which 6776 DBB to order ????

"boosted" is a pressed in 6 inch inlet that will not work with stock
location mounting point. AKA you don't want that one.:smile:
 
why would someone one a ported shroud?

A Ported Shroud compressor is a feature that is incorporated into the compressor housing. It functions by allowing some airflow to exit the wheel through the port to keep surge from occurring. This provides additional useable range and allows a larger compressor to be used for higher flow requirements without risking running the compressor into a dangerous surge condition. The presence of the ported shroud usually has a minor negative impact on compressor efficiency.

Surge is commonly experienced when the throttle is quickly closed after boosting. This occurs because mass flow is drastically reduced as the throttle is closed, but the turbo is still spinning and generating boost. This immediately drives the operating point to the far left of the compressor map, right into surge.
Click to expand...

TurboByGarrett.com - Turbo Tech103
 
6776 BB q trim

Any equivalence for 6776 bb qtrim in tangencial exhaust housing what part#
 
rogerv6,

Unfortunately, there is no such animal as a 6776 bb q trim and here's why.

Part number break down for 6776 turbo whether it be dbb or journal bearing:
67 = 67 mm inducer GT compressor wheel.
76 = 76 "P" Trim turbine wheel



The q trim verbage, refers to the 80 trim "Q" turbine wheel. In PTE speak, this would be the GTQ turbine wheel.

So a 67 turbo with a Q-trim (GTQ) turbine wheel would have the part number 6780.
Available with a dual bb or a journal bearing chra.


So a 6780 turbo (67 GTQ) would break down like this:

300-1575 E cover journal bearing.
300-1576 E cover dual bb.
300-1577 E cover dbb Boosted.

400-1575 S cover journal bearing.
400-1576 S cover dual bb.
400-1577 S cover dbb Boosted.

500-1575 SP cover journal bearing.
500-1576 SP cover dual bb.
500-1577 SP cover dbb Boosted.

600-1575 H cover journal bearing.
600-1576 H cover dual bb.
600-1577 H cover dbb Boosted.

625-1575 HB cover journal bearing.
625-1576 HB cover dual bb.
625-1577 HB cover dbb Boosted.

650-1575 HPS cover journal bearing.
650-1576 HPS cover dual bb.
650-1577 HPS cover dbb Boosted.

Two turbine housing options, THB3-80 (.63 A/R) and THB5-80 (.85 A/R).

Now, exactly how many PT6780R turbos have been sold and are out there for people to report results with, is unknown at this time.
There are a hand full of PT6780 journal bearing turbos out there, and they have the same stall requirements as a PT70 GTQ turbo does. If you are building a stroker motor to run mid 9's with and don't want a 70, then the 6780 is a viable option.
Hope some of this helps.

Patrick
 
after reading this, i would think that everbody here without a blowoff valve would love to get their hands on a turbo with the ported shroud.

does anyone have anything to say about the negative effect on compressor efficency? i am very very curious.

have any of you boys running this turbo gone into the 9's with it.
 
Guys:

Please take a look at the following link and share your thoughts. Figure 2 allegedly shows compressor wheel damage from the "dirty air" in the area of the ported shroud of a compressor housing.

Blouch Turbo Inc. - Information on our performance turbo products

Anybody seen any of this take place? Patrick, please chime in if you read this. I have a Precision PT6776RHPS which is still in the box, new, and I'm now hesitant to install it with the ported shroud housing.

Any help will be appreciated.

JT
 
Patrick:

Did you ever get a chance to test the H housing versus the HPS housing at the track?

Thanks,
JT
 
blownbuick said:
Guys:

Please take a look at the following link and share your thoughts. Figure 2 allegedly shows compressor wheel damage from the "dirty air" in the area of the ported shroud of a compressor housing.

Blouch Turbo Inc. - Information on our performance turbo products

Anybody seen any of this take place? Patrick, please chime in if you read this. I have a Precision PT6776RHPS which is still in the box, new, and I'm now hesitant to install it with the ported shroud housing.

Any help will be appreciated.

JT
Click to expand...

I've run a 70HPQ with ported shroud for the last 6 months or so. No problems so far. I read the article and not sure I understand why your hesitant? It refers to foreign object damage.
 
Here's the pic from the site. I'm not sure what they're referring to, so I thought that I'd check with the many knowledgable people here. I've started a new post concerning this issue.

JT
 

Attachments

  • turbofail2.jpg
    turbofail2.jpg
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Looks to me like they are refering to running the turbo without an air filter and sucking in dirt and debris.
 
BMF_Racing said:
Is there any benfit for me to get the ported shroud? This car is going to be street driven and the turbo will not be used to its full potential, max boost around 22 to 23psi occationally, but 16 to 18psi 99% of the time. I plan on using a L/U 3000 stall & a full 4" mafless cold air intake (maft pro). I was just trying to get the fastest spoolup with the least amount of stall because of the main purpose for the car in street driving.

Thanks,

Brad
Click to expand...
I would go for a 6265 bb if i were you or possibly even smaller. Running the 6776 at 16-18psi is a complete waste and will require way more converter than you should ever need for the intended performance level at those boost levels. Even at 22-23 psi on a 231 its not ideal. The 6776 with a .63 seems to have a lot of backpressure with a cammed and headed car when hitting 124-125mph too.
 
bison said:
I would go for a 6265 bb if i were you or possibly even smaller. Running the 6776 at 16-18psi is a complete waste and will require way more converter than you should ever need for the intended performance level at those boost levels. Even at 22-23 psi on a 231 its not ideal. The 6776 with a .63 seems to have a lot of backpressure with a cammed and headed car when hitting 124-125mph too.
Click to expand...

What is the ideal boost level for the 6776?

I might as well know what psi to set my WG at....
 
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