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Stock high rev boost creep? 0,6->1,0bar

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With open waste-gate still 14 psi

Update:
with waste-gate tied open I still get 7psi @ 4k rpm, than goes to 14psi till redline...
https://youtu.be/HyHDuydxjlM


Problem is i am running stock tune, so @ 14psi i'm seeing AFR's of 14.5 (between 3.5-4,5k rpm)
AFR at high rev's is good, 11 a 12.

My mods:
-Stock turbo
-3" Turbo back
-Pod filter
-FMIC
-EBC (turned off)
-Splitfire coil packs
-Iridium 7 plugs
-98 oct gas


Checked ignition timing (spot on -15deg)
Engine flushed
New actuator
waste-gate valve checked, all good

Any ideas???:annoyed::wack::furious::confused:

Original post:
He all,

I didn't really get any good results from the "search" so I'm trying it this way
I know that with an upgraded exhaust, boost creep could occur but i am running stock exhaust and cat...

When i floor it, boost is 0.6 bar (really steady)
than above 6K rpm the boost goes up to 0.9-1 bar

is this normal and what can i do too fix it?! doesn't seem likely that Nissan messed the turbo port up with stock setup...??
Don't know what it is supposed to do but this doesn't feel right
 
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Has someone installed some form of boost controller? Best thing to do would be to install and ebc so you can control it yourself. Also your stock actuator might not be setup properly which I think can cause boost creep
 
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No boost controller, and the EBC is on its way from japan (takes 2 months...)
the thing is that it holds boost quit solid between 3K an 6K rpm.. but from your reaction this isn't how it´s supposed to function
until i get my EBC should i just by-pass the oem BC?
how does the oem boost solenoid work, it is a strange setup IMO

(i do have a apexi filter btw)
 
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sibbers

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Check to make sure your hoses at the actuator or more like the feed from the cold side plastic nipple aren't cracked or leaking
 

John-

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My friend just had this problem on his S15, an EBC fixed it. Bypassing the factory boost controller did stop the creep, but lowered to .6 from .7bar.
 
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@ sibbers: shouldn't the boost constantly fluctuate with a leak or similar in the boost control routing?? because the boost is constant at low-mid rpm (but will def check it)

@ John: my boost is at +.6 bar so don think it will get any lower.. but what is the purpose of the boost control solenoid if the actuator is set at .6 ???
just to make sure wastegate is 100% shut bellow that?! a bit unnecessary i recon.. maybe my stock solenoid is busted as it should boost .7 bar stock instead?!
 

sibbers

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Thing with a boost leak is occasionally they will only show at higher pressures, especially round weak clamps. Really annoying and can make them harder to find but deffo worth taking a look, and it would only cause boost to rise if it feeds the actuator, so a boost leak elsewhere will just cause feeling issues and make your turbo work harder although it could result in that little bit of lost boost you're expecting possibly? Deffo have a good check around anyway, fingers crossed you'll find something obvious! Baffling. Maybe an EBC would help but it seems like something is wrong with the wastegate actuator. I've heard that cracks in the turbo @ the wastegate itself can cause issues. Might be worth searching that out just in case. Hopefully not!

Edit. I just searched. Don't think it's a cracked actuator :) it's usually the simpler things or the last things you touched that cause these issues (in my experience anyway)
 
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hahaha, you sir, make me sh*t rainbows!! "cracked turbo" :wack:
luckily I'm pretty stubborn and don't reckon it is something like that, I'm thinking the vacuum hoses, actuator setting or boost solenoid is leaky
only strange thing is that the boost is super solid at low-mid rpm range
so it should have something to do with flow
1. check for leaks using vacuum pomp
2. connect the actuator straight to the pressure side
if that fixes it wait for the EBC if not;
3. check turbo actuator setting

with the stock setup it should boost 0.7 bar across the hole range?
 

sibbers

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Lol @ **** rainbows! Yeah soz about that, hangover and mindless typing but I had a tiny crack in my wastegate once and I'd have never of known unless I took it off so it popped into my head and scared the rainbows out of you :D

yeah 0.7 across the whole range is normal for stock, no higher at any rpms.

Soz for my confused ramblings :) leaky hose or connection is deffo most likely!!
 
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I've been busy today,,

1. checked boost control lines for leaks; non at the pressure side<->actuator, when i put vacuum on the turbo intake side of the boost controller it leaks (don know if this is an issue because this might help prevent lag and once the boost is at max it closes?!)
2. connected the actuator straight up and turbo is laggy as hell 3K rpm boost is 0.45, at 4K boost is about 0.6 all the way up to 7K rpm
reckon the boost controller makes the turbo more responsive so might think my solenoid is polluted or broken

btw I measure the boost with the stock boost gauge, and am beginning to doubt the thing... is it accurate with a accuracy like -0.1 or could it fluctuate?

if i would just replace all the hoses what am i supposed to do with the restrictors in the original lines.. i don have 4mm line laying around so am using 3mm lines
 
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sibbers

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Hmm I really don't know... could it be that your wastegate is partially stuck open? ie: leaking gasses (spooling slower) and then not leaking enough at higher pressures? How are those rainbows coming on? ;) hehe jussssss kiddin' :D
 
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hahaha, rainbows are showing in the distance!
If the wastegate is stuck open than it would also lag with the original setup, witch (thank god) it doesn't!
gonna try and replace all hoses tomorrow, see what happens without any restrictors
any thoughts on the accuracy of the stock boost gauge?

thanks for your help mate!
 

John-

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I'm still thinking your factory boost controller is knackered. Get the ebc in!

The factory boost gauge isn't accurate. Compared to my profec b, the factory boost gauge can read up to .2bar out.
 
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the ebc (profec XD) is coming from japan.. so 4-8 weeks :,(
till then will just connect it back and dont rev above 6K...
seen more post about the .2 bar off, what that - or +? actual .5 did you read .7/.3?
 

sibbers

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Lol yeah just kidding :) Deffo sounds like the end is the way to go to replace the solenoid thingy that sounds bust. Pretty sure my gauge was accurate (when it worked) but who knows how accurate they all are? You can probably predict roughly what's going and I reckon you've worked it out anyway! Now to choose an ebc!
 
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got the Greddy profec in order @ jesse... just takes a long time to arive
with just a Apexi pod filter, how much boost would be safe (on ron95)? could .8 be run safe with oem cooler in coldish days?
am getting fmic, turbo back, nistune, wideband, feul pomp, etc but just for now
 

John-

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When I was running .7 bar, my gauge read .9, same with my friends one too!
People on here say you can raise it to .9 with all the mods you listed but running 99.
I personally wouldn't run .8 with just a pod filter and on 95.

When you get the boost controller set it to .7, it'll feel fast enough until you get all the supporting mods.
At least you won't have to worry about it going pop!
 
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Seeing my gauge go up to (on just the actuator) .6bar @ high revs i think it is pretty accurate
might be a boost leak then if it just gets up there in the higher rev regent..
wil try some fiddling with the vacuum pomp to check for leaks and replace as much vacuum hose as possible

i really want to run on ron95 with all upgrades as ron98 is super expensive and you can't get it in 9 out of 10 stations
don't mind the 10-15 % less power
 
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Got my EBC installed and still get massive boost creep... :furious:
EBC turned off = 0.4 bar, until 4k rpm, than it goes up to .9 bar all the way to limiter

put the controller on 1.0 bar and stays there steady but i get massive leanish (AFR 14.5) running when boost comes on... from 5k rpm it drops to AFR 12
if i set boost at .8 it is fine, boost creeps up to .9 around 4K rpm (AFR 12-12-5 and drops up top to 11.5)

the AFR i can understand, needs a tune in midrange
but that boost creep tells me something is of, valve or ignition timing?

car is running spitfire coils...

any help is appreciated, just need to stay near limiter till then :p
 

CMR

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Sounds identical to my old s15. Absolutely identical, il try dig the thread out I posted on SXOC.
Even with the actuator disconnected it till got creep up to 0.7 ish at 4k
 
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