My unorthodox 3.0L 16valve build using native 2.5 engine
11-28-2014, 09:36 PM
#31
Rennlist Member
Here's my take: I use Porsche springs whenever the cams will allow enough seat pressure and distance to coil bind. Otherwise, I use some good aftermarket springs. The challenge is finding aftermarket stuff that really is high quality and with excellent QC. I've been stung with broken (aftermarket) springs that make an awful mess of a good engine. Good springs are expensive. If the price seems 'reasonable', beware!
Over-reving to the point where the cam lobe loses control of the lifter is death to springs. Even Porsche springs will eventually break in that case.
I've got many, many track miles on engines that shift at 8000 using the S2 (sometimes on the exhaust where lift is typically lower) and the S springs. I've even missed shifts in the heat of battle with my own car and gone over 9K - springs held up fine (with good solid lifter cams). The Porsche springs will often work with performance hydraulic cams and will go to 7500.
Over-reving to the point where the cam lobe loses control of the lifter is death to springs. Even Porsche springs will eventually break in that case.
I've got many, many track miles on engines that shift at 8000 using the S2 (sometimes on the exhaust where lift is typically lower) and the S springs. I've even missed shifts in the heat of battle with my own car and gone over 9K - springs held up fine (with good solid lifter cams). The Porsche springs will often work with performance hydraulic cams and will go to 7500.
Last edited by michaelmount123; 11-28-2014 at 09:41 PM. Reason: added a few things
