Porting exhaust housing 6262

[Sweet6]

I am getting ready to port my WG hole. The unported hole is .9" it looks like and my THDP puck is 1.5". How big should I make the WG hole? I see a lot of guys saying 1.1" or so. Just wanted to double check.


TIA

 

[salvageV6]

My THDP is only 1.375" puck double check that measurement.

1.1" is about as big as you want to go with a 1.375" puck and you might have trouble with that, if it's an out of alignment housing which some are.

 

[Sweet6]

This is a THDP for a TTA. Not sure if it is different than the GN. I will double check my measurement too. But I could have sworn it was 1.5" But it sounds like 1.1" is good anyway. Last thing I want to do it go too big. :biggrin:

 

[Scott Atk]

They're seldomly perfectly centered on the hole. Best bet is to run the pipe for a period of time. When you remove it for porting there should be a nice carbon build up showing exactly where the puck seats. Use that as a guide for porting.

 

[NCTURBOS]

Some prussian blue, marking compund, and a scribe will do the trick as well...


K.

 

[Sweet6]

thanks for the tips

 

[TR Custom Parts]

I ported mine to 1.25 and still have boost creep! Running a 38mm external wastegate downpipe on my GN. Even tried a Turbosmart 38mm gate since they are supposed to be better than anything out there and same thing. Guess I have to go bigger.

 

[NCTURBOS]

The 6768 (HPQ) we just did has no creep until the top of 3rd gear. This is using a 3.5" intregal wastegate DP, and the stock boost solenoid. If the rain holds off we'll do some testing with slightly different boost controller set-ups, nothing too radical though.

Otherwise we're gonna pull the DP back off and check out the carbon tracing.


K.

 

[XLR8]

Put some type of marking fluid (I used latex paint) on the puck of the DP then attach the DP to the turbo, close the puck, remove the DP and you have an exact idea of how much to port the WG hole.

On a side note I was disappointed that I neede to port the WG hole since on a TE-44 I purchased years ago from Precision they asked what DP I had and ported the WG hole for that.

 

[bison]

1.1 inches is fine up to about 650 hp as long as the hole is tapered on the inside. Russ Merrit and i came to the same conclusion totally independently on this. Making it larger will cause boost drop off in 3rd gear as the back pressure overcomes the spring tension. Why give the exhaust bp more surface area to push on? I lost about .5psi from 5400rpm to 5750 rpm on a 133.4mph pass with a 1.1 inch hole on a 3.5" internal pipe.

 

[TurboBob]

on what turbo and turbine housing A/R?

Bob

 

[bison]

on what turbo and turbine housing A/R?

Bob

I had a 66 S trim t-netics .85 and he had a 67 GTQ .63. So the big exhaust wheels. Maybe a lot worse with a p-trim.