Boost pattern changed recently plz help
 

I have a Greddy boost gauge. The needle sits at 0 when you switch the car off and as soon as I start it use to sit at 750 mm HG. Now i notice that it sits at around 500 mm HG. Does it mean that there is some leak or problem with my turbos or is it normal?

Are you referring to the vacuum pressure? If you are, I beleive a decreasing vaccum means a failing motor. Or was it the other way around. I'm not too sure, but if you see your mechanic be sure to mention the unordinary readings. Or maybe some other nice members will add their responses and share their experiences.

I noticed that you were also having a problem with low coolant levels. It is possible that these problems are related. It sounds to me like your engine is going bad cause you're loosing coolant and your vaccuum readings are changing. Have you done a compression test? Check with a mechanic and ask him to verify the condition of the engine. I hope I'm wrong. Good luck.

hey faisal, this is bilal.

as rxshun7 said. get a compression test. for the time being dont drive your car hard.

secondly, in the coolant reservoir (some one correct me if i am wrong) you shouldnt be putting in water (especially not pakistani tap water). you should buy distilled water, and coolant (green liquid) and mix the proportions of the two depending on the weather. since its hot all the time in karachi the mixture shouldnt change much from summer to winter. dont put tap water in the car because pakistani water has way too many other chemicals dissolved in it, and it has dirt and god knows what.

for the compression test (if most mechanics dont know what is it) then take it to the performance shop that you told me about in karachi. they should know about compression.

secondly, your boost gauge measures the vaccum in the extension manifold. so a change in idle vaccum doesnt only mean changes with the turbo system. it could be due to a vaccum leak, or a weak engine block, or a faulty boost gauge, etc etc

i'm not sure on the conversion from mm/hg to in/hg, but wasn't 750mm/hg a bit high and that 500mm/hg normal?? I remember seeing other cars wehre 400-500mm/hg was normal.

Danny