Mazda RX-7 FD3S - Unstoppable

Last year, we visited Pan Speed to take a closer look at its RX-8 time attack car that has managed to lap Tsukuba in one minute flat, some 10 seconds faster than a stock RX-8 would ever hope to run. This year, however, the company got right back to its FD project with only one thing in mind: Breaking the 55-second barrier at Tsukuba. Pan Speed sure didn't hold back this time around with an all-new widebody conversion and a host of technical improvements,including a much more responsive engine. We met up with Pan Speed at Tsukuba for the car's first shakedown test.

There's no denying that Mazda created a small masterpiece with the RX-7. No matter how you look at it, this rotary-powered sports car is both ingenious and simple. All of the main requisites for making a car perform well are there. It's relatively light, well balanced, adequately powered, and has an honest, no-nonsense rear-wheel-drive layout. Dig deeper and at its heart the incredibly compact 13B twin rotor Wankel engine buzzes away-its size allows it to be placed right back against the firewall. With such a great package to start off with, it's almost a given that a car of this nature would thrive in the aftermarket tuning world. Pan Speed, a company that has been at the forefront of rotary tuning, has just rolled out of its small workshop this monstrous widebody FD3S.

This RX-7 managed to lap Tsukuba in 55.603 seconds at the Hyper Rev Lap Battle in December. Still running the older engine, it managed to finish in Second position overall, over a second behind the M-Speed GT-R. The target for this year is to go well into the 54 seconds, something that shouldn't be too hard to achieve with the new, more responsive engine and improved suspension setup.

The Pan Speed 13B meticulously prepared for its task by being subjected to a healthy dose of side porting. In rotary terms this is the equivalent of running some hot camshafts on a regular four-cycle piston engine. This is much more of a black art, however, than most will imagine and Pan Speed has had decades of experience in this sector with all sorts of hi-powered engines. Any amount of side porting can be detected as soon as the engine is turned on, as it seems to hunt up and down the revs until it settles into a menacing offbeat idle. Once the engine was closed up with upgraded apex seals it was onto the forced-induction improvements. To run the HKS T04Z, Pan Speed fabricated a 50mm manifold to feed the exhaust gasses into the turbine side of the blower. From there it's down to the massive 90mm straight titanium exhaust system to channel the spent gasses all the way to the back of the car.

Boost is controlled by a Blitz RC external wastegate, which works in conjunction with the dual solenoids of the Blitz boost controller module. Actual control of all this, however, is handled by the Motec M800 ECU unit that limits boost at 1.2 bar. This allows the engine to be extremely responsive without developing stratospheric levels of power that wouldn't be adequate for track use. For this first step of tuning the engine pushes out 503 hp, which thanks to the 2,403 pounds gives a very healthy power-to-weight ratio. No form of filtering is applied to the T04Z, and a rather large aluminum air guide channels fresh air from the bumper intake directly to it, in an almost ram-air type layout.

Once the intake charge has been compressed it's then passed on to the flat-mounted Blitz intercooler, which for optimal airflow has been mounted in a V-pattern with the radiator. To create an almost airtight seal against the carbon hood, the intercooler is surrounded with a sort of seal, again made from carbon fiber. This allows the air passing through the radiator and intercooler to be expelled immediately via the hood's outlet. This helps keep engine bay temperatures as low as possible. More custom piping connects the intercooler to the Pan Speed intake U-bend, where the two small valves for boost control are fitted. From here it's on to the stock intake manifold.