Question 1 - aftermarket wastegate actuators

[Peter Wilson]

Hi all,

Can anyone out there help me about wastegate actuators? There don't seem to be many threads on this...

I want to buy an aftermarket actuator set for 12 psi (same as I currently run via bleed valve), to suit a standard R33 turbo. Don't want a boost controller - I can do this with my right foot. Just something to limit max boost, without the spikes and variations of my bleed, and that looks stock.

My questions are:

Who makes them?

Where can I buy one?

How much?

How well do they work (spool up, driveability etc)?

Thanks guys, Peter.

[Cubes]

I used the stock actuator and elongated the holes where it bolts up. I then grabbed a big arsed screw driver and put pretension on the wastegate so it was unable to open as much.

This method has a really stable boost control. Every gear is near the same. Zero spiking and looks stock.

Your best bet would be to start off with a RB20t actuator as it holds around 11psi with a simple exhaust.

I was running 16psi though my rb20t actuator with the holes elongated.

It wouldn't drop boost up top, if anything it would creep up boost unless it was set correctly. Best bet is to do it on a dyno unless you like pulling over on the side of the road and adjusting it until you get it right.

The mod works the same as an adjustable actuator rod.

If you're keen you could cut the rod leaving the actuator in half, & make it an adjustable length rod.

[Iopia]

Hi peter

I bought a HKS adjustable actuator and works great

It has a stronger spring that factory ones which helps hold boost longer

as factory ones can taper off I also noticed its gets on boost sooner as well.

cost about $200 and takes a couple of minutes to install.

conntact bd4's www.bd4s.com.au or look for a local HKS dealer

[Sydneykid]

It has a stronger spring that factory ones which helps hold boost longer as factory ones can taper off

Sorry Iopia, can you please explain this? It has been my experience that once the wastegate is fully open (target boost has been reached) the spring in the actuator does nothing. Any boost drop off has been atributable to other factors (too small a turbo, poor flowing cylinder head, restrictive exhaust, etc). I need helsp understanding how the wastegate actuator spring preload helps this:cheers:

[Targa Tom]

Hi all,

Can anyone out there help me about wastegate actuators? There don't seem to be many threads on this...

I want to buy an aftermarket actuator set for 12 psi (same as I currently run via bleed valve), to suit a standard R33 turbo. Don't want a boost controller - I can do this with my right foot. Just something to limit max boost, without the spikes and variations of my bleed, and that looks stock.

My questions are:

Who makes them?

Where can I buy one?

How much?

How well do they work (spool up, driveability etc)?

Thanks guys, Peter.

Who makes them? Several AM Mobs

Where can I buy one? GCG Turbo's (sell HKS)

How much? $275 inc GST

How well do they work (spool up, driveability etc)?

Spool is relative to you engine turbo exhaust configuration. They just stay shut till the spring is overcome, ie 0.9bar.

To give the wastegate seating, some preload is needed, but a 0.9 spring is a 0.9 spring, and once it reaches that pressure it opens (unless of course you have so much preload the spring is bound already)

Easy to fit in place of OEM unit... put one on my mates circuit the other week and was into our first stubby in no time..

Good luck

TT

[wrxhoon]

Sorry Iopia, can you please explain this?  It has been my experience that once the wastegate is fully open (target boost has been reached) the spring in the actuator does nothing.  Any boost drop off has been atributable to other factors (too small a turbo, poor flowing cylinder head, restrictive exhaust, etc).  I need helsp understanding how the wastegate actuator spring preload helps this:cheers:

At high RPM, the pressure behind the wastegate flap can be great enough to overcome the spring pressure, and "blow" the wastegate flap open.

I'm not too sure if this is a problem with the standard R33 turbo, but WRX's suffer this problem.

[Cubes]

Iopia,

Boost drop off with the RB's is due to a crappy EBC that will not self adjust the duty cycle to achieve the desired pressure OR a the use of a bleeder.

Obviously a better actuator with a tougher spring will help hold a more boost but if you still use a crappy ebc or a bleeder you will still be limited to around 2-3psi above the actuator preset.

An adjustable rod reduces travel so it forces the turbo to make boost in the higher rpms as the flap won't open as much.

BUT with this method as I have experienced the boost build is not as good.

BUT it does the job nicely and in my case with the bodgy'd actuator bracket its for FREEEEEE!

For the fastest boost build and no boost drop up top a 'good' ebc that has fuzzy logic (adjusts duty cycle on the fly) is the only way to go.

A higher rated actuator also helps a more stable high boost. Some times with a low rated actuator EBC's tend to flutter up and down 1psi or so when pushed really hard. I.e a 7psi actuator pushed to 20psi.

[Peter Wilson]

Thanks guys - sounds like a doctored RB20 actuator or HKS item is the way to go. Who are cost-competitive HKS agents in Adelaide?

Is it true that RB20s run higher boost than RB25s? Do they also have a boost solenoid or do they just have a stronger wastegate spring?

Cheers. Peter.

[Cubes]

The RB20DET uses a higher rated actuator (from factory its ~9 psi I remember) then with an exhaust it bumps up to around 11psi.

The RB25DET's & VG30DET's are around 7psi, not totally sure on the exact rating, it is definately lower and they feel easier to pull the arm out.

VG30DET (190kw Cima & Leopards) & RB25DET actuator's are the same.

[Iopia]

-Joel-

Boost drop off with the RB's is due to a crappy EBC that will not self adjust the duty cycle to achieve the desired pressure OR a the use of a bleeder.

Sydneykid

Sorry Iopia, can you please explain this? It has been my experience that once the wastegate is fully open (target boost has been reached) the spring in the actuator does nothing. Any boost drop off has been atributable to other factors (too small a turbo, poor flowing cylinder head, restrictive exhaust, etc). I need helsp understanding how the wastegate actuator spring preload helps this

Ill try to explainas best i can I am in no way an expert and only reporting my own personal findings.

Firstly joel R32's dont have An EBC like 33's and i Have never used a bleeder, having tried the bending etc of a stock actuator i still found the HKS replacement easier to set/adjust and it works better.

The stronger spring helps more with quicker boost build up. As wastgate actuator dont just snap open once a set PSi is reached they open slowly up to 100% at the said PSI. In say a r32 which has a 9psi rating the wastgate will start opening around 6psi more so since r32's are getting on a bit now. The stronger spring helps over come this problem it still starts opening but it needs more pressure to do it.

As wrxhoon said the stronger spring helps keep the wastegate open when you get higher revs

Using the HKS Actuator I found both quicker build up of boost and steady boost till redline hope this helps guys

[R31Nismoid]

my ext gate wont open till im making 16psi, thats running a 7psi gate spring, with a bleed valve. I get no boost spike what-so-ever even running the bleed valve. It gets to 16, and stays there solid.

admittadly im running as ext gate, not integral, which probably plays a fair part.

but i've noticed in 5th, it opens just a bit earlier than its meant too. by about 400rpm i can just hear the gate leaking ever so slightly. A 14psi spring will solve that

[Cubes]

-Joel-

Firstly joel R32's dont have An EBC like 33's and i Have never used a bleeder, having tried the bending etc of a stock actuator i still found the HKS replacement easier to set/adjust and it works better.

I think you misunderstood my post.

I am aware the R32's use a basic actuator setup where as the R33's use a high low if you like type bleeder that is activated at certian rev's.

It is far from being an EBC.

I would never bend the actuator arm. Thats bodgy and lacks precision.

Redrilling the holes is a totally different story as it essentially has the same outcome as your adjustable actuator arm. Reduced wastegate travel!

An el cheapo or old school EBC will not hold boost in the higher RPM's.

You need one like the Blitz SBC-iD or AVCR that has the capability to adjust its solanoids duty cycle when the pressure at the plenum begins to drop, as there is always a pressure drop across the IC and piping at higher rpm's.

Bleeders and cheap EBC's cannot adjust for this.

I haven't tried a bleeder/actuator using the plenum as its boost source.

This could possibly prevent boost drop in the higher RPM's.

One Would have to try it to find out with a decent gated (ball and spring) bleeder.

My point is the RB's don't have issues with the wastegate being pushed open.

General bleeders, I have never seen one that doesn't taper off at high rpm to approx 2-3psi above the actuators std boost.

Obviously the goal is to have a nice hard ramp up on to boost without spiking while having a stable high boost.

If you are running 20psi its best have a ~1bar actuator then use a old' AVCR or such EBC. Try to match the actuator as close to the boost you will be running.

On the stock R33 turbo.

I wouldn't bother with anything more than a RB20t actuator.

On the RB20t.. I wouldn't change the actuator..

I would redrill the holes and put the money saved from the purchase of the actuator towards a bigger turbo.

Or buy a RB25DET turbo and use your old RB20DET actuator on that.

Redrill the holes adjust it for 14psi and make your 180rwkw.

Or.. chop the stock actuator harm & make up your own adjustable actuator.

Many options to save money and or use the money to improve the performance of the car.

[Sydneykid]

Hi guys, I use the Autospeed (with Norgren valves) style of boost controller a lot. It has one valve that controls the maximim boost level and the other stops the wastegate actuator seeing any boost until a preset level (I call it the minimum pass level). So I can set the max boost to say 1.1 bar and the min pass level to 1.1 bar. So the wastegate actuator sees zero boost until 1.1 bar, this means the full actuator spring preload holds the wastegate closed.

I don't get any boost drop off, well, as long as the turbo has sufficient airflow capacity to hold that boost level. I can lower the minimum pass level to say 0.75 bar and this softens the boost hit, better for racing in the rain. For ~$100 I haven't found anything that works as well and is so simple to set up.