Quote:
Originally Posted by TDIwyse
So what I was trying to do with the EWG was help "limit" the peak numbers from exceeding the "setpoint", as the analog gauge was showing peak boost numbers outside the K26 compressor map I had linked in the SCR Mod thread (re-attached here).
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Agree the pressure ratio is the first order of business, for each individual turbo. The higher horsepower guys (obviously you) have another problem and that is the x-axis.
Let's do a simple calculation with some conservative asumptions. Do you know the AFR at these full load rpm points? Smoke limit on the best of injection systems seems to be 16:1. I would use 18:1 to maximize the conversion of fuel to power. Let's take a middle 17:1. To get a targeted 350hp we'll need fuel to the tune of 0.38 lb/HP-hr. So, 350 X 0.38/60 X 17 = 38 lbs/min. Hmm, outside of the map ... this is why every tuner's torque curve drops off at higher rpms. For what it is worth, Meth/H2O injection will allow you to cheat this whole thing, by suppressing smoke and EGT. EGT is easy to understand. Lowering total AFR with Meth/H20 is more complicated.
Do have a KP39 compressor map? That little bugger has a max speed line @ 200K, but a lower max pressure ratio. This image combined with the previous should help. To get the system pressure ratio at any point just multiple the two together. Looks like a pressure ratio of 3.2 is very safe at 2,500rpm,
as long as you are using the 2 turbos to do it.