Overboosting & Knocking

[Turk]

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

[TommO]

What ECU are you running? What knock are you hitting?

[tm_r33]

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

[Turk]

running power FC

had a knock reading of 94

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

[Equinox]

Turn your set gain down on the boost controller....

[scarface]

the higher the gain the more it will spike

[TommO]

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

[Turk]

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

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

[666DAN]

Ramp rate on the dyno too low? On the road it's getting a taste of real life. Cut back your hi and lo by about 5%

[Turk]

Ramp rate on the dyno too low? On the road it's getting a taste of real life. Cut back your hi and lo by about 5%

I lowered set gain to 40 still knocked

i havent touched the gain which is at 15%

[TommO]

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

Edited November 5, 2007 by TommO

[666DAN]

I lowered set gain to 40 still knocked

i havent touched the gain which is at 15%

But what was max psi? Was it still high?

[The Mafia]

most likely a mix of boost spike, hot weather, bad fuel, and a tuner that didn't put enough load on the motor when on the dyno.

[Turk]

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]

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 November 5, 2007 by The Mafia

[Turk]

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

[NYTSKY]

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

Water/methanol injection

[R31Nismoid]

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]

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

[Turk]

Water/methanol injection?

how does that work

Water/methanol injection