Stock Valves @High Boost, RWHP
02-28-2009, 08:25 PM
#5
I wouldn't get too caught up in the worry about valve material untill you are really trying to push the limits of what you have and if you have a stock motor you will run into limits before you have problems with valves. I have seen people make 800rwhp on a stock set of heads with springs. I think it is a problem with longevity. Use comon sense. I wouldn't skimp on a big project's heads etc...
02-28-2009, 08:25 PM
#6
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Many people on here have run stock valves to 1,000+hp. There are multiple reasons people switch.
For example on my heads (L92) they come with a very large, and heavy intake valve. Most people replace this with the LS3 valve to reduce weight and help with valvetrain stabilty. Others replace valves to a different type of material thats less prone to heat soak, and less likely to cause detonation.
Manley, and Rev are two good companies. But you don't need to replace these unless you are one of those people who try to safety-proof everything.
For example on my heads (L92) they come with a very large, and heavy intake valve. Most people replace this with the LS3 valve to reduce weight and help with valvetrain stabilty. Others replace valves to a different type of material thats less prone to heat soak, and less likely to cause detonation.
Manley, and Rev are two good companies. But you don't need to replace these unless you are one of those people who try to safety-proof everything.
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03-01-2009, 10:28 AM
#8
So far mine has seen a couple dyno pulls to 15psi with stock 317 valves and has been fine. When its said and done it'll see peak boost at no higher than 13.5psi on 91 octane pump. I don't think you'd need to upgrade to stainless or inconel til your exhaust temperatures reach above average temps (caused from high boost - over 20psi, higher octanes - C16 type gas, and/or higher compression or a mix of these)
03-01-2009, 01:53 PM
#10
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It's a matter of heat on the exhaust valves. If you exceed the heat of the valve material it could stretch. Most will never see this issue here but it's something I would do if I were building a high HP setup and pushing it.
