Not that I am aware of. Shops can change the spring or actuator, but I am unaware of the kit shipping with different springs in the actuator.

Again, who did the install?

 

i am having the same problem you are having but much worse.

#1 is you need a different exhaust. i have the APS ST exhaust, however if i had it to do over again i would would get the 3" APS exhaust and just modify it.

#2 get the forged actuator. bottom line.

i am sure your plenum is fine.

my car was only making 4 psi and i dynoed at about 320.

Sam is the best. So you are in good hands.

 

it is imposible the change the spring in the actuator that comes with the kit with out breaking it.

 

Did sam get your car running right ( getting it to boost at 8 or 9 lbs )? will he know if i need the forged actuator? my car is getting towed there tomorrow, im very depressed about this whole thing. Hopefully Sam can get my car running right.

 

why is it being towed?

well i purchased my kit used. it seemed to work fine on the guys car i purchased it from. it is still not running right yet, but Sam and APS are working on it.
the aps st is extremely temperamental and extremely sensitive to back pressure. from my independent research the turbo that aps uses for the st kit is very poorly engineered.

 

It's being towed because it will have to be there a few days ( hopefully ) and I dont have a ride back to my house. I hope I will just need the forged actuator and we can call it a day.

 

I am flat out telling you, you need to buy the APS exhaust. APS will tell you the same thing when they find out you are running a different exhaust setup. The problem is most likely NOT with the actuator itself if the kit was bought new. It could be with the install and setting the preload on the wastegate.

I ask again, who did the install?

Sugar, to be fair, the two cars may show similar symptoms, but I HIGHLY doubt they are the same issue if he bought his kit new. I have first hand experience with a situation nearly identical to this where I had an issue and another saw something similar and they were not even remotely close to being the same

A quick check you should do is verify the boost solenoid is wired properly to the positive cable on the battery.

 

i hate to say this but dont fall into the "APS exhaust hype", back when I first had problems, i finally broke down and decided to buy the APS exhaust, I called GRD, Tuan talked me out of it, said it wasnt the issue. GRD made 400 at the wheels on a kit with the stock exhaust by changing actuators.

now there are some that will say it is a must, but it isnt. they just like polishing things. id hate for you to spend 1000 just to realize that isnt the problem.

 

well put, i dont want to shell out another 1000 and it not be the problem. Hopefully its something simple Sam can fix. Besides only making 4-5lbs the car seems to run fine.

 

Don't play off the exhaust like it isn't beneficial. I am not saying that this is the cause of his issue. I actually would put money on an install related issue He has yet to say who did the install and rather than have that place or person attempt to troubleshoot, he is towing it to GTM.

I think going to GTM is a wise choice, but I think it is install related issue:
improper actuator preload
boost leak
Improper wiring
exhaust leak

Could be any number of other things, but I will say the APS ST exhaust is a must have for this kit

 

4-5 lbs is basically spring pressure. That makes me think you don't have the boost solenoid wired properly.

WHO DID THE INSTALL?

 

the NEW kit was installed at my buddy's shop called Project Import. I felt very comfortable as they have done a couple other aps st kits on Z's.

 

im only getting it towed for convenience. Sam hooked me up with a cheap flat bed that would just make it easier for me, due to my hectic work schedule.

 

Why not have them troubleshoot the issue? I would love to be a reputable shop now days. Noone wants to dish out the money or effort to have an authorized dealer install the kit, but if there is issues, they get to troubleshoot and fix everything

Seriously, you posted about the exhaust before you put the kit on and nearly everyone said to get the APS ST exhaust and you ignored them

you brought this upon yourself

 

i just find it hard to believe that a different exhaust will double my boost. i know the kit is sensitive to back pressure and my exhaust has no back pressure?! its not like im running a restrictive exhaust.

You might be right, I probaly just need the APS ST exhaust. We shall find out tomorrow what the problem is.

 

+1...you definitely need to get the APS exhaust. Someone up here in NY just switched and is getting full 9psi tapering to a bit over 8psi...so thats one more that I know where the exhaust fixed the issue.

You can always fabricate a y-pipe but that doesn't necessarily mean the flow characteristics will be good.

 

You need to realize it probably isn't the exhaust at this point. It most likely is an install related issue.

I am curious how you know your exhaust has no backpressure? For one thing, for it to mate up to the APS dump pipe, you had to use the adapter supplied with the kit or had the exhaust modified. I am guessing you used the adapter as it is the easiest. That adapter tapers down to around 2" which will cause backpressure.

Before you tune, you will want to buy the exhaust. When it comes to turbos and such, you can't just buy the exhaust you think looks or sounds the best, you need the one that was strictly designed to fit and flow for the specific application.

 

first you say its probaly not the exhaust then you tell me to buy it? you are contradicting yourself.

Sam is going to find out whats wrong b4 he tunes it so it would be smart for me to wait until he tells me it is the exhaust b4 i start whipping out my wallet for a new exhaust.

thanks for your input though

 

Hi,

Everyone experienced different things with APS ST. I had a huge benefit of changing to a dual exhaust setup. I had a stock exhaust on with APS ST for a week and it only made 5psi no matter how much I shortened the actuator arm length. After a week, without touching the APS ST setup I installed a custom 3" dual exhaust and BAM! I was boosting in 9~11psi!! For me, the stock exhaust was pretty restrictive to produce anything over 5psi.

Also it's not Forge"d" actuator. It's Forge actuator. I have it and my boost stays solid throughout the entire rpm range. I think your single 2.9" exhaust and the APS actuator is the problem. Forge actuator is cheaper ($150), so replace that first. If this doesn't solve the problem, look into replacing the exhaust.

 

might as well replace the turbo while your at it too

i am just being a smart***. but for real. Sam is the man and he will tell it to you straight. if all you need is a new acctuator then he'll tell you that. if he thinks you need a new exhaust then he'll tell you that.

what kind of exhaust are you running anyway?