Viimati aktiivne: Mitte kunagi
Pole sisse logitud. [
Logi sisse
-
Registreeri
]
OTSING
|
Tänased postitused
|
Kuulutused
|
Reeglid
|
MOBIILIVAADE
|
KLUBIKAART
Liikmed
|
Abi
|
Statistika
|
Chat
Kiirotsing:
Eesti Audi Klubi foorum
»
S - Audid
»
20vT - tuuning
»
Turbod, boost
» Vasta
Vasta
Kes saavad postitada?
ja
Kasutajanimi
Soovid registreerida?
Parool:
Unustasid parooli?
Pealkiri:
Vormindamine:
Tavaline
Edasijõudnud
Abi
Andale Mono
Arial
Arial Black
Book Antiqua
Century Gothic
Comic Sans MS
Courier New
Georgia
Impact
Tahoma
Times New Roman
Trebuchet MS
Script MT Bold
Stencil
Verdana
Lucida Console
-2
-1
1
2
3
4
5
6
White
Black
Red
Yellow
Pink
Green
Orange
Purple
Blue
Beige
Brown
Teal
Navy
Maroon
LimeGreen
Postitus:
HTML on Väljas
Emotikonid on Sees
BBkood
is Sees
[img] kood on Sees
[quote][i]Algselt postitas: Maku[/i] It's all about airflow whether it is expressed in cubic feet per minute (cfm) or pounds per minute (lb/min). In any case it takes about 150 cfm per 100hp....so for 300 horsepower you need a turbo that
[roppus]
out about 450cfm. The real question is what pressure ratio or boost in psi is this airflow possible with your engine. You need to start thinking airflow and not "boost". [img]http://84.50.81.66/albums/album03/compressormap.gif[/img] Operating characteristics: The compressor operating behaviour is generally defined by maps showing the relationship between pressure ratio and volume or mass flow rate. The useable section of the map relating to centrifugal compressors is limited by the surge and choke lines and the maximum permissible compressor speed. [b]Surge line[/b]: The map width is limited on the left by the surge line. This is basically "stalling" of the air flow at the compressor inlet. With too small a volume flow and too high a pressure ratio, the flow can no longer adhere to the suction side of the blades, with the result that the discharge process is interrupted. The air flow through the compressor is reversed until a stable pressure ratio with positive volume flow rate is reached, the pressure builds up again and the cycle repeats. This flow instability continues at a fixed frequency and the resultant noise is known as "surging". The far left is the surge line, this is the point were the turbo starts to make boost at a given pressure ratio and turbine speed, you do not want a point on the left side of this line doing so will cause your turbo to surge at WOT, and when I mean surge I mean the turbo starts to spool but doesn't have enough turbine speed to build more boost and the car will start bucking madly and your boost gauge will start bouncing, this is murder on a turbo. It is imperative to size the turbo correctly so that this does not happen. In closing you have to figure out how much power you will be making at what boost levels and plot those points on the chosen compressor map to see where they fall in the effciency range of the turbo selected. Choke line: The maximum centrifugal compressor volume flow rate is normally limited by the cross-section at the compressor inlet. When the flow at the wheel inlet reaches sonic velocity, no further flow rate increase is possible. The choke line can be recognised by the steeply descending speed lines at the right on the compressor map. [b]ALLIKAS:[/b] http://www.rbracing-rsr.com/turbotech.html [b]MÕISTEID[/b] [b]Absolute Pressure[/b] – This is pressure when it is measured with respect to total vacuum. This is a true reading of all the pressure being measured. Absolute pressure is defined as ambient pressure plus boost pressure. ECUs measure absolute pressure so that corrections for altitude can be made for thin air. [b]Boost Pressure[/b] – Also known as guage pressure, this is pressure when it is measured with respect to ambient pressure. Boost gauges measure boost pressure. [b]Boost Threshold[/b] – This is the minimum engine speed at which the turbo will generate positive boost pressure. Not to be confused with lag. [b]Compressor[/b] – Also known as the ‘cold side’ of the turbocharger, this half is responsible for pumping air into engine. [b]Detonation[/b] – Also known as ‘knocking’ or ‘pinging’, this is the audible side effect of having excessive ignition timing advance for the prevailing mixture of fuel and air under the prevailing conditions. Excessive air temperature can also cause detonation. [b]Intercooler[/b] – This is essentially a heat exchanger placed between the turbo and the engine to remove heat from the air compressed by the compressor. [b]Lag[/b] – Simply put, lag is the time delay between a change in throttle position and the delivery of a noticeable increase in boost. [b]Turbine[/b] – Also known as the ‘hot side’ of the turbocharger, the turbine is the fan-wheel which is driven by exhaust gasses as they leave the engine. [b]Wastegate[/b] – This is the primary device for limiting boost pressure in the system. Essentially a pneumatic valve, usually controlled by the ECU, the wastegate is closed when exhaust gas is needed to spin the turbine until target boost pressure is reached, and opened to allow the remaining exhaust gas to bypass the turbine and go straight out the tailpipe. [b]EDIT:[/b] Omalt poolt lisan mõned lihtsad rusikareeglid nende kaartide lugemisel. Võtame näitlikustamiseks ette T3 TRIM 60 kaardi. [img]http://84.50.81.66/albums/album03/t3_60.jpg[/img] Tavaliselt öeldakse, et kui efektiivsus hakkab langema alla 70%, siis tuleks mõelda turbo vahetusele. See on üks asi, mida tuleks järgida. Järgmiseks, kui me vaatame kaardi X telge, siis seal on corrected air flow ja ühikuteks LBS/MIN. Rusikareegel on see, et see ühik LBS/MIN tuleb korrutada 10-ga (panna üks null taha), siis saab ka hobujõu. Näiteks konkreetsel turbol on max hobujõud ca 325-330hp. Y teljel on pressure ratio. Oleme vennasega neid kaarte vaadanud ja arvatud igate pidi ning lõpuks jääb ikka üks rusikareegel. X teljel olevast arvust tuleb maha lahutada ca 1,2 ja siis saab kätte ülelaaderrõhu. Antud juhul on 70% efektiivsuse piiril 1,6 bari (2,8-1,2=1,6) ülelaaderrõhku. [/quote]
Keela emotikonid?
Kasutada allkirja?
Lülita BBkood välja?
Saa e-mailiga teatis vastustest?
Teema ülevaade
See on pikk teema,
klõpsa siia, et seda vaadata
.
Eesti Audi Klubi foorum
»
S - Audid
»
20vT - tuuning
»
Turbod, boost
» Vasta
XMB Audi Club Edition
Täiendanud: indro, klem, j6mm & diversion @ 2002-2020
Eesti Audi Klubi ei vastuta foorumis tehtud postituste eest.
[Päringuid:
22
]
[PHP:
56.8%
- SQL:
43.2%
]