The Horse Sneeze=problem?

[Timbuick]

Looking for some tech input on this question out of general interest.
I picked this quote up from Meanchicken elsewhere on the board;
'I am now part of the "Don't horse sneeze your turbo for fun, Stupid!" club, and i've seen other posts refer to this issue.

Can spooling up and backing off harm the turbo if done too often?

 

[dr_frankenstein]

its called surge.

can be very destructive. ive seen compressor nuts back off because of excessive surge.

its not good. dont do it on purpose.

A.j.

 

[1984 t-type]

Dosent a B.O.V. stop that from happening?

 

[notacarlo]

I thought "surge" was during boost?

The "sneeze" is air backed up making its way back through the compressor/air filter when the throttle blade is closed abruptly.

There are two different camps on this, and has been discussed heavily over the past 24 years.

My GN had a 24 year old turbo and saw plenty of that "sneeze" It lasted 157,000 miles. I'm part of the camp that says don't do it on purpose, but it isn't hurting anything. The turbo finally failed due to user error with the wastegate.

 

[dr_frankenstein]

I thought "surge" was during boost?

The "sneeze" is air backed up making its way back through the compressor/air filter when the throttle blade is closed abruptly.

There are two different camps on this, and has been discussed heavily over the past 24 years.

My GN had a 24 year old turbo and saw plenty of that "sneeze" It lasted 157,000 miles. I'm part of the camp that says don't do it on purpose, but it isn't hurting anything. The turbo finally failed due to user error with the wastegate.

lol... ya know that has been a discussion going on for a long time!

either way, im with ya on the dont do it thing.

that push pull action really puts the hurt on the thrust bearing.

A.j.

 

[Timbuick]

The reason I asked was for practical purposes. Often i'm driving on twisty country roads and i'll start building boost then a slow car/blind bend etc will get in the way and i'm in 'sneeze' territory. Just dont want to needlessly damage the turbo.

 

[notacarlo]

You're not.

plenty of stock turbo cars still running around. Turbochargers are fairly stout pieces of technology. Abuse and neglect is what kills them. What you are doing is considered normal operation in my opinion.

and slow down. :biggrin:

 

[Timbuick]

'...and slow down'!!
I actually ended up reducing my boost capacity recently on the premise that i'd always run out of road/the law/my driving licence before I got to use 20ibs:biggrin:

 

[toomanymodz]

I would think that factors including the wheel diameter (heavier spinning mass), shaft diameter, bearing design, and how fast the turbo is spinning, all would impose varying forces to this equation. A 'sneeze' that may be harmful to one turbo may not affect another.

 

[notacarlo]

I have seen this question come up with bigger turbo's and proof that damage had been done....BUT in most cases it revealed neglect and poor maintenance and engine build quality.

 

[salvageV6]

I've never seen a horse die from sneezing, and never had a turbo die from it either. :smile:

 

[TurboBuRick]

I've never seen a horse die from sneezing, and never had a turbo die from it either. :smile:

X2 :biggrin:

 

[turbofabricator]

I killed a TE-63 turbo (built by ADP in Canada) due to Sneeze. Though mine sounded more like a horse FART. Then it SH!T itself. But, the real damage was caused by them installing a std thread nut in leiu of a reverse thread and no lock-tite, either, and insufficient wheel to housing clearance. The first time I lifted the throttle at WOT, it had a "contact issue" spun the nut off and broke the shaft in three pieces. Other than that one incident, I have never seen a turbo failure, made by a reputable firm, have an issue with the horse sneezing.

As a side note.....when you sneeze your heart stops. That is the only time during your life that your heart stops. (until the "end") So, technically, wouldn't that mean the horse dies (momentarily, anyway)

 

[Onalky87]

Could surging(horse sneeze),cause damage to the fins? Like bending them?

 

[Red C5]

I don't have one on my car.

 

[notacarlo]

Could surging(horse sneeze),cause damage to the fins? Like bending them?

No.

 

[garyk1970]

my ta49 went bad a couple weeks ago.....earliest sign was during the sneeze...ill be putting on a bov for insurance.every car is different...but it cannot be good to suddenly stop boost and it has no where to go.

 

[Brady87GN]

Since I haven't heard a horse sneeze anytime recently are you guys referring to the "chirping" sound heard when you spool up then have to back off the gas suddenly?? It's definitely noticeable in my car and I experimented today with spooling up and backing off a lot more slowly, something I'm going to have to get used to...

Thank goodness for you guys, having no experience I had no idea it might be bad for the turbo...

 

[notacarlo]

my ta49 went bad a couple weeks ago.....earliest sign was during the sneeze...ill be putting on a bov for insurance.every car is different...but it cannot be good to suddenly stop boost and it has no where to go.

It does have somewhere to go...right back where it came from. The exhaust pressure is reduced when you back out of the throttle as well. So the resistance on the turbine side is nil. The shaft is just fighting the rotating weight of the turbine and compressor. Yes, it would be better if the force put on the shaft is equalized, but the shaft is not stopping just slowing down. At 30+ psi I think this can become a problem, but not at 16-25ish.

 

[notacarlo]

oh, I forgot.....