at what psi is the stock b16 valve springs(dual in single ex) no longer safe?

 

I'd say under 14-15 psi there's no problem, if everything else is done right.

 

Boost pressure doesn't play too much role in the safety of your valvesprings-- that's more of a rev and cam thing.

 

ok it will only be revved to 8k and stock b16cams...i was just worried if it had like 15..18psi that it might try to push the intake valves open or somthin...just wanted to make sure...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccivic &raquo;</TD></TR><TR><TD CLASS="quote">Boost pressure doesn't play too much role in the safety of your valvesprings-- that's more of a rev and cam thing.</TD></TR></TABLE>

You have got to be kidding me.... If that were only true.

 

It would have to be alot of boost pressure to affect the opening and closing of a valve.

Im not sure of what the stock seat pressure is, but i doubt 18psi more is going to affect it.

So like dude said, its going to be more of a rev and cam thing than anything else.

 

the springs of the head Pr4 B18A have 180psi of pressure in the seat valve, you have need more of 180psi for open the valve......... in the b16 is the same..

 

exactly, so 18psi of boost pressure is not going to change much.

Pluse, the cam shaft is opening the valve so the only thing boost is going to do is make it close faster, which is what we want to avoid float.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93supercoupe &raquo;</TD></TR><TR><TD CLASS="quote">exactly, so 18psi of boost pressure is not going to change much.

</TD></TR></TABLE>



It's kind of like when people ask "how many pounds of boost can I run before my motor blowzzz up guyz?", it's not really about the psi. If you keep stock rev limit and completely stock valvetrain, you should be alright with probably 20 pounds or so, and thats being safe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tepid1 &raquo;</TD></TR><TR><TD CLASS="quote">

You have got to be kidding me.... If that were only true.</TD></TR></TABLE>
Care to elaborate? Like someone above stated.. it takes a lot more than 10-20psi to even affect the state of the valve.

 

Well you might want to rethink that, boost, revs, cam profiles, age of the springs, they all play a role. Dropping a valve is never a good thing. Also 18psi is different from a T25 to a GT42R, so you really need all the facts. Me personally, I always replace the valve springs in all my heads. Boosted cars are fun, but not when they're not sitting in your garage.

 

ITR valve springs
obd0 B16 cams
8200 rpms
27psi
62-1 Stage5 wheel.

= valve float for me....


Cracked a retainor. Lasted for 15 pulls on high boost

Get aftermarket Springs/Retainors, WELL WORTH IT!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMs1eeper &raquo;</TD></TR><TR><TD CLASS="quote">ITR valve springs
obd0 B16 cams
8200 rpms
27psi
62-1 Stage5 wheel.

= valve float for me....


Cracked a retainor. Lasted for 15 pulls on high boost

Get aftermarket Springs/Retainors, WELL WORTH IT!</TD></TR></TABLE>

lol damn right brad

 

why risk droping a valve to save a mere 3-400 dollars... it is piece of mind for me. I am not risking what I have invested over something like springs and retainers. maybe when I was running a bone stock motor and only pushing low boost I did for a short while, but not anymore... hell I run an f series though so what do I know.

my personal 2 cents.

 

im just going for around 300whp...so i didnt no if stock springs would be fine or not
t3to4b
lsvtec
log manifold
so what ever psi it will take to get me to 300whp...is what ill be runing

 

yea....

 

Seat pressure on stock b16a intake springs is like 50 lbs. 18 psi on the back of a valve does not equal 18 lbs, different units. The force on the valve is going to be equal to pressure times the effective area of the back of the valve head. If we simplify the area of the back of the valve to being equal to the flat side we can calculate:

18 psi*1.29in^2*3.14/4 = about 23.5 lbs.

So the seat pressure is now effectively 50-23.5=26.5lbs which is much more likely to float.