One of the more popular methods of combating this condition is the use to a pair or more of smaller turbos in lieu of a larger turbo to gain the same amount of boost. While introducing a extra degree of
expense and
complexity, the fact that a smaller
turbocharger has a smaller rotor, and thus less rotational mass makes this method quite effective. Some times it is taken to extremes, as was seen in
Ford's
GT90, which had a quad turbochaging set up. The resulting amount of exaust and intake manifold tubing was obscene.
There is another method of combating turbo lag, which is noisy,
dangerous, hard on equipment, and
lots of fun. It involved placing some sort of fuel delivery port upstream of the turbocharger in the
exaust manifold, usually some sort of
fuel injector. When braking through corners some fuel is dumped through this port, which ignites and keeps the turbo spinning like a top. This method amounts to controlled
backfiring of the engine. What fun...