Non A*E* Roots Numbers

[Lawrence E. Mayfield]

Been lurking around and listening to the talk of crank driven blowers. One
of the things that strike me is the damage potential caused by driving the
pump from the crank snout. Taking a 100 horsepower out the crank snout puts
a tremendous side load on the crank which causes flexing of the crank. I
know it is hard to visualize a big stout crank flexing but they do. What
happens then is that this stresses the block's main bearing webs and
subsequent cracking through the web to the cam bearing races. This is
probably the cause of many blown Ford 302 engines which have split the
block. Just a thought or two...

mayf

At 06:20 PM 6/20/99 -0700, Walter Sherwin wrote:
>
>
>>One of the more significant things to observe in the numbers posted here is
>>how LOW the VE for a Roots is at low engine/blower speed--these low VE
>>numbers at low speed translate to not much boost there until the revs are
>>up a bit!! A VATN turbo will actually get the boost up a LOT SOONER than a
>>Roots or a Screw huffer!! Get it up rates for VATN turbo/
>>Roots/conventional turbo are prolly sorta comparable to the same rates for
>>a 15 year old boy/ 30 year old man/50 year old man!
>>
>>Another point to consider--Don't even THINK about running a Roots or a
>>screw in "blow thru" configuration!
>
>
>
>
>
>I agree completely with your comments regarding the "Roots" blowers.   On
>the other hand, "Screw" compressor technology has come a long way over the
>years.  You might be surprised by the performance figures for an optimized
>screw unit, no matter whether you want to examine  1)Dry Discharge
>Temperature   2)Adiabatic Efficiency   3)Volumetric Efficiency   4)Parasitic
>Power   5)Internal Compression Ratio...........etc.  Sized correctly,  a
>screw(s) can nearly match the peak efficiency of a good turbo system, but do
>so over a much broader range, with near instant response (wet or dry).
>
>Do you have a URL for the VATN turbos?
>
>
>
>Walt.
>
>
>



L.E. Mayfield
124 Maximillion Drive
Madison, Al. 35758-8171
1-256-837-1051

http://www.hsv.tis.net/~mayfield

DrMayf at AOL.com
mayfield at traveller.com <<<<preferred


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