Two equal size turbos is right, single stage, and 50 psi should be correct too. I was reading somewhere that stock block engines had a pressure limit of 50 psi, "special" engines had lower limits. It was an effort to get more people into Indy/CART racing (open wheel) with less of a cash outlay. There were very few real stock block entries like Navarros (I think Smokey Yunick ran a Ford?), and rules were relaxed to include designs based on production blocks, which led to the aluminum AMC Indy V-8. On July 20, 2005 andrew hay wrote: > then, using a for atmospheric pressure and b for boost, > ( a * r ) - a = b > right? > > if so, r=2.4 gives b=20, and r=4.1 gives b=45, pretty closely. > > " With those numbers, the nomograph 650 - 700 hp looks about right. > " > " If I 'play' the calcs and assume a turbo can do atmospheric to > " 45psi in one step (for comparison purposes only) it would be > " r=4.1. > " > " It seems very likely that two turbos in series probably is less > " than twice as efficient (since obviously a lot of energy is taken > " out of the exhaust gas by the first turbo) a total r=4.1, far less > " than the theoretical r=5.76, seems ball-park reasonable. > > if my equation above is right, then for two equal-step turbos in > series the equation would be > ( a * r * r ) - a = b > and r=2.4 gives b=70! r=2.0 gives b=44. > > single stage compressors get less efficient as pressure ratio climbs, > so at some point two low-compression stages are -more- efficient than > a single high-compression stage. i believe it's due to heating of the > charge, which destroys density. > > " But 50 psi plus or minus has got to be the number, to get 700 hp > " from 182 ci. > > just fyi and fwiw, two turbos of r=2.1 give b=50 on the nose. > > also, you wouldn't want two turbos of equal size, which is what i > presume 'te06' suggests. since the first one has already compressed > the input charge by ~50%, the second should be about half the size. > one t06, one t04? > -- > you can improve turbo efficiency by spraying water [or alcohol, or a > mix] into the eye of the compressor. it soaks up the heat of > compression by evaporating right as the work is being done. > > going to run intercoolers? > ________________________________________________________________________ > Andrew Hay the genius nature > internet rambler is to see what all have seen > > adh@xxxxxxxxxxxxxxxxx and think what none thought ============================================================= Posted by wixList Archiver -- http://www.amxfiles.com/wixlist