c5dream

iTrader: (1)

Well, can those springs handle the lift? These PP gold springs sure are really heavy duty makes valvetrain noisy.

yak

iTrader: (15)

I have an X3 with PP golds. I cannot hear my valvetrain over the lope, and overall rumble. use a dual spring for the peice of mind

DONAIMIAN

iTrader: (18)

I belvie someone has used an X4 with with the 918's they can stand up to a lot more than people think.

yak

iTrader: (15)

you can use the 918's but you need to shim them in order to make them fit properly (pressure) you will make more power with a single spring too. With those fast ramp rates I would not run a single spring just incase i broke a spring at 7k

8banger

iTrader: (16)

What kind of shims? where would you get them?

PREDATOR-Z

There is a thread by J-Rod in the advanced section all about high lift cams and beehive lightweight springs.

Light valves
Titanium retainers
918's shimmed (.100) from coilbind
Stock rockers

Make for some of the best harmonicaly controled valvetrain at high rpms.

I've taken 918's till 7200 rpms on a drag only setup and only changed them once a year (on initial change none had lost any pressure (60 passes))

Those are awsome springs.