[Land-speed] Rear end efficiency

[John Staiger]

Doug,
 
I talked to Winters, Tiger and Frankland about your very question this past December at the PRI show.  As I'm in the market for a QC I had similar interests/concerns.  Discounting Frankland (no help whatsoever), both Winters and Tiger provided consistent data that I have paraphrased from memory below:
 
The loss from a 9" Ford, Dayna R&P, Spool, Mobil 1, standard test conditions was ~ 10 - 16 hp depending on ratio.
The loss from a "standard roller bearing" QC, Dayna R&P, Spool, Mobil 1, standard test conditions was ~ 6 hp more. (same as info below).
The loss from a "angular ball bearing" QC with RIM polished R&P was nominally the same as the 9" Ford.
 
Hence the low drag bearings and RIM processes reduce drag on average about 6 - 8 hp (as tested).  Tiger makes a very big deal out of this feature by selling their QC with all the low drag bearings, polishing, etc standard.  Winters offers the same setup, however you have to order the "options".  The short version -- the QC has more efficient R&P than the 9" or 12", however it is handicapped by the extra straight cut QC gears.
 
If my memory servers me, Tiger has a paper or some type of analysis on their website... it might help... then again... it might not... 

John
569

----- Original Message ----
From: John Burk <joyseydevil at comcast.net>
To: LandSpeed List <Land-speed at autox.team.net>
Sent: Wednesday, January 23, 2008 12:26:27 AM
Subject: Re: [Land-speed] Rear end efficiency

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
Land-speed mailing list

You are subscribed as lsrvette at yahoo.com

http://autox.team.net/mailman/listinfo/land-speed