Featured Ride Nissan Skyline GT from the UK
It all started innocently enough, as Barnes bought the non-V-spec model with the intention of leaving it relatively stock. Having previously elevated a GT-R R33 to above 500bhp, he wanted something a little less extreme to go from A to B in. However, when you work for a shop such as Sumo Power, an HKS and Spoon Sports dealer, it was easier said than done.
Unable to resist the temptation for more power and style, Barnes found out quickly that his car would remain anything but stock. And, it wasn’t long before the parts train started rolling towards the car. On first went an HKS intake and exhaust along with Iridium spark plugs. With these in place, the R34 turned the dyno to the tune of 404bhp on a GT-R Register rolling road event. Here, he also met Gary Passingham of GT-aRt who later chauffeured him around in his Skyline just for kicks.
In retrospect, Barnes saw this as a turning point: “That’s the problem with these cars; you go out in somebody else’s with more power and realize yours is slow.” Well, he wasn’t having any of that and as you would expect, a new project mandate was put into effect.
Frequent return visits to “the Pod” had Barnes contemplating full drag-spec. But the final push was the discovery that his R34 block was porous and thus needed to be replaced. Rather than source a new block, he used a well-seasoned R33 unit with high mileage. To compensate, it was slightly overbored and garnished with a new set of HKS forged pistons. The theory behind this is that a rebored block, which has had a life of stop/start usage, is tougher than a new one.
Internally, the new pistons are joined by an HKS billet crank and rods circulating on Nismo bearings. These run smoothly after getting submerged in high performance Neo 10W40 oil by an HKS pump while an extra quarter gallon is stored in a Trust sump extension. The sump is needed because this Skyline pulls 1.5Gs under acceleration and its internal baffles stop the oil surging. Similarly, baffles in the cam cover work in cahoots with the catch tank to separate good oil from bad.
Moving up the engine, the HKS cams and springs are part of a package designed specifically for drag use. A 280-degree duration for both intake and exhaust is the wildest profile you’ll find off-the-shelf from HKS, meaning the idle is pretty lumpy. A special 1.2mm steel drag gasket mediates between head and block, and is fastened with a Jun head stud kit. This is an interesting kit because it is sacrificial in that it is designed to break in certain situations thus protecting the bulk of an investment. So, if under immense strain the head starts lifting or the pistons meet the valves, the Jun bolts will snap and avoid the “worst nightmare” scenario. Fortunately, Barnes hasn’t been there… yet.
The head has been ported and flowed by GT-aRt using a secret recipe. What is so secret about it? Barnes is running a pair of HKS 2835 turbos because their power delivery is smoother and don’t stress the bottom end as much as the knockout punch of a single unit. The HKS turbos are rated to offer a 720bhp maximum, yet at only 17psi, Barnes’ Skyline is netting 773bhp – all due to the head mods. Clever stuff, considering there’s almost 32psi to play with.
Ingenuity continues with the ancillaries and the HKS Drag Damper pulley is one example. Traditionally, the crank pulley is solid steel but any balance imperfection is exaggerated at high revs. The new item, however, is filled with liquid, so centrifugal forces propel the fluid to the outer area of the pulley where it sets its own perfect level, smoothing out vibrations and acting as a counterweight for other internals. The only downside is that this pulley forfeited the air conditioning.
As the Skyline runs HKS’ F-Con V Pro standalone EMS, it was possible to replace the standard airflow meters with an HKS air map sensor, which is both more sensitive and allows more flow via the Super Power Flow induction. Further benefits include tuning power beyond 700bhp; it can also switch between two maps and has the ability to finely control each cylinder. At the opposite end of the airflow tract, a drag-spec HKS stainless steel and titanium exhaust runs a monster 100mm bore throughout its length and sounds like the eruption of Krakatoa, even at idle.
Cooling is taken care of in a number of ways. A Nismo pump stops cooled water from cavitating and getting all frothy at high revs while a Nismo thermostat releases the water at lower temperatures so the engine has a greater range to work with.
As for the intercooler, Barnes uses HKS’ drag-spec par-and-plate-type GT model. It’s about as big as it gets with a huge surface area and capacious end tanks. A fan has been mounted on the back of the intercooler to draw cool air to the hot side to improve flow and lower air charge temperatures. Spraying the front is a pair of CO2 nozzles, which virtually freeze the intercooler when activated. This is an effective method of making more power. Novel too, is Barnes’ planned use of a direct port nitrous kit. Obviously, it increases power but he’s going to use the gas for its cooling characteristics rather than performance, keeping the piston chambers at a reasonable temperature.
With a plan to achieve the magical 1,000bhp, Barnes needed an efficient fuel system. In the tank lies an upgraded HKS pump feeding a baffled swirl pot. This extra reservoir de-aerates the fuel so two Bosch pumps can draw unadulterated 106 octane 76 Cool Blue fuel. It then travels down Goodridge lines to an HKS billet rail with 1,000cc injectors by Sard. It’s not necessary at the moment, but another six injectors may be called upon to reach the 1,000bhp mark.
Power of that sort finds the weakest link quicker than Anne Robinson, so the whole drivetrain is tough. An HKS triple-plate clutch engages the R33-spec running gear, which includes an HKS 6-speed dog box geared for 229 mph at 9,000rpm. Stronger driveshafts designed to handle 1,200bhp are used on each wheel. Apportioning power between the axles are two Cusco differentials: a 1.5-way for the front wheels (including a diff cover extension, which holds more oil to keep it cooler) and a two-way for the rears.
Chassis-wise, drag-spec HKS products make another showing. One-off coil-overs were built by HKS specifically for the Sumo R34. Naturally, they include adjustable platforms and dampers, but also rose-jointed top-mounts. Once combined with Ikeya Formula traction adjusters, camber correction kits and center roll adjusters, Barnes is able to fine-tune the camber and toe-in values. He runs positive camber for drag so the wheels are pulled vertical under power, and then switches to negative camber on the road.
Inside, what looks like a roll cage is actually a tension set that acts like a strut brace, locking the center of the car and stopping body flex so as to increase traction.
The wheels themselves are 10.5×18-inch Do-Luck Double-Six alloys and are shod in new 285/30R18 Dunlop SP Super Sport Race tires. Behind the front wheels lie enormous Alcon discs with progressive 6-piston calipers, which is accomplished by using three different size pots.
Barnes’ secured European distributorship for Do-Luck products and his Skyline is a superb promotional tool for the aero parts. It features a full Do-Luck body kit. One interesting facet is the hood. Look closely and you should spot the raised center section, which increases airflow into the engine while simultaneously reducing drag caused by the windshield wipers, which are tucked up under the trailing edge of the hood. “It’s these little bits (that) take the extra tenths-of-a-second off your quarter-mile times,” Barnes reckons. Though at speeds approaching 200 mph, it was discovered that hood pins were needed to keep air pressure from lifting the hood clear off the body.
it’s going to get quicker! We mentioned than the ‘box is geared for 229 mph at 9,000rpm, yet in its current state the shift light is set at 9,500rpm. The rev limit is even higher at 9,800rpm. Once set up for 29psi of boost, the cams will be the limiting factor. Moving on to step three would allow the engine to rev to a screaming 11,000rpm. So, as you can probably tell, Barnes is still progressing on his march to Skyline quarter-mile domination. You’d be brave to take him, but at least with Sumo Power he’s altruistic enough to help make other people’s cars go faster too.
Story By Joe Clifford, Photos By: Max Earey – Courtesy Modified Magazine