Compressor Surge Anyone? (Vid)

[unicoladron]

Originally Posted by burnsauto

lol that's like one of my favorite videos.

[niberlin]

Nice sound! Got about the same noise in my tricked out ca18det

[Def]

Originally Posted by hellaflush

^^^ wtf?

and to further put fact towards the myth... all it is, is the charged air bouncing off the closed TB back through your pipework and being cut by the blades going the other way...

yes air can erode stuff - over 100's of years... and steel is a bit more sturdy than rock etc

Do not post misinformation.

Compressor surge is the compressor wheel aerodynamically stalling since the massflow through it drops too low for the flow to stay attached for a given pressure ratio. It has nothing to do with "air bouncing" and being "cut by the blades."

It's not that it "erodes" anything, it's that the wheel doesn't stall uniformly, so it will axially and radially load the CHRA bearings, and in extreme cases can cause the compressor wheel to disintegrate.

Obviously Garrett builds its consumer grade turbos "stout" enough such that they can handle the stress in the wheel, and while the bearings wear faster it is not the end of the world. The wheels would flow more and spool faster if they were thinner and weaker, but they have to survive destruction testing at some multiple of what they think the wheels would ever see in normal use. That said, a recirculated BOV/BPV will keep the turbo spooled up better than with valve and surging the wheel(it slows down very quickly as you can hear from the vid).

Fighter jet engines blow up from time to time just due to pressure variations across the compressor face introducing vibrations across the blades since they are more "bleeding edge" than a consumer grade turbo.

[slider2828]

Aren't GT2871R's around 1200?

[corriganjoshua]

that compressor surge has to be expanding the life of that little t25 ehh

[DirtyS14]

Originally Posted by corriganjoshua

that compressor surge has to be expanding the life of that little t25 ehh

Totally, thats what compressor surge is for.

Originally Posted by slider2828

Aren't GT2871R's around 1200?

Yeah... around a grand.

[McRussellPants]

Originally Posted by sillyvia13

vosko does...lol...

Vosko doesn't have a 1200$ turbo lol.

Originally Posted by Def

Do not post misinformation.

Compressor surge is the compressor wheel aerodynamically stalling since the massflow through it drops too low for the flow to stay attached for a given pressure ratio. It has nothing to do with "air bouncing" and being "cut by the blades."

nah, its the air bouncing off the blades and it causes the turbo to spin in reverse and whatever other bullshit I've seen about it.

I've had a T25 that I ran chatter on for about a year and as far as I know is still kickin, and I've had a GT28 that lasted about a year, I treated that thing like shit though, it probably would have gone longer if I hadn't shut it down hot all the time and what not.

I won't be doing it on the 3071 though. I'm also going to MAP so it doesn't matter as much and the no BOV definitely does put some lag back in the turbo. Its cooler than fouling out plugs once a month though.

POS T25 took longer to get going than most 30R cars I've ridden in/driven

[Def]

I picked up at least a few tenths of a seconds response recirculating my SSQV with no other changes. Makes sense as you're reducing the pressure ratio across the compressor by exhausting compressed air back into the intake pipe towards the compressor.

I honestly wasn't expecting to feel a difference, but it was easily noticeable.

[hellaflush]

def uses lots of big words to sound like he knows what hes on about

this is a turbo - not a fighter jet kthnx

[smelly240]

lol - spins backwards - bwaahaahaaa right.

[Def]

Originally Posted by hellaflush

def uses lots of big words to sound like he knows what hes on about

this is a turbo - not a fighter jet kthnx

Both have compressors...


...and I don't use "big words" - I use the CORRECT words to describe the subject.

[SoSideways]

Def does know what he's talking about.

I am still going to blow up the T25 though. Or try to. Just because it's a T25 damnit.

[Tops*]

My SSQV flutters, but I like the sound of compressor surge more. Yup, I'm doing this. I have some shaft on the T25 too. Bye bye turbo. New turbo's coming soon anyway.

[McRussellPants]

Originally Posted by SoSideways

Def does know what he's talking about.

I am still going to blow up the T25 though. Or try to. Just because it's a T25 damnit.

run 18psi through it that'll kill it faster than no blowoff valve or make a big vacuum leak. you'll be on T25 for a while trying to kill it with surge.

[SoSideways]

Originally Posted by McRussellPants

run 18psi through it that'll kill it faster than no blowoff valve or make a big vacuum leak. you'll be on T25 for a while trying to kill it with surge.

I don't plan on having it on too much longer, so either way, it's probably going to come off within a week.

Got an HKS 2530 turbo ready to go on. That thing will need some pampering... so the BOV will have to stay... oh well.

[burnsauto]

Originally Posted by hellaflush

def uses lots of big words to sound like he knows what hes on about

this is a turbo - not a fighter jet kthnx

thats a stupid thing to say. Do you know how fast a turbo actually spins? ..try super sonic speeds. Thats one of the reasons why you get them balanced, to help it from ripping itself apart (premature bearing/bushing failure). And dont knock on someone for using "big words".. he didn't. Don't belittle someone for being educated.

[spool_sample]

Originally Posted by McRussellPants

run 18psi through it that'll kill it faster than no blowoff valve or make a big vacuum leak. you'll be on T25 for a while trying to kill it with surge.

+100,000.

Compressor surge damage is pretty small compared to boosting the nuts off the turbo (IMO).

[SoSideways]

Well, on a Garrett ball bearing turbo, compressor surge hurts them pretty bad, compared to the Garrett journal bearing turbos.

[slider2828]

Hey on the GT2530, are you going to do what Yashio factory does? Basically grind the wastegate hole to the EXACT size of the wastegate. Removes pressure faster and faster response. Maybe swain and hone the inside? That would be sweet. If I had time to do it and had my 2871 sittin there, damn I would do.it.

[slider2828]

But his is compressor surge, but my SSQV flutters like that... Is that normal or I have it closed too much. I have it also recirc'ed

[DirtyS14]

Originally Posted by slider2828

But his is compressor surge, but my SSQV flutters like that... Is that normal or I have it closed too much. I have it also recirc'ed

If you have a bov and its still surging that means that its too tight. You want to loosen it up to the point where it does leak boost but can relieve pressure completely when the conditions arise.

Originally Posted by SoSideways

Def does know what he's talking about.

I am still going to blow up the T25 though. Or try to. Just because it's a T25 damnit.

[SoSideways]

Originally Posted by slider2828

Hey on the GT2530, are you going to do what Yashio factory does? Basically grind the wastegate hole to the EXACT size of the wastegate. Removes pressure faster and faster response. Maybe swain and hone the inside? That would be sweet. If I had time to do it and had my 2871 sittin there, damn I would do.it.

You'd still need a little WG flapper over hang on that hole so that you don't get any "blow by", which will cause all sorts of problems for controlling boost.

Not to mention that part of the turbine housing, from what I've read so far, is ok on strength, but once you start porting it, it becomes weak and can crack.

If anything, I might port it out a little, but I probably won't, because I just saw some videos of a member of another board with that turbo on his car, and the response is ridiculous already. He specifically made the video to show me the response of the turbo. I'll ask him if it's cool to post it here, but it pretty much hits full boost in 3rd gear around 3500rpm. Full boost being 1.15 Bar.

[sillyvia13]

Originally Posted by McRussellPants

Vosko doesn't have a 1200$ turbo lol.

ok...on his turbo's they surge..no matter cost...
if it was a $1200 turbo, it would surge..I would bet...
I was a track in NH, caanan, and he was running NO BOV, Surging more than I have heard any turbo...Sounded NASTY! from 400ft...
not to mention he killed it that day!! (the track not the turbo)

lol...

[DirtyS14]

Quick question, has anyone ever heard of a garrett t25/28 failing completely from compressor surge? Like not over time such seals, bearings etc, Just instant and complete catastrophic failure? such as an explosion/grenading....

[Matej]

I get compressor surge like that on my T25 even with my RFL for some reason, I like it though, and yes the BOV works, and sometimes it's even followed by a loud backfire, so it's like triple awesome.

[Kouki]

Originally Posted by Matej

I get compressor surge like that on my T25 even with my RFL for some reason, I like it though, and yes the BOV works, and sometimes it's even followed by a loud backfire, so it's like triple awesome.

LOL thats funny!

[DirtyS14]

Originally Posted by Matej

I get compressor surge like that on my T25 even with my RFL for some reason, I like it though, and yes the BOV works, and sometimes it's even followed by a loud backfire, so it's like triple awesome.

Actually Quail's S14 does this exact thing. Flutter/dump/bang!!!

[ame]http://youtube.com/watch?v=OuNTnA5A2Fo[/ame]

Those three sounds in quick succession make me

[Dutchmalmiss]

Been running a stock T25 w/ tight BOV spring WITH a recirculated set-up for 2 years. Same turbo today, no problems today. (knocking on wood)

[Def]

Originally Posted by DirtyS14

Quick question, has anyone ever heard of a garrett t25/28 failing completely from compressor surge? Like not over time such seals, bearings etc, Just instant and complete catastrophic failure? such as an explosion/grenading....

I really doubt it - the wheels/bearings are much too strong to die from something like that. It will cause more wear though, especially at really high boost/wheel RPMs. Like you run 24-26 psi on a GT2871R with no BOV and it probably won't be a happy camper going from 130k+ RPM in a stalled condition over and over.

[DirtyS14]

Originally Posted by Def

I really doubt it - the wheels/bearings are much too strong to die from something like that. It will cause more wear though, especially at really high boost/wheel RPMs. Like you run 24-26 psi on a GT2871R with no BOV and it probably won't be a happy camper going from 130k+ RPM in a stalled condition over and over.

Ok thats what I thought initally. So surge could never ever do as much damage as metal debris etc...