boost creeping issue..

[renxun]

damm ..! problem came never ending to my car.... always related to boost issue... before that im experiencing boost drop while accelerating due to high boost application and my wastegate couldnt hold my boost or leaking vaccum hoses... im not sure watever the reason is... i connect the hoses to the wastegate as if im connecting an actuator(single vacuum hose) but after that i changed to the correct setup(2 vacuum connection, 1 boost signal+1to boost control) and change the hoses to samco hoses this boost drop issue was solved...

but now my issue is i cant set the boost controller to the boost i wanted.... if i set to 1.4bar... it will creep the hell to 1.5-1.6 bar on my 4th gear or my 3rd gear at high rpm range....then i lower the boost to 1.2bar and it will still creep to another 0.2bar xtra... why the hell this is happening? issit my wastegate not big enough..? impossible also cuz im running on Trust 50mm wastegate..

btw im running a 1jz 400rwhp ...wat could be the possible things to happen? im afraid one day if i boost without noticing the boost and then only to find out that i fried my engine due to fuel leaning out

[BeRad]

electronic boost control?

what sought, where is the controller taking its boost reading from. and where are you taking the boost reading from to see its running more than the boost set, or are you taking it off the controller?

is it running .2bar more consistantly, or just every now and then?.....

is the wastegate a genuine gate or ebay copy? if its a copy thats possibly your problem, 50mm is more than enough i would think.

[renxun]

the boost reading is from the plenum inside the intake.......i see it using my normal apexi boost gauge... yes its an electronic boost control ..

yupe it ran 0.2 bar more consistanly... everytime i boost there will be 0.2bar more at high rpm ...

[2JZR31]

Only at high RPM? I had serious boost control issues with my GT35 internal gate. It would hold spring pressure of 10psi in first second and then at high RPM in 3rd the spike would start and quickly magnify itself to totally out of control boost. It would shot straight up to the boost cut, and would probably have kept going if there was no fuel cut.

The gate was too small so I opened it right out to 168% its size. After I done that the spike in the top end was gone, but I got new probs. The flap was being forced open due to the additional surface area for the exhaust pressure to act apon. This gave an extra 500rpm of lag. And effectively cause the same spring to be a 7psi spring instead of 10psi. So I fitted a stiffer spring. With a 15psi spring the lag went away, but I now get boost drop off at high RPM.... These probs can be a bitch to iron out.

[ganador]

Another thing to take into consideration is the length of the vacume hose going to the boost controler or wastegate. its best to keep them a sort as possible to eliminate boost spikes and such. Some people tend to want to mount the controller on the firewall so they end up with a long piece of hose running from wastegate to controler and then end up having boost spikes, not good.

[renxun]

so wat would be the problem of tis one then? i reli no idea... now i set my car to 1.2 bar.. so when it creep it will go the most 1.4bar which i still could take it with my current fueling..

[2JZR31]

What exactly is happening? Say you set it at 1.2 bar, does it rise to 1.2 bar then stay flat a until the upper RPM band where it will rise the extra 0.2 bar? If its consistently just .2 bar out, just set it to .2 bar less than what you want and forget about it.

What is the spring pressure with no controller connected?

[oldcorollas]

i vote that the exhaust tube to your wastgate is not well thougth out, so it not able to flow enough to control the boost...

got any pics of the manifold setup?

or your controller/wastgate are shit

[renxun]

the manifold setup is the aftermarket frm hks for garret single turbine application...came together with the wastegate pipe to mount my wastegate its located lower down behind..meaning to say its at bottom near my firewall...

spring preassure without boost control is 0.8bar

[chris davey]

Your manifold and gate sound similar to mine. I have Trust 6-2-1 mani with the wategate pipe heading down and to the rear of the car and I use a trust 50mm gate also. I am running a 15psi spring in mine and no boost controller at present. The boost guage shows that it is running 15psi but the datalogs on my ecu show that it changes between 13 and 16psi or sovery quickly. So it could be something to do with a very quick peak boost jump and then back to normal.

A full boost curve would probably help the situation if you can get one.

[renxun]

full boost curve? wat do ya mean by it?

[chris davey]

either on a dyno, with rpm showing and the boost curve or if you can datalog on your ecu you can do it also. You can see exactly what it is doing at various rpm's with different settings on your controller.

[VeeP]

are both your boost controller and boost gauge measuring boost from the same outlet?

[renxun]

veep ---> nope....boost controller measure boost from the turbo to intercooler piping while the boost meter measure boost from the plenum

[ganador]

all you really need to do is hook the gauge up to a vancume like. I think thats fine the way you got it RENXUN.