another cheap and easy way to improve the boost hold and response time of your factory turbo is to re-tension the often rusty wastegate adjuster.

the factory wastegate arm is not often not tensioned tight enough to give a strong seal on the wastegate, the more gas that slips past the wastegate during spool, the longer it will take to spool. plus boost controllers struggle to maintain a constant pressure when the wastegate arm is able to move around to freely.

since these wastegate arms are often overlooked during simple maintenance, plus with most GC8's running TD04 turbos over 12 years old, its probably something you should do anyway.

first thing to do is get the turbo exposed, while cold- spray some CRC or similar on the 10mm nut to loosen the rust, crack the nut and wind all the way up.



next, remove the circlip and lift off the arm, tighten the end piece all the way then stretch back over the wastegate arm, reattach the circlip and tighten the 10mm locking nut back against the end peice.

the waste gate arm should now be significantly reduced in travel, not such a problem for cars running boost controllers, although on an unmodified car, depending if you have headers, you may boost spike.



but lets say you dont have a TD04, something like a VF series, these wastegates cannot be adjusted, so often you need to consider aftermarket alternatives, these raise the standard 0.8bar wastegate to around 1 or 1.2bar and allow much greater resolution in boost control, these though- cost more then $10.

the alternative is to help the standard wastegate actuator with an external spring,

first thing to do is weld a small washer or hook to the wastgate arm,



next is to stretch a small heavy tension spring from the actuator to the washer.



in this example, we raised the wastegate pressure from 0.8bar to 1.7bar, you can obviously pick a weaker spring if you dont want to go so high...

similiarly, you can do this on a TD04 without the need for welding.



end result is your turbo will spool faster, will hold boost longer, your boost control doesnt need to work as hard.

you will however need to replace the spring eventually, the heat from the turbo will weaken it over time.

usual disclaimer, if you dont know what you are doing, dont do it.

otherwise, enjoy!

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Long live the WRC

Another brilliant DIY. Thanks Stace.
Just popped out to have a look at my car and had a thought. On the VF turbo, rather than weld on a washer, would there be any harm in drilling a small hole in the waste gate arm to hang the spring from?

Only that the spring may not have the leverage to pull tight enough,

Ive had this done with a few turbos over time, tend to find it works most effectively when everything is ceramic coated to reduce the heat getting into the springs. Another point is if you housing is already coated, you will need to grind the ceramic back before you weld...

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Long live the WRC

Could you put some heat shield type material over the spring to help reduce heat into it?
Do you have a rough gauge on how much you increase the tension with X strength springs? I have a VF22 tuned to 22psi

I have seen this mod where a trampoline spring was used. Lol.
Perfect fit.

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Have Fun.

Yep, i first tried this with one of those exercise tramp springs, but found agricultural spec springs from covs/bunnings being easier to get at short notice

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Long live the WRC

Very interesting read this.

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MY04 WRX
3" TBE | STI Top Mount | 3 Port | Walbro | Tuned to 155@wkw 210HP |

The washer is on my VF48, with the addition of the spring the car was past 1.5bar at the same rpm point it previously got to 1bar

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MY93 Impreza GX 1.8L, 0hp, 0nm

Because of over zelus people who clearly relate post count to someone actually asking a genuine question.
I'll have to rewrite my question.

I looking to "buy" NOT SELL a VF turbo.

Is it possible to replace the actuator yourself?

Is it hard to do?

I want to make sure that part of the turbo is working perfectly.

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MY04 WRX
3" TBE | STI Top Mount | 3 Port | Walbro | Tuned to 155@wkw 210HP |

It is diy yes, but i did include a disclaimer!

I dont think it was hard to do at all...

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Long live the WRC