Boost reduced?

[marlinished]

This is my situation and would like some feedback, from day 1 plunk in evo1 engine evrything stock with 2.5' front and 3' rear till N1 straight piping exhaust my boost is 1 bar.

Recently I changed to ngk plug cables, sheepdog bov(using r2d2 b4) and standard evo muffler my boost is 0.7 bar( which i now should be the case for stock but how come i was at 1 bar in the first place). I suspect it could be the exhaust change. Pls can someone satisfy my curiosity.

 

[jinkl]

marlinished : nops , its gonna affect ur boost at all
stock boost for usually evo,vr4,gsr and all are 0.6-0.7bar

 

[marlinished]

So any idea what happened?

 

[henria86]

hello
so u changed the exhuast to a free flowing exhuast?? an if u did ur going to have a faster spool up an u will see higher levels boost easy...
henri

 

[flushafteruse]

the standard evo muffler got restriction...better to use straight flow muffler..

 

[marlinished]

I was using straight flow b4 N1 ( boost 1 bar) but its too noisy so changed to a more restrictive muffler. So how do i keep 1 bar boost but not so noisy.

 

[jinkl]

marlinished i asume u earlier had a problem n now tis solved
0.7bar IS THE STANDARD BOOST, not 1BAR
so do not try boosting 1bar again, u gonna blow ur engine
as i know u r running stock ECU , dont play man

 

[marlinished]

Guess so. So will wait till i get a metal head gasket, fuel pump and fuel regulator before i touch my boost.

But still curious why I got 1 bar last time whith all stock parts?

 

[flushafteruse]

play safe bro...

 

[raise]

any aftermarket ecu for gsr?

hey bro,

any good ECU upgrade for GSR ?

 

[Battousai]

A free flowing exhaust will raise your boost levels. Stock exhaust with restriction will reduce boost.

Reason: Freer flowing exhaust reduces the pressure after the turbine blades = higher exhaust gas velocity across the turbine = higher boost.

 

[jinkl]

A free flowing exhaust will raise your boost levels. Stock exhaust with restriction will reduce boost.

Reason: Freer flowing exhaust reduces the pressure after the turbine blades = higher exhaust gas velocity across the turbine = higher boost.

errr , a less choke on the turbine housing will give better peak power at higher rpms

but reducing it dont think will enable higher boost

smaller turbine housing will increase spool up
but i dont think there is any reason for boost to increase for exhaust sizing change
summore 2.5" and 3" is not gonna affect it.

the problem here could be because there was an actuator problem or hose leak problem.

 

[jinkl]

A free flowing exhaust will raise your boost levels. Stock exhaust with restriction will reduce boost.

Reason: Freer flowing exhaust reduces the pressure after the turbine blades = higher exhaust gas velocity across the turbine = higher boost.

errr , a less choke on the turbine housing will give better peak power at higher rpms

but reducing it dont think will enable higher boost

smaller turbine housing will increase spool up
but i dont think there is any reason for boost to increase for exhaust sizing change
summore 2.5" and 3" is not gonna affect it.

the problem here could be because there was an actuator problem or hose leak problem.

 

[Battousai]

actually, it's well documented in tuning circles that upgrading to a free flow exhaust raises your boost by 0.3 bar or so. the stock exhaust is one of the ways to limit the boost from the factory.

 

[raise]

using straight flow

oh ya, forgot to inform you guys.

im using a straight flow exhaust as well.
consider no restriction already right?

A free flowing exhaust will raise your boost levels. Stock exhaust with restriction will reduce boost.

Reason: Freer flowing exhaust reduces the pressure after the turbine blades = higher exhaust gas velocity across the turbine = higher boost.

 

[jinkl]

Battousai : yeaps true , hehe , but this abang change bigger exhaust the boost went lower :) thts wht im trying to say

 

[raise]

aihh

do up the exhaust tot can get better response and power.
end up different pulak.
now if rpm more than 4, like got airplane sound.
u know la like the jet kinda sound.
lagi make my mind go crazy

 

[cyborgsabah]

last time when i use 3 inch downpipe and piping all the way to the back with straight flow muffler i also go 1.0 bar boost... if you want to use straightflow exhaust, keep the downpipe only slightly bigger than stock than only you can maintain stock boost around 0.6-0.7 bar... but not recomended coz stock boost not syok..hehehehe... so get a piggyback and tune your a/f for 1.0 bar... hehehe

 

[raise]

tension tension

tension tension ... hehehe!

 

[marlinished]

So my setting a bit off, standard manifold and down pipe then 2.5" till the middle then 3" till the rear muffler. So when i want to increase boost to 1 bar just change to straight flow muffler?

How will me changing to a full 3" setup differ?