Straight Bolt On Turbos

[WRXER]

Was about to say on my previous wrx, i had no issue with an internal gate causing boost to taper off.

[PhatRS]

Is it not more about the spring rate in the actuator of the internal gate? Most factory ones are between .5 and .7 bar and you are just pushing them too far when you up the boost to say 1.4 bar thats why so many turn to externals as its easy to put a 1 bar or larger spring in and run solid boost, if you could do the same with your internal.......same thing happens.

[Guest]

id be keen to get a higher psi spring.1bar acttuatr spring wuld be good!

[Pappu1]

 Qwerty']

[quote name='sti8u said:

on the other hand iv yet to see a internal wastegate that can hold 18psi to redline without tappering off,externals have shown this many times.

i would like to see a internal setup running with a decent ebc set on 17 18psi and see how it goes.

/quote]

Thats 1.6bar or 23psi ish - at redline. The boost curve was tuned to taper down abit tho.

Yes internal gate...

was that using a ebc on stock internal gate?

rather interested to know how it was done..

up till now i have always tapered down towards redline but recently tried to hold and it still tapered down..

as if the gate was being forced open with gas flowing thru it..

anyway - on a related topic - will the size of the exhaust system limit boost the turbo can make?

my thinking is that if there was more backpressure in the exhaust pipe (say a restrictor of some sort) than the turbo wud only make a certain amount of peak boost with/without wastegate as it can only push so much gas through the exhaust..

thoughts??

[Guest]

as if the gate was being forced open with gas flowing thru it..

Correct exhaust gas pressure is opening the wastegate - the pressure is greater than the wastegate spring. Its a sign the turbo is at the end of its flow capabilities. You can use a stronger spring but that causes all sort of other issues

anyway - on a related topic - will the size of the exhaust system limit boost the turbo can make?

my thinking is that if there was more backpressure in the exhaust pipe (say a restrictor of some sort) than the turbo wud only make a certain amount of peak boost with/without wastegate as it can only push so much gas through the exhaust..

Only in a case where you had extreme restriction - after all even on stock cars / exhausts you can probably hit 20psi freeboosting.

Boost does not always = power.

[Guest]

Here are 3 turbos - roughly the same boost levels. Making different power at similar boost.

[Pappu1]

No no lol not trying to force more boost

Just wanting to hold boost steDy

Currently turbo soils up to boost and by redline has dropped lower

In the graph u put above - what turbo was it pulling 23 to redline?

Currently trying to hold 18/19 to redline but keeps dropping to 16

Anyway based on what u said abt turbo reaching it's flow capacity - is this a factor of excessive backpressure - have a 2.25 inch exhaust which keeps noise nice and legal ish

Wat sorta power will that size exhaust support on vf turbo? Any thoughts

[funkytown]

that one is a garrett 3071r hybrid that sits in factory position, with rear housing to match (slightly smaller than genuine gt3071r)

the middle one is a factory vf34...

the first one - see if you can guess. I dont feel like ruining the fun.

[Guest]

 pappu said:

Anyway based on what u said abt turbo reaching it's flow capacity - is this a factor of excessive backpressure - have a 2.25 inch exhaust which keeps noise nice and legal ish

Wat sorta power will that size exhaust support on vf turbo? Any thoughts

High Pre turbo exhaust gas back pressure (egbp) (which blows the wastegate open) is a sign that your compressor is needing to be worked quite hard / spin very fast. Which in alot of cases means its running out of flow.

You can lower backpressure by having a larger post turbo exhaust.

No idea as there are too many variables. But if u want more power a better flowing post turbo exhaust will lower egbp and u will make more power.

[Pappu1]

hmmm maybe the 2.25 is then too small.. will try a 2.5 and see how that pans out..

have heard that bigger up pipe causes more lag - just heard from other not tried..

[PhatRS]

Qwerty is meaning that you will need a bigger exhaust not uppipe to lessen the back pressure after the turbo. Larger uppipe will lead to more lag especially if its not the restriction in the first place.

[WRXONP]

My vf23 has no trouble holding 22 pound (lol) till red line . . . . I have a 3 inch straight through exhaust and a 38mm external gate . It has a 14 pound spring which is probably the reason I dont get taper . . . . I am moving to a larger over sized up pipe . . -use to have one but it was rooted so want to see the difference this time round

[Pappu1]

Hmmm may have to 3 inch it I guess

Wrxonp - mate 22psi till redline is bloody good Hahah many of us can only hope of that with the nternal gate

Hmmm be very interesting to see how the new stup does on the dyno this time

[WRXONP]

Aw I run 20 pound daily but most of the time in traffic . Lol .. I cant make the dyno now . Got new set up so ran out of cash -dont think my exhaust would fit on dyno any way

[johnny5]

heard boost drops off cause of something to do with the loop control closed loop mode will stop this so maybe an ebc like hks or hdi will fix it maybe Im hearing bullshit not sure anyone know

[igkgunn]

Would heatwrapping the downpipe help too? Im thinking of doing this, not sure if itd be worth it or not though? Can anyone comment on actual gains from heatwrap?

[Pappu1]

Ok so tried to hold boost steady with hks Ebc on internal gate with a 3 inch exhaust

Nope still tapers down lots

Seems like he internal gate is no able to shut fully once cracked open

Well that's what I think anyway

Next option is to run external and see if that holds boost steady - no doubt it will based on what others are getting

Anyway, think I will stick to q restricted 2.25 inch exhaust as it seems to limit boost on top end to 16. That's good cos if there was a sticky solenoid or gate, by default the backpressure will limit boost and thus not allow any excessive overboosti g

Bit of a safety feature I suppose

Wil do few more tests to confirm the above theory

Anyway who knows for sure what is the v7. Sti map sensor max reading at

I'm thinking 25 but have heard others say 22.5 so u sure

Anyone knows for sure

[rex-leggy]

 funkytown said:

that one is a garrett 3071r hybrid that sits in factory position, with rear housing to match (slightly smaller than genuine gt3071r)

the middle one is a factory vf34...

the first one - see if you can guess. I dont feel like ruining the fun.

it wouldn't be your turbo would it jon?

did i win

[funkytown]

 rex-leggy']

[quote name='funkytown said:

that one is a garrett 3071r hybrid that sits in factory position, with rear housing to match (slightly smaller than genuine gt3071r)

the middle one is a factory vf34...

the first one - see if you can guess. I dont feel like ruining the fun.

/quote]

it wouldn't be your turbo would it jon?

did i win

my turbo? which 'one' are you talking about? Ive owned three

factory vf 23, Steve Murch vf23, and a genuine gt3071r

[Guest]

 pappu said:

Anyway who knows for sure what is the v7. Sti map sensor max reading at

I'm thinking 25 but have heard others say 22.5 so u sure

Anyone knows for sure

I was told 1.6bar by someone who should know.

*fixed for you

[Pappu1]

Hmm 23.2psi max ay

Sounds good

Is the unknown turbo a sm vf23

[vorigan]

 pappu said:

Hmm 23.2psi max ay

Sounds good

Is the unknown turbo a sm vf23

after speaking with someone that dyno tuned a certain persons car yesterday informing of all the veriables of all the setups and changing sweep rates ramp versus step on the dyno you can make it read whatever you like.

im due to be down welly way in the next month im so hanging out for a friendly catch up with customers.

[funkytown]

no pappu thats not one of my turbos.

they are all qwerty's

[Pappu1]

 funkytown said:

no pappu thats not one of my turbos.

they are all qwerty's

hahaha i was only guessing bro lol

go on qwerty - what is it..

sharp drop in hi rpm tho...

[PhatRS]

Money is on his std vf24 (i think it was a 24)