| [ http://www.twinturbo.net/net/viewmsg.aspx?forum=technical&msg_id=839668 ] If you look at the horsepower curve of a Z with xxx turbos and compare it to the horsepower curve of a Z with stock turbos, you can clearly see the difference in spoolup. The quicker spooling turbo will make more power earlier on in the rpm range. You can directly compare the power curve of each, and the separation between the curve produced by stock turbos and the curve produced by the other turbos really illustrates the difference in spoolup characteristics. Turbos like sport 500's spool up almost as fast as stock, as seen in the first graph on that page. The GT2530's, while often credited with having "like stock" spoolup clearly don't have spoolup like the stock turbos. Bernie even goes out of his way to state that. The second to last chart on that page shows the curves of all the turbos compared with each other. While some of the curves come from only 1 sample, they still give you a pretty good idea what the turbo will do. For example, you're not going to get a guy with a TD05-18G that miraculously spools like stock- all turbos of a specific model will be within a pretty small range. On just about all of the charts on there, the lag is directly proportionate to the power that the turbo is capable of putting out. That's because most turbo upgrades are spec'ed as close to optimally as they could get it. The only exception is the T25/T28's which have a ton of lag and don't make good power either, and as we all know that's because they were not designed properly to begin with. For all the others, the lag is proportional to the power. Even the new Sport 530's have slightly more lag than the old Sport 500's, and make slighly more power. In fact, you don't see any well designed turbo on there which produces more power AND has less lag than another type. That's the stuff that hype is made of but unfortunately reality doesn't coincide with the hype.
 |
