New turbo, no Boost pressure sound

turbopat

Member
Joined
Feb 26, 2018
I recently switched over from a 66 mm turbo to give you 70 mm Percision turbo. After the install I now notice that once I get out of the thrittle there’s no chipmunk sound?? Can anyone help me understand what may be wrong


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How much boost? Which cover? Ported Shroud

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What kinda cover do you have on the compressor wheel ? Also is it a new turbo?
 
I’m not sure. The turbo is 6766 precision brand new in the box. Gn1 3 in downpipe with external gate


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U don’t have a blow off valve correct? Post a picture of it
 
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this was during install. No bov... it was installed just as my old turbonetics was.
 
You have a ported cover bud
So it bypasses the compressor wheel .thats why no horse sneeze
 
I appreciate it! It all
Makes sense now lol!!! I am a bit new but wanted to make sure I hadn’t done something I shouldnt


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Looks just like mine.
Don't worry, you did really good.
Yes, the ported shroud S cover does away with the sneeze sound on decel. When the throttle slams shut, the backed up air in the intercooler and piping, now has a means of recirculating, vs violently sneezing back through the MAF sensor and air filter.

I preach it all the time and I'll say it again here. Any street driven Turbo Buick with a 62mm or larger journal bearing turbo, must have a ported shroud compressor cover, if you want the chra bearings and oil seal to live a long and healthy life. You also must have filtered oil to the turbo. The stock oil feed line, or replacement line sends unfiltered oil to the turbo in the stock configuration. If not, any FOD, failing lifter debris or engine bearing material will go straight to your new turbo and cause premature bearing failure.
There are multiple systems out there that fix this known issue. I recommend all of them. And don't forget ZDDPlus at every oil change.

Keep us posted and you're going to love that turbo.

Just my O2's worth.

-Patrick-
 
Ported cover is kinda like an integrated blow off valve ? Very cool.
What is the smallest turbo those are available on ? I have a TA49 now but am considering bumping up a notch with a turbo/converter upgrade
 
Ported cover is kinda like an integrated blow off valve ? Very cool.
What is the smallest turbo those are available on ? I have a TA49 now but am considering bumping up a notch with a turbo/converter upgrade

From PTE, that would be a PT6262 with the SP cover. Aka, ported shroud S cover, 4" inlet, 2.5" outlet.
Also fwiw on PTE turbos, if it has an E cover on it, you can't simply swap on an SP cover. The backing plate is different and would require a full tear down for the swap.
 
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