is there any real way to fix the boost taper issue? if so how?

 

um boost taper isn't an "issue," it's part of the package.

 

Forge wastegate will fix some of it. I don't know much beyond that.

 

Boost controller helps.

 

Get a bigger turbo.. ;p

 

i figure it was either the computer's bc doing it, or the turbo was maxing out its cfm rating. I figure a mbc would fix this to a certain degree but, going about installing one with the stock bc is beyond me. Dont want a CEL

 

On a friend's Evo X he is able to keep 26.8psi of boost up to 6.5k RPM, 24psi at 7k and 22psi at 7.5k RPM using HKS EVC 6 and Blitz upgraded actuator. It was the max he could get with the stock turbo, any extra preload on the actuator and boost will spike over 30psi, which isn't safe for the stock internals.

 

Get a tune and a boost controller.

 

An upgraded WGA as a Forge will greatly help you out compared to the stock wga

 

or 3 port selonoid from gm, do a search and there is installtion and tuning instructions somewhere

 

ECU controlled boost... my old setup from Works; held 22psi til 8K rpm without taper... required a different line I had to install (check and see if they offer something similar to that for the X) which was part of the mail in ECU tuning "brain flash".... but now I'm tuned on a mbc at 28.5lbs with a Hallman MBC (needed local tune and was easier going MBC) and notice very little taper at all, so cheap route=Hallman MBC

 

^ X != IX... don't put an MBC on an X please.

 

Likely that was an Evo 9 stock turbo right? On the Evo X turbo the exhaust side is similar but the compressor side is smaller than the 8/9 and runs out of flow above 5500 RPM's. Usually the best you can do on street gas is 26 psi up to 5500 then taper down to 19 psi at 7500. Getting more boost than that out of the Stock Evo X turbo is mostly hot air which can be done with portwork and stronger WGA with heavy preload where the max angle of the WG flapper is inducing boost creep.

The real solution is to get a turbo that can support the airflow you want to run instead of forcing the stocker to deliver super heated boost.

 

Yea i stuck a Hallman Pro MBC on and it didnt help with my taper at all

 

The problem you have is because of the "bleed" nature of the BCS+WG system.

Even when the BCS's are at 100% the WG STILL receives some +ve pressure, thus opening it...

A couple of options (cheapest to most expensive)
1) get a pill, this will restrict the amount of air going to the WG
2) get a interrupt based BCS (GM3port, Tactrix plugnplay, whatever)
3) get a boost controller

#2 is my preferred option...