rudypoochris Posted February 5, 2013 Share Posted February 5, 2013 Hey Guys, I know I have a 302 240z, but am actually asking about WAI (water/alcohol injection) as it pertains to my other car - an N54 335i. I hope you guys will help me out with this non-hybrid. I just got this built and running and my results were not really what I expected. I think the information here will be applicable to HybridZ as well. At least that's what I hope. Base setup: 2008 335i N54 Coupe Compression 10:1 with direct injection running 50-50 E85/91 mix Boost set to 17.5 psi (stock is 7.5 or so) so way off the map making 430whp After market intercooler and tune, no other modifications (stock DPs) Currently limiting boost to save turbos. I am NOT octane limited at this time and could probably hit 19-20psi without losing significant timing Turbo Tout is probably in the 350F range Adding WAI: I went with a Wannaspeed kit I modified. Two nozzles one in each cone filter injecting into 60mm intake tubes which have bends and such for about 2 feet before entering the turbos. The 50% meth/water mix is driven from a trunk mount tank with a check valve on the air line. Flow is measured using an Aquamist sensor with 100-1500ml/min scale (half graph is 750ml/min or so). Preturbo meth is triggered by boost switch at probably 8psi (just setup last night). Pictures: First Results: I ran the car with and without the meth water running last night. I used the exact same map and ran within 5 minutes of eachother. On the no meth run I was going downhill, on the meth run I was going up hill. The intercooler is heat soaking way quicker with meth on presumably since the specific heat of the meth air mix is much greater than air only. No meth: Meth: The curve to look at specifically (at least I believe) is "PWM". PWM refers to the duty cycle of the wastegate as controlled by the car. More PWM means the wastegate is held more shut. You can see PWM spike during spool up and rise the RPMs increase and the turbo is working harder to supply the required boost. In both logs, PWM is nearly identical. That is to say despite pouring 600-700 ml/min of meth water into the intake, the amount of work the compressor is doing has not dropped. I thought it would since the WA mix should be sucking up heat during compression leading to more air out of the compressor per turn (higher efficiency). Am I thinking about this wrong? Am I set up wrong? Should I try biasing more water or more meth? Maybe the mix has completely atomized before the compressor due to my long intake tract? Thanks guys, Chris Quote Link to comment Share on other sites More sharing options...
280zex Posted February 6, 2013 Share Posted February 6, 2013 I'm running water/methanol spray, the paperwork that came with the kit said not to spray before the turbo. The kit is from cooling mist, if this helps... Quote Link to comment Share on other sites More sharing options...
ckrell Posted February 7, 2013 Share Posted February 7, 2013 Your nossels should be as close as possible to the center of the turbo impeller. Just do 100 precent meth, theres guy cooling 25psi with no intercooler doing this 10m/l per turbo 15m/l post turbo Quote Link to comment Share on other sites More sharing options...
bradyzq Posted February 20, 2013 Share Posted February 20, 2013 Your nossels should be as close as possible to the center of the turbo impeller. Just do 100 precent meth, theres guy cooling 25psi with no intercooler doing this 10m/l per turbo 15m/l post turbo I would not suggest that at all. Do you need the meth for extra fueling? At your power levels, I don't think so. And if you do, it's not going to effectively reach the combustion chamber. Do you need it for knock resistance? With your E85 mix, probably not. Even if you do, water's octane rating is infinity. Try finding something higher than that! So why use meth at all? It's a dangerous fuel that burns with an invisible flame (until something else catches fire too.... then you'll know!) I suggest water injection only, and only post intercooler. Hypothetically, if you succeed in reducing the air temp below ambient before the intercooler, the intercooler will actually HEAT the air back towards ambient. Additionally, the water/meth mix will likely fall out of suspension on its way through the intercooler, thus being way less effective in the combustion chamber if it ever gets there. If I was a turbo compressor wheel spinning at 100,000RPM, I would NOT like to have droplets of liquid sprayed at me. When they hit the blades, it can't be good for the compressor wheel.... Quote Link to comment Share on other sites More sharing options...
Snailed Posted February 25, 2013 Share Posted February 25, 2013 Why are you trying to do by spraying water/meth if you are not out of fuel and it's not knocking anyway? If you want water and/or meth spray to work well, spray it in 6-8" before the throttle plate(s) or wherever it will give it some room to distribute more evenly (it won't but you can get close) but still as close to the combustion chamber as you can. If you want to see the wastegate solenoid pulse width go down, turn the boost down. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 25, 2013 Share Posted February 25, 2013 I think spraying Pre-turbo kinda distributes the hell out of it, personally! So did Smokey Yunick who referred to the turbochargers in his draw-through patent application as "homogeniser"... It will go through phase change going through the turbocharger, can't get any further dispersed than 100% liquid-to-vapor phase change! Quote Link to comment Share on other sites More sharing options...
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