no load boost

[avaien]

My friend with his gsx put on greddy intercooler pipes with a type s bov. He has a cone filter. He builds boost way too fast and too much for the stock boost solenoid. He will hit 20 psi easily and his car isnt really going anywhere. His exhaust manifold is missing one of the bolts and we think it is leaking, could this be part of the problem. We messed with the allen on the bov and it changes how fast the boost comes on and how much he gets. Why would it do this? We are doing a boost leak test tomorrow. Before this piping and bov his car ran decent.

 

[No_Skillz]

Aftermarket boost guage?

Check all your vacuum hoses especially around the wastegate, BCS, and compressor cover area.

 

[UofACATS]

His exhaust manifold is missing one of the bolts and we think it is leaking, could this be part of the problem. We messed with the allen on the bov and it changes how fast the boost comes on and how much he gets. Why would it do this? We are doing a boost leak test tomorrow. Before this piping and bov his car ran decent.

The pre-turbo leak would just make you spool slower, not hit 20 psi. On the bov adjustment, did you soften the preload on the valve? If so, you could be bleeding off some of that excess boost, changing your gauge reading.

Agree with "Skillz" about the lines. Just pull them off to inspect them, they can be cracked and leaking under the clamp, and still look good from the outside.

Are you running a MBC? Make sure your wastegate hose isn't off, torn, leaking, or somehow damaged.

 

[topstreet]

If any boost is being lost (bov, hose not on right, bad clamp) it is going to cause less boost. You have a waste gate and boost control issue. I agree that the lines on the solenoid, and waste gate need to be checked.

A boost leak test is not going to fix this problem. A aftermarket boost gauge T'ed into a good location like the fuel pressure regulator line is going to show manifold pressure like it should. If the waste gate is seeing a different pressure (lesser) it is going to give your system more boost. That is where you are going to find your problem. Not the gauge, unless you are still using the stock boost gauge, which is an electronic guess based on the air flow value.

Hope this helps.

 

[avaien]

Sounds good we will do a leak test and set the bov to the right preasure and also inspect all the lines. Something odd is that his boost gauge is tapped into his throttle body elbow. He has a hard line running to his gauge. Ive never seen this before, my gauge is teed into the fuel preasure line. He said his diesel budy did this, could this be a problem also?