external waste gate 0.8b spring

[Nano]

hi guys i run the car with a ram horn manifold with tial (new) 0.8b spring wastegate and it has never done fuel cut. the boost gauge reads 0.7b max.
what does this mean? is it boost leak? tired turbo?
is 0.7b instead of 0.8b is an important gap to say there are boost leaks somewhere?
thanks

 

[Murray]

What colour is the spring? is it red or yellow?

 

[Nano]

i dont know mate the wastegate was already assembled. it s a genuine tial and written 0.8b spring. ...

 

[Texx]

I'm using a large yellow 0.7BAR spring which gives a 0.6BAR peak pressure reading at the inlet manifold. Are you measuring pressure at the turbo or inlet manifold? If your gauge is connected to the inlet then I'd assume the reading your seeing is normal.

 

[Murray]

Check the colour of the spring, if its a big red one then you have a 0.8 bar spring, if its a big yellow one its a 0.7 bar spring.

 

[AdamB]

I'm using a large yellow 0.7BAR spring which gives a 0.6BAR peak pressure reading at the inlet manifold. Are you measuring pressure at the turbo or inlet manifold? If your gauge is connected to the inlet then I'd assume the reading your seeing is normal.

Agree with this, by the time you factor in frictional losses through the pipes etc the pressure will have decreased.

 

[weeJohn]

There will be a pressure drop when the pressurised air enters the larger diameter inlet manifold, where air is also being sucked out into the engine. Thats why the map sensor reads off there rather than at the turbo. As long as the map sensor reads what pressure goes into the engine then its all safe. You could blumb your wastegate into the inlet manifold but the longer pipes could then create a problem.

You are not seeing anything abnormal as the boys above confirm.

 

[elison]

0.7 seems fine for me.

 

[Nano]

yes the boost gauge reads inlet manifold. if it s fine for you it is for me as well
big thanks

 

[Murray]

When Rory had a .7 bar spring in the gate he would see .7 on the gauge taken from the inlet mani.
Check your spring.
Also what manifold are you running? Is the boost hitting peak then dropping off?

 

[Nano]

When Rory had a .7 bar spring in the gate he would see .7 on the gauge taken from the inlet mani.
Check your spring.
Also what manifold are you running? Is the boost hitting peak then dropping off?

its a zisco ramhorn mani with waste gate at the bottom near bottom hose of rad
when i floor it, it goes to 0.7b i ll check the spring but im pretty sure its 0.8b spring as it was written onthe box

 

[Nano]

another question guys, if i add a boost controller, could i turn the boost more than 0.7b just below 0.8b for eg ?

 

[weeJohn]

Yes

 

[elison]

Yes m8. With a EBC you will have no problem. Even above 0.8

 

[Guye]

Out of curiosity...(in agreement with Weejohn's post) are you taking boost reference for the wastegate from the turbo compressor housing or from the manifold itself? I found that using the compressor housing produced slightly lower boost for the rated spring than at the manifold. This was caused by pressure drop through the FMIC and piping. "X"psi at the compressor housing didn't mean "X"psi at the manifold. Manifold pressure was lower. When the reference is taken directly from the manifold, the turbine works slightly harder to compensate for any pressure drop as the spring still needs "X"psi to open the wastegate. The result is the manifold pressure matches the spring rate perfectly as it's manifold not compressor housing pressure which opens the wastegate. Hopefully that's not too confusing...

 

[Nano]

thanks for the reply mates. thats not confusing guye. so what you telling me is to block off the turbo compressor housing and run the wasteagate boost source to manifold instead? i ll try that thanks

 

[Texx]

The wastegate should be piped into the inlet between the turbo and throttle body, the diaphragm in the wastegate is not designed to cope with the manifold depression or vacuum created when the throttle is closed. For the most accurate boost control take your pressure source anywhere between the intercooler and throttle body, for ease of installation take your pressure source from the compressor housing of the turbo. Personally I would take the pressure source directly from the turbo and control boost using an EBC that's set up to measure inlet manifold pressure.