GTi with Go

In a recent article we featured John Paul Costanzo’s Suzuki Swift running an off-the-shelf based turbo kit – a set-up good for 178hp (131kW) at the wheels - see Mr GTi. Well, JP’s brother – Rob – was mightily impressed by the performance of the ‘charged Swift so he decided he’d whip up a custom turbo kit for the GTi he’d owned since 1994. Rob’s Swift alreday had all the easy bolt-on mods – extractors, exhaust, filter, throttle body, adjustable cam gears and chip.

But a turbocharger is what it really needed...

Rob (a professional sheet metal worker) fabricated a custom turbo manifold using TIG-welded ‘steam pipe’ bends. It’s a relatively simple design that works well. As you can see, the completed manifold has also been covered with a coat of high temperature paint from a spray can.

The chosen turbocharger is a Garrett GT17, as fitted to various late-model Saabs. Rob says this turbo is on boost by around 2000 rpm and it’s really pumping by 3000 rpm. Cooling the charge-air temperature is a standard Nissan S15 air-to-air intercooler, which was removed from Rob’s limited edition GT 200SX (see Two-Hundred to Treasure for our full feature). Note that a manually operated windscreen washer type water spray has been added to increase intercooler performance. Custom stainless steel plumbing (2 inch diameter into the core and 2½ inch out) routes through the engine bay and heat wrap is used to prevent the good work of the intercooler being undone.

The intake to the turbo comprises a K&N pod filter located near the battery with a plastic heat shield. On the exhaust side, Rob fabricated a custom 2½ inch dump pipe that leads into a 2¼ inch mandrel bent system. Rob admits 2 ¼ inch is probably a bit small at the current power output.

A sticky-beak around the engine bay also reveals an AutoTecnica blow-off valve, Autobahn ‘drift’ oil catch can, Top Gun 8.8mm leads with NGK platinum plugs, MSD coil and a bleed type boost controller. The engine management system is stock aside from the previously installed aftermarket chip and a bored-out airflow meter. Extra fuel comes from a Link extra injector and controller tuned by Motson’s Turbo and Suspension.

Rob is mindful of the limitation imposed by the 10.0:1 standard compression ratio; essentially, it means big boost is out of the question. As a result, boost pressure is kept to a maximum of 9 psi. Still, it’s a combo that achieves good off-boost driveability and a gentle transition onto boost. Peak power is 153hp (112kW) at the front wheels – some 70hp (51kW) more than was achieved with the initial round of bolt-ons...

Obviously, the torque loads applied to the gearbox are massively increased with the turbocharger but Rob says ‘box life is largely maintained by avoiding slam changes. There have been no problems with the standard driveline yet, though a heavy-duty organic clutch (from Direct Clutch) has been installed.

With approximately double the standard output, it’s a good thing that Rob decided to upgrade the suspension. Koni adjustable dampers and lowered King springs improve the on-road feel and appearance while Whiteline heavy-duty swaybars work beneath the body to help keep everything balanced. Rob also fabricated a custom front strut brace to improve front-end rigidity. Braking is improved using DBA slotted and drilled front discs and DBA slotted discs at the rear. Front pads are from EBC while the rear pads are (unbelievably!) 115,000km old originals...

Rob says it would’ve been an easy option to whack on an aftermarket body kit. Unfortunately, none really suit the original shape of the car and many suffer from quality issues so Rob has decided to keep a clean, near-stock appearance. Wheels are 16 x 7 inch YHI alloys wearing 205/40 Falken rubber.

Inside, the sporty GTi cabin is tricked-up with a painted instrument surround and centre console trim, a dash-mounted boost gauge, Momo steering wheel, a Rob-fabricated billet gear knob, Blitz turbo timer and a relatively old but high-performing sound system. An early series Pioneer CD head unit is wired to Canton front splits, Polk Audio 6 inch rear speakers (in a custom rear shelf) and a thundering pair of Orion 12 inch subs in a ported enclosure. A 4 x 100W RMS PPI amplifier gives the system true grunt.

Although Rob also owns that magnificent Nissan S15, he tends to use his turbo’d Swift as his weekend fun car.

"It’s just a whole lot of fun," says Rob.

"First and second gear are just a waste of time – even at half throttle it’ll wheel spin," he says with a laugh.

Still, given decent traction, it seems reasonable to assume that this little Suzi has the potential to rip down the quarter mile in the 13 second range. That’s a terrific amount of performance from a car with relatively cheap Do-It-Yourself mods and nothing OTT. It’s not quite as quick as his brother’s turbo Swift (which has more power, LSD and Suzuki Motorsport ratios), but it’s more than enough to cane any sleepy HSV or WRX drivers.

"I think I’ll put on a 2½ inch exhaust, upgrade the fuel pump and give it a re-tune and I think it should make even more power again," says Rob.

But, then, there is a longer-term plan to rebuild the engine with forged pistons so it can safely handle a greater whack of boost.

That outa help even things out amongst the Costanzo brothers...

Contact/Thanks:

Motson’s Turbo and Suspension                       +617 3277 7766
                                                                                   http://www.motsons.com.au/