no constant boost???

[Msp-titanium]

ok i am a newbie in this forum. I have a problem.
I set my mbc to 9 psi. When i it the gas the boost
go up to 9 psi and drop to 5.5/6 psi. If you have
an idea please help me!!! (attn)

my mbc i a turbonetic.
autometer boost gauge and pyrometer.

 

[mspeedpro]

try just tightening it really well- it shouldnt spike so high...
also try adjusting the mbc (very very slightly) then retightening it...

1 of those should fix it

 

[jersey_emt]

Does it stay at 9psi for a while then gradually come down to 6psi? Or does it only stay at 9psi for a fraction of a second?

 

[Msp-titanium]

the adjustement is very well the boost not goes up
past 9 psi but not stay at 9 psi when the rpm high
past 4500rev/min the boost drop!

 

[Msp-titanium]

Does it stay at 9psi for a while then gradually come down to 6psi? Or does it only stay at 9psi for a fraction of a second?

gradually this is normal?

 

[Emode]

if the boost is spiking quickly, maybe try this
worked for me
http://www.msprotege.com/forum/showthread.php?t=52377

 

[DSMConvert]

yes this is normal assuming you have stock exhaust. You should notice it droping just as you pass 5K rpms. This is due to the fact there there is entirely too much exhaust gas for the exhaust to handle...turning up the boost will not help this, but will just make it worse...I would recommed only running 7-8psi untill you can get exhaust on it...

 

[jersey_emt]

Yes boost falloff at higher RPMs is normal, it's partially due to the exhaust, but also from the plastic intercooler piping that expands under boost. When I put my hardpipes on, I noticed that the boost stays much steadier. Instead of dropping 3 psi, it only drops 1-1.5 psi.

 

[Msp-titanium]

if i understand the exhaust back pressure is
too high, i have to get a bigger exhaust.

 

[Emode]

correct

 

[Msp-titanium]

Thanks for your help guys (2thumbs)

 

[DiscreetSpeed]

ok i am a newbie in this forum. I have a problem.
I set my mbc to 9 psi. When i it the gas the boost
go up to 9 psi and drop to 5.5/6 psi. If you have
an idea please help me!!! (attn)

my mbc i a turbonetic.
autometer boost gauge and pyrometer.

whoa dude thats a big drop..even for a restrictive exhaust..doubtful

 

[Dr.Sound]

no, not doubtfull
same thing here.....and with other MSP owners that i know of arround my area.

get a catless downpipe, or a hi-flow cat. also get a less restrictive muffler.

stock at 9 psi i was dropping 3-3.5 psi
with 2.5 inch catless DP the drop was 1-2psi
DP + better muffler the drop is like .5-1psi

i'm sure if i get hard pipes then there will be even less drop

 

[DiscreetSpeed]

lol no drop..with open exhaust or stock exhaust

 

[Msp-titanium]

ok what i can do if i don't want to have
a pressure drop???? (uhm)

 

[Dr.Sound]

lol no drop..with open exhaust or stock exhaust

i'm pretty sure there was.....especially in second gear.
every MSP i've driven that ran higher boost had it, some more some less.

maybe u got lucky
who knows....there are people here that never had hesitation......

 

[Dr.Sound]

ok what i can do if i don't want to have
a pressure drop???? (uhm)

get a catless downpipe, or a hi-flow cat. also get a less restrictive muffler.

 

[Msp-titanium]

ok i will look for a less restrictive exhaust
thank you. (flame2)

 

[GotTurbo?]

quick ? when i'm boosting, with steady pressure on the gas, it peaks to stock level at 6.9 psi, holds then the bov vents, boost psi drops down, is that normal, now i'm confused.(boom01)

 

[Dr.Sound]

it should not vent untill u release gas.
at stock boost levels the boost should be held at arround 6.5 throughout the RPM ramnge.