510 four-link rear suspension conversion,worth the effort?
the stock semi-trailing arm rear suspension on the 510 is good but ive heard a four-link conversion improves traction and eliminates the camber change issue under load. is anyone running a four-link on a 510 in australia? and can you still register the car in victoria after the modification? dont want to build something i cant drive on the road.
Four-link is a big modification and VicRoads will require an engineer's certificate for the suspension change. Budget $500-800 just for the engineering sign-off. For a road-registered car I'd recommend upgrading the existing semi-trailing arm setup first. Stiffer springs, adjustable shocks, and a panhard rod to locate the axle laterally will transform the handling without needing engineering approval. The factory IRS on the 510 is genuinely good and most of its limitations are in the bushings and springs, not the geometry.
engineering cert is mandatory in vic for suspension geometry changes. the inspectors are strict on anything structural. if its mainly a street car id keep the factory setup and improve it rather than going four-link. save that for a dedicated race car.