Is there a benefit to having a lightened flighwheel in a turbo car? And effect on spool up characteristics?

 

Lighter the Flywheel/Crank Pulley/ Crank = The faster you rev= The faster you spool.

 

Spool is all about load...if your engine revs faster with less load then its going to take more RPM to spool the turbo. It isn't necessarily going to spool faster or slower, but it will change the RPM at which the turbo spools.

I have an 11lb flywheel on my turbo GSR and it still spools fast...3800rpm full boost on my GT3255b

 

That is 100 percent true, but ultimately the faster you can rev is the faster you can build load allowing a faster spool.

 

lightweight FW's can make it difficult to launch for some people.. it really depends on your preference