Valve Float! Onset at what stage?
Valve Float! Onset at what stage? Good afternoon to everyone.
I would like to research turbo users' opinions on "Valve float."
With FI, at what psi do some of you feel the stock valve springs will begin to be inadequate?
The reason I am asking is that I plan to run somewhere around 5-6#, intercooled (if that makes a difference). I do not wish to run more because forging connecting rods and pistons is out of my immediate budget (maybe next year...). I must keep my stock bottom end for now, and I've been reassured that 420-460 approximate rwhp will be fine for a stock bottom end with the right tune on an LS1 that might be driven hard but will virtually see no track time whatsoever for the time being (maybe next year...). First of all, do some of you agree with that?
Secondly, what about the valve springs. With this application, might I experience some valve float?
You guys all know so much about this stuff. I try to learn all I can by doing some lurkin' and only bother you guys when I have a serious post. I hope I can get some answers...
Much appreciated!
I would like to research turbo users' opinions on "Valve float."
With FI, at what psi do some of you feel the stock valve springs will begin to be inadequate?
The reason I am asking is that I plan to run somewhere around 5-6#, intercooled (if that makes a difference). I do not wish to run more because forging connecting rods and pistons is out of my immediate budget (maybe next year...). I must keep my stock bottom end for now, and I've been reassured that 420-460 approximate rwhp will be fine for a stock bottom end with the right tune on an LS1 that might be driven hard but will virtually see no track time whatsoever for the time being (maybe next year...). First of all, do some of you agree with that?
Secondly, what about the valve springs. With this application, might I experience some valve float?
You guys all know so much about this stuff. I try to learn all I can by doing some lurkin' and only bother you guys when I have a serious post. I hope I can get some answers...
Much appreciated!
Originally Posted by 8KickassRS9
boost wont effect valve action. valve action will effect boost. if u do a cam of any kind you will need springs.
as quoted from another member
I have to agree that boost will effect your valve spring choice, I just don't know how much it can become a problem or at what psi it is an issue.
This is one of the biggest problems that I face at this point. As long as I stay in low boost, the springs can handle it. However, the more you push, the worse it will get. Upgraded springs should do the trick. I plan on going with the comp dual's. Hopefully that will solve the problem. Although, I wouldn't suggest leaving the problem alone because it can ultimately cause more problems than just loss of power.
It depends on the condition that your valve springs are in. Some stock vehicles we don't see any problems with valve float under boost. On vehicles that have the problem typically, between 6-8 psi the valve float starts on vehicles that have the problem.
A fairly cheap solution would be to install CC 918 springs. They replace stock and will solve the problem. Ignoring valve float will eventually lead to a failed spring. A failed spring can mean simple valve damage or having to replace pistons and heads......very risky.
A fairly cheap solution would be to install CC 918 springs. They replace stock and will solve the problem. Ignoring valve float will eventually lead to a failed spring. A failed spring can mean simple valve damage or having to replace pistons and heads......very risky.
Originally Posted by 8KickassRS9
boost wont effect valve action. valve action will effect boost. if u do a cam of any kind you will need springs.
Most folks say "8 psi?!? pfft, my springs are 300 lb close, they won't even notice the boost". However, it isn't that simple. The force that the boost enacts on your valve is a function of the area of the backside of your valve and the differential pressure between the cylinder and the manifold.
Lets say you have a turbo fully spooled on the freeway to 8psi capability and you just dropped the hammer. For that moment in time, the amount of additional force that your intake valve spring needs to pull the valve shut can be up to an additional 50 lbs of force just from boost alone.
