Longtime Austin, Texas resident Mark Rolston has become a bit of a legend in Texas road racing circles lately, thanks in large part to the car you see before you. When it first hit the track with its new powerplant late last year, it took quite a few Vipers and Ferraris by surprise. But the story of this car is a lot longer than those two sentences. It's taken over ten years of trial and error (lots of error) to get it to where it is now (much like Super Street but with a better end result - JN).
Mark's been into Z's of all types since he got his driver's license, his first high school car being a '78 280Z (so very disco!). He bought this particular '71 240Z 11 years ago as a fun weekend toy. Having had lots of experience with autocross, he wanted to try his hand at something more serious and competitive. A plan was hatched to prep the car for regional NASA road racing.
The first version of this car was basically what you see in most street Z's: a firm suspension, a bit more power and a gutted interior. Version one featured a mostly stock L28 (from a newer 280Z) replacing the torquey but somewhat anemic L24. With the associated suspension mods the car was very fun on the street and at the local autocross, but was not quite as competitive as Mark wanted it to be.
Feeling the need for more power, the plan was to build a race-prepped L28 to take the place of the first one. After lots of machine work, time and plenty of money, Mark had his dream engine. After extensive tuning, the car made just a shade over 250hp. Not too shabby for a naturally aspirated, two valves-per-cylinder, single-cam engine first designed and engineered some time in 1967. This version certainly proved to be fairly potent out on the track. While still not able to beat up on the truly fast cars, it at least took Mark from the back of the pack to somewhere in the middle. And then the unthinkable happened; while doing well in a race late in the season, a sudden oiling problem caused that engine to self-destruct in spectacular fashion. As he coasted into the pits with the same powerless end as a Super Street project car, Mark was determined to not have it happen to him again.
He decided to stop messing around with the old school bits and get into something stronger, more powerful and more reliable. Not wanting to stray from the Nissan family, the choice was abundantly clear. Mark had to have the heart of Godzilla itself, the almighty RB26DETT. For the uninitiated (or you Honda heads), this engine is the very powerful inline-six, dual overhead cam, twin-turbocharged beasty found in the late model Nissan Skyline GT-R. But such a swap would not be without its roadblocks, either.
Needless to say, since the GT-R was never officially imported into this country, RB's aren't exactly growing on trees. Mark got on the phone with a few importers and finally found a lightly modified engine set from a wrecked R33 and then proceeded to have it shipped over. Somewhere along the way, some silly J-dude pressure washed it and filled one of the cylinders with water. By the time it got here, that cylinder was wasted. The replacement engine itself wasn't exactly in tip-top shape, either.
Instead of trying to get it running in stock form Mark opted to do it "right" the first time. He had already spent heaps of money on it, so why not go all the way? The internal guts were replaced with basically everything Tomei offers for the RB. And while most opt for the single-turbo conversion for maximum power, Mark wanted to keep it simple and tractable for road race duty. With that in mind, he simply upgraded the stock twin snails with rebuilt GT2871R turbos. While not making the big numbers that the monster single turbo setups make, these Garrett compressors are no wimps. After tuning the Autronic SM4 stand-alone and changing the stock injectors out for whopping 1,000cc units, the engine pumped out a staggering 612whp at 8500rpm. But don't let that high RPM number fool you. It makes plenty of power all over the rev range. Torque is massive and everywhere. With the custom front mount intercooler and piping, it keeps its cool amazingly well, even in the tough Texas heat. And keep in mind the car still only weighs around 2,500 lb.
 |  |  |
To get it to hook up with this much power, lots of fabrication work was needed. Using a beefy Z32 transmission (to do away with the AWD) and an HKS twin-disc race clutch, the power gets to the rear effectively. But that stock-based rear suspension also left a lot to be desired. Mark and his friend Chris Olney (ace fabricator at Charlie's Fab in Austin who also masterminded the RB swap) ripped out everything in the back and replaced it with custom-machined aluminum bits to tighten it up and make it as strong as possible (it helps that Mark has access to a top-of-the-line CNC machine). They also added a NISMO R200 LSD for that extra bit of traction. After driving it around a few days the front suspension showed its shortcomings, so another trip to Charlie's resulted in a custom aluminum front suspension to match.
Now that the car was well sorted and obscenely fast, it needed some help in the cosmetics department. The crew at Al's Bodyworks in Austin got the nod to bring the outside up to spec. With a modified MSA front spoiler, BRE rear spoiler, and custom-molded fender flares the shape was coming together. To release some of the monster engine's heat, a vented carbon fiber hood was swapped in favor of the stock piece before they applied the Porsche 911 Turbo Atlas Grey metallic paint with contrasting bright silver stripes.
When the car was unveiled at a race last year, it took a lot of people by surprise with its good looks and brutal speed. But it's no trailer queen. While it spends most of its life in Mark's garage, he never passes up an opportunity to take it out and beat on it as hard as he can. He's learned now what most of us Datsun freaks knew already; when something breaks it's not always a bad thing. Sometimes it's just an excuse to replace it with something better.
 |  |  |
 |  |
Fast Facts'71 Datsun 240Z
Owner Mark Rolston
Hometown Austin, Texas, Y'all
Daily Grind Product Designer
Power 612hp at 8500rpm
Under The Hood Nissan RB26DETT; Tomei PONCAM cams (10.2mm lift, 260-degrees intake, 270-degrees) exhaust with adjustable cam gears, Performance Upgrade valve springs; CP pistons; Total Seal rings; ported head; modified intake manifold runners; Garrett 2871R turbocharger (x2); custom intercooler and piping; Precision 1,000cc injectors; Aeromotive A1000 fuel pump and regulator; custom dual-feed fuel rail; 034 EFI high current ignition with ignitors; MSD Super Conductor wires; NGK plugs; custom spark plug cover; custom dual 3-inch to 4-inch air intake; custom downpipes and exhaust piping; custom five-quart oil pan; HKS oil pump; external oil cooler; Accusump external oil reserve system; Northern dual-pass radiator; Tomei Expreme header; custom chrome header heat shield; Magnaflow muffler (x2)
Drivetrain '95 Nissan Z32 transmission mated to RB26 housing; HKS Twin Plate clutch; NISMO R200 LSD; modified Nissan Z31 Turbo axles and CV; custom driveshaft
Brains Autronic SM4 computerized fuel injection and boost controller
Stiff Stuff Tokico adjustable shocks; Eibach springs (385-lb front, 345-lb rear); Suspension Techniques rear antiroll bar; custom ArizonaZ billet front suspension arms, rear differential mount, mustache bar
Rollers Street: 18x11 Boze Mesh; 285/35R18 Hoosier Sports Car DOT Radial Wet; Track: 18x11 CCW Classic; 285/35R18 Hoosier Sports Car DOT Radial
Stoppers Wilwood custom six-piston 13.3-inch front, four-piston 12.5-inch rear; cockpit-controlled adjustable brake bias control; steel braided lines
Outside Porsche 911 Turbo Atlas Grey metallic paint; custom fiberglass fender flares, dry-carbon fiber hood, MSA front and BRE-style rear spoilers by Al's Bodyworks
Inside Corbeau Forza seats; Simpson five-point harnesses; modified center console; MOMO steering wheel, shift knob and pedals; fire extinguisher
Ice BYO iPod
Props Chris Olney of Charlie's Fab; Al's Bodyworks and J.C. Bond; Jason and Clint at Tuning Concepts for the tuning and dyno work; Brian at BMEP Fuel and Tuning for the initial engine tuning; Motion Dynamics; Corkey and John at Automotive Specialists
Tidak ada komentar:
Posting Komentar