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View Full Version : Boost Leak!?



BoostDrmr
10-23-2012, 06:21 PM
As the title states I have what I would call a serious boost leak. The car starts and runs great, it just wont boost past 10psi and even when your building boost you can hear the the leak. Its a loud whish or pish type noise of air escaping. At idle on cold and hot, I average between 16 and 19 vacuum. I currently have a K&N filter, gillis style valve, stinger dual piston bov, and an aftermarket boost gauge, autometer cobalt gauge. On cold start, I have an erratic idle of plus or minus 1 to 2 hundred rpm, but when its good and warm....the idle is almost solid around 1000, no fluttering. With the bov I have ZERO drivability issues with it, shifts fine, starts fine, etc.

Ive been reading that I could have a blown gasket either between the manifold and head or manifold and turbo, or that the wastegate is stuck open, or maybe some seal in the turbo is blown. I wanted to run it past you guys and see what your thoughts are on the issue. It is a 1986 SVO with presumably a stock 86 turbo and E6 manifold. Ill say this also to help put more into out there that I have a MGW shifter assembly, which btw is badass. But, for now i have no shift boot etc, so basically its a big hole there where the shifter is, I can literally see the road as im driving. But, as im driving and go WOT, no matter the gear I get exhaust fumes inside the cabin. So, I know I have an exhaust leak of some sort, but the question remains is it coming from the downpipe maybe or the gasket thats blown out either at the head/manifold or manifold turbo, or maybe a combo of one of those and the downpipe loose? Because i can see the bolts arnt all the way tightened when I look from the engine bay, and ill attack that here in the next day.

I know this is alot to be putting out there, and im sorry. But, I wanted you guys/gals to have as much info as possible. If ive forgotten something please let me know.

MikeFleming
10-23-2012, 08:10 PM
Most likely places are the inlet and outlet hoses to the charge cooler. Verify those first.

Mike S
10-24-2012, 07:04 AM
What is the source for the boost/vacuum signal for the BOV?

BoostDrmr
10-24-2012, 07:49 AM
Straight off the tree on the wall.

brownsvo
10-24-2012, 10:32 AM
It is probably one of the rotted silicone couplers holding the intercooler on.


Well it was on mine :)

BoostDrmr
10-24-2012, 11:35 AM
yah, thats what im thinking. as im using the T silicone coupler from stinger for the bov and that works fine, but the one from turbo to intercooler looks to be original, cant be sure tho. so im getting a replacement for that from stinger.

BoostDrmr
10-28-2012, 11:07 AM
ok, so slight update. i removed the gillis style boost controller and ran strictly off the wastegate. it wanted to pretty much overboost it seemed. hooked the BC back up and it wants to only hit 10, adjusted it and it shakily hits 12 with hesitation, adjusted more and its solid at 12 but struggles to reach there it seems. any ideas?

BoostDrmr
10-28-2012, 02:57 PM
ok, another small update. earlier when i was messing around, i left the vacuum line from the wastegate unhooked, hence overboost. with it connected to the turbo it spikes to 9 and holds a solid steady 8. but with the gillis style valve installed, it does the wonky boosting i described in the post above this one. i have the side port hooked to the waste gate and the bottom port connected to a vacuum source. and yes internally the ball is below the spring. the ONLY conclusion I can come to is that I have a weak spring in the BC.

Stinger
10-29-2012, 05:29 PM
You can verify boost controller function with a regulated air compressor. Just feed air into the bottom of the valve regulated down to 10psi and slowly add boost until the controller opens. It's best to use the boost gauge in the car to verify how much pressure you're feeding into the controller as the gauge on an air compressor isn't very accurate below 30psi.