Boost Fluctuation Issue

[zafeniak]

Hi guys, I have a R33 GTS-T with the following mods:

FMIC

Straight through exhaust (3inch)

COld air intake system with POD filter

Turbosmart boost controller running strange boost levels.

Ok, so my intention is to have the car running at 10 PSi, however, it doesn't seem to be doing that...

When I put my foot on the accelerator, boost goes up to 11.5 PSI, then drops to 10 PSI (at about 4000 RPM)

at about 5000 RPM it will drop down to 9 PSI, then after 6000 RPM it will go up to 10.5 PSI.

What's causing this to happen, could it be a faulty boost controller?

The reason I am asking is because I want to install a Apexi NEO SAFC on the car, however, I know that the tunners will tune the car to a specific boost level, and mine are all over the placem thus, it would defeat the purpose of me instaklling it now.

Would an electronic boost controller solve my issues? Would it hold the amount of boost constant no matter what condition the car is running in (hot / cold etc)?

Or should I just get a power FC (which I am assuming can control boost levels?)?

Cheers

[jeffworld2]

i would suggest that with the straight exhaust, it is easier for air to go through the turbine wheel than to bypass it through the tiny wastegate. so even though the wastegate is open, its going through the turbine randomly when it gets backed up.

either that, or your boost controller is somehow shagged. i'm assuming its just a bleed valve, so it should be one setting only type operation not fluctuating between like an ebc can.

a good ebc may help control it, but you may want to look into trying someone elses exhaust for 10 min. to get the wastegate enlarged by gcg etc is a big job for a gain you can only see on your boost graph. it would be possible to tune around the problem and still get a smoothish result if the tuner is ok

[Devils_Advocate21]

its something to do with how you have set the boost on the controller hence why it is up and down, similar to gain settings on the profec b style controllers, hence the fluctuation is my guess at it?

[zertek]

i had the exact same problem in my old R33. i removed the little boost controller and just ran the hose right through to the actuator. then went for a test drive and boost was smooth and stable. give it a go, might even just be a dodjy boost controller

[zafeniak]

i had the exact same problem in my old R33. i removed the little boost controller and just ran the hose right through to the actuator. then went for a test drive and boost was smooth and stable. give it a go, might even just be a dodjy boost controller

If you run it straight though to the actuator wouldn't you be running close to stock boost?