how much psi to break 300whp
 

Alright, so im about to buy a tial wastegate for my new setup but im kind of stuck as to what bar spring to go with. right now im between .7 bar (10.2psi), .8 bar (11.6psi), or .9 bar (13.1psi). the new setup is as follows: low comp vitara pistons, eagle forged h beam rods, all new bearing and gaskets, arp head studs, crower stage 2 turbo cam with springs and retainers, garrett t3/t04e 60 trim, etc.

what im wondering is how many psi should i shoot for to make over 300whp? i realize it will have alot to do with the tune, but im having it done by a well known tuner on an AWD Dynojet. i just want a ball park estimate. anyone?

RE: how much psi to break 300whp
 

Im probably wrong, but i wanna say 16ish give or take a few

RE: how much psi to break 300whp
 

what exactly does the wastegate spring have to do with it? why not just invest in a boost controller so you can change it to whatever you want?

RE: how much psi to break 300whp
 

^ because with external wastegates, you can adjust the amount of boost by changing the spring.

External wastegate > Boost Controller

RE: how much psi to break 300whp
 

^ bingo. i want my boost regulation to be precise. they call boost controllers death knobs for a reason haha.

RE: how much psi to break 300whp
 

so you want boost regulation to be precise along with the boost creep right? or does that not apply the same at higher levels of boost? and every reference i've ever heard to that death knob is when people get boost happy and turn it up and turn it up againand eventually over do it because they can turn it up.

RE: how much psi to break 300whp
 

Usually boost controllers have a limiter setting. My greddy profec b did.

RE: how much psi to break 300whp
 

Maybe it's just me, but I don't like using anything that tricks my engine... o2 simulators, boost controllers, ebay chips... they're all the same to me. Personally, I think if you want to up the boost, do it the right way; don't trick an internal wastegate to think it's getting less vac than it actually is. But then again, that's just my take on it.

And I have no real proof of this, but I just don't see a boost controller as being just as reliable as an external wastegate.

RE: how much psi to break 300whp
 

...Might want to find out how boost controllers work before you comment on how they're "bad".

They're called "death knobs" because moron DSM kids stick the $40 unit on and turn up the boost because hey, more boost is fast right?

Boost controllers do not trick the engine. The engine and ECU management system knows exactly what is going on. Boost is simply controlled by when the wastegate opens, that's all the boost controller does. It changes the pressure that the wastegate opens.

60trim depending on how efficient your setup is... 15-19psi.

RE: how much psi to break 300whp
 

well all ive heard of them is basically what you just described about dsm kids, so i appologize for being misinformed. id still rther have a tial external wg than an internal with a boost controller.

my system should be fairly efficient since it has shiny new bearings and that stage 2 camshould give some serious lift. I think i'll try for 16 psi, and if not get a new spring and retune. thanks sov.