Ok i thought i would start a new thread as my recirc thread has become a bit long.

 

Right basically i cant boost past 17-18psi it will hit 17-18psi then drop down to 14 or so..... its not the ebc as ive had the actuator pipes off and it still wont boost past the above pressure. fyi i dont have the stock actuator solenoids anymore.

 

the ebc does make a difference, if set to 0% it will boost a steady 10-11 psi

on 100% of course it will on boost to 17to18psi depending on gear... anyway this is irrelevant seen as ive had the actuator pipes off.

 

i have ditched the recircs hoping they were leaking, I fitted a single Bov which dumps nicely with no leaks.... This has not cured the problem.

 

The car idles nicely so im pretty sure there are no boost leaks(i have tested for these!) these would be pretty obvious if they were the problem. Im going to do another boost leak test 2mow and test it at 18 psi to see what happens.

 

Can anyone suggest any possible causes or tests i could perform to resolve this its getting annoying now and holding me back from my remap......

 

Thanks in advance.....

Edited January 19, 201015 yr by j1mmytt

..also - [another] daft question - what are the specs for your turbo's?

Have ya got stock IC's matey?

 

 

Was just about to ask that question... Now the fact that the car idles smoothly doesnt rule out the fact there is a leak at higher boost pressures. maybe the system can take 14 psi, but not anymore than 18 as maybe a small split in a hose that opens and closes? Or maybe an ill fitting jube clip thats allowing pressure past once it exceeds 18psi or so

What about the quality of your vac lines - maybe they are collapsing?

I have spent enough of my Tuesday evening pondering your [lack of] boost young man - talk to ya tomorrow - have a good one and good luck with the leak test - betcha find something ;-))

what happens when driving and it hits 18psi? does it fall over itself/stumble or just steadily drop down again.

 

Are the wastegates actually closing properly?

I have spent enough of my Tuesday evening pondering your [lack of] boost young man - talk to ya tomorrow - have a good one and good luck with the leak test - betcha find something ;-))

 

Thanks mate ;)

what happens when driving and it hits 18psi? does it fall over itself/stumble or just steadily drop down again.

 

Are the wastegates actually closing properly?

 

yeah it drops slowly back to say 14psi.... no stumbling. I cant tell if the wastegates are closing :( if they are not sealing/closing properly then that could be the prob BUT like i said above the pressure drops slowly. strange

a comon problem on the 200sx can be the induction pipe (ie the one between the air meter and the turbo) collapsing under vacume when at higher boost. perhapse try a run without the air filter and see if you get a few more psi. if you do then it will be an induction pipe collapsing

How have you tested for leaks ? A smooth idle is no indication, sounds like at higher pressure a leak is being forced open.

I would agree with Legrath, I am not sure if I am reading it right but you said you would boost test the car at 18psi, only go to 4ish psi or you will blow seals on the engine!

>Just to add, i have fitted hks actuators so im pretty sure they are strong enough to hold 17psi for sure..... unless they have been set to low BUT if they hold base pressure at a steady 10-11 psi surely this eliminates that possibility? sticky actuator stuck open slightly?

 

I think this is your problem (actuator base pressure set too low)...

The rule for (larger) turbos with internal wastegates is to set the (actuator) base pressure to about 2/3 of the max. boost you want to be running.

 

and 2/3 of 17 psi (the max you are currently able to boost) is....

 

try to increase the base pressure by resetting the actuator-arms (fiddly but do-able with the engine in the car)

..or only do the LH turbo (where the actuator-arm is best accessible) for testing purposes only..to see if it helps to increase the max boost.

 

 

> Im going to do another boost leak test 2mow and test it at 18 psi to see what happens.

 

I suggest you don't try that...you are likely to blow out gaskets with that kind of pressure on a non running engine.

lymon makes sense, for reference, my base boost is 18psi to let me get to higher boost levels

Been on the pm with jimmer last night, i decided that i would put some pressure through each actuator pipe and see which one opens with the lowest pressure, then i can decide which one to adjust, im hoping one will open to early as this would point to the problem, il also do another boost leak test, btw I do it the traditional way, pressureising the system from the intake... correct? ok il only test it at 4psi but i really doubt this is the prob. i thought a high pressure test would be a bad idea but someone else seemed to think different.

if you do decide to boost leak check to 18psi or even 30 psi as you mentioned too... film it!

if you do decide to boost leak check to 18psi or even 30 psi as you mentioned too... film it!

 

lol yeah will do haha.......

god i really hope its something simple like an intercooler pipe or something....... this car has never been simple.

I agree with Eric, actuator set wrongly. Seen this lots of times on the stock garett actuators that come with the GT28RS turbos, usually can't boost past 15psi as the exhaust gas pressure just opens the wastegate!

With your aftermarket ones you should be OK as long as you have the correct springs in them and set them up properly.

 

Also, as I said, that chip you're running is for a similar setup, NOT exactly for your car until we map it so DON'T push the boost other than for a quick test until it's mapped!

I agree with Eric, actuator set wrongly. Seen this lots of times on the stock garett actuators that come with the GT28RS turbos, usually can't boost past 15psi as the exhaust gas pressure just opens the wastegate!

With your aftermarket ones you should be OK as long as you have the correct springs in them and set them up properly.

 

Also, as I said, that chip you're running is for a similar setup, NOT exactly for your car until we map it so DON'T push the boost other than for a quick test until it's mapped!

 

Im definately not pushing it, just trying to sort out this problem so i can get it up to you..... will be a waste of both of our times otherwise.

I agree. you should check the closed holding pressure on your wastegate actuators .

Had it a few times before .

So Jimmy - any progress - watching with interest?

nope not yet, not had a chance to do anything... being working like a slag..... will update soon, wont have time this weekend either,gota spend time with gf :(

ok progress....

 

i spent last weekend doing a few things to the car.

 

I tested for boost leaks and yay i found one..... It was coming from the passenger turbo inlet pipe, oopsy.. the weld was not perfect and was leaking past quite badly so after hours of taking it off and welding the leak it was fine and ready to be fitted again.

being quite an obvious leak, i was almost certain that this must be the problem.... NOPE still wont boost past 17psi although seemed a little better running. While performing another boost leak test i noticed air leaks out the dip stick if it isnt plugged in enough, is this normal? The car doesnt smoke at all so this seems strange and the dipstick doesnt pop out while driving or boosting either, little worried about that.

 

Anyway i got it back up on the axle stands and tested the actuators to see if they were opening as they should.....

Well i can say the passenger opens at about 15psi 1bar hmmmm seems normal, so i tested the drivers side, this ones just opens at about 9-10 psi quite hard to read the gauge as it has quite a high range, it goes upto 180psi lol

 

anyway im going to have a go at adjusting the drivers side actuator, its a shame it is the drivers side as this one is the hardest to get to :( very tight in there.......

 

so do we recon this is the problem and while im at it do you lot recon i should set them a little higher say 17psi? which should give me a good base say about 15psi...

 

your thoughts plz guys..........

Thanks James

From what you describe jim, this seems to be the problem. 1 acuator fighting the other for greater boost., or so to speak. I think, because the 300 is a V6, everything has to be balanced just right, equal properties on both banks. Set the drivers side up and post back ur findings matey. Hope it works out for u bud.

 

Al.

Edited February 1, 201015 yr by AlanZ

From what you describe jim, this seems to be the problem. 1 acuator fighting the other for greater boost., or so to speak. I think, because the 300 is a V6, everything has to be balanced just right, equal properties on both banks. Set the drivers side up and post back ur findings matey. Hope it works out for u bud.

 

Al.

 

What im going to do is T off both actuator pipes into one pipe then push 15-16psi thru the pipe and keep it there while i sdjust the actuators, il adjust them so they are just about to open at 15-16psi...... sounds like the best way to get them opening sequentially.

From what you describe jim, this seems to be the problem. 1 acuator fighting the other for greater boost., or so to speak. I think, because the 300 is a V6, everything has to be balanced just right, equal properties on both banks. Set the drivers side up and post back ur findings matey. Hope it works out for u bud.

 

Al.

 

You are right the vg30dett does need to be balanced but the turbos feed the opposite bank to the side they are on, so they have slight self balancing affect.

You are right the vg30dett does need to be balanced but the turbos feed the opposite bank to the side they are on, so they have slight self balancing affect.

 

And through the balance bar on the plenum and the balance bar i have fitted for the Bov will help balance things out also.