External Wastegate Question

[TurboBRZ]

This is my first car running an externally gated turbo - prior they were all internally gated.

I have the bottom hose of the external wastegate connected to the pressure line from the front of the turbo housing, and the top of the wastegate connected to a boost controller.

The thing is that when I start the car up, the wastegate is partially open with exhaust billowing out the wastegate pipe. To my knowledge this is not supposed to happen until the proper boost is achieved in the system to push the spring up and allow exhaust pressure to escape. I'm thinking there is something wrong with my wastegate but wanted to pose the question here to make certain.

[Sportsguy83]

Originally Posted by TurboBRZ

This is my first car running an externally gated turbo - prior they were all internally gated.

I have the bottom hose of the external wastegate connected to the pressure line from the front of the turbo housing, and the top of the wastegate connected to a boost controller.

The thing is that when I start the car up, the wastegate is partially open with exhaust billowing out the wastegate pipe. To my knowledge this is not supposed to happen until the proper boost is achieved in the system to push the spring up and allow exhaust pressure to escape. I'm thinking there is something wrong with my wastegate but wanted to pose the question here to make certain.

The top line is vented to Atmosphere. The boost controller goes to the bottom/side port.

The turbo pressure line goes into your boost controller.

[Sammakko]

it depends on the number of ports on your boost controller. is it a restrictive type, or a bleed-down type? (2 port or 3 port)

[Sportsguy83]

Originally Posted by Sammakko

it depends on the number of ports on your boost controller. is it a restrictive type, or a bleed-down type? (2 port or 3 port)

This was the right question to ask, I only gave half the answer

[Sammakko]

Originally Posted by Sportsguy83

This was the right question to ask, I only gave half the answer

it probably also depends on what brand of wastegate he's using?

i abhor external wastegates, personally. well... only when they're dumped to atmosphere.

[Sportsguy83]

Originally Posted by Sammakko

it probably also depends on what brand of wastegate he's using?

i abhor external wastegates, personally. well... only when they're dumped to atmosphere.

mine's recirc, I dislike dump to atm.

[TurboBRZ]

I set it up as per the following image:



The wastegate I am using is the stock one that came with the kit - which resembles the one in the photo above with 2 vacuum ports.

The boost controller I am using is a manual one rather than electronic:





This boost controller is temporary. The tuner I spoke to said he likes to use the STI factory boost controller plugged into our factory harness and control it via the tune - so that's what is likely to happen when I bring it in to be tuned, but for now it's manual.

[Sammakko]

try disconnecting ALL lines from your wastegate, and see what happens. does it still open? then you have a problem. the bias spring should keep it closed, at idle.

[TurboBRZ]

Originally Posted by Sammakko

try disconnecting ALL lines from your wastegate, and see what happens. does it still open? then you have a problem. the bias spring should keep it closed, at idle.

I will give that a try first and see what happens.

[TurboBRZ]

Originally Posted by Sammakko

try disconnecting ALL lines from your wastegate, and see what happens. does it still open? then you have a problem. the bias spring should keep it closed, at idle.

I did this first thing this morning when I got up - both vacuum lines are disconnected and it's still letting exhaust out the dump tube (I don't like dump tubes either - wish it was a recirc).

So I am assuming this is a problematic wastegate?

Also the engine still idles like crap and dies several times before I can feather the throttle to get it to actually idle a bit later... I'm confused as to what is causing such a troublesome start when there is no boost going into the motor - so it should run like stock?

[Sammakko]

Originally Posted by TurboBRZ

I did this first thing this morning when I got up - both vacuum lines are disconnected and it's still letting exhaust out the dump tube (I don't like dump tubes either - wish it was a recirc).

So I am assuming this is a problematic wastegate?

yup, sounds like it. is it a 38mm? i have a Tial i could sell you, brand new in box. Vband though.

[TurboBRZ]

Originally Posted by Sammakko

yup, sounds like it. is it a 38mm? i have a Tial i could sell you, brand new in box. Vband though.

Yeah 38mm. It's not a v-band one though, it has a 2-bolt flange with hex bolts (which will be a pain in the ass to remove).

I emailed the seller on ebay to let him know he owes me something, whether a partial credit towards purchasing a tial or...?

[Sportsguy83]

Originally Posted by TurboBRZ

I did this first thing this morning when I got up - both vacuum lines are disconnected and it's still letting exhaust out the dump tube (I don't like dump tubes either - wish it was a recirc).

So I am assuming this is a problematic wastegate?

Also the engine still idles like crap and dies several times before I can feather the throttle to get it to actually idle a bit later... I'm confused as to what is causing such a troublesome start when there is no boost going into the motor - so it should run like stock?

You're running the stock tune with the turbo MAF housing?

The MAF table needs to be adjusted for the bigger MAF housing to fix the idle problems.

The grimmspeed EBCS and similar are the ones used to control boost via the ECU with Ecutek. I have mine setup per their instructions (the port that says to inlet in our cars is VTA). I called Grimmspeed about how to set it up between your setup and the one I ended up going with, and they said your setup is an overcomplication not necessary to control boos with their solenoid and that I should use the configuration below.

[STV3]

Did you install the valve seal when installing the waste gate?