No, this has been brought up before and I've never seen him post on it. It would be intersting to read what he has to say. If he has posted on it and I missed it then I appologize. But, as stated in this thread, no one really knows exactly what is going on with this issue.

 

He's spoke on it before, but I think it was on the other board. I didn't pay too much attention to it since I didn't care about it at the time.

 

Here you go (I was interested in the answer myself):
https://my350z.com/forum/showthread....light=actuator

 

I've had conversations with at least a half dozen customers that have hit the 11-12psi limit. My hope is that HKS or APS will sell a conversion kit/new wastegate setup, that will allow for higher boost levels.

I'm subscribing to this thread.

 

My G is going under the knife (@ Z-car garage), APS TT and built 9:1 CR LB next month. We will try to adjust the default actuators to about 10psi so that the contoller can obtain up to 20psi at full duty cycle. This can be adjusted on the bench (before install) with a pump. If this does not work adequately I have been looking below for a more adjustable replacement actuator.

http://www.forgemotorsport.co.uk/co...001&inc=product

The "FMAC049 - Adjustable Actuator T2" looks like it might fit.

Note you want to deal with the actuator "off the car" during install. Not really enough room to do it in place after the fact. The default APS map will be inadequate (un-safe) and needs to be conservatively re-mapped before adding even the new base of ~10psi of boost. A base of 10psi would be precarious with the base 91/93 map.

 

Thanks for the link, I am not sure how I missed that. However, his answer still isn't as detailed as I would like, and he assumes that everyone has a Unichip dealer/programmer next door. I do NOT have access to program changes, so I doubt I can use a solenoid for boost regulation, I guess I should just look for a pressure regulated actuator??? Am I on the right track here?

 

Thanks for the link! (http://www.forgemotorsport.co.uk/con...oduct=FMAC049). We would be looking for the 17.5-20lb spring size, correct?

 

If you wanna up the boost , your tuner will "have" to have map control of the unichp. Once you can map the unichip A/F/Timing , you also have boost solenoid control. Unichip comes with an integrated boost controller.
The boost controller is used in addition to a stiffer actuator spring. Unless you intend to run around at >17.5 psi all the time , a spring that stiff is not recommended.

I am looking at the (9-15) psi spring. I want the "spring -only" boost to be as low as possible (~10psi) and have ~20psi be at 100% duty cycle for the boost control solenoid. Note I don't expect the APS snails to be very efficient at 20psi, so that is just tuning headroom for a race gas map.

 

Ok, so you are saying theat there are two decices used for boost control. The mechanical actuator that opens at X amount of pressure and a control selenoid that opens/closes as needed to control pressure. Is this right?

 

I can confirm... a customers car with built motor will not go over 9-9.5 psi with HKS EVC Pro with untampered APS wastegate actuator arms. I will be tampering with them soon.

 

There is another factor at play here that throws a wrench into these numbers. The wastegates on internally wastegated turbos like these open in two seperate ways, one good and one bad. The good way is a function of boost pressure pressing on the spring via the vacume hose attached to the actuator.

The bad way is a funtion of the build up of pressure in front of the turbo blades that will actuall push the wastegate open if the preload on the actuator is insufficient. In this case the amount of boost reaching the actuator via a bost controller solenoid may be irrelevant because the wastegate is being pushed open from inside the turbo housing.

The turbos supplied in the APS kit have very large wastegates which means a large surface area for the built up air to push against. The actuator arm preload is somewhat adjustable, but not by much, so its still iffy where and at what point the supplied wastegate actuators will open even when they are pre-set before install.

 

Yes basically. The Actuator springs hold the WGs shut til they is mechanically overcome. They are not easily adjustable on the car and can be considered "set and forget".

The boost contoller uses a solenoid which modulates the +psi seen by the diaphram (via the vac/boot line) in the actuator inorder to add even more boost (holding the WG closed) with additional force.

My intet is to have two maps. One for around ~500rwhp onn91 and another 100 octane at the dragstrip (>600rwhp).

 

Charles, if you don't have enough preload adjustment you might get more adjustment by replacing the lock nut on the actuator arm with a low profile nut. The ***** of it is the bend in the arms requires removing them to make any adjustments.

 

The factory garrett cans usually can see a 2-3 psi adjustment range by tensioning the rod. The Forge Motorsport actuators will work good, BUT, you have to watch how they are hooked up. If you source a positive only pressure source they will work fine and can be setup with many spring combinations to minimize "tricking" the actuator with any boost controller. There have been issues with tearing diaphragms in relation to vacuum pull and how the internals of the top of the Forge actuator body are machined.
It is also VERY simple to source various pressure range of Garrett actuators which I am sure APS will have accessible in the near future as more knowledge is gained in the marketplace. One thing they won't do is promote selling 12, 15, 17 psi actuators to people who don't have the ability to properly tune the car. If you talk to Peter or any of the APS distributors, they should have no problem setting your kit up for the higher pressure ratings while going over what it takes to implement those pressures into your motor. The turbos are certainly capable of an excess of 20psi and probably nearing 720rwhp but the technology around the car is not necessarily there yet for alot of us. In a couple more months, there will be more cam choices, cnc cylinder head programs, etc..... to make use of the airflow the turbos can push.

 

Subscribing...

I'll post what Peter told me you had to do to raise the boost on the internal wastegates through PM in a few minutes...

 

ttt

 

There's not an issue as far as I'm concerned - the boost pressure actuators are controlling the boost pressure exactly as intended by APS engineers.

The APS twin turbo system was designed to operate between 8 to 9 PSI out of the box.

With a low restriction APS true dual exhaust system and test pipes (this ensures very low total exhaust back pressure) it's possible to run up to approx 12 PSI and fortunately the fuel system in the APS twin turbo system is large enough to support this boost pressure/mass air flow.

If you want to run higher boost pressure than 12 PSI then you would need to fit higher poundage boost pressure actuators to increase the boost pressure - nothing new in this and there are a number of different poundage boost actuators to suit the application.

let me know if you need any help or assistance in this regard.

Thanks

Peter

 

Maybe you don't realize that some countries on the planet are actually on significantly different times zones to the US - I need some sleep at times too.

If you ever need any info on APS products or tech assistance I'm onlt a pm or email away.

Thanks

Peter

 

is this the out of box setting or is a boost controller needed to run 8-9lbs? I thought most ran about 6-6.5 lbs out of box?

 

The boost controller/solenoid is included in both the APS twin and single turbo systems.

The actual boost pressure will depend on the performance of the exhaust system on the car (as it does with all brands of turbo systems) and if the exhaust is well designed the boost pressure will be approx 8 to 8.5 PSI.


If the exhaust system on your Z is very restrictive (because of very high back pressure in the exhaust system) then the actual boost pressure may well be a little lower than 8 PSI.

Thanks

Peter