GT-R'en har større turbo (IHI RHF6-VJ23, kulelagerturbo), større intercooler, større bremser, forsterkede råder, forsterket girkasse (som om det hjelper...), kortere rattutveksling, hardere fjører/dempere/foringer osv.
Skal han ha den original er GTXen et godt valg, da den er mye kjappere på ladetrykket enn en GT-R, og føles nesten vel så rask ved "vanlig" kjøring. Skal det trimmes er GT-R'en klart å foretrekke. Turboen på en GTX er ikke god for mer enn ca 220-230hk, men en GT-R turbo er god for opp til minst 300. GT-R'en har heller ingen boostcut funksjon i styreenheten, og ladetrykket justeres mekanisk. Dette betyr at bilen ikke trenger å chippes, da den fint klarer å levere bensin opp til 1,5bar med originalhjernen.
I følge de med erfaring på 323GTR mailinglista på Yahoo Groups, vil en GTR som har 2,5" eksos fra turbo og åpent conefilter (typ KN, BLITZ osv) gi minst 250-260hk ved 1bar ladetrykk.
Vedlagt følger en tekst fra Mazda Press Information som forteller litt om forskjellene på GTX og GT-R. Det er er presseskriv fra da GT-R'en kom ut på markedet:
THE MAZDA 323 4WD GT-R IN BRIEF
The Mazda 323 4WD GT-R is an ultra-high-performance, evolution model of the sporty full-time 4-wheel drive hatchback series, supplementing the current GTX which continued in production. The GT-R features upgraded specifications and a distinctive , unique exterior design.
The 3-door hatchback has an overall length of 4,080 mm on a 2,450- mm wheelbase. Width is 1,690 mm with front and rear tracks of 1,430-mm and 1,435-mm respectively. It is 1,390 mm tall. The car's minimum ground clearance is 150 mm unladen, 120 mm when fully laden.
Kerb weight of the 323 4WD GT-R is 1,210 kg and 1,240 kg with optional ABS ( anti-lock brake system) and steel sunroof.
The GT-R is readily recognizable by its bold front-end design, featuring a huge lower-fascia/bumper with large air-intake opening, and twin fog lamps and a bonnet with a prominent bulge. Additionally the car has extended fender flares covering larger 15-in. aluminum wheels and low profile-tyres. A rear roof spoiler is shared with the GT-X.
The GT-R's well -appointed, fully instrumented "cockpit" is augmented by a Momo leather-wrapped steering wheel and matching gear-shift knob.
The temporary spare wheel is carried on the luggage compartment's "floor" , still accommodating 230 litres of volume (by VDA measurement), which may be increased to 415 litres by folding the 60/40 split rear seatback. The luggage compartment contains a useful "hidden compartment" normally occupied by the spare wheel.
The type BPD engine in the GT-R has been tuned to deliver 13 percent more power and 8 percent more torque over the GT-X. A larger turbo-charger and a larger intercooler have been adopted in the GT-R. The engines strengths , both power and torque characteristics, are in the mid-through-high-rpm-zone, above 3000 rpm upto its maximum allowable 6500 rpm on a 8.2:1 compression ratio, requiring premium unleaded fuel.
The engine is mated to the type G5M-R 5-speed manual transaxle with strengthened gear train , driving all four wheels via a planetary-gear center differential fitted with a viscous-coupling limited-slip device. The center differential splits torque 43 percent to the front wheels and 57 percent to the rear. The final drive incorporates a multi-plate type limited-slip differential.
Mazda's all-independent suspension with Macpherson front struts and TTL (trapezoidal twin-link) rear struts, battle proven in the World Rally series, has been further refined with firmer bushings and specially tuned dampers. Rack and pinion steering with a quicker overall ratio and engine-rpm-sensing power assistance is standard.
Disc brakes are used all around, the front ventilated pair having an effective diameter of 222-mm and the solid rear rotors an effective diameter of 244-mm. The total swept area of 1,286 sq. cm is 21 percent larger than that of the GT-X model. The standard vacuum servo assist is replaced by a hydraulic servo when the optional electronically controlled 4-wheel ABS is ordered.
