overboost in my 96 sti wagon

[1996scoobydoo]

just what it states my car over boosts sometimes normally only if i put my foot flat to the floor in lower gears was just wondering what it could be? Im guessing its just the hose to the actuator? previous owner replaced it with blue silicon leads and possibly there not the best . have cable tied around the hose but still seems to happen. it boosted over 20 psi!! :\'(

[nickch]

check the hoses around the wastegate for leaks?

[boon]

Might have too small a restrictor in the boost feed line off the compressor cover? Depends if he reused the factory pill or what.

Also could be a sticky boost solenoid.

[Kiwi_Fozze]

Stock downpipe or aftermarket?

[lachlan]

with bigger/longer hoses and the stock pill it could cause a temporary over boost .

[pedro]

Boons on to it..I say wrong/no pill..

[Guest]

I have never had an issue with over boost from running larger vac lines or no pill just slightly slower spool. Thats on stock d/p vs bellmouth w/twisted d/p, TD04/VF23/22 w/matching internal. Held the same boost to redline regardless of vac line/pill when on ecu control.

[1996scoobydoo]

stock downpipe

[Marky]

What else is changed

Maybe the solenoid is sticking open?

Some cars seem super sensitive to different pills being used or bigger hoses etc, even just the way things are sent into a T piece can change how much bleed off happens

Then some cars DGAF and will run happily regardless of what you fiddle with

If in doubt just replace the stock setup with a bleed valve, prob solved

[1996scoobydoo]

not much really got a bov . have borrowed some proper clamps for the vac lines to see if maybe the cable ties were not good enough. would be good if that was prob solved also it can spike and go to almost 20psi but then goes down to 16-17 within a second? sorry for the lack of knowledge this is my first turbo car and still learning

[Rosssub]

 1996scoobydoo said:

not much really got a bov . have borrowed some proper clamps for the vac lines to see if maybe the cable ties were not good enough. would be good if that was prob solved also it can spike and go to almost 20psi but then goes down to 16-17 within a second? sorry for the lack of knowledge this is my first turbo car and still learning

Take the Blue hoses off, block one end and blow through them on by one. Probably find a small Tear/Split, right near the Turbo Outlet. I\'ve tried Silicone for Waste Gate Hoses and they\'ve split from Heat/Pressure, every time.

Change the Waste Gate Hoses for High Temp Rubber, or OEM black Hoses.

Then see if your Waste Gate Actuator Diaphragm holds Vac. Put a Hose on and suck, then see if it holds it. You could have a Leaking Diaphragm? Still opening the Gate, just not fast enough to counter the Boost Spike, or hold OEM Boost Levels constantly.

Then clean out the Boost Solenoid with Carb Cleaner, till the fluid runs clear.

Then test that the Waste Gate Shaft itself isn\'t Seizing, or Tight as it\'s first trying to open.

[1996scoobydoo]

cheers for all the help mate will get onto that this week !

[Rosssub]

 1996scoobydoo said:

cheers for all the help mate will get onto that this week !

Sweet, good luck.