Boost Creep Gt3076

[scotty nm35]

Lol, split dump. :facepalm:

Have you checked the flapper travel with the actuator disconnected?

[jet2nv]

yep and i bought the dump pipe of (the mafia) its not the normal split dump

he made it i think from memory or am performance did but im in the process of getting a bell mouth made as ive got the rear housing machined tried different actuators, flapper travels fine and doesnt foul on anything

[DVS JEZ]

Do the exhaust gasses from the wastegate port line up with the split dump ?

Id be suprised if the bellmouth doesnt solve it.how much bigger is the new flapper

[jet2nv]

my rear housing is the photo stao put up on the 1ST page of this thread

when i removed the turbo there was a fair bit of carbon around the wastegate/screamer hole in the dump pipe so it looked like had trouble

i had to rule out the actuator so i tried a 1 bar 17psi 18 psi 20psi and they all went straight up to 23psi fairly quickly in 3rd/4th/5th

[discopotato03]

My issue with "split dumps" , particularly for these IW Garrett turbine housings . is that the fabricators often merely holesaw a round hole through the flange plate and weld the seperate tube to that .

This is my theory , the gasses out of a turbine housing are hot and getting real hor by the time the waste gate was to open to regulate turbine speed/boost pressure . Hot gasses want to expand and don't like a passage opening up and then closing particularly into a round hole with sharp edges , a bit like a non matching manifold/port flange .

I think to make a propper split dump you need to have a matching sized and shaped hole through the flange plate and the tube/duct then needs to grow in section to handle the gas flow rate .

I honestly can't say through experience but logic suggests that any restriction between the waste gate and where the seperate duct meets the exhaust down stream will limit how much the waste system flows and if it doesn't flow enough it won't control boost .A restriction doesn't have to be the waste gate itself and you should view the waste section as from the valve to where it rejoints the rest of the system .

If you go the seperate tube particularly with a modest AR turbine housing I think this is somewhere that a little overkill size wise is a good idea .

I don't want to reignite the split vs bell mouth dump debate but with these Garrett GT30 IW turbine housings you already have a partial divider between the turbines outlet and the waste gates valve so the waste flow won't go straight into the main outlets path IMO .

The bellmouth with give a large area for both to vent into and you shouldn't get any pressure rise higher than what the turbines outlet has , if you did with the split duct then you're behind the eight ball boost control wise anyway .

A .

[jet2nv]

to true from most posts and tuners ive spoke with ive been advised to use a bellmouth as my one from experience isnt the best lol prob would have something todo with getting my head/manifold/turbo flange and turbo all machined and port matched so id assume from those extra gasses are not going to be helping what so ever

im just wanting to know if it could be something else im overlooking or havent thought of

[DVS JEZ]

Just to check, where is the boost pressure source coming from?

Have u checked that line for splits?

Does the boost rise to 23psi instantly or does it hold 18psi then creep to 23psi with higher revs?

[jet2nv]

the boost source is of the hotside cooler piping not far from where most of the nipples are on the turbo front housing

it hits 16psi then raises with the rpm upto 23-25psi when i just have the actuator with no boost controller

when i use my gizzmo ebc it shoots straight to 23psi lol

[AngryRB]

split dump on internal gated turbo = cheap man's mod = fail

if your going to split it then go external gate, gt30 will perform so much better..

[FordyR31]

Unsure if its been mentioned but is there anything obstructing the rod from the actuator to the gate? The actuator may be fine but if the rod hits something the flap may not b opening far enough for the gasses to pass through at higher rpm. Might be something free to check.

[jet2nv]

nothing is stopping it from opening completely and my gt3076 .82 make 289rwkw at 17psi by 5650rpm but that wasnt a complete tune as we were still trouble shooting so theres no real need for a ex gate as im wanting to stay internal

if a xr6 can make 450-500rwkw i think a little gt30 on a 2.5 litre can make 300-320rwkw without the need for a external gate so my next job is to make/fit a bell mouth dump pipe

just a little upset with the forum member off here who sold me the dump pipe and say it was perfect and made 312rwkw

[AngryRB]

shes going great mate, i guess its just as far as boost control and a bit of extra lag is all compared to an external, but thats some respectful power output

[scotty nm35]

No two setups are the same.

Try running a new hose directly from the boost source to the actuator. If that fails, perhaps try another pressure source? The .82 with a larger wastegate port should flow fine. Only by changing the dump will you know if it's a problem I guess.

My GTX over-boosts with a 45mm external gate hanging off the side, but it is caused by my soft limiter backing out timing at 7300 revs.

[jet2nv]

with my gizzmo ebc im seeing 19psi by 4050rpm so giving the mods ive done ie all the porting and so forth i shouldnt see less then 300rwkw from the way it looks atm

[DVS JEZ]

U have to remember that the guy u bought it off left it standard.

U have port matched and machined out the manifold and the turbo which may be affecting it

[methz]

this prob has nothing to do with much, but last time i tried running my vac source from the hot side i got nothing but spiking, eventually going back 2 inlet manifold for vacum source and it worked perfectly.

[discopotato03]

It may not suit me personally but for easier power and less regulating issues the mid sized turbine housing may have been a better choice for you .

I feel the big issue with most integral gates is that its hard to get the exhaust gas to turn 90 degrees and flow out the port when the gas speed is high .

The larger the housing AR the lower the gass speed is through the housing for a given output . Externals if located properly make life a lot easier because they tend to be larger and flow better when open - if located properly .

You occassionally see externals plumbed to an IW housings std outlet and you have to ask if its much better than the original flat valve .

Just on those XR6T hybrid GT3582R/GT3576Rs . Ford went with the larger 1.06 AR turbine housing - and like all Garrett IW T3 flanged GT turbos - used a GT35 turbine in a GT30 housing . They went bigish on the hotside and smallish on the compressor housing because it was intended to be a low boost pressure sollution for a reasonably big 250 Cube/4 litre I6 .

I reckon the later versions went back to the 76mm compressor because the overall package better suited their needs and boost control was probably easier as well . Anyway at over 300 Kw they are supposed to pull fairly hard in a guesses 1800 odd Kg barge .

That same Ford spec GT3576R could be an interesting turbo to try on a street RB30 with the right sorts of things done to it .

A .

[KiwiRS4T]

this prob has nothing to do with much, but last time i tried running my vac source from the hot side i got nothing but spiking, eventually going back 2 inlet manifold for vacum source and it worked perfectly.

Probably not related. I moved my boost source from the vacuum manifold to the top of the compressor housing on the turbo. You don't really want vacuum in that line.

[The Dan]

It may not suit me personally but for easier power and less regulating issues the mid sized turbine housing may have been a better choice for you .

I feel the big issue with most integral gates is that its hard to get the exhaust gas to turn 90 degrees and flow out the port when the gas speed is high .

The larger the housing AR the lower the gass speed is through the housing for a given output . Externals if located properly make life a lot easier because they tend to be larger and flow better when open - if located properly .

You occassionally see externals plumbed to an IW housings std outlet and you have to ask if its much better than the original flat valve .

Just on those XR6T hybrid GT3582R/GT3576Rs . Ford went with the larger 1.06 AR turbine housing - and like all Garrett IW T3 flanged GT turbos - used a GT35 turbine in a GT30 housing . They went bigish on the hotside and smallish on the compressor housing because it was intended to be a low boost pressure sollution for a reasonably big 250 Cube/4 litre I6 .

I reckon the later versions went back to the 76mm compressor because the overall package better suited their needs and boost control was probably easier as well . Anyway at over 300 Kw they are supposed to pull fairly hard in a guesses 1800 odd Kg barge .

That same Ford spec GT3576R could be an interesting turbo to try on a street RB30 with the right sorts of things done to it .

A .

Exactly.

Which is why the XR6 Turbo doesn't suffer from these same issues.

Finally someone who agrees with me

[GotsWapan]

My mate has a rb30det with the ford turbo I/W on it. He has spiking issues aswell. Tuned to 16psi as far as I know and it spikes to over 20psi.