Originally Posted by
jeffwrx
Just out of interest if pre- 96 sti and wrx's have the same heads, how come the sti /wrx ra , has a higher rev limit , just i have a pp chip/ecu from a wrx ra with the higher rev limit, fitted in my 95 wrx and was told not to rev it past 7000rpm as the hydraulic valve lifters can't keep up past 7000 rpm, not that i want to rev it past that , just wondered whats different , cheers
As you said, Hydraulic lifters can pump up at higher sustained rpm's but the Early STi's with Hydraulic heads have lightweight hydraulic lifters fitted - each one is approx 10g lighter (when stripped and cleaned) than the WRX one's - that makes for a nice weight saving on the valvetrain.
STi Version 2 RA had Top hat Inner shims instead of hydraulic lifters.
Mick