Welcome Guest [Log In] [Register]
Posted ImageWelcome to the all new Geo Metro Forum. We hope you enjoy your visit.

You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features:

Join our community!




Username:   Password:
Add Reply
Stiffer valve springs - anyone have them?
Topic Started: Feb 10 2010, 12:19 AM (2,400 Views)
Dallas


suprf1y
Feb 15 2010, 05:01 PM
Keep in mind that's 28 psi on the wrong side of the valve (coming into the intake port) when the valve is closed.
I meant peak combustion pressure between all that boost and n/a
Offline Profile Quote Post Goto Top
 
3tech
Member Avatar


Compression, and cylinder pressure are not a factor in choosing springs. One has nothing to do with the other.
Offline Profile Quote Post Goto Top
 
mwebb
Member Avatar
FOG

Dallas
Feb 16 2010, 12:57 PM
suprf1y
Feb 15 2010, 05:01 PM
Keep in mind that's 28 psi on the wrong side of the valve (coming into the intake port) when the valve is closed.
I meant peak combustion pressure between all that boost and n/a
what ?

ambient baro = about 15psi at sea level , a bit less at higher elevations .

boost = i dunno , 7 8 psi for most OEM turbocharged systems .

combustion pressure can get to 500psi , but most of the time very much less depending on conditions and the system involved ...
but not relevant as that will hold the valve closed .
and in a normal world the cam will not try to open the valve during combustion .
so peak valve seat pressure is not a function of the valve spring .

the spring s are tested at 28 psi

an NA engine may have 20" of vacuum at idle 25" on decel
vacuum peak of 12.5 psi which is being resisted by a 28 psi spring ...
that works
28- 12.5 = 15.5 in reserve , so you can not exceed 15.5 psi of boost and have the valve close
but there is no boost on decel.

what relationship are you referring to ?
Offline Profile Quote Post Goto Top
 
earthtoad


google "Ferarra" or something like that........
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
« Previous Topic · Engine Tech & Diagnostics · Next Topic »
Add Reply