Richard, Here we go one at a time.
1. How much HP is lost through the rear end? An article about a
>competition coupe (early 90's) used a 7.5 rear gear because it took 10
>less HP to turn it (compared to a 9) and the salt is too slick to hook
>up the rear and overload it. I would think a 9 inch rear would be needed
>to run the paving at Maxton.
HP loss to the drive line is 15% to 25%. depends on what parts your
using and how theire set up. One of the best rears to reduce HP loss would
be a 12 bolt Chevy...Kugal did this...a 9" Ford is actually one of the
worst...but their strong. You can actually get a special center section to
put a 12 Bolt Chevy R&P in a 9" Ford housing...but at a steep price.
>2. Noticed that no one seems to use a quick change rear (what I've seen
>at least), is it the cost or drive train loss?
Actually there are quite a few QC's out there in LSR...I use one in my
car...replaced the old 9" I used to run. Their really not all that
expensive, perhaps less when compared to new 12 bolts, Ford 9", Dana 60's
etc. And spur gear changes are $60 or less with about 66 different
ratios...from 4.11 to 1.83 that could be used in LSR...and change the gear
in 5 minutes or less. Now you can get a Ford 9" out of the junk yard for a
few hunderd dollars...you can get 3 or 4 additional gear sets also...but by
the time you buy all that junk yard stuff, bearings, spools etc. you'll have
as much money invested as a new QC. A QC isn't as inefficient as some
people claim...hypoid angles and all...there is an extra set of gears to
turn...but the 10" ring gear is a better lever than the others.
Anyone interested in a new Winters QC contact me off line.
>3. Anyone want to estimate how much HP would be needed push a D/GMR to
>225? I see that the record is from 93 at 223 by B. Unser. Is that the B.
>I think it is? This record is very close to C/GMR of 225. Was this just
>a hot setup that worked and made the record difficult to break?
Would guess 600+ HP.
>4. I'm waiting on a rule book but wanted to know if going to fuel or
>blower bumps you up a class without a cubic inch change? Thought I read
>that somewhere but can't verify it.
No it puts you in a Fuel class or Blown, Gas or Fuel class.
Example: D/GMR, D/FMR, D/BGMR, D/BFMR.
John "love my Quick Change" Beckett
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