valve springs for boost.
12-03-2009, 11:14 PM
#21
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if you are going to upgrade the valve springs, with something like patriot's extreme, then there will be a chain reaction of spending. you will need to upgrade the pushrods, factory pushrods will not like the added stress (there where actually designed to be the first thing to break in the valvetrain) , and then you will need to upgrade the timing chain, a dual roller would be nice but not necessary. if you do not do it and your timing chain snaps, the motor is pretty much done.
12-03-2009, 11:40 PM
#23
When I first put my turbo together, I was on a bone stock LQ9 long block. The only thing that I changed was the pushrods. Granted, I only reved it to 6200 RPM but I put 15 psi of boost to it with no valve float. I have serious doubts that 15 psi would have any effect on valves floating unless the seat pressure is already on the very low end of what the cam needs.
12-03-2009, 11:52 PM
#24
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i have patriots extreme valve springs, comp 7.4 pushrods, stock rockers, jp dual roller, ls7 lifters. so far they have help up to 13 psi very well. will be pushing it some more after i switch to twins
12-04-2009, 08:23 PM
#25
Sorry for the slow response.. I spin the car to 6500rpm when racing, but the float was happening just above peak tq. I was seeing the float at 13lbs of boost. The valvesprings were/are shimmed. Running cadillac lifters at the moment. I have not pushed the car in a long time. No clue if the float is gone since I dont race the car anymore.. I will be upgrading the valvetrain soon. FMS is going to put yella terra's on her and put new valve springs on her.
12-13-2009, 06:25 PM
#28
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^^^ yea until you snap your timing chain, and it is just a mater of time with those springs, even worse if you have a bigger cam.
you need to upgrade to a dual roller or atleast something better then the stoker.
if the timing chain goes your motor is done
and "good to about 15 psi" is a bad statement, because 15 psi on a 67mm turbo is much different then 15 psi on a 76mm turbo.
you need to upgrade to a dual roller or atleast something better then the stoker.
if the timing chain goes your motor is done
and "good to about 15 psi" is a bad statement, because 15 psi on a 67mm turbo is much different then 15 psi on a 76mm turbo.
12-13-2009, 07:41 PM
#30
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I use comp 918s installed at 1.65 with a .550 cam on my 5.3. I have ran into valve float on patriot duals with 15 psi. only had 5k on them with .600 lift xer lobe on my 382
