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hey everyone,

noticed some strange behaviour a couple of times, wondering what might be the cause.

background:

im having a little trouble with my boost controller at the moment, it seems to have a mind of its own and will overboost up to some pretty scary numbers. when this happens, knock level goes through the roof on the pfc hand controller, but only for an instant. so short an instant in fact that the engine light doesnt flash (or i dont notice it)

the following has happened exactly twice:

if im driving hard in third, then i quickly shift to 4th, as soon as i put my foot down the car will feel like it has no power at all, it doesnt even rev. both times i backed off straight away so as to prevent any damage to the engine.

the first time, max knock level was at 149 and peak boost at ~1.5 bar

the second time i had the hand controller on the map tracer so i didnt see the max knock, but peak boost was at about ~1.4 bar

i dont know what knocking sounds like, but from the descriptions ive been told, i did not hear any knocking either time.

can anyone shed some light on this?

thanks

p.s. on a side note: if i have the hand controller on the map tracer, do some driving, then switch back to the channel monitors, will the max levels have updated? or do they stay the same as they were before i changed to map tracer?

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[email protected]? fark

You should def be able to hear 150, without a doubt. The ole "pebbles in a tin can" is still the best description i reckon.

What are your mods, what have you changed? Does anything coincide with this issue?

Edited by GeeTR

mods are:

3" turbo back with metalcat

fmic

pfc

pod with box

stock turbo with a turbotech boost controller that's meant to be set at 12psi

the rest is stock

i thought about clutch slip, but wouldn't the engine rev out?

any suggestions?

when an engine experiences severe knock, can it be expected to significantly reduce the power output so much so that its hardly noticeable?

is it possible the fuel pump could be over/under supplying causing the mixture to run very rich/lean? i'd think very very rich would give similar behaviour, but what are the odds of that?

the problem is, on the dyno the boost is pretty flat (fluctuates between 11 - 12 psi) and everything appears normal.

heres a (bad) picture of my latest dyno sheet

EDIT: took out the boost controller. back to stock boost and car is 100% fine. time to save for an EBC. moral of this story? dont trust a $30 ebay boost tap

post-35909-1204177596_thumb.jpg

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