after several attempts to solve the mysterious boost drop, its still unsolved, but some interesting things are happening.

we added some helper springs to the wastegate arm to assist in the swingvalve closing better, no help. we then wired the swingvalve shut and turned the MBC all the way down and disconnected the actuator rod. with the puck completely shut, i made 3-4 lbs of boost. kinda weird, youd think id build a lot of boost but not the case. we then let the swingvalve hang lose with no tension, again 3-4 psi.

hmm, no change with the puck sealed shut, or swinging freely.

we then capped off the bov to check for leaking there. none.

so heres the facts,
1. no leaks in pressure side from pressurized test
2. free flowing exhaust.
3. manual boost controller, excluding the unichip boost maps(tuned 93 maps)
4. actuator rod tightened all the way down.
5. no exhaust leak before the turbo.
6. stronger couplers and heavy duty clamps.
7. bov sealed and no leaks, and bov set screw adjusted in every position, and no more recirculating of the bov.

even after all this, still losing boost.

so now the turbo is in the hands of a well known turbo builder here, who custom builds hybrid turbos for several race cars and big name companies. hes tearing it down, inspecting everything, checking tolerances, checking parts, measuring things, etc, etc. hell, maybe even changing compressor wheels, who knows what ill come back with. maybe a 42R compressor wheel. :bow: \ im also gonna get the intercooler pressure tested.

anyway, all the information you guys could ever want about this turbo will be available soon. i wonder if i should contact garrett for warranty info or APS?

 

In addition to peoples posts here id also contact APS as they should be able to point you in the right direction.

I'll assume you were joking about warranty as your already having the turbo rebuilt by someone else.

 

I am not sure if tig and Peter are getting along so well nowadays.

 

ditto. that horse has been severely beaten.

 

Wow, are you doing this out of your own expense? Man if you are that sucks. Are you getting any support from the APS? I am not trying to start anything here. Just a little curious. It seems like your going through alot of crap just to get the thing to work properly. Good luck and keep us updated please.

 

yeah its out of my own pocket, but most of it is nothing but my time, having to mess with it all the time, i made a device to pressurise the system, i had a boost controller, the guy working on the turbo is a good friend of mine, so it isnt really costing me anything except time.

 

Sounds like your going threw every nut and bolt . Sure hope you find it since your not getting any help from the people that got your money for the kit . I ended up preasurizing every thing at once...intercooler ,pipes , plenum , motor , and exhaust to find a leak.
Good luck

 

how did you pressurise everything at once, i could only do the intake side, how did you get the valves to open to allow air into the engine?

 

Hey Tig.....Kopo got the APS exhaust for the ST installed and he said with the stock actuator it is holding boost till redline....hmmm.. time for exhaust?

 

I capped off the exhaust . Made a capped off pipe [2 3/4 inch. diameter ] And hooked up a air compressor line fitting to the end of it . Disconnected the intercooler pipe right before the BOV and hooked that 2 3/4 dia. pipe to the intercooler pipe . I set my compressor to about 25psi . You will always have one or more exhaust or intake valves open , so it will compress every thing

 

boog, i did that but something right by the manifold started clicking, must be the idle air control solenoid, i didnt think it was getting all the way thru to the exhaust side.

 

zman,

i wouldnt buy that APS exhaust if it only cost $100. i know people who build turbos and know my exhaust and say it should flow enough for 600+hp. just because APS welds some pipe together and sticks and APS stamp on it, dont mean squat. my turbo is getting dissassembled this week to get fully inspected. im gonna get to the bottom of this issue, id rather spend the 1000 price for the exhaust on upgrading to the correct turbo internals. its funny how the turbos dont have garrett stamped on them and APS wont release any details or specs on the turbos. they probably used some cheap *** knock off turbo cartridges. we will know soon enough.

here is a thought. APS says the kit is built to drop boost to be safe on the internals correct? BUT, if you buy the exhaust from them, which causes the kit to maintain boost, does that mean the kit is unsafe for the car now. they are full of crap. APS doesnt know whats going on.

 

Hmmm...I ended up having to try it 3 different times , before I got the exhaust to seal .I couldnt have gotten lucky and shut the motor off at the right time 3 times . Never heard any clicking by the manifold . Only the air leak on the plenum , and then nothing after I fixed the leak .

 

Yeah something is definitely up on APS's part... Let us know when you get to the bottom of it (but im sure I dont have to tell you that)...

 

boog, so you did it with the car cranked?

 

NO , NO , NO...I just meant , I tried 3 times , at different times . That the motor was at different spots each time I shut it off . And each time I was able to put preasure in the exhaust

 

ok thats what i thought

 

I have a question for APS TT guys. Has anyone thought about tapping the upper pan like the Vortech does? One on each side, this would raise the return lines.

 

It would result in less downhill drop which would be worse for oil return to the pan. Vortech can do it since the snail is mounted very high under the hood..

 

its funny how the turbos dont have garrett stamped on them and APS wont release any details or specs on the turbos. they probably used some cheap *** knock off turbo cartridges. we will know soon enough.

Tig,
I buy garrett ball bearing turbos, especially gt2871r's, quite a bit and none of them have come with Garrett's little "plaque" on them. I measure each wheel as the turbos come in. What part of alabama are you in?