How dangerous really is compressor surge to your turbo

[Flamereka]

I know what turbo surge is, but I am wondering how bad it really is.

I know it pushes air back towards the turbo, but how fast can damage occur?

And on alot of domestic cars with turbos i don't see them running BOV's and alot of stockers don't either.

????????

P.S. Felt I needed to add some ? marks to make this sound like more of a question

[silviaNE]

It depends on how much boost you are running. If you are running small amounts of boost, the damage will ocuur slowly. Also if you rev your engine to 7 grand and just let it coast. do not do this, at least spend a few dollars on a bosch unit. this will prolong your turbo greatly. it isny worth the risk for the damage it will and it will, cause your engine.

[WDRacing]

Ok, lets say you have your compressor wheel moving at 25,000rpm, then you force it to rapidly slow down....eventually it will unass itself from the turbine shaft, or cause premature shaft bearing play.

I also read in the other thread that you said drag cars don't run BOV's, this is incorrect. You also said with a BOV you slow down turbo spool, this is infact the complete opposite...by blowing off the charge air you are preventing your compressor from slowing down with all the backpressure from the closed throttle plate.

WD

[FrEaK]

Almosst every stock car i've seen runs a bypass valve or a BOV, but they aren't always vented into the atmophere making them to hard to hear... but they are certainly there...

[JESTER]

Wont the fines on the compressor bend or warp?

[C-Kwik]

The surge that occurs when you close a throttle is the same that occurs when you run too much boost at too low a flowrate for the turbo. You'll end up with a similar failure. Likely, the thrust bearing will eat it, and usually the seals and shaft bearing quickly follow. Then the compressor wheel will likely start touching the compressor housing as it spins. Or simply put, it will kill the turbo.

[FrEaK]

thrust bearing eating it = not good

[oi138]

Almosst every stock car i've seen runs a bypass valve or a BOV, but they aren't always vented into the atmophere making them to hard to hear... but they are certainly there...

turbo s12's do not have one. And I'm pretty sure old 280z's don't and maybe even z31's.

[FrEaK]

really? so then the compressor keeps spinning? that doesn't sound like a mistake an engineer would make... maybe i'm wrong...

[oi138]

Yeah pretty dumb but ya know. I know for a fact that turbo s12's don't have one. Cause I just helped build up one. and we had to add a bov. The 280z and z31 was just a guess but i remember reading that. I know that none of them come with an intercooler.

[FrEaK]

well... now i know... thanks...

[Turbo_Nismo_EC]

Please enlighten me on this. Due to the fact that the gentleman that I am about to talk about is EXTREMELY hard-headed, maybe this thread can help me convince him that what he is doing is HORRIBLE to his turbo. It's easily said....just like this...

98 Hyundai Accent.......28 psi.....no BOV.....sounds like a horse when he les off the gas.(sounds like pfpfpfpfpfpfpfpfpfpfpfpfpfpfpfpf...if you can figure it out).

Can anyone tell me what this noise is? I think it is air coming out of the intake it is compressed so hard, but that is just me.

[FrEaK]

Uhh im sorry your firend is a liar... he is sure as hell is not boosting at 28psi..

[Turbo_Nismo_EC]

YES, yes he is. How it is still holding is news to me, but I've riden in the car and it reads anywhere from 26-28 psi at full boost in 5th gear.

I'm not going to get into an argument on whether or not he is boosting that much, I just want to know if he is going to kill his turbo soon, and what is going to happen to it when it does die. Cause yes, oh yes, it's going to die....you haven't heard the compressor surge on this thing. Ironically, I wiggled the shaft on the compressor side of the turbo when we replaced the rubber connector, and it has no shaft play.

[FrEaK]

Well icant say i believe you but chances are he'll bend or snap a vane... if he snaps one it could cause huge problems internally... no to mention the amount of oil it would spray....

28psi on an accent... hmm