Fast Fours Mag reviews the APS
Intercooled Twin Turbo system for the 350z
The crux of kit is centred on a
pair of APS-spec Garrett turbochargers. Based
on the GT25 ball-bearing model, these only huff
a moderate7-8 psi of boost and sit on a pair of
cast exhaust manifolds. This may only be a mild
boost application, but remember the engine internals
are left untouched and, after heavy testing, APS'
own data shows that Nissan has rather over-engineered
the VQ engine for a possible power increase at
a later date.
The
compression ratio of 10.3:1 is quite high for any
turbo motor drinking premium unleaded. APS have
countered this with the use of a large, bar-and-plate,
twin-entry intercooler, anda uniquely upgraded fuel
system. Utilising a 700 hp Walbro pump and 4-Bar
fuel pressure regulator (3.5-Bar as standard), APS
500 cc injectors mate with their own loom to avoid
any cutting or soldering of the original injector
loom.
A UNlchip plug-in computer monitors boost pressure
and ignition mapping. The only engine modification
is the fitment of an APS 7-litre sump that helps
reduce oil temperature and comes with twin oil
return drains for the turbos.
So what's the result? Well considering a standard
350Z will push out a respectable146 kW to the
treads, David's Zed is now cranking out an impressive
300kW to the ground. That's well over15 kW per
pound of boost pressure! Remember, this is a completely
street legal car designed for every day use. But
it's not just the peak power figure that tells
the story - leaving the engine's compression ratio
as standard has resulted in an extremely driveable
car, as there's no lag to speak of. David comments
that the car punches from any point in the rev
range, and has a huge torque band. "In general
every day use the fuel economy is good, if not
better than before. There's much more torque,
thereby enabling the use of higher gears - I'm
using sixth a lot more. On a recent road trip
to Sydney, the car used approximately 80 litres
of fuel. You could say it has a range of approximately
700 km per tank, which is pretty dammed good."
Since the addition of the twin turbos, David
has ventured to Calder Park where he found that,
like many factory clutches, the 350Z's was the
least forgiving part of the drive train. I caught
up with David the night he raced the car. "It's
not designed for this much power as I've obviously
found out tonight." Easing it off the line,
David still produced a tidy time slip reading
in the thirteens (The Nissan ran 14.4 at 96.8
mph in N/A guise). "The clutch was really
slipping badly in second and third gear on the
last pass, so I had to short shift it. With a
good clutch I'm confident it'll run a low 12.
The APS test car ran an 11.98 running at 9 psi."
At the time of writing, David had just fitted
an APS triple-plate carbon unit to a significantly
lightened flywheel, before finishing this upgrade
with a short shifter (25% decrease) from Rogue
Engineering in the US.
David is quick to point out that he didn't build
the car for Straight line activities. The twisty
stuff is what the 350Zchassis is renowned for.
The big Nissan is home to many upgraded Nismo
parts including the suspension. Nismo S-Tune coil-overs
Lower the body a sensible 20 mm and render a classic
stance Without compromising ride quality. S-Tune
front and rear sway Bars are also fitted, while
David sourced a sweet enhancement From the USA
in the form of a set of Rays Engineering Nismo
LM-GT4 lightweight wheels. Measuring 18x8.5-inches
up front and a wide 9.5-inches down back, 245
front and beefy 275 rear tyres do a great job
of transmitting the Zed's broad torque band to
the tarmac. The GT4's are also the lightest forged
aluminium wheels Rays Engineering makes in an
18-inch, while the body kit is mostly Nismo (the
Aero-spec kit). David wasn't keen on the rear
bar, so he's added a modern touch in the form
of the C-West carbon fibre guard pods. "Most
of the Nismo parts are available through Nissan,
but I purchased mine over seas as it's much cheaper.
It really pays to shop around," David adds.
As David's 350 is the Track Spec version he was
lucky Enough to receive the Brembo brake upgrade
as standard equipment. Combined with some Endless
pads, David adds that braking cohesion is more
than adequate, even with the vast power Increase.
Peering into the cockpit conjures up images of
how Comfortable this car would be to drive hard.
David had Ideal Seat Company bolt in the Recaro
SRIII bucket seats. They look So factory that
you just assume the yare. Also snugly fitted is
An array of products from Defi. The Defi instruments
are among Some of the funkiest-looking in-car
accessories on the Market today and David's got
a Defi Link controller II, Link BF boost, fuel
pressure, oil temp and sensors, water temp, oil
pressure and of course the Defi Link display.
So what's next on the agenda for the Nissan,
David? "Now that the new clutch is in, I'm
looking forward to some more track time. It's
really at home on a quick circuit like Sandown.
This car has far exceeded my expectations as far
as enjoyment and excitement. The two-year journey
has been just great and I hope it will continue
into the future. If I ever get bored with it,
Maybe I'll look at some forged internals and up
the boost, but I think that time is a long way
off yet."
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2004-2005 AutoTech Engineering