question about wastegates

[netrati]

This may be a dumb question, but here goes. I don't really understand how wastegates work completely. I know they control boost by letting off exhaust gas before it gets to the turbo. Here is what I don't understand. If you have you wastegate spring or whatever it's called set to .8 bar and your boost controller set to 1 bar how does that work? What does the spring in the wastegate do? Also if you have a .8 bar spring can you boost lower than .8bar? say .5bar? Thanks

[S14Drift!]

The spring in the wastegate is the minimum boost you will be able to run...

Then the boost controler (manual or electronic) just bleed or control the boost line going to the actuator, therefore it won't open until the boost controler send the a boost value to the actuator that is equivalent to the spring in the wastegate actuator.

[netrati]

So what's the benefit of having a 1.2 bar instead of a .8 bar spring?

[S14Drift!]

The problem...is with a 10 psi spring, even if you unplug the wastegate actuator pressure line, it will start to open by itself at a certain boost pressure cause the exhaust flow become strong enough to make it open slowly..and then you have reached the maximum boost for that actuator!

I had that problem on my SR20DET, I couldn't boost more than 16 psi cause of the actuator...I was on my way to put a stronger spring (stock actuator is 7 psi) but I blew my engine before that

[nsmo30tt]

hmm i was also intrested in this because i don't know alot about turbos and wastegates except for the basics .. so.. say you have a 14psi spring can you run at 20psi using a boost controller.. because ive been looking around and the max spring i could find was 22psi what if you wanted to run 30 psi..

thanks

[R31Nismoid]

Have you tried reading the sticky thread?

http://www.skylinesaustralia.com/forums/ex...zes-t43638.html

[bluegts]

He is asking about wastegate spring sizes and reasoning, not external wastegate sizes....

[TiTAN]

If you put a 1.2bar spring in your waste gate the minimum boost you will be able to set your controller to is 1.2bar. If you are going to be running high boost pressures you are better off running the higher spring rate as it will control boost far better than a .8 bar spring.

[R31Nismoid]

Yeah - go read page two, goes into springs, as do a dozen other threads because ive posted about it plenty

[nsmo30tt]

ahh thanks titan im very well experienced with engines ect but forced induction is a hole new thing to me that ive never had to deal with