Not Guilty GT-R

 

It’s fair to say you learn a bit by the time you’re onto your third, fourth, fifth or sixth modified car. The chase for all-out power typically loses impetus and extra focus is given to reliability, drivability and legal considerations. Adriano Rosson knows the story all too well. Having owned a WB Holden with nitrous and mini-tubs, and a coupe of overtly modified Nissan Skyline GT-Rs, he got tired of being booked so took a slightly different route with this machine.

Adriano picked up his current R33 GT-R as an unfinished project. Sure, the motor was brought up to N1-spec and the head was ported but the previous owner’s money ran out when it came time for the bolt-on aftermarket equipment. There was a lot of work to do – and Adriano was the man to do it!

Knowing the strength of the N1-spec motor, Adriano had no hesitation fitting some pretty serious go-fast gear - but nothing over the top or that would attract too much unwanted attention. The exhaust manifolds were match-ported to the head and twin HKS GT25/60-5 turbochargers were bolted on. A pair of 3 inch dump pipes feed into a custom high-flow exhaust employing Di Filippo and MagnaFlow resonators. The result is a legally compliant 91dB(A) sound pressure level at the tailpipe.

Cooling the 1.2 Bar boost rush is a Trust 100mm thick ‘drag spec’ intercooler. Interestingly, Adriano fitted the Trust ‘cooler in conjunction with standard Nissan plumbing – this maintains a totally stock under-bonnet appearance. A pair of plumb-back HKS blow-off valves hide inside the right-side guard (in the stock blow-off valve location).

One of the biggest under-bonnet surprises is the retention of the factory airbox assembly. You’d reckon this is a big power limiter but look closely and you’ll find the airbox has been sneakily equipped with extra air passages. A K&N panel filter and de-screened airflow meter go further to ensure minimal intake restriction. A peruse of the engine bay will also reveal the 20 row oil cooler and a custom catch can that drains oil back into the 9-litre sump. You won’t find any breathers venting to atmosphere here!

The fuel and engine management mods are completely stealth. Chances are you haven’t noticed the 720cc injectors, the Sard upgrade fuel pump or the plug-in A’PEXi Power FC programmable ECU. The ignition system is standard.

Adriano says the HKS GT25/60-5 turbos are much quicker to spool than the set-up used in previous GT-Rs and have no problem achieving a measured 268kW at the rear wheels on 1.2 Bar boost. In fact, based on experience, Adriano says these turbos are begging for some more boost. And that’s exactly what they’ll get in the next couple of weeks – Adriano is keen to find out how much power there is with 1.7 Bar boost and race-grade fuel in the tank.

After experiencing the ‘joys’ of a savage twin-plate clutch in his previous ‘R, Adriano decided to upgrade the driveline with nothing more than a single-plate aftermarket clutch. A modified Exedy pressure plate delivers around 4000 pound clamping pressure (which is no problem when you’ve got a hydraulic clutch). The standard gearbox and diffs remain, although they have been rebuilt as a precaution.

Traction is assured by the Skyline’s active AWD system but Adriano has added some extra grip and handling poise with some new wheels/tyres and suspension mods. The guards are filled by 18 inch ROH wheels which are custom built to maintain the original track measurement – the police stung Adriano for illegal track measurements in his previous GT-R... Tyres are 265/35 18s front and rear. At the time of our photo shoot, the car was equipped with subtly lowered King springs with R34 GT-R dampers. Castor and camber is also adjustable. Track applications call for Tanabe adjustable coil-overs and there’s a set of adjustable Koni front dampers sitting in the shed ready for the quarter mile.

Inside, Adriano has kept the car pretty well standard. Non-standard equipment includes an AutoMeter boost gauge and intake air temperature gauge (which rarely points above about 40 degrees C when running on boost). An Alpine head unit and amp can be found in the cabin and there’s a pair of Alpine 10-inch carbon fibre subs living in the boot floor. It was essential the subs were mounted to consume minimal space as Adriano often needs to squeeze a pram into the boot. You’ll also find a pair of child seats strapped onto the back seat - yep, this GT-R really is unique!

Not long after our photo shoot, Adriano ran the car down the quarter mile in full street trim (18 inch wheels, ‘street’ suspension and child seats in the back!) and came away with a 12.1 second ET with a very strong 121 mph top-end. And that was with only one attempt... A high 11 second pass seems well within reach with no further mods. Not bad for a car that doesn’t get hassled on the drive to and from the track – Adriano say he was once pulled over for a roadside emissions test and came aay with flying colours!

This is certainly one of the cleanest GT-Rs on Australian roads and Adriano knew all it needed was the big rims, window tint, clear indicator lenses and some cabon fibre inserts in the rear wing to effectively enhance the look. It’s a simple formula that receives all the right kind of attention - nothing that makes the plice do a U-turn and engage in a pursuit...

But with another child on the way,Adriano recognises his time with GT-Rs is nearing an end – the two-door body simply isn’t practical enough. He is keen to find out what power it’ll make with some more boost and then it seems likely the pair will part company. If you’ve got around AUD$39,000 to spare and you’re genuinely interested, Adriano can be contacted through michael@autospeed.com Hmmm, investment time!