Turbo Keeps Boosting?

[ClutchBurndout-:(]

hey guys, this is more of a brainstorming thread than a "help me" thread, but im trying to figure out what the f**k is going on with my system, im running a stock S2 turbo on my R33 gtst, its been tuned to 12 pound with stock ecu, stock injectors, with a fmic, pod and 3 inch exhaust decat system.

Whats happening is in "what it seems" to be just 1st and 2nd gear, when i plant it it just keeps boosting, i pull off when it hits 14 pound, but i have a feeling it will just keep going, now apart from that being a problem in its own, when it boosts PAST 12 pound it feels realy rough and not as smooth as the 1-12 pound spool up you get when i plant it, this worries me ALOT. Im not an expert in the field but to me it feels like its a combination of running lean past 12 pound (which might have something to do with the stock ecu) and a leak or something going wrong that keeps pumping pressure into the turbo.

I am also running a boost controller, and i have turned it down 2x half turns at a time and its still boosting up to 14 (when i back off) even though it was tuned to 12 pound.

I am posting this just after giving the car a drive and after sortov suspecting the worst, i do not want to drive my car the same anymore, im not a hoon or anything but every now and then i give it a squirt.

Does anyone know whats going on with my system!? is there a leak? is it running lean? what is letting the turbo boost past 12 pound?

any help is much apreaciated!

cheers

[paulr33]

either youve got the controller hooked up wrong and its in unlimited boost mode, ie, nothing is holding, and it just keeps climbing (actuator never opens)

or the boost controller is set too high, and in the other gears or engine load some of the boost bleeds off

either is bad and should be fixed

when did it first occur? or has it always been like that?

check all pipework for the boost controller etc

check the vac lines. check the actuator actually opens

when the boost flies past 12psi the stock computer will activate its self protection

and you may also have the engine detonate when boost exceeds this level

[ClutchBurndout-:(]

either youve got the controller hooked up wrong and its in unlimited boost mode, ie, nothing is holding, and it just keeps climbing (actuator never opens)

or the boost controller is set too high, and in the other gears or engine load some of the boost bleeds off

either is bad and should be fixed

when did it first occur? or has it always been like that?

check all pipework for the boost controller etc

check the vac lines. check the actuator actually opens

when the boost flies past 12psi the stock computer will activate its self protection

and you may also have the engine detonate when boost exceeds this level

its always been like this since it was tuned, it was tuned by sabbadin so i know its been done right, they checked all the boost controller pipework. how do i check that the actuator opens properly?

[H@ME]

could also possibly be a faulty manual boost controller, or actualtor. but try what paul has suggested first..

[Birds]

Sounds like there is a vacuum hose leak or your boost controller is stuffed. Try removing it and connecting the vacuum hose to the actuator. It should then run at stock boost as per your actuator. If it is still boosting too high then it may be that the actuator itself is stuffed / stuck in the closed position, making infinite boost because there's no wastegate opening to relieve pressure.

[ClutchBurndout-:(]

Sounds like there is a vacuum hose leak or your boost controller is stuffed. Try removing it and connecting the vacuum hose to the actuator. It should then run at stock boost as per your actuator. If it is still boosting too high then it may be that the actuator itself is stuffed / stuck in the closed position, making infinite boost because there's no wastegate opening to relieve pressure.

i think you could be right with the hose leak somewhere, as for the actuator, we changed the turbo from a S1 to a S2 one, and the same thing is happening, so unless its coincidence that the actuator is faulty i dont reckon the problem lies in the actuator

[paulr33]

its covered in the nissan r33 service manual, you should download it and check for yourself, well worth a read

you need to get a pnuematic pressure gun thingy and attach it to the actuator, and keep building pressure slowly until the actuator rod moves

it should move around 0.70kgcm2 from memory (its in the service manual, the exact number)

if the rod doesnt move, its failed or broken / damaged etc

if the rod moves freely then your boost controller is mangled, damaged, setup wrong, adjusted incorrectly, or faulty

replace or remove and try again

its unlikely the actuator has failed, as its such as simple and old device

its likely your controller has something wrong, is setup wrong, is set too high or something else

try removing it, the car should run stock boost, around 0.70kgcm2 or +5ish on the stock guage

[ClutchBurndout-:(]

ok i will take some picks of the boost controller setup to show you guys, you could be right it might be setup wrong, like a said im a nooby with it all.

[ClutchBurndout-:(]

ok i took a pic of the controller setup

-the red dotted hose comes from the intercooler pipe and into the side of the boost controller

-the teal colored arrow on the controller points inwards into the controller

-the yellow hose is going to the actuator

-the green hose the top of that little gadget is blocked as you can see

-the orangey brown hose goes to one of the pipes under the 2 big pipes shown in the pic, the pipe that it goes to cannot be seen in the pic but its metal and about and inch wide and i think its part of the blow off system

does this setup look right?

[paulr33]

what the hell is teal? blue dude, blue

the old stock solenoid has two vacuum hoses, both should go nowhere, check and confirm this

its too hard to tell from the pic

[chrissso]

You say it's happening in only 1st and second, but not third or more? Sounds like a boost spike.

[ClutchBurndout-:(]

lol blue sorry. ok the solenoid is not shown in the pic? like i said... nooby here

[chrissso]

Yeah, the solenoid is there, the orangey brown one plugs into it.

The orngey brown is the bleed off, which I thought goes back to the turbo intake.

I think theres a restrictor in the pipes somewhere, possibly in the red one. Check this for flow... I can't be sure...

The setup looks right though.

Did you pull a t piece out of this setup and replace it with the boost controller?

[ClutchBurndout-:(]

You say it's happening in only 1st and second, but not third or more? Sounds like a boost spike.

if it were a boost spike it wouldnt feel rough or leaky or not sure how to explain it once it passes 12 p

[ClutchBurndout-:(]

Yeah, the solenoid is there, the orangey brown one plugs into it.

The orngey brown is the bleed off, which I thought goes back to the turbo intake.

I think theres a restrictor in the pipes somewhere, possibly in the red one. Check this for flow... I can't be sure...

The setup looks right though.

Did you pull a t piece out of this setup and replace it with the boost controller?

the orengy brown one goes to another pipe wich is the blowoff into the intake i think?

[ClutchBurndout-:(]

i was doing a bit of reading, i have a 3 inch dump pipe witch includes the flap inside the same pipe, could the boost creep be because of this? its alot of boost creep, from 12 to 14+pound

[Guilt-Toy]

i think there is a imaginary problem here in your head.

go to a 110 zone. put car in third gear and floor it. how much boost does it run ?

get back to me with the answer

[chrissso]

if it were a boost spike it wouldnt feel rough or leaky or not sure how to explain it once it passes 12 p

Well you haven't explained yourself very well.

Here's example of creep versus boost.

The boost creeps from 12 to 14 over say 5000rpm.

or it hits 12 at 2500rpm and then spikes to 14 at 2700rpm.

which one is it?

If it's creep, then you need to get a ECU and get a tune. There's a whole lot of explanation and debate as to why, but this is the proven answer. If you need to know why, then search.

If it's a spike, then look for the aforementioned restrictor. The solenoid needs it to control the boost properly, and you don't need it for the boost controller.. Boost controllers tend to spike a little anyway.

Do what ^guilt-toy says and get back to us.

[James_03]

put the pressure gun onto the actuator and test it like paul said to do. Check the reading.

if the actuator rod moves within the specified pressure reading, then I would probably run the vac line directly to the actuator and take the controller out of the loop.

If it runs fine like this, then either the controller is bad, or it's been plumbed incorrectly. First take it to 110 but as I would like to know what happens there too.

[ClutchBurndout-:(]

Well you haven't explained yourself very well.

Here's example of creep versus boost.

The boost creeps from 12 to 14 over say 5000rpm.

or it hits 12 at 2500rpm and then spikes to 14 at 2700rpm.

which one is it?

If it's creep, then you need to get a ECU and get a tune. There's a whole lot of explanation and debate as to why, but this is the proven answer. If you need to know why, then search.

If it's a spike, then look for the aforementioned restrictor. The solenoid needs it to control the boost properly, and you don't need it for the boost controller.. Boost controllers tend to spike a little anyway.

Do what ^guilt-toy says and get back to us.

i dont realy understant what your trying to say with the boost creep and spikes but this is exactly what happens, I floor it in second for example, and its climbing normaly in psi to 12 pound, it makes a small pause at 12 then continues climbing to 14 pound, it dosent spike instantly from 12 to 14, it just climbs the same it would from 1-12, and as i said, i dont know for sure but i dont think 14 is what it stops at, it could keep climbing but i dont want to try it lol.

i will also try the 3rd gear option mentioned to see what happens, i have given it a little bit of a go but it seemed fine, but i didnt realy reach the higher rpms.

also, i blocked off the orangy brown hose seen in the pic this morning, nothing has changed.

cheers