Todd's sure fire blower sale - Fred,

[EFISYSTEMS at aol.com]

Hi Mike,
      Output temps vary from supercharger types (ie. roots, screw, or 
centrifugal),,,,but in regards to the roots,,most "street" blowers are not 
teflon stripped as they will make alot of heat just from the friction of the 
teflon and the fact at part throttle there is very little fuel or air moving 
through the charger.....a good example of this is the $2000 Weiand 6-71's 
which are a glorified Detroit rebuild(a little tighter clearance).....but 
they still look pretty cool sticking out of the hood of a street car on 
saturday night..........but you'll never see a good blown gas anything with 
nozzles in the ports as the blower will create too much intake air temp and 
lose efficiency, or in effect, pumping losses..........the more boost the 
higher the heat,,,,,the higher the helix in the rotors the more efficient the 
charge as it is not "batting" the air as much as it is moving it,,,,but again 
higher helix causes transient problems as it is effectivly rolling the air 
forward and a screw is harder yet as it internally compresses before release 
with built in pressure ratios decided by the size and shape of the "pie" 
output.........but once it is in a boost above 5 lbs I have seen mixtures 
between cylinders to even out......and above 30 lbs to be almost 
even............even with the fuel entirely dumped above the 
rotors.........as for an example of temps.......572 BBC with an 8-71 making 
12 lbs of boost and 1050hp having and Intake air temp of 315F and a screw 
type making the same hp on the same engine at 9 lbs of boost with only a 170F 
air temp.......which one do you think is going to require less 
octane??????.....anyway hope that helps..
-Carl Summers


In a message dated 6/20/99 7:07:12 AM Pacific Daylight Time, ECMnut at AOL.COM 
writes:

<< Subj:	 Re: Todd's sure fire blower sale - Fred,
 Date:	6/20/99 7:07:12 AM Pacific Daylight Time
 From:	ECMnut at AOL.COM
 Sender:	owner-diy_efi at esl.eng.ohio-state.edu
 Reply-to:	diy_efi at efi332.eng.ohio-state.edu
 To:	diy_efi at efi332.eng.ohio-state.edu
 
 Hi Todd,
 Leaving out the issue of "HP req to run the blower",
  If you pump 15 lbs of boost (at 400+ deg F) into a 440, she
 she prolly won't live long at all, on pump gas.  Check with BDS
 or other old timers for some helpful temp/flow boost curve data.
 The old GMC design makes lots of heat.  I've been digging for 
 some old docs on the above for a "prepped" 671, and can't find
  it anywhere.  BETTER YET, Carl Summers,
 (AKA the Whipplecharger man) are you out there?  
 He is likely to have data from output temps for different blowers.
 Mike V
 
 > Hpwdy Bill,
 >  
 >  Just wanted to mention that if you pumped 15 lbs. of boost into say, a
 >  440, you will DEFINITELY be pushin WAY more than 100 hp, more like 400+
 >  additional....depending on the type of fuel being used....
 >  
 >  Later....
 >  
 
 
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