Last July Tony Prerra posted that he had done a chassis dyno comparison
between a QC , 9" & a 12 bolt dropout . He found the CG was the worst , the
9" was 6 hp better & the dropout was a total of 10 hp better .
I asked for more details and he wrote back :
"Engine was an XO GMC , all ratios were about 2.47:1 , 6200 rpm in high gear
, 140 deg , having the dry sump on the rear on or off made little difference
, oil temperature made "some" difference , gears were "shot pened" , Synergy
nascar qualifying oil "
I assume these were done on the same day . With conventional oil it would
seem the differences would be greater and a change from cold to hot would be
noticeable .
>I asked this question on landspeed.com and never got an answer. Can
> anyone tell me when and where there has been testing done on the
> efficiency of the different styles of rear end gears. Quick change, Ford
> 9", GM, etc. Is it a SWAG or is there data. I know the NASCAR guys do a
> lot of work on the 9" R & P I get from them. Has anyone done the same
> thing to a quick change and measured the results. There must be a SAE
> paper or something like it out there.
> Doug Odom in rainy big ditch
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