Jump to content
HybridZ
dpuma8

How do I pick a wastegate spring to work with a manual boost controller?

Recommended Posts

I have an N42 block with dished pistons, N47 head, 38mm Tial wastegate, Megasquirt, 550cc injectors, and a GT3076R .64 turbo ready to go on my car.  From what I am reading on this site, the N47 is not a good head to run boost on so I am planning on running 5psi until I can find a P90 head.  I have purchased a cheap manual boost controller but I do not know what spring I need for the wastegate.  This car is street driven and will never see the track.  I eventually would like to see 15psi.

 

Can anyone recommend a specific spring that I need for my setup?  I am super confused as to what spring to get in conjunction with a manual boost controller.

Edited by dpuma8

Share this post


Link to post
Share on other sites

I have an N42 block with dished pistons, N47 head, 38mm Tial wastegate, Megasquirt, 550cc injectors, and a GT3076R .64 turbo ready to go on my car.  From what I am reading on this site, the N47 is not a good head to run boost on so I am planning on running 5psi until I can find a P90 head.  I have purchased a cheap manual boost controller but I do not know what spring I need for the wastegate.  This car is street driven and will never see the track.  I eventually would like to see 15psi.

 

Can anyone recommend a specific spring that I need for my setup?  I am super confused as to what spring to get in conjunction with a manual boost controller.

Well if you need to run 5 psi early, then you will certainly need a 5psi spring.

 

As for what spring to use when you go up to 15psi, there are a couple things at play.

 

1) if the spring is too soft (low PSI), then even if you use a MBC, you may not be able to get very High psi's as the wastegate flapper will push open.

 

2) The degree to which the above will happen depends a lot on the size of the diaphragm in the wastegate. With an external gate, I wouldn't be surprised if you could hold 15psi even on the 5psi spring.

 

3) I would however choose about a 10psi base spring. I feel that the closer your spring is to your MBC setting, the more stable the MBC operation will be.

 

Hope that makes sense.

 

Mark

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×