[V8] HP loss at altitude?

[Mike Arman]

>From: Ed Kellock <ekellock at adelphia.net>
>Subject: Re: [V8] HP loss at altitude?
>To: <v8 at audifans.com>
>Cc: Anthony.Hoffman at tinker.af.mil
>
>I have heard this about turbos in airplanes. It was referred to as 
>"normalizing".
>If I could do even just that on my v8 here at 6000 feet, I'd love it. But 
>then if one were to accomplish that, why be so frugal with the power 
>increase? ;-)


Problem is as boost goes up, so does the effective compression ratio - even 
though the *physical* compression ratio remains the same.

Choice of aviation fuel is basically 100LL, 100LL, or 100LL, and if we went 
to 1.5 bar, we'd have detonation out the kazoo. Remember you can hear this 
in your car, but not in an airplane (engine noise, wind noise, radio 
chatter, screaming passengers, etc.), and you do NOT want to break an 
airplane engine at high boost during a maximum performance climb to clear 
hostile terrain.

In the old days, aviation high test was 145 (purple) and was used in WW2 
fighters. This fuel is long gone, consequently anyone lucky and rich enough 
to own a Mustang or Spitfire flies around at part throttle openings - full 
throttle on these engines plus the available 60" of boost (!) on 100LL 
equals instant expensive shrapnel plus a forced landing. Ugh.

Remember also that aircraft fuel systems are considerably lower tech than 
automotive fuel systems. Exclusive of the avionics, there are more 
semiconductors in the interior light delay relay of a V8Q than in your 
choice of any dozen general aviation aircraft. No knock sensors, no 
automatic ignition retard, no engine position sensors, nothing, just two 
glorified tractor magnetos, spinning permanent magnets and all.


Best Regards,

Mike Arman