Why do the engine upgrades only significantly effect the Sultan?

[F63]

It would seem as though the other cars' engine upgrades don't do jack sh*t and are simply a waste of money. But why does it seem to be like a second turbo boost for the Sultan? Any specific reason? Is the Sultan the quickest non-super car?

[Chyrus]

The Sultan is the fastes 4-door Sedan^

[WildmouseX]

It's actually a sports car, and not sure if it's the fastest, but the most versatile

[lRushdown]

Looks like it increases acceleration the same amount on every vehicle to me. Maybe it's because you're buying turbo first, and for most good cars the turbo will appear to max the acceleration in LSC. Then you buy the engine upgrade and you can't see the extra accel that it's adding (because the LSC bars only go to 5, and the true max is 10). But the Sultan's accel starts so low that you can see some of the accel it adds even after buying turbo.

 

edited typo

Edited October 28, 2013 by lRushdown