Looks like an interesting document :smile:

However it mainly tackles airflow restrictions upstream of the compressor - not water injection.

My reference to EGTs was in relation to WI :smile:

A few small points,

1) by adding the water/methanol you displace some air and so don't get as much of an increase in efficiency as you might through cooling alone during compression.

2) water and oil get drawn into the turbo all the time, methanol does not. The seals in a turbo are not designed to interact with methanol and over time (I know someone said they had been doing this for a year) the seals could degrade and the turbo might fail at a fraction of it's intended life.

Erosion of the blades is not a major concern as I have said previously, as the breather for the engine feeds back into the intake before the turbo; any oil mist will be going into the turbo in the same way water would and so turbos are designed to withstand this type of particulate flow.

A lot of turbos are water cooled to deal with the high exhaust temps of petrol engines, you could seperate the cooling system from the engine cooling and cool the turbo more effectively. This would allow you to decrease charge temps by not imparting so much heat in the first place.

More small nozzles are better than one large one, as they cause less turbulance.

John, there is a section in the article that addresses turbo shaft HP and drive pressure. There is also an energy balance that shows that reducing compressor heat (either be reducing restriction flaws, OR by misting) would reduce EGT. How much, remains to be determined.

Yeah, well the pressure ratio is not exactly a new concept, is it.
One could argue that misting actally increases airflow restriction because it changes the viscocity of the fluid :? ...
Someone else could argue that there is a decrease in restriction because temperatures are not allowed to to grow (with precompressor injection)
Maybe there are more factors affecting airflow and who knows what the overall result is (may it's variable too!)

We really need proper scientific experimentation don't we
Controlled environment, repeatable results, the lot...

Actually, I have struggled with the reality, that evaporating water, while it absorbs energy, does not necessarily relieve the exhaust of the job of supplying it. It is a thermo dilemna that I have argued back and forth.

Has that compressor been isolated to water damage only? IOW, was filter in place entire time? Nice detailed pic, but it does not have the characteristic water damage. That looks like sand.

The turbo picture was takem by Larry, Hotrod. He explained the damage is due to many other things as well, read the fist few pages of this thread. I hav e also heard report from PuntoRex but his image link is gone. I have emails him and hope he may find them so that I can re-post them here.

perhaps this pic can be layed along side an earlier image from, say a year ago, to determine wear progress.

The picture I posted yesterday is the same as the picture psted a few years ago. I have some server problem and lost some of the pictures in the original post. I didn't realise until I looked at the link a few days ago.