Boost suddenly declined

[GTIEVO3]

kRiminaLz,

Ur the red putra we met at santai, ttdi? if yes of course i remember. Btw ive checked the vacuum hoses and its not leaking. I'll check the hoses connected to the piping and my rpm and boost reading while idling is normal.

 

[GTIEVO3]

Btw how can u tell whether the BOV is leaking?

 

[kRiminaLz]

b.o.v leaking? hmmm...
we can hear the psssssssssing sound frm the b.o.v n the boost meter reading starts moving (-)...
or if not, while boosting it opens too fast while approaching certain boost, in this case, your b.o.v cant withstand the pressure anymore.. but u're using ssqv rite? hmmm...
i'll try to check back with the mechanic, i'll reply later tonite..
why dont u ask jan first? liza's b.f..

 

[stroker_kit]

Originally posted by GTIEVO3@Dec 8 2004, 16:21
Btw how can u tell whether the BOV is leaking?

u'll get blow off's sound even it is not supposed to blow.... happen at a very high boost level...normally sqv can withstand 2bar... anything above that, will give u a premature blowoff's sound... tested on a 2.5bar boost level highly modded kancil... ...

or maybe when u say ur boost decline gradually, ur refering to a boost spike...
full boost 1.3 then slowly decline to 1bar and u run 1bar all the way. this happen when u suddenly want to full throttle ....
plus if u use an aquarium valve as ur BC, the spike is even worse...and u just cant get a steady max boost....

 

[GTIEVO3]

kRiminaLz,

Ill check my BOV with Jem 2nite. Very much appeciated your input

Stroker kit,

My boost doesn't decline gradually but could not reach previous max boost i.e 1.2, highest could go rite now is 0.9-1.0 at 7,000 rpm

 

[stroker_kit]

if thats the case, then there could only be a few reasons...

1. leakage on intercoller piping
2. blowoff worn out
3. wastegate/actuator worn out
4. u boost controller tak cun, specially if u use those cheap aquarium valves.....

worst is ur turbine housing leaks, but this dont usually happen, unless u run a very hi boost where ur turbine cannot tahan.... sometimes the fin of ur turbine could also be the cause.... one case ive seen where the fin hits the compressor wall cos the fin shaft loose a bit. the grinding effect made the fin smaller and the compressor housing bigger, thus reducing the boost generated.... check ur fin as well. make sure there's only a little space between the edge of the housing and fin...

 

[kRiminaLz]

dude, did u boost frequently while u're in penang? carik makan with those boys there? hehehehe...
i bet its certainly b'coz of the actuator (change my opinion abt previous reply)... it has started to loose out... it's not that effective anymore.. try it out..
mine also i cant boost 1.2-1.3b anymore...
now only can settle down at 0.9-1b.. heh, must find a wastegate now.. hmmm broke ler... :D

 

[GTIEVO3]

kRiminaLz,

Most of the time the boost were maintained at 1.2 max but once it spiked to 1.4. I'll check the actuator as well....