.63 A/R Garrett Exhaust Housing

[1KWIKSIX]

Am switching over to my .63 A/RGarrett exhaust housing from my original Precision .63 A/R on my DBB 5857SP turbo. Bison machined this up for me some years ago.
Years ago, I opened up my Precision waste gate hole to 1.110" and radiused the inside to control boost spike and boost creep.
Think it may have been a little too large. Although witness marks show the puck was sealing fully.
The Garrett is brand new and .83" waste gate hole size.

Just want to keep boost spike and boost creep at bay. Can anyone recommend an appropriate waste gate hole size for a street driver on the Garrett housing. Only running 94 octane pump gas and no more than 20lbs boost at this time. Razors Alky kit is on my radar screen for my next purchase , but will be some time down the road.

Thought I read no larger than .090" waste gate hole or it could adversely affect spool up.
FYI....running a THDP with 1.5" puck.

Any thoughts?
Thanks in advance.

dave

 

[jasjamz]

Looks like you should go to a standard wastegate. Port the hole to allow a tad more than 1/8th inch sealing. This takes time to get right. Don't rush it. I have gotten stock style wastegates to control a 5858, 6262, 6765 and 6766 to 20 psi and lower. You can do it. Perfect spool and dead flat control is best for an external setup.

 

[dank GN]

Here is mine . I have a external gate so I wanted to enlarge it to match the pipe it was bolted up to

 

[1KWIKSIX]

Nice! Makes sense to have such a large hole with an external gate, but since mine is an internal waste gate (THDP), I don't wanna go too large.
Hey, are those stainless steel studs in the exhaust housing?
I'm looking to do something similar. Would appreciate any info on them.
Thanks
Dave

 

[turbobitt]

Am switching over to my .63 A/RGarrett exhaust housing from my original Precision .63 A/R on my DBB 5857SP turbo. Bison machined this up for me some years ago.
Years ago, I opened up my Precision waste gate hole to 1.110" and radiused the inside to control boost spike and boost creep.
Think it may have been a little too large. Although witness marks show the puck was sealing fully.
The Garrett is brand new and .83" waste gate hole size.

Just want to keep boost spike and boost creep at bay. Can anyone recommend an appropriate waste gate hole size for a street driver on the Garrett housing. Only running 94 octane pump gas and no more than 20lbs boost at this time. Razors Alky kit is on my radar screen for my next purchase , but will be some time down the road.

Thought I read no larger than .090" waste gate hole or it could adversely affect spool up.
FYI....running a THDP with 1.5" puck.

Any thoughts?
Thanks in advance.

dave

You can also salvage the housing by using one of Bison's stainless steel plates sandwiched between the housing and elbow to give it a new smaller hole to seal against.
AG.

 

[dynoman]

You can also salvage the housing by using one of Bison's stainless steel plates sandwiched between the housing and elbow to give it a new smaller hole to seal against.
AG.

This is what I used when my WG hole was misaligned . Bison has them with or without holes .

 

[1986 Buick GX1]

It seems at lower boost levels (20 psi w/ a larger turbo) a larger hole is needed to expel a larger volume of wasted exhaust gas to control the boost and when running higher boost levels (27-30 psi) the larger hole will allow more area for the exhaust pressure to push the puck open limiting boost, so a smaller hole is required to get to the higher boost level (more exhaust is going through the turbo to make boost and less is going through the waste gate).

With the new housing you'll be using having a .83 hole size you'll be able to port it just large enough to control 20 psi now, but may be too large when you add the alky kit and run higher boost.

(Edit) running an HD acuator with heavier spring tension should help keep the puck closed at higher boost levels, may work in lue of a smaller hole.

Unfortunately each set up is a little different and takes some experimenting.

I've ran a TA49 turbo for years with approx. same hole size as your old housing (1.10) at 20 psi and it worked great.

I've converted to E85 and want to run higher boost (28 psi) and have read a .95 hole is a good place to start.

(Edit) I will be using one of the fix-it plates mentioned above starting with a .95 hole and go from there.

That's all I know for now.