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| For some reason, the upper link is a heavy and probably expensive forged steel piece instead of a stamping. The upper link has to snake around some stuff and is an odd shape so maybe a forging is easier to make in an odd geometry as perhaps it is hard to form an elaborate stamping unless an expensive progressive die is used. It has an eccentric so camber can be adjusted to a degree. The upper arm has a forward cant which defines the forward instant center and controls the amount of antisquat in the suspension geometry. Look for an aftermarket part with more camber adjustment and lighter weight here. |
Overall, we were pretty impressed with what we saw with the suspension geometry and the suspension in general. This is a very pure and straightforward suspension which will work well out of the blocks and be highly responsive to tuning by the aftermarket and racer. We can’t wait to see what the aftermarket will cook up and we have some very good ideas of what it will take to tweek the car correctly. We are available for consulting!
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| Another view of what is probably a pretty firm subframe bushing and the small diameter anti sway bar. Like the front sway bar the rear sway bar has short moment arms so it is stiffer than it looks. This also makes for lighter, albeit more highly stressed, bars. |
More proof that the FR-S was designed to be a driver’s car is the factory standard equipment limited slip differential. An LSD is essential as it allows the driver to steer with the throttle and greatly help corner exit traction and acceleration. A manufacturer actually providing both RWD and LSD in a compact car is so refreshing. The FR-S LSD is a gear type, much like a Quaife or Torsen unit. It works by the spider gears driving worm gears instead of the side gears in a conventional diff. When the axles spin together the spider gears allow the whole differential to work freely. If the axles turn at different rates, the spider gears put a thrust load on the worm gears driving their ends into the differential case locking the differential together. A gear type LSD is great for a lower powered car working smoothly quietly and seamlessly. When the power gets above 400 hp or so, a clutch type diff is preferred for a more consistent lock at high power levels.
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| The rear diff is thankfully a Toyota unit that is already used in the IS250, IS300, Non turbo Supra and just about all mid powered Toyotas. This means that any number of good aftermarket clutch type differentials can readily be found for the car. |
Getting an aftermarket clutch type LSD is going to be a piece of cake for the FR-S and drifters and grip drivers will both rejoice. The diff used is the same found throughout the Toyota lineup in mid powered RWD cars such as the IS250, IS300 and non turbo Supra. There are many excellent aftermarket LSD units available for this diff.
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| The stock diff is an LSD unit which is great news. It is a gear type that uses thrust loads on the helical worm gears to create a locking action. The Toyota part is very much like a Quaife or Torsen diff. This sort of diff has been used on the Supra, Sentra SE-R, Early FD RX-7's and Audis. It is very smooth and works well on lower powered cars. For higher powered cars, a clutch type diff gives more predictable lock up so the stock diff should be fine until folks start swapping EJ25's or turboing the stock engine! |
In reviewing the design of the FR-S, we are very excited about it; it is the right size, the right weight and most importantly, the right price. The FR-S has a great style unlike any low priced compact car that has come out from any of the manufacturer for years. It should be blessed with sparkling performance and a ton of tuneability from the aftermarket. With pent up demand from years of enthusiast yearning, the FR-S should be a good seller and will firmly put the Scion brand on the respect quadrant of the map! We can’t wait to get our hands on one!
