boost just keeps increasing

[otto]

Hi guys,

Im having a problem where my boost keeps increasing with rpm which i originally thaught was due to my boost controller but now dont know what it is.

As i accelerate boost comes on at 2800rpm (7psi) and manages to hold till about 4000 where after this it just slowly increase till i have a max 10+psi at 7000 rpm. its like the wastegate just cant waste enough is this possible on std turbo(the factory solinoid has been removed and i just have a hose going from plenum to w/g actuator).

My mods are 3in turb back exaust, hks type s cooler, adjust cam gear, 910 fuel pump.

Origially the exaust was restricting the movment of the w/g but i ground it out today and it now seem to have full travel ie, arm is parallel with the front to back of car. but the problem still there. i have driven the car with the actuator off and w/g lockwired fully open and it still manages to make 10psi by 7000 (this was before i grinded the exaust but seeing as ive still got the prob ide say it would still do it now)

im wondering weather the std actuator has enough travelin it i pulled it out and had a play it seems to work smooth with no leaks.

anyone got any ideas as im all out?????????

[wreckedhead]

mechanic might help

[otto]

thanks for the tip champ, but i enjoy workin on my car and fixin the probs myself.

[Jay95R33]

I'd say it's still related to your wastegate. Maybe it's sticking ? It might have full travel, but it's possible that the actuator just isn't moving it right open ?

J

[Black33]

have you got a split pipe dump pipe?

[otto]

no its just a one piece 3inch they also used the standard flange off the original pipe and just shaped the 3 inch pipe to fit.

[otto]

the wastegate itself seems to have a very smooth movment. is it possible that the actuator doesnt have enough travel to open the w/g enough

[JAS-25T]

if it is the standard actuator, it should be fine to move the standard???? wastegate

therefore i doubt it would be that unless its faulty, try and push 7psi through it with a compressor or something, and see if it pops open

try maybe 10psi if 7psi works

then maybe try something higher

[DJ_L3ThAL]

if your just running a hose that means it will run at infinite boost that your setup will let or 'factory' so 10psi is about right i think with those mods, esp cam gear

is it still doing it with a proper ebc connected ?

[otto]

dj l3thal, but then wouldnt i be getting the 10psi at around 3000rpm instead of at redline,

jas-25t, might give your compressed air trick a go.

[DJ_L3ThAL]

oh so its at redline hmm, yer definitely weird then, sounds more complicated like blockage, air compressor clean sounds the go

but did it just happen, or did it happen after u installed something, if so what did ya install?

[DJ_L3ThAL]

also could simply be the gauge, blow out the vaccum hose to the gauge for blockage, and test the gauge with a compressor too , worth a try, or if your factory gauge still works, watch that to see if it jumps with the aftyermarket gauge

[HoeTrain]

Just a thought, but could it be possible that someone previously had an external waste gate/dump pipe fitted, welding up the hole one the current outlet (waste-gate outlet) from the turbo? They may have removed it along with the dump pipe when they sold the car. It would be strange if this was the case but it is something I have seen once before. Anyway, just thought.

[Revhead]

I have a funny feeling you're looking at it the wrong way... I don't think the wastegate isn't dumping enough exhaust gas to hold your boost, I reckon the wastegate isn't completely shutting, making the boost you *should* be getting come on much slower. This fits in with the descriptions you have given.

It's extremely unlikely that, with a stock turbo and only a fuel pump/cooler/cam gear, the wastegate would become restrictive.

[otto]

thanks for all your imput guys but every thing im tryn just doesnt seem to work. and i dont understand how if i disconect my actuator from the w/g (the machanical linkage) and tie off the w/g in the fully open position and go 4 a drive i can still get 10psi+ by redline.

revhead, if what ur sayin is the case what can i do to fix it.

[cameron]

have the same problem and found that their was oil in the actuator !

[HoeTrain]

have the same problem and found that their was oil in the actuator !

This is very common due to the engine not using an oil/air sperator.

[HoeTrain]

My apologies, I totally mis-read the opening thread.

My understanding is, and im open for corrections here, is that if you have the hose connected directly from the plenum to the waste gate actuator you will have trouble coming on boost. This is because the factory hose has a tiny restrictor in it which stops the actuator opening up in direct relevance to the pressure in the plenum. If that hose was disconnected it would not actuate and bring the boost up in a steeper curve, but be careful because it will over boost (ka-boom). I'm assuming that the complaint is that the boost is not hitting 10psi @ lower revs.

[Revhead]

To check it, unbolt the actuator from its mounts and see if you can pull the gate further closed. If it won't go any further, pull the dump pipe off (yes, pain in the butt) and make sure the gate actually seals properly, and that nothing stops its movement.

If that does help, you can either bend or shorten the actuator bar, modify the bracket on the actuator to mount it slightly further from the rear of the turbo, or look at some other method of making the gate shut properly at standstill.

[RBVS]

runing a hose straighti from plenum to actulator is going to give you your minimum

machanical boost. The wast gate will open as soon as it reaches 7psi which is around the standard spring rate. having a 3'' exhaust will flow alot better than stock which will increase boost and excessively more in the top end which is what you are seeing. i ran 10psi minimum then when removing the cat could not run less than 13psi.

I dont think there is anything wrong, i would sudjest a restrictor or bleed valve to bring boost on strong to 10psi for more stable boost control.