FWIW, I experimented with pre-turbo water/methcooling about 30 years ago. It works and works Ok but dont expect reams of power over a traditional cooler setup. It works and thats about it. When running water/meth, there is no real hard and fast rule on nozzle size. Just run as much water as the engine will handle. It will bobble and missfire with too much. Its just a matter of trial and error. FWIW, I ended up arriving at 0.55mm je on a 1.6 lite motor blowing about 12 psi boost and used a manifold mounted pressure switch and a generic washer bottle and pump. I made my test nozzle out of brake line bundy and soldered the end over and kept drilling the solder out until the engine bobbled. Largest size I went to was .80mm. Just went down to the next size that allowed the most water without any bobbling coming onto boost and machined a permanent nozzle up out of a brass bolt the bolted thru the air filter cover aiming down the throat of the SU carb I was using back then. Going from .5 to .8mm made no discernible difference in performance but the water bottle drained out so quickly on the bigger jet it became a PITA in the end. I I also played with some pretty serious concoctions of chemicals, and to be quite honest, plain old water worked as well as the best mixes of jungle juices I tried. I never really noticed any difference between water/meth and plain water. I dont really subscribe to the claims that the water will erode the compressor either. That engine ran for year upon year with that water setup with no discernable pitting or erosion to the blades. E
I have been doing a fair bit of research lately on this and what Tas has mentioned is very much what most the people who have been using this for a long time say, there are people who have been using pre-tubo injection for years on the same turbo who claim no issues. the other aspect I am finding that there is some consensus that pre turbo does not need the amount of atomising that post turbo does, I am a tad weary of this comment myself but it has been put out there.
The few people i have spoken to that run these setups have 9-10 second cars. I was told with a good high pressure pump that compressor wheel damage won't be an issue at all as they have run these setups for years. I was told however that people have made dodgy setups with crushed copper pipes(LOL!) that haven't destroyed the comp wheel so to say but have "dulled down" the tips of the wheel which is still very bad.
I'd imagine big drops of water pre turbo will destroy a compressor quick enough. Maybe the water mist atomises further in the hot air once it is compressed, so atomisation is not so critical pre-turbo? Large enough droplets injected post turbo would cause damage to the engine, hydro lock, oil degradation, cylinder wall corrosion etc. The finer mist pre turbo, less chance of compressor damage, maybe? Thoughts? How about injecting very hot water to vaporise before /in the plenum? EDIT: with a small nozzle size, would you need a water pump or, depending on water tank position, would the pre-turbo vacuum be enough to draw the right amount of water?
I was under the impression that the off the shelf kits mostly injected just before the throttle body.. e.g. snow performance.. http://www.snowperformance.net/product_images/product_variation-installation_pdf-8.pdf Granted they are generally talking about a 50/50 water/meth mix as well. Biggest issue I thought was people doing cheapo setups with retic spray heads, whereas you need a super fine mist for it to really work.
The OP is a different related question not referring to a kit. You are right in most "KITS" are pre throttle body pre turbo is an additional method that nets complete different gains
Correct, but it looked like it had looped back around to post turbo setup's which are basically what the kits are.
Instead of bypassing your a2a coolers, why not add the water injection on top? On a side not, those who have experimented/ tuned with water injection, how much timing advance have you managed with it?
Very similar timing wise to e85, timing advance over 98ron is heavily dependant on what car/engine/setup etc. I dont have wmi experience on zeds but I do on skylines.... 6-10degrees advance over a 98ron tune was the norm with pre tb wmi and pre turbo however pre turbo always made more power.
Read my original post, it would be for the drags ONLY. The idea is to run 2.5" intakes and 2.5" outlets, along with a 2.5" U pipe to the TB's.....this would remove any possible restriction and/or boost drop from the FMIC(if at all) and would allow me to see if the larger piping (2.5" vs 2") would net any gain. As for your second question my answer is still no, pre turbo injection works very well at lowering IAT's and suppressing detonation. I know of several cars running 35+PSI with no cooler on 98RON and straight water pre-compressor.
