I have a 2l 04 Euro STI which I just installed a HKS turboback exhaust, and now it overboosts due to creep.

Any guides on how to port the turbo to stop that, and enable me to press the pedal all the way to hear this exhaust :-)

 

Turbo back meaning youve de-catted it?A remap is the best way(ecutek).Common problem with de-catting

 

So you have a full decat? is that what your saying?
If so, be warned that STi's can spike with full decatted exhausts, your best bet is to get the car remapped though i dont know who would do it over in Denmark? (Ecutek remap)

Tony

 

Yep - Fully decat. Just heard that a porting of the oe VF35 would cure it until I drive 1600km roundtrip to Holland to get a remap....

Erm.. "can" spike... Does 1.6-1.7 bar and screems from the turbo, so lets go after 1ms

 

Mine spike badley after a de-cat had to take it easy til it was mapped.Thats the only 100% cure i've been told.

 

Down side is that a spike can cause det and kill your engine, id not give it any serious stick until you have the remap

Tony

 

I'm not - That's the thing..

So - remap is the only way go kill the overboost, no need to port the turbo?

 

As you say no need to port,Just get re-mapped asap,and take it easy till then

 

Thanks guys.... Taking the car on a 1600km roundtrip to Mark at EMS (nearest ecutek mapper) soon then

 

I know in the classic shape with the two port solenoid there is an oriffice in the tube between the turbo and the t-piece (the other pipe goes to the actuator).the oriffice hole size is 1.2mm if the hole is made bigger there is less boost and if the hole is made smaller it will have more boost.i had to adjust mine to prevent overboost but i dont know if the newer scoobs have this oriffice fitted or not.

 

As mentioned above, increase the size of the orrifice/restrcitor.
Just run a small drill bit through it to get a dusting of brass, then go for a run.
Very small amounts make big differences.

On my VF28 0.1mm difference in size can make upto 0.2bar difference in spikes.

 

Discuss the problem with Mark before you go to see him.
I have experienced boost creep with TD05-06 20Gs of which I have a lot of experience.
The solution has been to port out the waste gate to the maximum possible diameter. You could map the boost less aggressively but porting the WG allows you to ramp up the boost nice and early.