Performance impact of using bigger wheels?

[Tecate]

I have a 2000 GTS, considering replacing the stock 16" yokos with something at 18", what would be the performance impact of doing this? I understand the basic physics, but... how would the car's performance change? Difference at launch, low-RPM vs high-RPM, low speed vs. high speed, etc.? I'm thinking about dropping in the blitz supercharger and nos at some point, if that makes a difference.
If anyone has a good web/book reference to recommend, that would be awesome..
Also- after changing the wheelsize, what else needs to be done to re-calibrate the car? wheel alignment, etc.?
Thanks..P

[erok]

http://www.grassrootsmotorsports.com/plustest.html

18" wheels will make it hard to keep the stock rolling diameter without going with super low- profile tires. Then you'll have to worry about rim damage. But they do look good.

[larryd]

if yer worried about performance then dont get 18s..its that simple.. they dont slow u down that much but its enough to get beat :)

[Tecate]

Thanks for the link. Sounds like larger wheels would improve handling but might not help launch/straight line times that much.. and the money could be better spent somewhere else if improving drag times is the goal. In the article that erok mentioned, they used flying starts, but got better times with the larger wheels. I bet there would be less improvement without the flying start..

[QWKsilvr808]

I lost 13hp to the wheels at the 6k lift crossover with my 18's vs. my stocks. The car doesn't seem terribly slower while running on the street, but it is just a tad. For track days I just swap the stocks on.

Depends on if you really like the LOOK of the 18's and aren't very hardcore into the street racing scene. I like the look, but I race on the track, so it works for me.