Sorry guys and gals, but when it comes to lookin' sexy, the 2 seater twin-turbo 300ZX has it all over the mighty Skyline GT-R. A ZX says "hey, check me out - I'm a genuine ballsie sportscar". And the GT-R? Well, it's a 2-door version of a family car that's got a few flares, scoops and wings bolted on. It's nothing you can't do with a bloody Hyundai Excel for God's sake (yipes, that ought to get a few people red with fury!). So it seems the only thing holding the brilliant Zed back from GT-R-equalling stardom (other than the love-it-or-hate-it ATESSA all-wheel drive) is its slightly inferior performance.
But that's e-a-s-i-l-y fixed...
Take a look at John Marinaccio's 1990 twin-turbo Zed and you'll start to realise how much potential there is lurking in the bowels of the Zed's factory VG30DETT motor. Just consider that the dual turbo'd stock VG produces 209kW and 388Nm (that's more torque than the R32 GT-R!) and you can see we're talkin' a very serious motor here. So serious, in fact, Melbourne's JPC workshop have just completed assembling an anticipated 1000hp VG drag monster... Not surprisingly, this road-going ZX doesn't have quite that much grunt - but it sure as hell has a lot more than the factory's already-generous serving. And - needless to say - it's now fast enough to make most GT-Rs look like an utter joke. Not many cars can lay that claim to fame!
When John took up ownership of his beautiful-in-black Zed-Ex (after previously owning a locally delivered atmo 2+2 model), he quickly recognised that there was a heap more power just waiting at the VG's floodgates (wastegates?). So it wasn't long before he handed his gorgeous Zed over to a workshop for a substantial power upgrade. John didn't mind spending up fairly big - so long as he was getting good results in return. Definitely, there's no point in doing things by half on a car like the twin-turbo 300ZX. But unfortunately things didn't turn out quite as planned.
First off, the factory air-to-air intercoolers were replaced with a single cut-down truck intercooler positioned in front of the radiator. Then, a pair of new hybrid turbochargers took over from the standard units, which are prone to disintegrate at high boost levels. These new hairdryers were set to deliver a maximum of 22 psi boost through the new more efficient heat-exchanger. Next came the one mod that was probably the major cause of much woe to follow... The workshop hung a dirty great external wastegate onto the intercooler piping. The idea here was probably to have it function as part of the boost control system - but we won't go too far into that just yet... Following this, pressure build-up post turbine was reduced thanks to a full mandrel bent 3-inch system (which sounds totally animalistic and sexy at the same time!).
Not wanting to stuff around, John gave the nod to go ahead to a top-notch MoTeC M4 programmable ECU, which allowed for precise tuning and the removal of the factory airflow meters. A Bosch 044 pump was also installed to increase fuel flow accordingly.
At last, the job was done - or so it should have been.
John was now an eager beaver and his Zed was set to be a real GT-R eater. Unfortunately, though, it turns out that it wasn't... To cut a long story short, there were quite a few problems the arose with the newly modified engine, plus the 4-speed Jatco trans was simply not up to it - despite receiving a "performance" re-build. Understandably quite jacked-off, John turned his business elsewhere - to JPC (who just happened to be the blokes who built that 1000hp VG drag monster!).
Taking over the job, Mark first had to identify what was wrong with the existing package. He told us (in no uncertain tones!) about the intriguing external wastegate set-up that was hung off the intercooler pipe; apparently, all it did was over-speed the new turbos to death! The damage Mark found was substantial. Totalled - one brand new hybrid turbocharger, along with some obvious bottom-end knocking to boot. Mark reckons some of the engine's bottom-end bearings were completely shot (which is probably due to detonation caused by the measured 14.7:1 air-fuel ratio at full noise...). 14.7:1? That's leaner than the Eiffel Tower!
In the next instance, the crew at JPC built John a decent motor that would be capable of handling much higher power. Drawing on his knowledge gained with the 1000-horse drag car, Mark left everything standard internally, except for slotting in a set of 7.9:1 CR Cosworth pistons. "They're a virtually bulletproof engine and the bottom-end's got a really strong, tight little cradle," explains Mark. But, before final re-assembly, it was also decided to "clean up" the DOHC 4-valve-per-cylinder heads - which are reputedly pretty good even ex-factory.
Following this, JPC trashed everything that was located up-stream of the turbos. The intake now starts off with dual pod-type foam filters that deliver air to a JPC-specified roller-bearing T3/4 turbocharger hung off each cylinder bank. These are driven to up to 20 psi and are saved from over-speeding by twin 32mm Turbonetics external wastegates. Of course, you need two of everything on a V-engine!
Mark says that for the fuel system, they decided to feed juice through a set of six Bosch 351 injectors, which suckle from a custom fuel rail. The previously fitted Bosch 044 pump was retained. Then - with the MoTeC M4 management system already wired in - all he then had to do was go through and re-map the bugger. Spending a fair amount of time on his in-house chassis dyno, Mark punched at his laptop until the maps were all looking right - and the air-fuel ratio meter was now up around the 11:1 mark. Thanks for that, Safety Sam...
JPC reckoned there was no reason why they couldn't run an auto trans identical to those used in their killer 10-second VLs. And John felt comfortable in doing this because it was a 'box that had already proven its worth in other equally powerful cars. Accordingly, the Jatco 4-speed auto came out altogether and was replaced by - wait for it - a heavily tricked and manually shifted Holden Trimatic (which was the work of RaceMatics). A 4000 rpm TCE torque converter was then coupled up to fully replicate the package that JPC recommend for stove-hot VLs. Sure, it is a lot harsher than the standard Jatco's shift, but at least this thing will hold together without the shadow of a problem.
Happy that the engine was sweet, the turbos were healthy and the trans wasn't going to drop its lunch, Mark - again - drove the Zed onto the rollers of his chassis dyno. It was gonna make more than 160kW this time! It was a tense moment for all those present - especially poor John! No doubt though, his blood pressure eased back down again with the good news of the power output - a fat 280kW at-the-wheels (on 20psi boost and running Avgas). Aha - at last, the 300 had the go to match its show! And that was proven absolutely beyond a doubt when the car ran an easy 11.2 second quarter in full street trim (including street tyres and a full sub-woofer sound system).
Quick - let's go find a GT-R to play with!!!
So - at long last! - John can now safely say he owns a mighty quick Zed - probably the quickest in Oz. When driven on the street it also behaves remarkably well for such a powerful car - but, boy, does it attract plenty of looks! The slinky (lowered body), the dark tinted windows and the custom meshed front 'bar makes this thing look even sexier than a top supermodel. And who wouldn't instantly fall in love with those amazing 18-inch Myrtle rims (a brilliant choice there, John!).
However, we have to say that we certainly don't agree with John's latest idea for the Zed though... He's thinking about selling it - and after all this! Yep - that's right - he owns a 11 second Zed with all the desirables a human could think of and he's contemplating parting company in a few months' time... So - if you are a genuinely interested party, please contact Mark at JPC for the pricing details. And how much is it? Let's just say that John's spent around $90,000, but he'll talk turkey at about half of that...
Contacts:
JPC (Johnson's Performance Centre)
+61 3 9465 2244
RaceMatics
+61 3 9335 1011
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