Boost Creep Gt3076

[LANDSCRIBBLE]

I am having the same problem with boost spike. 18psi or 14psi actuators both shot up to 20-23psi everytime. Boost source from a weld on nipple after the turbo elbow. Intake leak tested OK. Tried just about everything. I am running a HG ATR43G3 internal gate. my concern was also around the wastegate hole/flapper. But since you're still having the same issue after porting etc, im lost.

[jet2nv]

Yeah the next thing left for me todo is the bell mouth dump pipe, or even a softer actuator as most of my friends with hypergear actuators that are 14psi spike to 18/20psi

[hypergear]

I am having the same problem with boost spike. 18psi or 14psi actuators both shot up to 20-23psi everytime. Boost source from a weld on nipple after the turbo elbow. Intake leak tested OK. Tried just about everything. I am running a HG ATR43G3 internal gate. my concern was also around the wastegate hole/flapper. But since you're still having the same issue after porting etc, im lost.

The .82 type A/B turbine housings don't usually creep boost, How ever there has been a person reporting this issue, luckily he was local. What I've found is there is one stud hole that sits behind the wastegate flapper, the thickness of the material there is 10mm for oem stud, while 25mm bolt was used instead, So the extra length of the bolt pressed against the gate making it unable to move. That bolt is the one on top right corner if you are looking at it from behind.

our 14psi actuators holds 15psi on a free flow setup, and 17.5 with extended wastegate lever. The high pressure actuator holds 18psi and 21psi with extended lever. Most of our brand new turbochargers has extended levers, are fitted with a 14psi actuator.

With your 3076, I did not looking into your dump pipe, this is certainly a split dump pipe, as your turbine housing already had the wastegate divider built in, making it sealed in a chamber. While most internal gate would open to 45 degrees, the gate acts as a lid, trapping hot air inside the chamber causing boost creep. That also explains why a big 38mm internal gate would still boost spike on your setup.

Solution would be getting a bell mouth dump made, or mill out the wastegate divider on the turbine housing.

[LANDSCRIBBLE]

The .82 type A/B turbine housings don't usually creep boost, How ever there has been a person reporting this issue, luckily he was local. What I've found is there is one stud hole that sits behind the wastegate flapper, the thickness of the material there is 10mm for oem stud, while 25mm bolt was used instead, So the extra length of the bolt pressed against the gate making it unable to move. That bolt is the one on top right corner if you are looking at it from behind.

our 14psi actuators holds 15psi on a free flow setup, and 17.5 with extended wastegate lever. The high pressure actuator holds 18psi and 21psi with extended lever. Most of our brand new turbochargers has extended levers, are fitted with a 14psi actuator.

i'm sure the flapper was swinging out as far as it could, but i'll double check that, thanks. i've still got that 7psi actuator you gave me, i will see how it goes with that on aswell.

[DVS JEZ]

Larger wastegate flap sorted the recent boost creep issue out on an ss1 rb20, perfectly flat boost now

[GTScotT]

what size was the replacement flapper Jez? and how much power have you got it cranking now?

[hypergear]

It was a 38mm gate in a small .64 rear housing. that gate comes standard in all SS2, G3 and G2.5. Turbo made 227rwkws on 17.5psi from a Rb20det.

[camoo]

hey all, just an update.

I ended up getting a bell mouth 3 1/2" DP, figured i would try that before porting the gate.

It didnt completely solve the problem, but it did help.

It now only creeps 1.5 PSI, which is alot better.

Made 276 with max boost at 17 PSI

[discopotato03]

Yeah well its not impossible for a split outlet pipe to work but the extra effort and cost is hard to justify for what you gain . The simple effective way is make the open one and not be shy on tube size .

A .

[jet2nv]

Any new updates guys

[mark33gtst]

I also have this issue. I have an I/w .82 gt3076r. It always creeps to 21 + psi. I have the gcg split dump fitted. I believe this is the cause of the problem because although the waste gate appears to open enough because of the angle it partially blocks the wastegate pipe. I'm going to remove it and get another pipe made or this one modified. Ill let you know how I go.

[jet2nv]

Any updates

[Cyifly]

Mate convert to external Gate problem solved

[jet2nv]

Theres No need for external gate, I'm just waiting for my new 3.5 inch bell mount dump to be made just seeing if others have had success, stao and Abe from havoc made a easy 330/340rwkw with internal wastegate currently mines at 324rwkw so I'll see how this dump goes once its made

[Cyifly]

True true fair enough then. I was thinking of future if and when you chase even more power (damn hp itch) externally gating will give you that opportunity now and I the future.

Here's a wee list of mind mate sorry bit log copied it from other post.

Thought I'd have a look and add my info car is currently on the build again bigger turbo and intercooler

But here is some figures when finally complete and

On Dyno will post sheets of new power.

Currently 427kw revs taken to 8800.

Cracked r34 gtt 25det neo

Fully forged from ground up.

Valves seats rings arp head bolts, studs

Wiseco forgiez

Tomei poncams stage 2

Rc 720cc injectors Greddy intake

Hypertune 90mm throttle body

4 inch intake piping all round

SARd external gate

Custome sinco top mount mani

ARE surge pot fuel pump wallbro x 2

Nismo engine mounts to stop torque bend ( still engine pulls hard lol)

Hks t04s 1.0 exhaust wheel (nice change at 4000rpm no valve noise means no cops lol)

Apexi avcr

Apexi el2 gauges oil pressure,temp water And boost

Apexi rsm

3 1/4 inch exhaust with cat back

Arc cold air intake box

Spitfire coilpacks

Upgrade vct module It's awesome keeping vct trust me

Basicly it there's heaps of other things but that's basic core stuff.

427kw atw at 1.4 bar boost

On Bp 98 ultimate

Oh and vipec ecu

Nice to see heaps of other tough 25 and 20dets reppin.

[

[DVS JEZ]

Theres No need for external gate, I'm just waiting for my new 3.5 inch bell mount dump to be made just seeing if others have had success, stao and Abe from havoc made a easy 330/340rwkw with internal wastegate currently mines at 324rwkw so I'll see how this dump goes once its made

Are u trying to avoid the boost creep or are u chasing the 6kw?

[Checkbuzz]

GT3076R (52T), 0.82 A/R IW Garret rear, GCG split dump, 274rwkw (PULP) @19psi on Garret 1 BAR actuator

Full boost @3000rpm... No boost creep at all!

IMO the GCG split dump is a thing of beauty and works perfectly

[scotty nm35]

Yeh right, 19psi by 3k on a GT3076 with 0.82? Must be a 3L right? Most guys only hope to get that sort of response with a 0.63 rear, and no split dump is going to make that much difference.

[R32Abuser]

Yeh right, 19psi by 3k on a GT3076 with 0.82? Must be a 3L right? Most guys only hope to get that sort of response with a 0.63 rear, and no split dump is going to make that much difference.

EDIT:

I have a 3L, 9:1 Static CR, GT3076R with 0.82 rear and I make 14-15 PSI (1 Bar) by just under 3000 in 3rd/4th on PULP (BP 98).

19 PSI is in at about 3300RPM odd.

I guess its achievable but 19 psi in before or at 3000RPM. I wouldnt mind seeing a dyno plot to back it.

This is ofcourse unless its a stroker 3.2 or 3.4 lol

Edited November 28, 2012 by R32Abuser

[discopotato03]

I have not seen the results of a 52 trim GT3037/GT3076R on an RB30 so I'm not sure if or by how much the slightly smaller trim compressor affects spool/boost threshold . Me thinks a higher CR like 9.5+ would pull up a bit more low end torque pre boost and make it a little more linear with the boot in .

A .