boost conrol, how does it work Options

[urbandork]

What are the mechanics behind contorling the level of boost? im a little confused as to how i would contorl it using a ct26 turbo. What do i need and how does it all work?

Also whats the waste gate for?

[rjbibeau]

the wastegate controls the boost setting. people use a BOV to control it to their likes and use a boost controller whether it would be a manual or an electronic controller. a wastegate closes the flap so it allows the turbo to spool and it's actuated under vacum pressure.

[urbandork]

So how do i adjust the boost level? do i adjust the bov or is it the waste gate that is adjusted?

If i hear you right the waste gate keeps in check the presure and any thing over the selected presure is vented via the waste gate?

[rjbibeau]

the wategate is set at a factory setting the ct-26 usdm setting i think is 8psi and the jdm wastegate is set at 10 i believe. yes if you want to run lower boost your gonna need an aftermarket BOV

[urbandork]

r you saying that if im fine with running 8 psi then i dont need a blow off valve on my intercooler pipping? I always thought the bov was used to vent presureized air when the tb was closed. Is this now vented through the waste gate? no right? i still need a bov no mater the psi i plan on running.

if i want to run lower then stock boost the bov as well as the waste gate would vent excess pressure? What if i want to run higher boost?

lol still learning and trying to get the jist of things can you tell?
thanks in advanced

This post has been edited by urbandork: Feb 25, 2005 - 3:30 AM

[urbandork]

how do i run higher boost? do i have to change the waste gate set up or get a manual boost contoller?

[Newbie]

Basically what happens is that you have the wastegate from the factory where the turbocharger is made from. It is made to detect the factory specified boost pressure, and once the wastegate detects more than the specified pressure, the wastegate opens, making the exhaust gas bypass the turbine.

Bypassing the turbine wouldn't create any boost, and the wastegate may open little bit to control the boost pressure itself. Having a boost controller will trick the wastegate, so the wastegate will detect 5psi, when you are boosting 10psi. Once the desired boost pressure is reached, the controller then exceeds that stock wastegate release pressure, opening the wastegate to prevent further boost development.. I hope that helped to figure things out for you.. I'm tired and some of these may not make sense.

[urbandork]

no i got the jist of it.

[mark_426]

An external wastegate is used with larger turbochargers that do not have an
internal wastegate..like a T3 or T4 garret turbocharger. You need a
standard stock manifold for use with a T25,T28.,14b,16g type bolt on
turbo.

The external wastegate is what controls boost pressure from the turbo by
letting the exhaust pressure in the exhaust manifold out bypassing the
turbo.

The wastegate essentially acts as a BOV. It is what keeps you from spooling
your turbo too much and blowing the turbo.

[Newbie]

I think mass boosting will blow the engine before the turbo.
And that would suck if your wastegate malfunctions and stays closed.. Eeek..

This post has been edited by Newbie: Feb 26, 2005 - 11:56 AM

[urbandork]

Just to make sure not matter what set up i have im guna need a BOV on my piping some where right?

[Hanyo]

how does the Apexi Boost Controller work?

[Fox-N-It2]

The wastegate controls the exhast thus controling the speed of the exhaust turbine which controls the speed of the compressor turbine. The slower the turbine goes the less it compresses which controls the boost. A boost controler is placed between the vac line from the compressor housing and the wastegate. It makes pressure buildup on the wastegate spring take longer thereby making the gate open later when there is more pressure in the system.

Bov' serve more to relieve the turbo when the throttle closes so that the back pressure created doesnt harm the turbo. They are not entirely necessary in applications under 8psi from what i've read.

A good book is of course
Maximum Boost by Corky Bell
ISBN 0-8376-0160-6
Go pick it up at your locak book store

[mark_426]

hanyo - I believe it is essentially a solenoid - an electronic valve. It probably would open to the desired pressure at the desired RPMs, and when adjusted, the solenoid opens futher or less far to alter flow. I dont know though, just a guess.

fox - i think that the stock ones don't need replaced until over 8 or so pounds, because thats what they are made for; not that they aren't required.

[urbandork]

Bov' serve more to relieve the turbo when the throttle closes so that the back pressure created doesnt harm the turbo.  They are not entirely necessary in applications under 8psi from what i've read.

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thanks this is what i had originally thought it was for.