09-18-2019, 10:06 AM | #15 | |
Drives: A10 LT4 Join Date: Aug 2016
Location: Deep South TX
Posts: 1,094
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09-19-2019, 12:15 PM | #16 | |
Drives: 2018 Camaro ZL1-1LE Join Date: Jul 2012
Location: Western NC
Posts: 405
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But unfortunately it's a bit more complicated (and costly) to GM than simply upgrading to a stiffer valve-spring to support higher-revs. Because the valve-train works as a complimentary system of matched components - upgrading to a spring capable of handling 8-9k RPM, also involves upgrading the lifters. I've never pressure tested a stock hydraulic lifter, but I would imagine that the lift pressures for a 9K rpm capable-spring would eventually collapse the existing stock hydraulic units - it wouldn't be a matter of "if", but "when". Then course then you're upgrading to stronger pushrods and rocker-arms as well. I've bent more than my share of pushrods (on LS-based motors) - it doesn't take much. Finally GM has to consider the fuel-economy penalty associated with the increased resistance of a stiffer spring. While that may not matter to most of us - as a manufacturer, every single mpg could mean life-or-death for a product.
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2018 Camaro ZL1/1LE
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09-20-2019, 03:59 PM | #17 |
Drives: 2018 Hyper Blue ZL1 1LE Join Date: Dec 2018
Location: CA
Posts: 1,360
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I tried my best to make it clear that I wasn't trying to create a higher revving ZL1, or upgrade the ZL1 valve-train for sustained high RPM capability or raising the RPM limiter AT ALL, just to protect it during the unlikely event that an M6 owner downshifted too low or an A10 had an issue like this, so the valves don't float and hit the pistons. If they have to upgrade the lifters too, well worth the better protection.
With my Evo X, it was pretty simple to add GSC single high rev springs and go from stock 7600 RPM capability to over 9000. No change in lifters or anything else in valve-train, except cams With these 9500 RPM springs I was able to raise my rev limit on my built motor 2.0 to 8700, and it spun like a top with zero issues for several years and many great track days. I doubt the effect from higher rated springs on gas mileage with the ZL1, if any, would be noticeable. |
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