What's new

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

Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
hmmmm, i guess you didn't solve it and your car burned down to the ground?
maybe vvt is off/busted?
problem is that the car feels strong and fast...
 

CMR

Joined
22 August 2011
Messages
417
Reaction score
0
Points
16
Location
Yorkshire, UK
Country
Couldn't find the thread on my phone. The car got written off and stripped for parts so never did sort it.
Il try find it on the pc tonight

It seems to be specific to the s15's sr20det or the T28R as I did find someone else with a very similar problem.
 
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
@CMR: What did you rule out?

My first step now will be detaching waste-gate flapper and inspect movement/test drive, to rule that out
hopefully that's it and i just need a actuator
 
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
I fixed it (i think), faulty actuator

Removed the actuator lever from the waste-gate and checked if the waste-gate moved freely (what it dit, thank god)
Then put pressure on the actuator, starts moving at .4 bar and completely open @ 1.1 bar
range should be; 0,387 - 0 , 440 bar

 
Last edited:
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
AAAAAARGH !@#!%#%
Replaced the actuator, new one is a bit better but still got crazy creep...
Lever starts to open around .38 bar and completely open around .9 bar

This tells me that the setup is ok, so either my exhaust gasses have to much energy or the waste-gate can't cope with the amount of gas
stock S15BB turbo should be fine or else this would be well known issue

Next step:
-???
-remove turbo and port the flapper hole... but this shouldn't be necessary

could valve timing or ignition have anything to do with this??
 

immy21

Joined
9 November 2012
Messages
120
Reaction score
0
Points
16
Location
Edinburgh
Country
Disconnect the actuator (remove e clip), then go for a run. See what it boost to by the limiter and then you will know what it will creep too.
If your intent on running low boost, I suggest put the cat back on, use a bung or set boost and have it mapped rather than the hassle of arising about with porting the turbo just to keep power low.

"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"

It's mainly the 3" exhaust that's making it creep. For reference, my s14a with similer mods except 2.5" mongoose exhaust (no cat) and journal t28 crept to about 10psi by redline with the actuator disconnected, 'fixed' it by putting 17-20psi though it :wack: with mapping to suit of course.


https://youtu.be/KwYkvYNuymE

https://youtu.be/3gOiUUOGU9I
 
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
Thanks for the help mate, appreciate it!
what did your creep do in say 4th gear, kept rising??

On my other turbocharged Nissans I was always able to hold super steady boost on actuator alone (so 7psi till rev limiter)
Before I start mapping I want to have everything working perfectly. (with stock cat-back i also had this creep :,( )

I want to be able to set low boost for fine tuning the maps apart from WOT

I just have a gut feeling something is not as it should...
 
Last edited:

immy21

Joined
9 November 2012
Messages
120
Reaction score
0
Points
16
Location
Edinburgh
Country
Vids were taken in 2nd but 4th gear was roughly the same from what I can remember.
 
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
Gonna try and inspect my waste-gate hole this weekend,
then see if the timing of the exhaust cam is correct and a compression test... than i am all out of idea's
 
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
Could anyone check at what pressure their waste-gate starts to open and at what pressure the gate is completely open?
 
Joined
19 November 2015
Messages
17
Reaction score
0
Points
1
Location
UK
Country
how can the stock turbo make 14psi with the waste-gate tied open...?! should be impossible...
You think you have a stock turbo but actually it isn't or you have a cheap turbo elbow that doesn't allow the poppet valve to fully open
 
Joined
1 May 2015
Messages
117
Reaction score
0
Points
0
Location
The Netherlands
Country
Definitely got a cheap elbow (good quality tho), but allows fully opening of the waste-gate... (also had creep with stock exhaust setup, just only above 6K rpm)
Turbo sure looks/feels like a S15BB (checked this cause it was the only thing that would make sense to me)
I feel like a complete Noob but am pretty experienced with turbo cars.... :confused:
Just gonna get Nistune and set boost on 15 psi, fingers crossed it will stay steady
 
Top