Fully locked diffs in RWD front engined live axled cars.

[Al Weyman]

I was surprised to discover that when the IROC NASCAR race cars were used on a road course they used a fully locked diff not a slipper but used a slipper on an oval course. I am having trouble getting power down to the ground on my reasonably powerful front engined RWD car and wondered if I should go the same route. I have spoken with a friend who raced a powerful SDI and he recon he locked the diff up so tight it may as well be fully locked so i wondered if anyone else has had any experience circuit racing (road racing in the US) with a fully locked diff and what were your impressions of the set up. I would imagine with a FWD car it would be undriveable and with an IRS car unneccessary which is why I am asking about a front engined rear wheel drive car with solid live rear axle which by its very nature will tend to lift a rear wheel at high cornering speed and loose traction.