when do you need heavier int vlv springs?

[DTanklage]

with the stockers on the intakes (and 60's on the ex) i have been to 3200 rpm and 50 psi boost

when do you need to install heavier intake valve springs?

don

[DTanklage]

ps - rpm is not going to go any higher with this motor but boost will

only another 10 psi tho

think i am at the stock springs limit now or do you think i can get away with another 10 psi???

[boostedve]

i have been told 3600 to 4000 rpm but you should do both the intake and the ex. with my truck i have been 3800 with stock springs a few times with no prob yet.. im not to sure about the keepers and retainers..
boost on the other hand your prob at your max with it i would be lookin for some head studs...
boost..

[PToombs]

Mark at PDR told me if you do 3200 or more regularly, 60# on all of them.

[DTanklage]

did he say why?

3 grand really isnt a lot of rpm

[cummins king]

probaly just to sell them, but if your doing the head you might as well throw them in, then you have some assurance

[DTanklage]

probaly just to sell them...

but if your doing the head you might as well throw them in, then you have some assurance

thats what i was thinking too...

increased seat pressure does more than just 'sound cool'. it also wears everything out quicker (except the seats, IF valve float was occuring) and it decreases effeciency (takes power)

[PToombs]

Well, I'd rather spend $110 on springs than $500 on a new head, and pistons, rods, new turbo, and what ever else gets f'ed up when the piston and valve meet at high speed.

[TWorline]

I have heard that with high boost pressure the valves can hang open at high rpm especially if the stock springs are getting weaker due to high mileage.