ITR

iTrader: (1)

Does anyone knows if the following is boost creep too?
I am getting this reading first 0.82 then spike in transition to second turbo to 0.90 or 1 then falls to 0.5 and stay constant. I am also getting various readings like 0.72 spiking again to 0.9 and then falls to 0.65. I'm running on a mid-pipe and stock ecu and i am now in the process to order a bonez high flow cat. But i am still wondering if the problem is just appearing because of the mid-pipe. Can anyone suggest anything please?
If i'll do a restriction plate for the time being, would i fix the problem?
Could this be a tuning problem?


Many Thanks !!!

dgeesaman

iTrader: (7)

Yes, a restrictor plate or a high-flow cat will reduce the spike. The higher flowing the exhaust, the faster the boost changes and the more a stock ECU will allow a spike to develop.

This is only a tuning problem in the sense that you need a tunable boost controller. I suggest a manual boost controller for simplicity, but electronic boost controllers are equally effective.

Dave

ITR

iTrader: (1)

Many thanks Dave! But would just a boost controller solve the problem? Thanks again!

u lose

a boost controller will not fix boost creep. the wastegate is not able to vent off fast enough cause more boost.... port the wastegate or just go with the high flow and you should be in better shape.

ITR

iTrader: (1)

Thanks u lose. That's what i thought too. When you have boost creeps or spikes, does the boost pattern vary every time?

rynberg

You don't have creep....your boost is actually falling off at higher rpm, from what you posted. It sounds like you have some problem with your turbo control system, a slight leak, or failing check valve/solenoid/line. Once you find the problem, THEN you might creep.

IamRobbyah

Port the wastegate, its not that hard.

write up

twisted7

iTrader: (3)

haha porting the wastegate doesnt always help it didnt help me at all, and i ported mine to 1.3" A high Flow cat will be pretty much the only thing that wont allow as much creep... im boosting 7psi and creep up to 9-10psi in higher rpms....

windom

iTrader: (1)

Yep, especially when it's actually cool outside (15-30F) like here. The ultimate solution I've heard is porting it more, and welding on a new flapper door. I haven't tried this yet, as I'm going to a single turbo with external wastegate.

ITR

iTrader: (1)

Thanks Robbyah! Very precious material in your link!

rynberg, my boost on the primary turbo is getting to between a min of 0.72 and a max of 0.86 . What might be wrong? I thought that this is boost creep. Thanks

axr6

The answer is not always that clear cut.

I just pu on a brand new set of NS BNRs. They came with only one actuator nipple so, controlling the boost with my PFC was not an option. Initially I just ran against the WG spring and had 7 psi boost. No problem, no boost creep of any kind.

Then, I put in a Type S Profec boost controller. After setting it up and loosing 400 RPM in boost response I also have boost creep in the LOW or OFF settings only. It creeps when the Profec is turned OFF, from 7 to about 10 psi, and creeps in the low setting from 10 psi to 12.5 psi. It, however, does not creep in the HIGH setting. It is solid at 14 psi and is solid when set at 16 psi.

Who knows what is going on? BTW, I do have the max size porting with the extra large flapper installed on the WG. So, obviously, there can be more reasons for boost creep than the size of the WG port.

Albert

dgeesaman

iTrader: (7)

Boost creep would tend to occur only above 4500rpm, and your boost might look like: .86, .86, .86, .86, .87, .88,.89,.90,.91... until you take your foot off the gas. Punch it hard again and it will start again from .86,.87,.88,.... The point is that with boost creep you never see a maximum boost, the longer you stay in hard throttle at that rpm the higher the boost goes.

Boost spikes usually show as a brief moment of extra high boost, usually right between 4500-5000rpm, and then settle back down to a normal maximum boost.

So I want to confirm your boost pattern: you get a solid .82 bar from about 3000-4500, then .9bar between 4500 and 5000, then it drops and stays at .5 bar from 5000-8000.

Do you currently have a boost controller? Stock ECU? If you have all stock, I'm curious what boost you get when the wastegate and precontrol solenoids are unplugged. I would expect it to be a steady 8-9 psi (.6 bar), and it will be a lot safer for your engine.

I also strongly recommend you start by looking for boost leaks. That spike may be enough to push open a leak that is venting some of your secondary boost.

Dave

ITR

iTrader: (1)

Thanks dgeesaman! You have been of lots of help. I am currently running on a stock ecu and I don't have a boost controller either, just all sotck. What's strange is that yesterday the same thing happened but my final boost was again stable at 0.65. I'm getting kind of crazy.

ITR

iTrader: (1)

Anyone? Thanks

NAN777

it's normal for stock ECU to have spike on that kind of setup...mine... as soon as i put my foot down.... it shoots up to 0.85 BAR then the internal wastegates will regulate it down to 0.65 Bar.. and stay constant....

a boost controller will defenitely help....

ITR

iTrader: (1)

thanks NAN777! I guess its better if i invest in a boost controller defore doing anything else.

dgeesaman

iTrader: (7)

Yes, especially before the engine blows. Boost spikes are the perfect breeding ground for detonation.

Dave

ITR

iTrader: (1)

Dave, installing a more powerful fuel pump (with stock ecu), would i'll be doing a reliable modification?

Thanks for your support!

Ken