robertkania

hey, i recently put in a turbo for my prelude but the problem is that when i start the car and im driving around for the first 10 mins or so the blow off is nice and loud but after driving for a bit it goes significantly quieter. could it be from the turbo flooding because im using a 10 AN oil return line but there is a kink in it. i gotta get a 45 degree hose end thing. could that possibly be flooding it? and i have a leak in the pan from the oil return flange. im trying to fix that atm but could it be loosing oil pressure or oil which causes that? its a turbo xs bov and it shows that i still get boost when the bov sounds

TRex

What kind of turbo do you have? From mt expereince a blockage/ obstruction of the oil return line would affect the turbo seals. If you check the hotside of your intercoler pipes you should be able see if any oil has passed these seals..

So when the blow off valve does not go off does you boost guage still how your hittting boost?

robertkania

yup it shows almost exactly the same boost on the gauge when it goes off and when it doesnt

zeeman

iTrader: (1)

pull over when the BOV gets quieter and with the car running pop the hood, then open the throttle body with your hand and rev up the engine to like 3000-4000rpms, when you let go you should see/hear/feel the BOV open and release the pressure, if its not, either the vacuum source for the BOV isn't that good (likely if you have tee'd off the fuel pressure regulator a bunch of times) or theres something wrong with the BOV itself....wouldn't be a surprise given the brand.

Is it an adjustable BOV? If so, maybe try tightening or loosening the BOV.

Fix that kink in your return line ASAP before you cause damage to the turbo. I've seen return lines so messed up it won't let the turbo spool until like 5000+rpms (little t3 turbo on a h22).

MPR

Yeah for the bov to operate optimally it should have it's own separate vacuum line to the intake manifold (after the throttle body).

Check that first.

And a #1 rule with turbos, the oil drain line off the turbo must be large, unobstructed and gravity drained. Other wise it will kill the oil seals in the turbo.

robertkania

yea im not driving around atm until i get those things fixed. also i just noticed that i have an exhaust leak in the turbo manifold where the wastegate is supposed to be, the turbo is internally wastegated so i just blocked the hole although exhaust fumes still come out, could that do anything?

zeeman

iTrader: (1)

that will just make the turbo spool slower and make your exhaust louder. It won't cause your BOV to not work.

A BOV is a simple device really, it stays closed under boost/low/mid vacuum until the high amount of vacuum the engine produces when you take your foot off the gas will pull the valve open and release the pressure in the charge pipes.

TRex

The leak in your exhaust manifold is a huge boost leak. If your goning to be driving the car at all try and avoid heavy boosting cause its not gonna make any power and i think it may screw aound your trims and you may run rich or lean. All the hot fumes could also hurt things like your o2 and alternator if you drive it for exteneded amount of time( weeks/months ) without getting it fixed.