Stock and only hitting 5psi......Where to look?
Posted: Tue Oct 07, 2014 6:55 pm
Hey guys!!! First I want to say that this board is AWESOME!!!
Before I get any "do a search" comments, I have done a search, many searches, and I have been doing lots of reading, but there is a lot to process, especially with a car I am not yet familiar with. I just got my completely stock '92 SS last week and the learning curve is very steep. The car has 158k miles on it and is in pretty good condition overall and looks well taken care of throughout its life. The car runs very well, so I figured it would a good idea to get a boost gauge right away to make sure the turbo is performing properly and I am hitting stock target boost before I start with any mods such as an intercooler, the Apexi intake, or exhaust.
So I picked up a mechanical Autometer SportComp boost gauge and installed it last night. It only came with a Tee for 1/8" vac lines so I was relegated to installing it on the vac line that comes off the Cylinder 1 intake runner near the charcoal canister. I would have preferred putting it on the reference vac line going to the BPV, but that is 1/4" hose. I have ordered a 1/4" tee and it should be here by the end of the week.
At idle vac is a solid 21 in/hg and on decal in gear it drops to 25 in/hg. With moderate throttle input it quickly comes out of vac and climbs to 0 psi, but at WOT it won't seem to hit anything more than 4-5 psi of boost.
Now the interesting part, and something I was only able to verify with the boost gauge........as soon as I get into positive boost pressure, a whistling sound starts coming from under the hood. It increases a little louder with more throttle input but really stays very constant as long as I am in boost.
So it would appear that I have a boost leak somewhere after the compressor, or... the wastegate or BPV are not working properly. Any other ideas? And is there a diagram somewhere on this board so that I can be certain that I have checked all vac lines and connections? Is there a good way to test the wastegate and BPV?
Thanks in advance!!!
Before I get any "do a search" comments, I have done a search, many searches, and I have been doing lots of reading, but there is a lot to process, especially with a car I am not yet familiar with. I just got my completely stock '92 SS last week and the learning curve is very steep. The car has 158k miles on it and is in pretty good condition overall and looks well taken care of throughout its life. The car runs very well, so I figured it would a good idea to get a boost gauge right away to make sure the turbo is performing properly and I am hitting stock target boost before I start with any mods such as an intercooler, the Apexi intake, or exhaust.
So I picked up a mechanical Autometer SportComp boost gauge and installed it last night. It only came with a Tee for 1/8" vac lines so I was relegated to installing it on the vac line that comes off the Cylinder 1 intake runner near the charcoal canister. I would have preferred putting it on the reference vac line going to the BPV, but that is 1/4" hose. I have ordered a 1/4" tee and it should be here by the end of the week.
At idle vac is a solid 21 in/hg and on decal in gear it drops to 25 in/hg. With moderate throttle input it quickly comes out of vac and climbs to 0 psi, but at WOT it won't seem to hit anything more than 4-5 psi of boost.
Now the interesting part, and something I was only able to verify with the boost gauge........as soon as I get into positive boost pressure, a whistling sound starts coming from under the hood. It increases a little louder with more throttle input but really stays very constant as long as I am in boost.
So it would appear that I have a boost leak somewhere after the compressor, or... the wastegate or BPV are not working properly. Any other ideas? And is there a diagram somewhere on this board so that I can be certain that I have checked all vac lines and connections? Is there a good way to test the wastegate and BPV?
Thanks in advance!!!