Boost drop?

[MirageAsti]

My boost used to be 0.8, now by the looks of it, only 0.6.. 0.7 spike then drop to 0.6 bar. What can be the cause?

 

[DanzEterna]

vacuum leak?

 

[MirageAsti]

Vacuum leak? Will that cause boost leak? I think its caused by the wastegate or BOV not holding boost?

 

[vspec]

in my case, it was the wastegate

 

[MirageAsti]

the wastegate failing? i can hear chatter from the wastegate

 

[jun_ng_1208]

Mine was with the boost controller last time, was using 'tulang ikan' boost controller back then, boost all the way up till 0.9 bar then dropped to 0.6 on high rpm...changed it to boost tee & its all good now :)

 

[ixeo]

Manual boost controllers work either using leak, or ball & spring type like boost tee. I've got a used original turbosmart boost tee for sale if you're interested.

 

[ahloy74]

Bro, do a boost leak check. Google it, you would be surprised to know all the clamps are potiential leak point. Did mine and changed all the clamps to a bolt type clamp.

 

[MirageAsti]

Just done making a screamer pipe just now. Boost back up to 0.8 lol. Backpressure problem?

 

[ahloy74]

Just done making a screamer pipe just now. Boost back up to 0.8 lol. Backpressure problem?

Hmmm...kind of wierd....never heard this can cure a boosting problem but true enough, you solved it..

 

[MirageAsti]

Actually kind of overboosting to 1.2bar right now.. Screamer pipe normal problem..

 

[MG42]

is this 4g63 or 4g93?

 

[ahloy74]

Actually kind of overboosting to 1.2bar right now.. Screamer pipe normal problem..

Meaning the screamer outlet is kind of small and making the venting of exhaust gas via wastegate is rather less. Now more exhaust gass will turn the turbine and making higher boost. Correct?

 

[Hadi17]

Just done making a screamer pipe just now. Boost back up to 0.8 lol. Backpressure problem?

In my case I set the boost to 1 bar and when I boost, the meter shows more than 1 bar..
It goes more than 1 bar like 1.1 . why is that so ? and I get some backfiring after boosting kuat sikit .

 

[ahloy74]

In my case I set the boost to 1 bar and when I boost, the meter shows more than 1 bar..
It goes more than 1 bar like 1.1 . why is that so ? and I get some backfiring after boosting kuat sikit .

Hadi, think thats normal. It is called boost creep. Its the nature of your wastegate spring. If you use electronic boost controller, this creep can be minimised. Not very sure bout the backfire though. If not mistaken, mitsu ignition sys is wasted spark. Sometimes you get this kind of pop sound when gear changing in normal manner. Not tarik time. Think so...