will essentially think, it's pulling in winter air, as opposed to hot summer air, and we all know winter air makes power. That is why T_inlet plays a huge impact on power.
The downside of doing this is if you dont evaporate all the liquid before it enters the compressor, the rotating assembly on this small a turbo spins at close to 180k-200k RPM or more. A water droplet that has not evaporated, being a liquid, at those impeller speeds acts like a bullet and can cause erosion to the impeller vanes.
If one can manage to evaporate the entirety of the injection of water/meth before entering the compressor, you get to reap the rewards of running less wastegate duty cycle, lower turbine speeds, lower IATs, more air flow, higher efficiency (greatly reduced outlet temps) etc... I am not up to date on the latest rally doings, but I think that the rally guys and some other sanctioned race teams love to spray meth into the compressor for this reason.
So this is where the filter element comes in. The filter can manage to soak up, any liquid droplets that have not vaporized, you would be protecting the compressor from liquid and allow the droplets to adhere to the filter element and evaporate. At this point, you would almost gaurantee no water droplets cross over the filter element, and would just sit in the element and evaporate as air flows over them.
I have personally experimented with this method on my BMW 135i back in 2009-2011 with good results, which is why I am doing it now. I used to spray 1000ml/min into the turbos at the filter elements with an observed reduction in wastegate dutycycle, this confirms that the rotating assembly is spinning slower because target boost comes in at a lower impeller speed. So the turbos were happy. I ran this way for 2 years on stock turbos.
Anyway, we are digressing. But in theory, the METH MOUTH intake snorkel is for those who have aftermarket filter elements and understand how to use pre compressor methanol injection. Also, this is experimental so don't hold us to anything yet since METH MOUTH has not been released or tested on this platform.
There are probably idiosyncrasies that this platform has that we are not familiar with, yet. Which is why I am introducing this to the community for basic input and possible beta testers who run heavy tunes and methanol injection and are willing to try this method of cooling..
Note that, when you spray methanol in this manner. You CANNOT rely on it as a fueling supplement, since you cannot time the methanol stream to make it to your combustion chambers as you would do in port methanol injection. This is only for controlling IATs.
If anyone has any input, it would be nice to hear what you think. Thank you
- D