Boost oscillation?

B

billy187

Member
Last week when the car went onto the rollers was told that it had boost oscillation? what does that exactly mean? the car should have easily made 400bhp but only made 335bhp because of this, now i was told it was due to the boost controller being faulty? (not holding boost) its a greddy profec 2, is this really that simple that theres no way of setting it up correctly? was recommended to change the boost controller and then to adjust the map through the power fc but thought id definently make sure that this controller is dead before i go changing it?
 
Last edited:
gtir_pimp

gtir_pimp

New Member
well do you have a boost gauge so you can watch the boost when you nail it? actually the greddy controller shows the boost on the screen! get someone to watch it when you floor it down the road to see if it does go up and down. also who set the controller up? because there are some functions like start boost, gain, etc that can make the boost do this!
 
B

billy187

Member
gtir_pimp said:
well do you have a boost gauge so you can watch the boost when you nail it? actually the greddy controller shows the boost on the screen! get someone to watch it when you floor it down the road to see if it does go up and down. also who set the controller up? because there are some functions like start boost, gain, etc that can make the boost do this!
Click to expand...
i dont know who set the boost controller up as i bought the car done up a while ago now, ive got a seperate boost gauge aswell? so am i just looking to see if the boost increases in psi? looking at the rolling road print out the power seems to just wiggle around after 5000rpm and the curve doesnt go any higher after that...it did this on both low and hi boost...
 
GTIR-LOZ

GTIR-LOZ

New Member
you could have the boost limit set at whatever your max is then the controller lowers the boost by a set percentage to whatever you have set it too hence why the boost goes up then down try setting the boost limiter up
 
Fusion Ed

Fusion Ed

Active Member
What turbo is it? This is quite common on profec b and say 3071 and is a pain to smooth out. Its a mechanical resonance between the turbo and the controller. Usually not helped by the way they are plumbed in.
 
B

billy187

Member
GTIR-LOZ said:
you could have the boost limit set at whatever your max is then the controller lowers the boost by a set percentage to whatever you have set it too hence why the boost goes up then down try setting the boost limiter up
Click to expand...
i see what you mean, so theres definenetly a chance that the controller just needs setting up correctly? im not gonna mess around with it myself as i wouldnt know where to start but i guess il have to find someone who knows what there doing :roll:

il post up the dyno graphs later so you can see exactly how the curve just drops off....
 
B

billy187

Member
Micra Ed said:
What turbo is it? This is quite common on profec b and say 3071 and is a pain to smooth out. Its a mechanical resonance between the turbo and the controller. Usually not helped by the way they are plumbed in.
Click to expand...
yep you got it right its a 3071, any advice? :oops:
 
gtir_pimp

gtir_pimp

New Member
have you got the instruction booklet for the greddy? its very east to adjust the limiter. i have done it. another way to tell if the limiter is kicking in is when you put your foot down look at the controller and it will flash from blue to red. does it do this?
 
B

billy187

Member
gtir_pimp said:
have you got the instruction booklet for the greddy? its very east to adjust the limiter. i have done it. another way to tell if the limiter is kicking in is when you put your foot down look at the controller and it will flash from blue to red. does it do this?
Click to expand...
i havent got the instruction booklet :cry: never really looked to see if it flashes red but will take the car for a blast over the weekend and see what happens...
 
gtir_pimp

gtir_pimp

New Member
do you actually know what boost its running? can you post up your settings on the controller hi and low
 
Fusion Ed

Fusion Ed

Active Member
You need to keep all pipes as short as possible. Take the actuator supply from just after the compressor, to the solenoid then back to the actuator. Also keep the boost sensor pipework as short as possible, take from a separate connection from the outlet of the turbo, compressor and again try to keep pipes very short. Finally if you still have issues put a small restrictor of about 0.25-0.5mm in the actuator pipe.

Failing that use a bleed valve (!!) and all will be well!!
 
B

billy187

Member
Micra Ed said:
You need to keep all pipes as short as possible. Take the actuator supply from just after the compressor, to the solenoid then back to the actuator. Also keep the boost sensor pipework as short as possible, take from a separate connection from the outlet of the turbo, compressor and again try to keep pipes very short. Finally if you still have issues put a small restrictor of about 0.25-0.5mm in the actuator pipe.

Failing that use a bleed valve (!!) and all will be well!!
Click to expand...
hmm i take if i need to do that theres no point playing about with the boost controller? :?
 
gtir_pimp

gtir_pimp

New Member
actually here are my settings...

-low boost -hi boost
-set 55% -71%
-gain 20% -20%
-set gain 100 -120
warning 140 -20%
limit 2% -2%

low is about 1bar and hi is about 1.2
 
red reading

red reading

Active Member
Micra Ed said:
You need to keep all pipes as short as possible. Take the actuator supply from just after the compressor, to the solenoid then back to the actuator. Also keep the boost sensor pipework as short as possible, take from a separate connection from the outlet of the turbo, compressor and again try to keep pipes very short. Finally if you still have issues put a small restrictor of about 0.25-0.5mm in the actuator pipe.

Failing that use a bleed valve (!!) and all will be well!!
Click to expand...

do as edd has said,as adjusting the settings is'nt going to sort it out, and gtir-pimp your setting's won't work on imran's car as i think you have a gt28?? turbo and imran has a 3071 :doh:
 
You must log in or register to reply here.
Top