Help settle a disagreement about a turbo/water cooling/compressor surge.

[MongolPup]

So I'm having a bit of a disagreement with someone and would like to solicit some outside opinions. Background:

Motor: 1996 Nissan SR20DET (out of an automatic 1996 Silvia)
Turbo: Garrett BB T-28 (came on the motor, EBC turned OFF, boost 7-10 pounds)

The car left the shop without a blow off valve or coolant lines to the turbo (as well as huge problems with the motor like a dented oil pan/30+ base timing etc). The turbo went bad in a week and a half (roughly). The person I'm talking with says that it is impossible to kill a turbo that quick, and that it was NOT because of the lack of coolant/a blow off valve. This is in 100 degrees + days in Georgia.

The first turbo came off, and another T-28 went on. It has a blow off valve, but still no coolant lines.

Here are my questions to you:

1) How likely do you believe it is because of brutal temps and compressor surge that the first turbo went?
2) How long do you give the second turbo before it goes?

[Flicktitty]

why would you run a 2nd turbo without lines?

[bigOdom1]

a bb turbo without oil/coolant lines will not last very long.

[landins13]

kaboom grrrrrr boom

[MongolPup]

why would you run a 2nd turbo without lines?

EXACTLY what I said.

a bb turbo without oil/coolant lines will not last very long.

It has oil lines lol

[orion::S14]

Coolant lines are for longevity...you need to add them, but it's not going to kill a turbop (BB or not) in a few weeks.

And seeing as it IS a BB turbo, it's less prone to damage form compressor surge...again, not the cause of that first one dying. No BOV isn't that hard on a turbo...but it will cut the life in half, probably...versus running a BOV. Again, it's a longevity issue, not a 'dead in 2 weeks' kinda problem.

My guess: Poor oiling (you said dented pan, right?)

???

- Brian

[Sileighty_85]

Straight from Garrett's website
TurboByGarrett.com - FAQ's (http://www.turbobygarrett.com/turbobygarrett/tech_center/faqs.html#t9)

Water Lines
http://www.turbobygarrett.com/turbobygarrett/images/tech_center/turbo_optimization/Garrett_water_cooling_instructions.jpg Water cooling is a key design feature for improved durability and we recommend that if your turbo has an allowance for watercooling, hook up the water lines. Water cooling eliminates the destructive occurrence of oil coking by utilizing the Thermal Siphon Effect to reduce the Peak Heat Soak Back Temperature on the turbine side piston after shut-down. In order to get the greatest benefit from your watercooling system, avoid undulations in the water lines to maximize the Thermal Siphon Effect.

What is compressor surge?
The surge region, located on the left-hand side of the compressor map (known as the surge line), is an area of flow instability typically caused by compressor inducer stall. The turbo should be sized so that the engine does not operate in the surge range. When turbochargers operate in surge for long periods of time, bearing failures may occur. When referencing a compressor map, the surge line is the line bordering the islands on their far left side.
Compressor surge is when the air pressure after the compressor is actually higher than what the compressor itself can physically maintain. This condition causes the airflow in the compressor wheel to back up, build pressure, and sometimes stall. In cases of extreme surge, the thrust bearings of the turbo can be destroyed, and will sometimes even lead to mechanical failure of the compressor wheel itself.

Common conditions that result in compressor surge on turbocharger gasoline engines are:

A compressor bypass valve is not integrated into the intake plumbing between the compressor outlet and throttle body
The outlet plumbing for the bypass valve is too small or restrictive
The turbo is too big for the application

[ericcastro]

its not the blow off valve.
your barely boostin shit.
blow offs at that low are for ricers who like the sound of them chirping.

ITS THE COOLANT LINES!!!
how would it not go bad quikly with no cooling system in place??

[johngriff]

its not the blow off valve.
your barely boostin shit.
blow offs at that low are for ricers who like the sound of them chirping.

ITS THE COOLANT LINES!!!
how would it not go bad quikly with no cooling system in place??

If you try to drive it like a ricer, forcing compressor surge w/o a bov.

I've seen it.

Seen.

IT.

[MongolPup]

Coolant lines are for longevity...you need to add them, but it's not going to kill a turbop (BB or not) in a few weeks.

And seeing as it IS a BB turbo, it's less prone to damage form compressor surge...again, not the cause of that first one dying. No BOV isn't that hard on a turbo...but it will cut the life in half, probably...versus running a BOV. Again, it's a longevity issue, not a 'dead in 2 weeks' kinda problem.

My guess: Poor oiling (you said dented pan, right?)

???

- Brian

Yes the pan was mauled.

Straight from Garrett's website
TurboByGarrett.com - FAQ's (http://www.turbobygarrett.com/turbobygarrett/tech_center/faqs.html#t9)

Water Lines
http://www.turbobygarrett.com/turbobygarrett/images/tech_center/turbo_optimization/Garrett_water_cooling_instructions.jpg Water cooling is a key design feature for improved durability and we recommend that if your turbo has an allowance for watercooling, hook up the water lines. Water cooling eliminates the destructive occurrence of oil coking by utilizing the Thermal Siphon Effect to reduce the Peak Heat Soak Back Temperature on the turbine side piston after shut-down. In order to get the greatest benefit from your watercooling system, avoid undulations in the water lines to maximize the Thermal Siphon Effect.

What is compressor surge?
The surge region, located on the left-hand side of the compressor map (known as the surge line), is an area of flow instability typically caused by compressor inducer stall. The turbo should be sized so that the engine does not operate in the surge range. When turbochargers operate in surge for long periods of time, bearing failures may occur. When referencing a compressor map, the surge line is the line bordering the islands on their far left side.
Compressor surge is when the air pressure after the compressor is actually higher than what the compressor itself can physically maintain. This condition causes the airflow in the compressor wheel to back up, build pressure, and sometimes stall. In cases of extreme surge, the thrust bearings of the turbo can be destroyed, and will sometimes even lead to mechanical failure of the compressor wheel itself.

Common conditions that result in compressor surge on turbocharger gasoline engines are:

A compressor bypass valve is not integrated into the intake plumbing between the compressor outlet and throttle body
The outlet plumbing for the bypass valve is too small or restrictive
The turbo is too big for the application



Funny thing, he quoted that too and said it's just for durability after shut down, not during actual operation. He mentioned that lots of turbo cars come from the factory without blow off valves and that isn't a big deal. That's why I wanted outside thoughts.

[Sileighty_85]

What exactly happen to the turbo? blown oil seals? extreme shaft play?

[MongolPup]

What exactly happen to the turbo? blown oil seals? extreme shaft play?

Picture is worth a thousand words right?

http://photos-g.ak.fbcdn.net/hphotos-ak-snc1/hs086.snc1/4903_95158986781_640641781_2364534_8355339_n.jpg

We pulled the hotside pipe off the end tank and oil poured out of it (reminded me of Nate the Great's syrup). Seals.

[Sileighty_85]

is he runing an oil restrictor?

[MongolPup]

is he runing an oil restrictor?

Every line coming to/from/within a foot of the turbo is completely stock.

[s14unimog]

Can you verify that the oil is coming from the turbo and not your crank ventilation? Your engine install is becoming quite comical to read about...Tyler and you still friends? LMAO....and totally kidding

I've personally run OEM SR20 T25's (I know yours is a BB T28) on my past KA-T setup for over a year without coolant lines, so that is definitely not your issue; just allow adequate cool down time. A known fact about BB turbo's are their lower requirement for oil; if you do not have a restrictor in place you can bet your bottom dollar it will pass oil. Knowing how this swap came to be, I would recommend you verify that it is in place. Should be around 0.030".

another worry to set to rest is not having a BOV....its not imperative but definitely not a good idea. That back flow of air is loading the central bearing, which will effect the tolerances over time; eventually it will be enough for oil to pass.

[sr20boostn20]

my oil cooled turbonetics piece is still running hard as hell and its oil cooled only, not that that's really relevant,


100% if it was running hot at there was no bov, and you were beating the snot out of it, it blew up from compressor surge. in that situation the stress from teh temp and the surge on the wheel will pop it in mins.

[s14unimog]

my oil cooled turbonetics piece is still running hard as hell and its oil cooled only, not that that's really relevant,


100% if it was running hot at there was no bov, and you were beating the snot out of it, it blew up from compressor surge. in that situation the stress from teh temp and the surge on the wheel will pop it in mins.

Are you kidding me, pop.... pop what?

[ILoveJDM]

my 180sx came from japan with an s15 spec r turbo, running oil lines and no coolant lines, and no bov.

added a ssqv after 1 month, and i DD and tracked this for 7months/20xxxkm's @ 1 - 1.15bar without any problems

im guessing the turbo was ran like this for sometime, 60,xxxkm+ as the water inlets were brown and crusty.

when i removed the turbo it had next to no shaftplay and was in great working order, made boost like crazy and didnt smoke.