S/Cer a bit faster to deliver the flow I required. Going
much smaller on the S/Cer pulley meant sacrificing
belt wrap and possible belt slipping issues. Instead, I
decided to enlarge my stock crank pulley. Shown
here is the stock pulley with the alternator ribs
machined down to establish a nice flat and round
interface for my larger pulley ring. The beginnings of
the pulley ring is chucked up and I'm fit checking the
tolerance between the two mating parts.
machine the "V" grooves on my lathe. No go, way to
much tool chatter, even when trying to cut the grooves
like threads. Next I moved to the mill. I tried double
sided cutters and other processes but the only one
that worked was to make a custom cutter by
combining a specially ground tool to a 3/4" shaft and
spinning it very fast. I feed the ring into the cutter
using the mill table to establish the "V" depth and
used the rotary table to cut the groove around the ring.
It took about 5 cuts per groove to complete one V
groove. At that point I drop the mill knee to establish
the next groove centerline and start the process
again.
and stitch welding at the interfaces. The surface was
given a rough texture by sandblasting to get better
belt grip.
can't be seen in this view is that there is only enough
room between the pulley and oil filter housing to slip
the belt over. That's a big as it'll go without modifying
the housing. To make 500 hp, I'll need to do just that.
treatment to achieve better belt grip.
slipped above 8 psi boost. I re-designed the routing
as shown in the second shot. This design produced
much better belt wrap and tension could be adjusted
at the alternator just like stock. The idler pulley used
the alternator pivot bolt for attachment. I used a
12mm bolt turned down at the end to the stock 8mm
threads. This produced a very stiff and strong attach
point for the pulley.
pulley system. Also shown is the front S/Cer support
plate which also supports the two idler pulleys. It's
fastened to the alternator bracket and block with four
bolts.
larger exit location. Shown is my template used to develop the
new cover. After the template was completed it's cut into several
pieces and used to transfer the cuts and folds onto 6061 sheet
stock. The single piece is then bent, folded and welded into the
final product. Not shown is the work done on the input side of the
airbox. The stock snorkel is removed and replaced with a large
dia venturi shaped air horn. I feel those long funnel shaped air
intakes on the market simply add another turn the air flow must
negotiate and are the wrong shape to begin with as they tend to
accelerate the air flow and turn it at the same time. Not good for
optimum flow. This idea of "ram air" is simply a marketing ploy. If
it worked, F1 cars would have much larger air intakes. In fact,
most formula car use very small air intakes relative to the rest of
the system. This ensures positive pressure and good flow
characteristics to the throttle bodies for even air distribution.
bypass valve tube is welding into place completing
the throttle body manifold. The blower to support
plate strut is in place. This strut reacts torsional loads
and triangulates the entire support assembly for
strength and stiffness. The IC filler cap has been
welded in place on top the charge cooler. The dual
water inlet and outlet hoses have been combined to
individual "Y" fittings at the air cleaner box cover. The
single hoses route to the front mounted heat
exchangers. The fabricated air box cover and
connections to throttle body are complete.
Connections to the coolant tank are complete.
each) terminate at their respective "Y"s where single #
12 hoses route forward to the front mounted heat
exchangers. I was able to utilize the passenger
compartment heater hose for the return line as routing
hoses down the center tunnel is a pain. In addition,
the heater line is quite large and resulted in lower
pressure drop. I re-routed the original heater hose up
front to keep the heater functional.
design sizing and configuration of these exchanges was similar
to the IC. In other words, maximum frontal area and min depth.
As outside air passes through ANY radiator it warms quickly.
As it passes through the core it picks up more heat but at
decreasing rate. Since it is the delta difference between the air
and core temperature that dictates heat transfer, most of the
"work" done by the outside air is done after about 1.5 inches of
core depth anyway. Locating the exchanges directly in front of
the radiators meant relocating the hood latch mechanism (I
used hood pins) and the large harness bundle that crosses over
the upper radiator support. I fabricated a special bracket that
secured the exchangers and the stock AC reveiver/dryer. The
base of both exchanges are secured to the lower radiator
support brace using riv-nuts.
gpm (gals per min) pump. The bottom picture show
my current design which uses a 15 gpm pump. Net
system flow was 2 gpm and 4 pgm respectively. The
extra 2 pgm reduced my max IAT by 20F to 130
degrees after 20 minutes on the track on a 80
degree day . One of the benefits of the water-to-air
IC is the ability to incorporate a "holding tank" for the
water. The tank serves several purposes. If
designed correctly, it prevents water pump cavitation
(just like a good oil pan) while the vehicle undergoes
various G forces on the track or street. It also allows
expansion of the water and separation of possible air
in the system. More importantly, due to the large
thermal capacity of water, it acts as a thermal buffer
during periods of extreme IAT swings. Intake temps
significantly BELOW ambient can be achieved by
adding iced water to the system. With enough mass
(tank volume), IATs could be kept under 100F for an
entire 20 minute track session (they would start out
low and slowly creep up as the water temp gradually
increased).
under the hood. One of the downsides of the water
cooled IC are increased complexity and more weight.
The radiator is a Chevy style Griffin racing model I
modified to fit the NSX. Two fans draw air through
both radiator and IC heat exchangers.
