Mazda RX7 Series 6
Balance of power R and D Project
When the FD Series 6 RX7 was released it was touted as one of the best handling Japanese cars on the market. It was extremely well balanced and could easily out-perform a lot of traditionally great handling cars from Europe. Like most things in life there is always room for improvement and upgrading the suspension can take the little Series 6 from being good to simply awesome.
TEIN Inc. Suspensions have been tuning the Series 6 RX7's suspension with their renowned coil-over suspension since the car was released on the JDM market and have applied that knowledge to the Australian market. Fulcrum Suspensions are the official distributorship for TEIN in the Australian market. Both companies being suspension specialists have recognized that Australian roads are vastly different to the Japanese roads that the product was originally developed for. TEIN Inc. sent their Research and Development (R&D) Manager Mr. Ippei Sugano to Fulcrum Suspensions Headquarters in Brisbane to further develop the TEIN Super Street Coil-over suspension for Aussie conditions.
Ippei was in charge of testing different damper valve and spring rates to configure a suspension that will be more suited to the average Australian road, which can often present drivers with poorly maintained or inconsistent surfaces. By performing the R&D process on the RX7, TEIN and Fulcrum aimed to increase cornering speed, predictability and give the driver more control.
The TEIN suspension used is completely height adjustable, however it is shipped at a preset height that is most suitable to Australian roads and still remains legal. Ride quality is largely determined by the Damper Force adjustment dial that sits on top of the suspension. If you are planning a day at the track and require an unyielding firmness than twist the dial as far clockwise as you can. If you want a bit of comfort the start twisting it in the opposite direction. For each click you hear means a softer setting. Somewhere between 8 and 10 is usually most suitable for the street.
Factory cars rarely come to close to the 100mm ride height level. This particular example was lowered by 25 mm (or an inch if you are old school). The new ride height gives the car a sleeker and more purposeful look.
Often the need for high performance suspension is overlooked, and some modifiers seem to think if it looks low than that is good enough. Having ridden in a FD RX7 that was literally scraping the ground, describing the ride as being rock hard was being very generous. The owner had modified the engine with a turbo you could lose your cat in, it had close to 500 horsepower. The power delivery of the engine was very laggy and when the boost finally kicked on it was a matter of hang on for dear life. Sounds like fun? Well, no actually. Because this particularly FD RX7 had no suspension travel, there was not enough weight transfer taking place as the laws of physics usually dictate. What would happen was the tyres would easily break traction and make getting anywhere really fast seem impossible and he would get beaten by people with much less horsepower. A good quality well set up suspension package will go along way to alleviate this issue, sure it won't look as cool but you'll be ahead of your 'fully sick' competitor.
The owner of this FD Series 6 RX7 has only one thing to worry about now and that is trying to get out and enjoy his car as much as possible. He can relax knowing that he is driving on state of the art suspension that has been developed with our roads in mind. Next time he decides to attack some of his favourite corners he doesn't have to worry about finding some bumps on the apex because Ippei, the R&D manager from TEIN Inc. has spent many hours coming up with the right ingredients for a confidence building drive. Anyone who drives a high tech car should now be able to order this dish straight off the menu.
Mr. Ippei Sugano takes the FD RX7 on its Ride Evaluation Test. An experienced tester can tell a lot from the seat of the pants drive, and the pre installation drive gives a good basis to see where the improvements can be made.
Corner weight scales give you an accurate snapshot of how much weight each of the four shocks will have to support. One thing that is interesting to note is that this is a stationary measurement. If your car is accelerating more weight will be transferred to the rear shocks and if you are stopping the bulk of the weight will transfer to the front. The TEIN Coil-Overs will allow you to control this transfer of weight using the Damper Force adjustments.
Starting with a platform that is light and has an almost 50/50 weight distribution certainly gives a performance advantage. The FD Series RX7 scores an A plus 
for its identical weights in each corner. Putting your car on a corner weight scale would be especially beneficial if you have transplanted a heavier or lighter engine into your car, i.e. An RB26dett into a 180SX will generally make it front heavy but you can change damper and spring rates to compensate. You will see how much the weight distribution has been altered and you can have the Damper Force and Rebound rates modified in your TEIN suspension when you order it to suit.
As far as standard suspension goes the spring and strut set up on the FD RX7 is ok but like most OEM cars is marred with a little body roll and the ride tends to crash through the bumps a little. The age of the car doesn't help this.
Ippei removes the standard suspension from the car.
Although its a very simple modification, most cars do benefit from strut tower braces. This is standard in the FD RX7 and helps to keep the body rigid. The strut brace must come off to remove the suspension.
Ippei measures and collects data from the standard suspension. A crucial part of TEIN R&D is to make sure without a doubt their suspension is far superior to the OEM product it replaces. To do this they must know every minute detail of it. The data is used to help develop new products and refine what they already have.
Ippei measures both the opened and closed lengths of shock to determine the length of travel standard Mazda shocks have. The standard shocks are compressed using a trolley jack under the hub. It is also important to remove the spring while performing these tests.
The same shock compression tests are performed on the TEIN suspension, Ippei declares that the upgraded TEIN suspension will offer about 25mm of extra travel. The occupants of the car will now enjoy an increase in comfort as the suspension can handle more inconsistencies on the road.
Ippei re-assembles the TEIN Suspension with the springs for installation prior to the road test. Ride height is set using the adjusters on the thread. Ultimately the ideal height will leave a clearance of 100mm. It is quite easy to adjust using the C spanner included in the kit. Japanese kits tend to leave a clearance of 90mm as that is Japan's legal ride height.
Story and Photos from Chris Gentle.
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