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Old 09-10-2012, 07:55 PM   #1
OC_Nooby
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Default ATP GT3076R Internal Wastegate + MBC issue, Can't Surpass 22PSI

Hey Guys,

So I have an ATP GT3076R that came with a stock 12-14psi Wastegate. My plan was to up the boost via MBC to about 24psi. My issue is that I can only hit 22psi and it would tapper to 20-21.

I tried a Grimmspeed MBC and a Turbosmart Dual Stage MBC. Both seem to be limited to around 22 psi. Can my Wastegate spring be too weak to handle x amount of boost?

Is there anything I can add to the system to help out?

I found this:

http://www.atpturbo.com/mm5/merchant...egory_Code=WGT

This should substantially help I think but is it the proper solution? I don't mind buying it if its proper. Also if my Wastegate is the problem then wouldn't it be cracking open earlier then it needs too thus the tapper?

Thanks!
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Old 09-10-2012, 08:46 PM   #2
holyjoetart
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Sounds like your BPV/BOV is leaking
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Old 09-10-2012, 09:00 PM   #3
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Quote:
Originally Posted by holyjoetart View Post
Sounds like your BPV/BOV is leaking
You might be right, I have a BOV. I could put my Go Pro in my engine bay and see what happens! (if its cracking open)

Also I could just crush my stock bpv and see if I can hold more boost.

Last edited by OC_Nooby; 09-10-2012 at 10:20 PM.
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Old 09-10-2012, 10:06 PM   #4
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What is the internal wastegate set to hold? The rule of thumb is that you can't run more than double the pressure (reliably)
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Old 09-10-2012, 10:13 PM   #5
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Why are you just cranking boost up blindly How are you determining its only making 22psi? Gauge, logs, etc?
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Old 09-10-2012, 10:18 PM   #6
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Quote:
Originally Posted by Schister66 View Post
What is the internal wastegate set to hold? The rule of thumb is that you can't run more than double the pressure (reliably)
ATP states 12-14psi on this particular wastegate

Quote:
Originally Posted by BlazeRex View Post
Why are you just cranking boost up blindly How are you determining its only making 22psi? Gauge, logs, etc?
I'm logging via romraider, gauges, have det cans etc (not doing it blindly). I can see it not wanting to produce more boost/sustain no matter what I do with the MBC.
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Old 09-11-2012, 04:53 PM   #7
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Alright, put my bpv back on (crushed it) and still in the same situation as before. Getting 22psi nothing more.

Could I have a boost leak? I smoked the motor 2 months ago and had no leaks so I'll rule it out. Wastegate creeping open?

Wouldn't a lot of gt3076r owners have this issue though?
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Old 09-11-2012, 05:31 PM   #8
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Log MAP not MRP, see if you read over 22
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Old 09-12-2012, 02:32 AM   #9
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Quote:
Originally Posted by BlazeRex View Post
Log MAP not MRP, see if you read over 22
Yah, one of them reads 18.43 max. I changed that so its reading right.

Strange thing happened today though. If I go from 1-5 full blast it hits 22 psi and stays there. Now if I'm on the highway in 5th and stomp on it the boost surpasses 24psi and the car goes know where fast. You can hear the turbo go but the car is like blah. I guess this ATP GT3076R is a hair dryer up there.

Reading this from my boost gauge (didn't have laptop).
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Old 09-12-2012, 12:29 PM   #10
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Quote:
Originally Posted by OC_Nooby View Post
Now if I'm on the highway in 5th and stomp on it the boost surpasses 24psi and the car goes know where fast.
It sounds like you're knocking, your car is retarding timing trying to save itself from popping.

What intake/inlet are you running?
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Old 09-12-2012, 03:55 PM   #11
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Quote:
Originally Posted by OC_Nooby View Post
I'm going to buy a stiffer wastegate spring and see if it helps. No reason a MBC shouldn't be able to allow the turbo to produce more boost.
Yeah, this is the next course of action. The MBC can only do so much, and backpressure will force open the wastegate no matter what.
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Originally Posted by pet3r View Post
It sounds like you're knocking, your car is retarding timing trying to save itself from popping.

What intake/inlet are you running?
What??
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Old 09-12-2012, 09:20 AM   #12
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What are you tuned for? It sounds like you're well on your way to blowing things up.
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Old 09-12-2012, 09:59 AM   #13
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What are you tuned for? It sounds like you're well on your way to blowing things up.
I'm tuned for 22psi and its a very safe tune if I may say so.

I'm going to buy a stiffer wastegate spring and see if it helps. No reason a MBC shouldn't be able to allow the turbo to produce more boost.

For simplicity sake, let's keep the tuning out. Assume it's perfect. I'm playing with a MBC so I'm not using the stock system/ecu to control boost. I'll try the bov and see if I can reproduce.


Recap:

I've used 2 mbc's, bpv/bov and with the bpv I can cause the car to overboost if I'm in 5th gear.
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Old 09-12-2012, 05:04 PM   #14
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Your car will pull timing when it knocks. This slows your car down, even though you might be maintaining boost levels.

If it's a silicon intake hose, it could be collapsing on high boost.
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Old 09-12-2012, 05:50 PM   #15
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On a ATP 30R, in fifth gear, not at speed, Of course the car isn't going to go anywhere. its a 30r. Full spool is what, 3800/4000 rpm?...you'd have to be doing over 100 at least. No one should be loading a larger turbo car, on pump gas, in 5th gear, not at speed, its a recipe for disaster. My guess if your car is reading full boost, not at speed, that your boost gauge is broken. Verify with a datalog...but if you'd been loading the car, again, not at speed, chances are you'll need more then just a new boost gauge.

& knock has nothing to do with the car not reaching target boost. My guess is you are out of the limitations on whatever boost controller/diaphragm setup you are running.
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Old 09-25-2012, 07:59 AM   #16
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Quote:
Originally Posted by sexyyrex View Post
...No one should be loading a larger turbo car, on pump gas, in 5th gear, not at speed, its a recipe for disaster. My guess if your car is reading full boost, not at speed, that your boost gauge is broken. Verify with a datalog...but if you'd been loading the car, again, not at speed, chances are you'll need more then just a new boost gauge.
Why does that scenario worry you so much?

My setup hits 20psi at about 3300 in 5th gear, at about 65mph. It's not a disaster, it's just a waste of time. 5th gear sucks for acceleration, and it takes a few seconds to build 20psi at such low RPM.

In 6th, if I floor it at 2500 RPM, it takes almost 10 seconds to reach 20psi, 3000 RPM, and 80mph (they all happen at once). I've only done that once (in the name of science) but it was almost two years ago and the motor still works just fine.

It's certainly a lot more satisfying to shift down, but high boost in high gears really shouldn't blow up your car.
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Old 09-12-2012, 07:36 PM   #17
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I don't hold it. I know it's a disaster if I'd hold it. Boost gauge/log read the same. This turbo fully spools at like 4700rpm which is weird. I don't have AVCS but it can't play such a big roll in spool timing I don't think. (2.5l sti)

Anywho, the more I tighten down the boost controller the more it will over boost in 5th gear (1-5 WOT run). Currently will over boost to 24psi and come back down to 22 psi. Though 1-4 seem fine, slight overboost but most noticinle when shifting into 5th for a sec it will spike during a full on WOT run.
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Old 09-12-2012, 09:30 PM   #18
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You're pretty much overloading the wastegate to mechanically creep, that's why its overboosting like that. And yes... AVCS does make a difference....
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Old 09-12-2012, 09:43 PM   #19
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I had same problem but ended up I had intake leak lol.
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Old 09-12-2012, 10:33 PM   #20
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Quote:
Originally Posted by BlazeRex View Post
You're pretty much overloading the wastegate to mechanically creep, that's why its overboosting like that. And yes... AVCS does make a difference....
You think a wastegate spring upgrade will help? Essentially a siffer spring mention for 22psi instead of 14psi which it currently is? I've just herd stories that this is not the issue but gah, this isn't making sense.

Quote:
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I had same problem but ended up I had intake leak lol.
Don't say that!!!! I smoked the intake a while back. Didn't have any issue.
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Old 09-12-2012, 10:44 PM   #21
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honestly, a 30R with a 14psi spring and a MBC should have ZERO issues hitting 22psi. it sounds to me like your wastegate is stuck open. try pushing the flapper open and closed a few times by hand to see if you can break whatever is causing it to stick open free. then see if it helps you hit your target boost.
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Old 09-13-2012, 02:40 AM   #22
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Quote:
Originally Posted by amalgrover View Post
honestly, a 30R with a 14psi spring and a MBC should have ZERO issues hitting 22psi. it sounds to me like your wastegate is stuck open. try pushing the flapper open and closed a few times by hand to see if you can break whatever is causing it to stick open free. then see if it helps you hit your target boost.
The wastegate looks closed but could be a hair open. The flapper moves and takes quiet a bit of pressure to open. I'll try adjusting to see what happens.
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Old 09-13-2012, 11:19 AM   #23
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its going to take alot of force to open it, you are overcoming 14psi of spring tension. even the 8psi vf turbos take a decent amount of force to open.
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Old 09-13-2012, 12:59 PM   #24
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its going to take alot of force to open it, you are overcoming 14psi of spring tension. even the 8psi vf turbos take a decent amount of force to open.
Your saying by hand it would be really hard?
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Old 09-13-2012, 01:20 PM   #25
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yes, by putting your hand on the actuator arm and manually actuating the wastegate flapper open and closed is going to take some effort because you are overcoming the spring tension.
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