Question on boost profile.

Is it better to have the wastegate closed all the way from say 1k rpm's till whatever so that it builds boost from the get go?

Or is it better to have some taper up and then maintain?

 

It's best, and by best I mean...fastest spooling, to keep the WG puck(flapper valve) on its seat until a couple psi before your max boost setpoint. So, e.g., if you set max boost to 22 psi, then you'll want to preload the WG to 18-19 psi.

There are a lot of variables in your particular setup that impact on your particular turbo's boost profile. But,to maximize fast spool you've gotta set WG preload to the point where boost just starts to overshoot your preset limit and then back off the turnbuckle 1/2 to 1 complete turn.

How are you controlling boost, are you working with a manual or electronic boost controller or the factory BCS? If you're using a MBC shoot me a PM and I'll walk you through how to optimize spoolup.

 

Factory BCS, I can make it behave however I want with the settings on the ECU but I wasn't sure what is optimum.

Right now boost starts to come on @ 3K. By 3.5K it's 2 psi under max and by 4K it's maxed.

Also... why is it that if I do a WOT run from 1st thru 6th it won't boost as high as if I was cruising around in 4th and floored it.?

 

Bump

 

Because you're never at peak boost rpms if you do that. Instead, you're never below 5500rpm, and our boost does not peak at 5500rpm - it peaks at 3500-ish. Pretty simple.

 

It's always simplier than I think it will be... thanks.