Basically, driveshaft loops are required on any front-engine, rear-wheel-drive vehicle that has either had an engine transplant or substantial modifications to the original engine that result in a power increase of 20 per cent or more. They are required to be 360 degrees around the driveshaft, and be as close to round as possible. You also want it to be as small as possible, allowing for clearance as the suspension articulates.
• Material: they need to be made from at least 5mm thick mild steel by 50mm wide. I use five-inch schedule 40 pipe for the loop itself, and make that 60mm wide to make the 50mm flat bar nicer to• Location: they need to be within 250mm of the front universal of each driveshaft. The measurement used to be 150mm, but that was changed to 250mm a few years back to help with packaging on some cars.• Attachment: each side needs at least two 3⁄8-inch or 10mm bolts, with nylocks or spring washers. They also need a doubler plate inside the floor that is 3mm thick mild steel, with a minimum surface area of 3000mm. A common size example would be 50x60mm.
