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littlejap33
05-30-2007, 09:51 AM
jw what turbo surge is and what does it do to ur car

ryan0
05-30-2007, 10:04 AM
# Surge is the left hand boundary of the compressor map. Operation to the left of this line represents a region of flow instability. This region is characterized by mild flutter to wildly fluctuating boost and “barking” from the compressor. Continued operation within this region can lead to premature turbo failure due to heavy thrust loading.

# Surge is most commonly experienced when one of two situations exist. The first and most damaging is surge under load. It can be an indication that your compressor is too large. Surge is also commonly experienced when the throttle is quickly closed after boosting. This occurs because mass flow is drastically reduced as the throttle is closed, but the turbo is still spinning and generating boost. This immediately drives the operating point to the far left of the compressor map, right into surge.

Surge will decay once the turbo speed finally slows enough to reduce the boost and move the operating point back into the stable region. This situation is commonly addressed by using a Blow-Off Valves (BOV) or bypass valve. A BOV functions to vent intake pressure to atmosphere so that the mass flow ramps down smoothly, keeping the compressor out of surge. In the case of a recirculating bypass valve, the airflow is recirculated back to the compressor inlet.



http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_systems_tech_center.html

Coolguy949
05-30-2007, 10:50 AM
In laymen's terms: When the turbo is flowing more air than the engine can suck in. It causes charged air to want to flow backwards out of the compressor. It can destroy a turbo because the turbine is under load the turbo and the compressor wheel is wanting to spin slower than the turbine. On larger turbos this can happen at lower RPMs in higher gears. Also, a BOV set too stiff may induce surge.

LiquidLife
05-30-2007, 01:11 PM
Barny terms:* BOV releases pressure when you bring your foot off of the gas, without a BOV,
The turbo has all this pressure built up but it has no where to go but backwards; causing damage.

It's like throwing a stick into a a fan, except imagine the stick being built up pressure having no where to go but back into the fan, and the fan being the turbo.

flashfoto
06-10-2007, 08:34 PM
Total F'ing moron terms: A surge (in this case we are talking about air surge) is when an overload of air gets pushed into the car via the turbo. It has to go somewhere but the car is already dealing with all it can handle. Kinda like a kid with a beer bong and you pouring a keg into it while he's drinking. Not good. Warning: blowback may occur! teehee

See also:

surge* * *noun, verb, surged, surg·ing. –noun
1. a strong, wavelike, forward movement, rush, or sweep: the onward surge of an angry mob.*
2. a strong, swelling, wavelike volume or body of something: a billowing surge of smoke.*
3. the rolling swell of the sea.*
4. the swelling and rolling sea: The surge crashed against the rocky coast.*
5. a swelling wave; billow.*
6. Meteorology. a. a widespread change in atmospheric pressure that is in addition to cyclonic and normal diurnal changes.*
b. storm surge.*

7. Electricity. a. a sudden rush or burst of current or voltage.*
b. a violent oscillatory disturbance.*

8. Nautical. a slackening or slipping back, as of a rope or cable.*
9. Machinery. a. an uneven flow and strong momentum given to a fluid, as water in a tank, resulting in a rapid, temporary rise in pressure.*
b. pulsating unevenness of motion in an engine or gas turbine.*

–verb (used without object) 10. (of a ship) to rise and fall, toss about, or move along on the waves: to surge at anchor.*
11. to rise, roll, move, or swell forward in or like waves: The sea surged against the shore. The crowd surged back and forth.*
12. to rise as if by a heaving or swelling force: Blood surged to his face.*
13. Electricity. a. to increase suddenly, as current or voltage.*
b. to oscillate violently.*

14. Nautical. a. to slack off or loosen a rope or cable around a capstan or windlass.*
b. to slip back, as a rope.*

15. Machinery. to move with pulsating unevenness, as something driven by an engine or gas turbine.*

LiquidLife
06-11-2007, 11:50 AM
^I like my barney terms more... LOL

flashfoto
06-11-2007, 08:50 PM
^^^ I know, I thought that was funny. I just figured I would keep the trend going. LOL

LiquidLife
06-11-2007, 08:58 PM
Nice

JOOTZ
06-11-2007, 11:39 PM
Turbo "stall" occurs when the drive pressure (exhaust) pretty much goes away (usually due to letting off the throttle), so the pressure on the compressor side is more than the pressure on the turrbine (exhaust) side. The pressure in the intake then backflows through the compressor, and out through the air-cleaner. This is the loud sneeze sound you hear when you shift.

Surge is the chirping sound caused for various reasons (everyone has their own opinion as to what)but the basic idea is that the turbo is alternating between boost and stall conditions really quickly, as the drive pressure packs the intake until the intake pressure overcomes drive pressure, and backflows through the compressor, until the intake pressure is low enough that the drive pressure takes over again and starts cramming air into the intake, until the intake pressure overcomes the drive pressure again, and the scene repeats over and over again (deep breath...).
TURBO STALL is the formation of local flow deficits that rotate around the compressor. Flow deficits or cells are a region in which local mass flow is near zero. These cells rotate at an angular speed which is a fraction of the rotor speed.

English version: Each compressor blade pushes an equal amount of air through the turbo. If, for some reason, one or more blades push less air, then a low flow area is created. This low flow, or flow deficit, does not pass through the compressor, but spins with it at a slower speed than the compressor is spinning. The blades, spinning faster, pass through this low flow cell and drop their air load and upon exiting the cell pick up the load. This loading and unloading of the compressor blades, fatigues the blades and results in possible failure. It can also push the compressor in to a surge condition.

TURBO SURGE is the axis symmetrical oscillation of flow through the compressor that can include reverse flow.

English version: The normal flow of air through the turbo compressor wheel is slowed and/or reversed, then accelerated back to normal. These repeating oscillation cycles cause uneven thrust loads on the bearings and if the oscillations hit a harmonic frequency of the compressor blades, they can cause blade damage.

The quick and easy version for the rest of us: Turbo stall is the loss of normal air flow through the turbo compressor wheel in certain areas of the compressor wheel, and if the area gets large enough, can lead to turbo surge. Turbo surge is repeated momentary loss and then recovery of all normal air flow through whole compressor wheel.

LiquidLife
06-12-2007, 08:42 AM
:roll: