water injection vids

[sambb]

I've been looking a lot lately into water injection after having a good chat with an engineer who is good mates with my mech. He pointed me in the direction of a video he made of an insane turbo cosworth that he and a co collaborator had designed a custom inlet manifold/plenum for. It is a centre feed log style plenum with internal trumpets and at the end of the log he used a site glass to film the water injection through. The water injection was only a 0.4mm nozzle postioned between the intercooler and throttle body. Have a watch - you won't believe the chaos in that plenum once the injection begins! I bet it'll scare a few people on here who run bigger and/or multiple nozzles.

https://www.youtube.com/watch?v=2PyWLE3gMw0

Then I found a couple of pre compressor injection vids. Both are pretty scary. One has a really good looking match between cone size and inducer diameter, the other looks a bit rudimentary with some water drips that look like they could kill blades and a cone that doesn't look like a good match for the inlet. Neither of the pre compressor vids put me off doing it but what did surprise me is the amount of water vapour blow back that runs far enough up the TIP on throttle cut to probably mess with the MAF.

https://www.youtube.com/watch?v=F51xymg33-w

https://www.youtube.com/watch?v=LO0MGrkEWzI

anyway, they're pretty interesting viewing.
sam

[IanPGonzaga]

nice videos!!!

so what is best???

[sambb]

Very very broadly, Pre compressor makes the turbo behave like a bigger one, reduces EGT's and gives lower post turbo charge temps but has no effect on in cylinder cooling. Pre compressor can directly make you more power. Post compressor has different effects depending on where you inject. Further away from the cylinders it is used as an auxillary way of cooling charge temps and the closer to the cylinder you get it becomes more about knock control through lower charge, inlet valve, combustion and head temps. Strangely it doesn't lower EGT's though. For post turbo water injection you are unlikely to make more power directly (you could if you have water/meth and are tuned for it though) but you could indirectly if timing had previously been pulled in response to knock or if it had a really drastic effect on inlet temps on very hot days
This is water injection I'm talking about. I won't run water/meth because of the unknown of how meth can affect your AFR's. So what is 'best' really depends on what problem you are trying to solve.