... i was wondering if anyone out there runs this setup or knows anything about it... i have been told with this little budget valvetrain upgrade, you can safely rev to 8500-9000rpm... any truth to this?... i was told that this is possible because the intake springs are stiffer than the exhaust springs... lemme know... thanks...




Modified by 1.8T_EG at 8:10 PM 4/25/2003

 

Running the itr intake springs, with the gsr intake springs on the exhaust side is exactly what the itr head runs. If you are using stock cams such as si or gsr, the lift is not enough to bind the itr springs even at 9K. You'll be fine till 9K.

 

... thanks... so 9k is about the limit?... i am just trying to figure out where to set my rev limit... lemme know what you think... thanks...

 

Without having the spring rates, and other pertainent information of the stock cam/spring set-up I cannot give an accurate answer.

 

i always thought the type R springs have less spring tension, then stock gsr. the way type r are able to rev higher is because the valvetrain is lighter. so w/out type R valves, wouldn't u have less spring tension and a heavier valvetrain and possibly a better chance to float a valve? i also heard type r valvesprings have .040'' more clearence to avoid coil bind.

 

Spring tension, or spring rate of a spring for a higher lift cam MUST be stiffer. The spring rate basically dictates how the spring is going to take the higher lift of the cam when it pushes against it. The stiffer spring dampers the oscillations that a softer spring would experience. The softer spring with a higher lift cam at high rpms would yield valve float since the oscillations of the spring would be to great. The type r valve train is lighter from the material properites of the valves. The dimensions and material properties of the retainers and springs could be lighter, but I really have no idea. I am still teaching myself cam/rocker design but this stuff is very basic.

 

thanks for the info boosted_hybrid... anyone else have any thoughts?... lemme know... thanks...