vortex’s blog

I’ve come to the decision recently to take my Series 4 RX7 to the next level..

I came so close to selling it, but when I posted it I just couldnt go through with it. It also co-incided with the 2008 SA Rotors Birthday Cruise, I remembered I was a Rotor-head, through and through.. I was thinking of taking the easy path and buying a Skyline - simply for the ease of upgrade in them.

I’ve decided to follow a more interesting path, I’m going to work my RX7 into a fast street car slash circuit stormer - with the ultimate goal of being the quickest street-registered Rotary around Mallala I have a huge task ahead to achieve that goal, considering a local RX7 Series 6 is pulling better-than-IPRA times around there (on slicks). In addition to competing at various events at Mallala, I would also like the car to be eligible for events such as Classic Adelaide Rally, Legend of the Lakes Hillclimb and other hillclimb and tarmac rally events.

My RX7 is a good starting point, already has a nice free flowing exhaust on it, TEIN Coilovers, RX7 Turbo Limited Slip diff and front strut brace. It is at the moment only a 13B 6 port N/A motor; this means it will be considerably more expensive to upgrade the car to the point I want comapared to if my starting point was a 13B Turbo RX7. My engine goal is 13B Turbo Extend Port with around 400HP at the rear wheels.

I have a lot of work to do, and plan to do it in stages:

Stage 1:
Brakes: I have found some awesome 6 pot and 8 pot FC calipers online, however they are INCREDIBLY expensive.. $5,200 for AP racing calipers, disks and pads. Considering I paid $7k for the car, can I justify these (and how the hell would I pay for them)? Will upgraded Disks, Ferodo 2500 pads and RBF 660 fluid be enough? Perhaps the full upgrade cannot be justified at this point, until Stage 2 or 3 is complete. I hope to also install ADR compliant braided brake lines front and rear during stage 1 upgrades.
Wheel and Tire package. 16×7 front and 16×8 rear wheels with Advan A048R tires (IPRA tires), kept off the car for track use (and perhaps the odd hills run) only.
Interior: Upgrade drivers seat, possibly passenger seat, to Sparco FIA compliant fixed bucket seat. Upgrade stock wheel to Sparco Suede wheel. Fit CAMS compliant fire-extinguisher*.
Exterior: Fit CAMS compliant Battery triangles and tow points*.
Engine: Upgrade the cooling system with a PWR radiator and Thermo fan, remove mechanical water pump and install Davies Craig Electric Waterpump. Remove (useless) air-conditioning. Leave heater connected.

I have marked Stage 1 upgrades required before I can compete in Modern Regularity with an asterisk (*). Modern Regularity is a CAMS event where you’re essentially racing the clock rather than the other competitors. I would also like to compete in Super Sprints, however I have not determined what the car elegability requirements are at this point and weather my Stage 1 requirements meet the entry requirements for Super Sprints.

Stage 2:
Engine. It’s all about the engine, baby!
Grab a Series 5 Import motor, and disassemble. Ideally I can find a shortblock without all the ancillary turbo’s and junk I wont be using, and perhaps even one that’s had it’s internals ported and balanced already. Inspect parts and clean. I’ll have to send the plates off to a builder such as Rohan Ambrose or REVS for porting. Add some extra dowells to strengthen the block.
I already have a TO4e/T66 Hybrid turbo for the car. This is a grunty turbo and aparently good for 650HP. Plenty of grunt.
I will need an external wastegate to control the boost. Which one, I dont know. I assume a large one that flows a lot of exhaust!
These engine upgrades also imply fuel system upgrades, too. I’ll have to add a surgetank and few Bosch fuel pumps to supply the juice. Injectors will need to be able to supply a lot of juice, so 4 x 800cc might be enough; perhaps 2 x 800cc and 2 x 1000cc might be more suitable.
ECU: This will need to be able to control fuel and ignition, and any Motec/Haltech/Microtech should fit the bill. I’ve heard Microtech’s are more suited to Drag applications, so that will be investigated at the time.
Clutch: I will need to investigate more at the time, but a brass button clutch or a twinplate may be the way to go here.
Exhaust: Exhaust will need to be modifed to connect to the rear of the turbo via a custom dump pipe. Ensure the ability to remove the catalytic convertor is there for track use only.
Dyno tune. Once everything is fitted, the car will need to be dyno tuned; hoping to find about 400HP at the rear wheels.

When stage 2 is complete, I expect the car to be quite streetable still. It will ideally still have a full interior, stereo (while limited; no subs etc - simply headunit and some average speakers).

Stage 3:
This is where things will get a little more serious. The suspension should be on the way to being adjusted nicely and matched to the rest of the car; but with the new engine no doubt weight distribution may have changed and this will alter the handling. Also if a rollcage is installed at this point that will no doubt affect the chassis stillfness and therefore handling and roadholding as well; and this will need to be taken into account in the suspension setup.
Interior: Complete interior strip, including sound deadner. Install roll-cage.
Brakes: 6 spot calipers will need to be considered as will upsized brake rotors, as being able to reach the goal of ‘fastest registered rotary around mallala’ will require some decent stopping power!
Outside what I have listed, I am not exactly sure what Stage 3 will exactly require yet Such is the nature of a project like this, as you learn about what’s needed you add to it later
Exterior: Perhaps coinciding with the roll-cage install, a complete strip of the car back to baremetal and spray paint in arctic white would be nice. Always loved white FC’s!

Anyway, that was more of a brain-dump. Here’s hoping I can follow through with it!