Re: the Navarro Six, O-ring questions

[farna@xxxxxxx]

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


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