I have an interesting noise coming from the motor at full boost. When spooling, there is a higher pitched clicking noise, im wondering if its knock, but have never heard it like this. The car is boosting a max of 14 lbs. It boosts PERFECTLY to around 6-7lbs without hesitation, or the odd sound. Then it keeps climbing at an uneven rate to around 10 where it tapers and holds, but still isnt smooth, all the while making that heavy "valve tick" sound. I have ONLY done this when trying to track down the problem, so I havent been out beating on the car. So far I have checked everything except the air inlet hose for boost leaks, as this leak would have to be after the turbo. Those connections are good. I vacuum tested the BPV up to 20 lbs and it holds pressure, I also tested the bpv connection to the intercooler and it is solid as well. I have tried octane boost (as im on 91 octane here) I have very minimal mods, mostly suspension. There is a GM boost solenoid, an uppipe, ported turbo and intercooler elbows, and a sti catback. The noise started before those were installed, but wasnt really noticed until i got into the warmer climates where my windows have been down. I was told the car has been pro-tuned, which might explain some of this crap. It isnt anything crazy like rod knock, thrown bearing, or piston slap, as there is no noise at idle or lower revs, even including low boost. There was no shavings or anything crazy in my oil. Its not something that raises my eyebrows towards daily driving it. I do however want to track this down. Ideas of mine are now to see if it IS some sort of knock, replacing spark plugs, pulling timing, etc. I dont live close to any actual tuners, so there arent many options for me in that field, unless i take a trip into san diego or LA and set an appointment. Open for suggestions guys. I can also give any more info on it that I can. Heres my list: '02 wrx wagon, just hit 125k. New timing belt, tensioner, water pump, thermostat, serpentine belts. "pro-tune" gm boost solenoid, sti catback, ported some parts, and an uppipe. Theres a bit done to the suspension and drivetrain, but the actual powertrain is hardly touched. and heres what i've done so far to rememdy without any luck: fresh oil change, new air filter, checked all boost lines, checked bpv for vac leak, different gas stations. (ALL only sell 91)
tighten I believe... usually its cause as it builds boost it pushes the flapper open... tighten liek 1 turn.. dont go too far though as it is increasing boost ability
yep just looked it up. I'm almost positive this is whats causing it now, sounds exactly like my issue. suprised i didnt stumble across this before, its pretty obvious. the quick research i did said that 3 turns tighter is an average number to fix the issue. I remember the loosening because of some boost spikes we encountered. The reason is probably the new turbo that I ported. Its off of an '04.
thanks a bunch nate, i'll try it out tomorrow and see if it fixes it. If anyone else has anything to throw in, let me know. my ears are open and I want extra suggestions, even though we probably just pinned it.
yeah just start with 1 turn at a time man... with a proted turbo that one turn may be more like 1.5...
Sometimes people say they hear the BCS clicking too. I hear mine, but that is pretty much only while its building boost, so I doubt you'd be hearing that.
Wastegate flutter is a mechanical sound. It's perfectly normal. While turning your wastegate arm may reduce the sound, you are actually severly inhibiting your car's ability to control boost by doing that. Again, wastegate flutter is perfectly normal. It's just another sound that turbo car's make.
