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Overboosting & Knocking

Turk

By Turk,
in Engines & Forced Induction

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Turk Enthusiast

Turk

Posted
Posted

Hi, I have a problem with my car overboosting and causing it to knock

here is my set up

GCG HF/BB

555 HKS injectors

Pro spec B2 B/C

FMIC

it was set to 15psi high boost and 10psi low boost on the dyno

on the road high boost climbs to 17.7 psi and low to 12.2psi low

my boost controller on high is set at

gain 15%

set gain at 50

the over boost cause to knock after 6000rpm

any ideas why

cheers

joe

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tm_r33 Experienced

tm_r33

Posted
Posted

when my m8s car was on high boost it started knocking at high revs... then at most revs... then at all revs... the knocking getting worse and worse... turned out he had done a big end bearing. probly nothing this major in your car just a thought thats all

TommO Grand Master

TommO

Posted
Posted
running power FC

had a knock reading of 94

on the dyno it showed a nice straight line at 15psi at peak getting 252rwkw

Take it to your tuner and get him to adjust the tune - it's not a matter of adjusting the boost controller, esp considering on a freezing night you'd be likely to get a spike again anyway... rather you should try to ensure the tune is better...

So speak to your tuner :ninja:

Turk Enthusiast

Turk

Posted
  • Author
Posted
Take it to your tuner and get him to adjust the tune - it's not a matter of adjusting the boost controller, esp considering on a freezing night you'd be likely to get a spike again anyway... rather you should try to ensure the tune is better...

So speak to your tuner :ninja:

this is been an ongoing problem on dyno its sweet on the road in spikes even with the boost contoller of it boosts to 12psi

TommO Grand Master

TommO

Posted
Posted (edited)

even with a perfect EBC it'll still spike a bit - I'm surprised your tune is so close to the limit that a tad more boost causes knocking. Why not richen up the tune (or take out a tad of timing) a little so at least you can drive the thing properly whilst identifying your issue :ninja:

Edited by TommO
Turk Enthusiast

Turk

Posted
  • Author
Posted

Thanks everyone, its really fustraiting me I had the spike problem with it before, i was informed that the OP6 housing will fix it. but im back to square 1

I'm to the tuner 2moro

if i get them to tune

13psi high boost do on the road i should get 15psi

8 psi low road 10psi

maybe that will work

The Mafia Grand Master

The Mafia

Posted
Posted (edited)

why don't you just have one tune at one set boost, and control the power with your foot?

I have one tune running 300rwkw and 18psi of boost.

When I want half power, I use half throttle?

Edited by The Mafia
Turk Enthusiast

Turk

Posted
  • Author
Posted
why don't you just have one tune at one set boost, and control the power with your foot?

I have one tune running 300rwkw and 18psi of boost.

When I want half power, I use half throttle?

how do you do that when its on man.. all you wanna do full throttle and punch the gears,

how do you get 300 stock engine no knock

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
how do you do that when its on man.. all you wanna do full throttle and punch the gears,

how do you get 300 stock engine no knock

a decent tune.

I ran 370rwkw, no spike, no knock.

Its a combination of things.

Plus your running a PFC - so you cant have two maps unless your running a datalogit and change it everytime you change boost setting.

Power/boost is controlled by the right foot. I ran 24psi daily without issue

NYTSKY Grand Master

NYTSKY

Posted
Posted
a decent tune.

I ran 370rwkw, no spike, no knock.

Its a combination of things.

Plus your running a PFC - so you cant have two maps unless your running a datalogit and change it everytime you change boost setting.

Power/boost is controlled by the right foot. I ran 24psi daily without issue

370rwkw with the RB25?

Sounds like a handful lol

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