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Re: Corky Bell's Book[2]



 This opinion is also shared with Joe Moragn and it does seem to work.He
told me in one conversation that the biggest gains on our cars comes from a
better turbocharger and intercooler set-up.
                                                              Neil
At 02:50 PM 9/10/97 -0600, Carl Morris wrote:
>All,
>	I just thought I'd mention a few things that I
>find interesting about the book.
>
>Corky's opinion on what NOT to spend time/money on:
>
>1. Big cams, heavy port work, expensive high RPM parts.
>
>	He points out that the forces due to combustion
>are only about 20% of the load on the pistons, crank, and
>rods on a naturally aspirated motor.  Everything else is
>stress due to RPM and simply compressing the charge.  
>Since the RPM related stresses get squared every time you 
>double the RPM, you only have to drop your peak RPM about 
>10% to put yourself at 80% loading, which gives you the 20% 
>margin you need to double your horspower without any additional 
>stress on the motor(assuming you're not causing any pre-ignition 
>or detonation).  The point is just that for a given strength of 
>motor, you can gain more power by running more boost and less
>RPM than vice-versa (doing both is not an option once the motor
>is maxed out).
>	To me, this sounds like an argument for putting better 
>rods in our motors (the weak link) which would make them good 
>for about 7000 RPM, but leaving the stock redline
>alone and buying efficient turbos and intercoolers and
>running lots of boost (and good enough gas for that boost).
>
>Corky's opinion regarding porting:  It works, but taken to the 
>extreme, it reduces low RPM driveability and there's no need for
>it if you have (once again) the right turbo and IC.  The
>problem is that most turbos are only efficient to about
>3:1 pressure ratios.  For you guys at sea level that'll
>get you to about 30 pounds of boost, probably as much
>as you can use even with race gas.  Up here at this
>elevation, that only gets me to about 24 pounds of boost.
>I'd probably need to do some porting if I were trying to
>max the motor out on race gas and keep the boost within
>the turbo's efficiency range.
>
>
>Corky's opinion of what TO spend time/money on:
>
>1. You guessed it, turbos and intercoolers.
>
>	A turbo that will run in the 70% efficiency
>range at 400-500cfm, and a good, large frontal area
>fairly thin low restriction front-mount intercooler.
>This, combined with a fuel system that will deliver
>a consistent 13:1 A/F ratio will make monster power
>on our motors, without huge internal motor mods.
>**********************************************************
>
>I guess this should all be taken with a grain of
>salt, but I do find it all interesting, I consider
>the source to be as reliable as any other I know of...
>
>-- 
>Carl_Morris@StorTek.Com
>