Greetings..

My boost reading has always shown 20psi readings all the way till redline.. (picture attached)

Recently though, it has not been going above 17~18psi under the same driving conditions, fuel, etc... Very rarely now it shows a reading of 20psi (morning first few boosts..)

Readings are on 5th gear, car is all stock except for a test pipe replacing the catalyst pot.. Boost gauge is connected to intake manifold perfectly as shown in the forums here..

I hope the problem can be solved and really appreciate any feedback..

Thank you,

Wael
EVO7

 

i'd say boost leak.

 

Help!!? :-)

 

If it were leak, it would have always shown a pressure drop.. why is the pressure coming back to normal 20psi at times ?

any clues?

wael
evo7

 

Has the weather gotten warmer? If you set your boost in cold weather then it warms up then it will not be as high. You can adjust your boost controller accordingly. Vice versa if you set it up in the summer then winter sets in and it will be higher. Just the properties of air temperature.

 

I really thought of that.. But i made further tests:


- boost is going up to 20psi only a couple of times when car is really cold in the first time i take it out in the morning.. otherwise after 5minutes or during the rest of the day, it's 18psi..

so i think temperature variations (air density) is not the real reason behind this loss..

wael

 

If you are boosting that much in the first five minutes of driving that is the worst thing you can do to your motor. You are making more boost, probably, because your oil is cold and thick and you have high oil pressures still. Your engine is not protected at all. You should wait to boost until at least your coolant temp is up to normal operating temp. I wait even longer than that for my oil temp gauge to show some temp as well. Don't be so hard on your car.

 

i usually warm my car a few minutes to reach optimum (9pm position) level..
Moreover, i cant boost my car immediately after moving because i have to get out of the small streets to the main highway which takes about 5minutes.. so on average i dont boost my car except after 10minutes of idle+normal driving...

i cleaned the air filter with back pressure air from a station compressor gun.. result nothing changed..

wael

 

I think the main point is that you are not experiencing anything out of the ordinary. Boost is not electronically controlled. It is mechanically controlled and there will always be variances.

 

My boost always drops below 20 at redline, starts at 21psi drops sometimes to 18 at redline.

 

Ok if the boost is mechanically controlled, could the drop of boost throughout the rpm range and after 15minutes of driving be a WEAKENED spring (waste gate, BOV, actuator... dunno which one retains pressure to the engine!!)..

In such a case, is it now adviseable to buy an Halman MBC and just set my boost right at 20psi once and for all?!

Suggestions appreciated pls!

Thanks,

Wael
EVO7

New gtech results:
0-60 in 5.02
1/4 mile in 13.7 secs
Wet ground conditions..

 

SUrprisingly, today was a 19~20psi boost all the way on 5th.. like somehting has been magically repaired or triggered back.. funny but am crossing my fingers..

wael

 

damn this!~ it's back to 17psi now.. what is happening?!!

wael...... :-(