So I have been hearing that a few guys are having issues getting their APS TT kits to go past 9 or 10 lbs of boost. I understand that the fuel system is only designed to go to 12 lbs but if you program the Unichip to go to 12lbs should it not do it?? Is there an issue here with the wastegates or what??

 

I have heard there are issues with the wastegate spring, but no one has confirmed this. At this point its all speculation. I will be a very upset APS customer though if mine doesn't go to 12lbs....

 

In my other cars you could just put a stiffer spring and washers. I think it's hard to do on the APS TT though, don't remember the reason.

 

If I were you I would be upset not only if it didn't go to 12lbs but if it wouldn't go past 12lbs. Escpecially since you are building your motor and all.

 

Well, I'm only planning on running 12psi for now, until I can get it to an authorized Unichip tuner (another sore spot). Errr... maybe I should just go buy a Greddy...

 

Look at the bright side, unlike me you are not to far from Tuan. I would kill to have that guy tune my car.

 

This is the problem....a few guys can't get to the 12lb mark....I think only nitrous350 did it with his but he used an HKS boost controller to get it done. I think Tuan at GRD also got close to 12lbs but everyone else has had trouble getting to 12lbs. I am thinking that APS may have had Garrett set their turbo's with lighter springs to keep the boost down.....due to the fact that their fuel system is only good to 12lbs. Makes sense because it would give them a safety cushion to keep the kit from running out of fuel and blowing up......APS would never want that.

 

Well I am sure when APS releases their upgraded fuel system they will include new springs if this is the case.

 

Not that far??? Its a 5 1/2 hour drive!!!! I'm not sure if you have ever driven around Chicago, but its NOT a fun place to navigate. He better do some damn good work once I finally get it to him!

Once I get my car back I plan to 'mess' with the boost controller, although I am more interested in turning the boost down then up.

 

Lol....That's not as bad as my 23.5 hour drive. And how does 505rwhp @10.5 psi on a stock motor and still no damage sound to you? Is that good enough? That's what he has on his car....been running for almost 6K miles.

 

Once you have the motor out to build try adjusting the wastegate arm shorter. Maybe 3 full turns. That should get you a couple more lbs. I plan on putting my Z back on the dyno this week and run 12psi instead of the 11psi on 93 pump. When I was running the stock cats at 8-9psi I did have a hard time trying to make more boost, but as soon as I installed the APS test pipes and Exhaust 11 psi was easily attainable without adding to much duty cycle in the boost map.

Tuan

 

Tuan,

While you're here....

I'm having my motor built right now, with Arias 8.5:1 pistons, pauter rods, APS TT, custom cams, APS exhaust, and a few other things I sure I am forgetting. Once the car is done being built what will I need to do to get it to 600whp? I am planning on bringing it to you to have it tuned and whatever fuel system upgrades I need.

 

You do have a point there, I guess. If you ever decide to make the trip you can sleep on my couch on the way!

 

Unfortunately, its not just a matter of new springs like on the GReddy external wastegates. The Garrett actuators cannot be upgraded without being replaced which really should be done off the car.

 

When we added test pipes and the Stillen catback the boost went from 8.5 to 10 and made 421/417 but it was so lean we had to remove the test pipes until it can be tuned.

 

Where can new actuators be bought? I don't know anything at all about replacing them, so details would be nice!

 

Direct from Garrett or possibly HKS because they use a lot of Garrett turbos. Sharif mentioned that as an option. Problem with Garrett is the lack of desire to deal with the public directly. This is something that APS should address for those of us with built motors who want to go with their kit and higher boost.

 

Garrett distributors are much more responsive. We have used HKS actuators in the past with great success.

 

Thanks guys. It seems funny to me that Peter is quick to resond to posts regarding the purchase of APS products, but he rarely seems to get around to answering the questions asked by those of us who have already bought their products. Not being able to run over 12psi is rediculous after the money I spent for this setup JUST to run high boost!!! I'll look into HKS and see what I can find. Is there anything else I need to know to find one that will work with my application?

 

Maybe because it's the middle of the night in Australia?