what does the spring in the wastegate do? what is the difference in lbs? And for a motor making 270-290 hp what size spring is necessary? ( tial wastegate)

 

The spring regulates boost pressure. You can have a 7lb wastegate spring and it will stay at 7lbs. You only need a boost controller is you want to exceed the wastegate pressure.

Well the spring rates dont go according to horsepower. They go by psi. So for a motor making 270hp at the flywheel will need about 9-10psi of boost on a stock internal turbo honda. I belive a .4bar spring is 7psi. So you would need a boost controller to get it up to 10psi.

 

so I should get a .7lb if I want it to sit at .7psi? so for my setup .2 to .9 .7 is best?

 

List your whole set up.Engine,turbo,engine management,etc.....