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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 6CMI8WGIn/s8pcl+NkIjSw==

<SEC-DOCUMENT>0000908255-04-000048.txt : 20040728
<SEC-HEADER>0000908255-04-000048.hdr.sgml : 20040728
<ACCEPTANCE-DATETIME>20040728174538
ACCESSION NUMBER:		0000908255-04-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040728
FILED AS OF DATE:		20040728

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BORGWARNER INC
		CENTRAL INDEX KEY:			0000908255
		STANDARD INDUSTRIAL CLASSIFICATION:	MOTOR VEHICLE PARTS & ACCESSORIES [3714]
		IRS NUMBER:				133404508
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		200 S MICHIGAN AVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60604
		BUSINESS PHONE:		3123228500

	MAIL ADDRESS:	
		STREET 1:		200 SOUTH MICHIGAN AVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60604

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BORG WARNER AUTOMOTIVE INC
		DATE OF NAME CHANGE:	19930628

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MICHAS ALEXIS P
		CENTRAL INDEX KEY:			0001044005
		STANDARD INDUSTRIAL CLASSIFICATION:	MOTOR VEHICLE PARTS & ACCESSORIES [3714]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12162
		FILM NUMBER:		04936930

	BUSINESS ADDRESS:	
		STREET 1:		200 S MICHIGAN AVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60604
		BUSINESS PHONE:		3123228500

	MAIL ADDRESS:	
		STREET 1:		200 SOUTH MICHIGAN AVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60604
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-07-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000908255</issuerCik>
        <issuerName>BORGWARNER INC</issuerName>
        <issuerTradingSymbol>bwa</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001044005</rptOwnerCik>
            <rptOwnerName>MICHAS ALEXIS P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 SOUTH MICHIGAN AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60604</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-07-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>74560</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>laurene h. horiszny as attorney-in-fact for alexis p. michas</signatureName>
        <signatureDate>2004-07-28</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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