of the water pump pulley on 1988 and later L98s resides a rather large
10lb steel disk, lovingly refered to as the “frisbee”. There has been
much debate on the Forum about it’s purpose and the benefits/risks of
During a Q & A session at Corvettes at Carlisle 2001,
I posed the question to Gordon Kellebrew as to the purpose of the
“frisbee”. His resonse was that this disk was added by GM in 1988 to
absorb vibrations when the A/C compressor turned On/Off. He said that
they later found that this caused the serpentine belt to chirp uppon
sudden changes in engine speed and so it eventually removed from engines
in later years.
Early in 2001 I removed this “frisbee” when
installing a new water pump on my 1988 L98. Subsequent 1/4 mile time
slips showed a consistent increase of 1 mph in trap speed. This amounts
to a 10 hp gain.
So, not only is the “frisbee” not needed on the
water pump pulley, but it actually robs us of about 10HP. Removing it is
truely a “free mod” that nets about a 10HP gain.