Nissan Silvia’s have always had extremely strong support from the aftermarket automotive suppliers both here in Japan and overseas, and why not? The Silvia has to be one of the best all round packages out there. On the circuit, at the drag strip and of course out drifting, the S-series Silvia’s have always done well in many categories of motor sport in Japan. So just how far can you go with an S15 Silvia? Well, that’s where Sequential come in. Based in Suita, northern Osaka, they were founded in 2000 (Sequential requested that the owner remain anonymous) and have two workshops, one in Suita and one in Kobe. They do all mechanical work in house and specialize in ‘one-off’ enhancements Visit their website at: http://www.sequential.co.jp/
This has got to be bad timing…
After one failed attempt the week before, I finally made it to the Sequential workshop in the trusty R32 Skyline. I was late about 30 minutes, but as I arrived I saw that the mechanics were only just opening the roller doors at 11am… strange, I thought they opened at 10? As soon as I pulled up I was told that I had to move my car, as they were expecting some clients to arrive sometime in the next hour… that was strange too because where were the clients going to park? The place was already full of cars! Oh well, just go and park at the Yakiniku restaurant next door. Something was telling me this wasn’t going to be an easy photo shoot…
“Ohayou Gozaimasu”, Kitayama-san greeted me with a little restrained look on his face. He quickly told me that no less than three clients were on their way, so he won’t be able to help me out for at least 45 minutes, maybe more. I told him it was ok, and asked if I could start photographing the car without him. “Hmmmmm… (long pause)… Ok” Kitayama said, he then quickly disappeared into the showroom. He looked like he had 100 things on his mind, any more small talk would probably stretch the friendship… So where was the car? Oh, there it was, right at the top right corner of the car yard behind, what, 5 other cars. But never mind, the sun was out, it wasn’t too cold (actually it was about 4 degrees) and this car was worth the trouble!
Wow. Just about every square inch of the car was modified in some way and on closer inspection it became obvious that the car wasn’t for street use, in fact it was so low to the ground that even getting it on a flatbed truck would require removal of the front bumper. Known as the ‘Waru Ichi Gou’ ( ‘悪1号’ or translated directly, Bad number 1), the Sequential Fire SF-15 Silvia was built for one thing only… circuit racing. During the interview, Kitayama made it clear that the SF-15 wouldn’t be modified anymore, and that they would be starting a new project based once again on a Silvia. For the time being though, the SF-15 is still their flagship demo car.
Without a doubt, the bodywork of the SF-15 is the most striking feature. Starting with the body kit, it’s an original ‘one off’ design from Sequential incorporating the front bumper with huge carbon fiber splitter, front fenders (50mm wide), side skirts, and truly awesome rear fenders. The rear fenders really need an article all for themselves! Sequential have widened the factory rear fenders 50mm by attaching fiberglass ‘blister fenders’, to do this metal had to be cut around the rear wheel arch, then the metal forward of the wheel arch was bent to make the large ‘air intake’ you can see in front of each rear wheel. The blister fenders were then painstakingly sanded and molded into place giving what is a truly remarkable finished product. So smooth is the transition from factory metal to blister fender that you’d be hard pressed to tell whether or not the guards have been widened 50mm at all. Kitayama-san wasn’t sure why I was so interested in the rear fenders, as any number of Silvia’s from various Japanese tuning garages have similar work done. The rest of the aero package is made up of ‘off the shelf’ parts, including a Yashio Factory carbon bonnet and carbon trunk lid with carbon plate reinforcements, Sard carbon GT Wing and a one off carbon rear diffuser (not on the car). Carbon canard winglets, carbon dummy headlights – it’s not road registered remember – and Craft Square Tuning Competition mirrors complete an original and striking S15 Silvia aero package.
Lifting the carbon bonnet, the first thing that practically slaps you in the face is the HKS 3037 turbine followed closely by the Greddy intake plenum. But let’s start with the engine though, it’s been pulled down, balanced and rebuilt using a TODA 2.2L kit, TODA 272 degree cams, Trust ‘H-section’ conrods, balanced and lightened crank, TODA reinforced valve springs, HKS 1.2mm metal head gasket , NA throttle body, the above mentioned HKS 3037 with HKS special racing wastegate and the Greddy intake plenum. The turbine exhales through a one off stainless steel exhaust manifold, a straight through pipe to replace the catalytic converter and on to a one off titanium muffler with full titanium piping. SARD 830cc injectors are used and fuel pressure is provided by a Bosch fuel pump. The intake air enters through a BLITZ SUS Power air cleaner with custom piping then travels through a Trust 3-layer intercooler then on to the plenum. Cooling the engine is taken care of by an RG aluminum radiator with a nice air deflector attached to the back that feeds the hot air out through the air vents in the carbon bonnet, and not to mention the twin HKS S15 oil coolers. Kitayama-san described the engine management system as a “Sequential special ECU”… another one off item, Sequential proudly point out that they haven’t used a piggy back or sub-computer at all, they’ve only modified the standard ECU’s chipset as well as using a ‘NEKO Corporation’ A/F meter and controller which is a different approach to the usual HKS or APEX engine management systems. Kitayama-san also quoted a power figure of 550ps, but that figure was from mid last year, so he didn’t want to go too much into it’s present state of tune… but more on that later. As for the driveline, an OS Giken 5-speed close ratio gear set has been installed into the Silvia gearbox and an EXEDY twin plate clutch transmits power through to an ATS Carbon LSD.
The suspension is somewhat of a mixed bag brand wise too, RG JTC N1 fully adjustable dampers (Sequential special modified version) with Bestex springs rated at 12kg/mm for the front, 10kg/mm for the rear. The suspension arms continue the mixed-brand approach with Cusco adjustable pillow and upper mounts, Cusco toe control arms and Ikeya Formula roll center ‘Type A’ lower arms. Braking has had some serious money spent on it with R33 GT-R Endless 6-pot calipers up front and Endless 4-pot calipers at the back with Endless vented and slotted rotors all round. Sequential frequently change the wheels on this car, but currently they’re Final Speed ‘Eraser’ alloys in 17×9.0JJ front and rear wrapped with Yokohama Advan Neova A048 S-tires in 255/40/17 sizes on all four corners.
Now to the interior, which is all business starting with any unused parts stripped and thrown away… or just put somewhere for safe keeping. The single black Recaro SP-GII seat with Sabelt 4-point harnesses dominates the otherwise empty cabin while most of the modifications are confined to the dashboard. Just about every orifice in the dash has been covered with carbon fiber panels with even two of the five air vents covered up. The air conditioner and audio system area is now home to the HKS EVC3 boost controller, NEKOcorporation AF700 Air/Fuel monitor, NEKOcorporation LCD640 Air/Fuel controller and a host of minor switchgear. Hiding behind the MOMO Type 07 suede steering wheel is the SARD Stack ST8100 display system with single analogue tachometer and LCD readout that takes pride of place where the factory instrument cluster once was, sitting nicely in a SARD carbon fiber meter panel kit incorporating a vertical row of shift lights. Body strengthening inside the cabin comes in the form of a one off roll cage, with the battery, fire extinguisher, ECU and associated wiring all carefully laid along the bare painted floor. In the trunk, a lot of additional bracing has been installed mainly due to the down force produced by the Sard GT Wing… apparently it works, so a lot of pressure is applied to the top of the trunk which would probably buckle and eventually break without the additional support.
So that wraps up what is one of the more serious circuit S15 Silvia’s in Osaka. Sequential have made Silvia’s their main focus, as can be seen on any given day outside their shop. But they tune all makes and models, in fact their EG6 Honda Civic ‘WARU #2’ (悪2号) was there as were a couple of Mitsubishi Lancer Evolutions and others. While I was taking pictures of the garage area, a black R32 Skyline GTS-t was being worked on, which has possibly the craziest body kit in existence on it. On of the mechanics told me that it was most definitely a one off (how many times have we heard that at Sequential!) and it was pretty much an extension of the owners personality… was he joking? If that body kit tells you something about the owner, then I don’t want to meet him! As work was being done to the car at the time, I couldn’t get shots of the front bumper, sorry! Needless to say the front bumper is similar to the rear but with large holes for the intercooler etc.
The Sequential employees were very friendly despite being incredibly busy, there were actually 4 customers in the shop plus the 3 clients that had car troubles mentioned earlier…. and this was a Sunday! I’ll definitely be going back to see their other demo cars, Kitayama-san might even take me out in his personal S14 Silvia K’s drift car, which also happens to be his daily driver. Oh and Sequential will be debuting their all new Silvia demo car at the 2005 Osaka Auto Messe on February 11 – 13.
Car: S15 Nissan Silvia
Torque: ‘about’ 58.0kg/m
Engine Tune: Balanced SR20DET, Toda 2.2L kit, Toda 272 degree cams, Trust conrods, balanced and lightened crank, Toda reinforced valve springs, HKS 1.2mm metal head gasket , NA throttle body, HKS 3037 turbine, HKS racing wastegate, Greddy intake plenum.
Driveline Tune: Silvia gearbox with OS Giken 5-speed close ratio gear set, EXEDY twin plate clutch, ATS Carbon LSD.
Aero Tune: Original ‘one off’ design Sequential body kit incorporating front bumper with carbon fiber splitter, front fenders (50mm wide), side skirts, 50mm rear fenders. Yashio Factory carbon bonnet and carbon trunk lid with carbon plate reinforcements, Sard carbon GT Wing, one off carbon rear diffuser, carbon canard winglets, carbon dummy headlights, Craft Square Tuning Competition mirrors.
Suspension and Braking Tune: RG JTC N1 fully adjustable dampers (Sequential special modified version), Bestex springs rated at 12kg/mm for the front, 10kg/mm for the rear, Cusco adjustable pillow and upper mounts, Cusco toe control arms, Ikeya Formula roll center ‘Type A’ lower arms, R33 GT-R Endless 6-pot calipers (front) Endless 4-pot calipers (rear), Endless vented and slotted rotors all round.
Wheel and Tire Tune: Final Speed ‘Eraser’ alloy wheels 17×9.0JJ front and rear , Yokohama Advan Neova A048 S-tires in 255/40/17 front and rear.
Special Thanks: Kitayama-san and Murota-san for juggling 3 customers and my interview at the same time.
Text and Photos: Justin Karow