9/17/2016
PerformanceMods
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PerformanceMods
Disclaimer:Nearlyeverymodificationonthispagehasthepotentialtoharmyourengineifdoneincorrectly.
IassumeNOresponsibilityforlostwarrantiesordamagecausedbyownerswhoduplicatemyefforts.
MODIFYATYOUROWNRISK!
ImprovedAirflow
Likemosttuners,Ibeganwithmyintake.Despitethe
factthatdynorunsonMYCARprovedonlya1hp
differencebetweenapaperfilterinthestockboxandno
filter/boxatall,Istillexperimentedwithcones,"coldair
intakes,"andother"improvements."Fastforward
severalyearsandIfoundmyselftiredoftheboyracer
soundtrackandseekingaquietersolution,notto
mentiononewhichdidn'trequirecleaning/replacing
every10,000miles.Thestockairboxisknowntoflow
over170hp,evenwiththeaccordianpipe.Andthere's
nodoubtthestockfilterhasmoresurfaceareathanjust
aboutanyotherfilteravailable.SoIreturnedtothe
stockairboxandfilterafteryearsofmessingaroundwith
alternatives.Ithelpsmaintainarelativelystock
appearanceand,let'sfaceit,does'thurtathingtobe
there.Saveyourselfsometimeandmoneybyleaving
thispartoftheenginealone.There'salmostnothingto
begainedbyreplacingituntilafterprofoundupgrades
havebeenmadeelsewhere.
IalsoinstalledanintakemanifoldfromaEuropeanPD130PassatTDI.ThismanifoldisidenticaltothePD150's,but
withdriver'ssideinlet.Somesaythisintakeisn'tthebestimprovementfortheintakemanifold.Buteveryoneagreesit's
farbetterthanstockandisknowntoflowover200hp.
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NewEngineProgramming
Changingtheengineprogrammingprovidesthemost
dramaticincreaseinperformanceofanysingle
modification.Itshouldbeanyone'sfirstmove.Youcan
countonareliable2030%increaseinpowerand
torquefrommostprogramswithouttheriskofdamaging
yourengine.Moreaggressivetuningisavailablefor
appropriatehardwareupgrades(keepreadingfor
examples).Naturally,thedrivingexperienceisgreatly
enhanced.I'veusedUpsolute,Rocketchip,Alligator,and
MaloneTuningprograms(inthatorder).Ibelieve
RocketchipandMaloneprovidethebestflexibilityin
tuningforcarsmodifiedbeyondasimplechipupgrade.
MaloneTuningismoreaccessible.I'vereadgoodthings
aboutTDTuning.com,too.Plentyoffolkslike"tuning
boxes,"too.TheyhavetheirmeritwiththeolderTDIs.
ButI'mbiasedtowardchangingtheprogramitselfsince
apropertuneoperatesthecarintruthinsteadofvia
sensordeception.Thechoiceoftunerisyoursand
shoulddependuponyourlocationandtimeframe.MycurrentprogramisamildlyaggressiveMALONETUNING
program.MyECUalsohasa3barMAPsensorforgreaterboostcontrolathigherpressures.
MoreFuel
Mynextpowerupgradewastoreplacethefuelinjectornozzleswithlargerunitsformorefuelflow.IusePowerPlus
performancedieselinjectionnozzlesbyFratelliBosioofItaly.Theyprovideabetterspraypatternandflowmorefuel
thanthestocknozzles.Theresultisa1020%increaseinpowerandtorque,dependingonyourchoiceofnozzle.My
currentsetofPowerPlusnozzlesarePP502s.TheALHguyswithlargeVNTturboslovethem.Butthesmokeisabit
obnoxiousinwastegated1Z/AHUapplicationsonstockturbos.IthinkPP520sareabetterchoice,maybePP357s,
eventhoughthey'llmakelesspower.I'lltrysomePP764swhenImovetoalargerturbo.BTW,alwayshavetheinjector
poppressuresbalancedwhenreplacingthenozzles.
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PerformanceMods
AdditionalFuelingUpgrades
IinstalledaPD100TDIintank"liftpump"tosupplymyinjectionpump(IP)withfuelpressurizedtosixpsi.This,
combinedwithamodificationtotheinjectionpump'scasepressurereliefvalveknownasthe"KeystoneMod"(pictured),
makesthecaratadmoreresponsiveandkeepsmytimingspotonallthewaybeyondredlineforimprovedtopend
power.CAUTION:ThispumpispoweredviarelaytriggeredbyN109sopumpingisstoppedintheeventofanairbag
deployment.DONOTwireittotheignition!FYI,Idonotrecommendtheuseofmosteconomicalexternalfuelpumps,a
popularalternativetothemoreexpensiveOEMliftpump.Someworkwell,butyouneedtobecarefulwithyour
selection.READHEREforanexplanation.AnotherbenefitoftheOEMliftpumpisthereservoirsurroundingthepump.
Itwaslikelyintendedtokeepthepumpsubmersedinfuelforcooling.ButI'velearnedthroughexperiencethatitalso
ensurestheenginecannotbestarvedoffuelduringaggressivemanuevering(competitivedriving)whenfuelissloshing
aroundinanearlyemptytank.Theadditionofafuelcoolerisanoptionalfuelingupgrade.Coolerfuelmakesmore
powerandhelpscoolthefuelpump(s).Sincetheinjectionpumpcreatesalotofheatwhenpushingmorethanstock
levelsoffuel,it'snotabadideatocoolthefuelbeforereturningittothetank.Thenewer,morepowerfulTDI'shave
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PerformanceMods
themsotheymustserveapurpose.Iuseafourpass
transmissioncoolertocoolmyfuel.
TurboUpgrades
Turboswapsareaseriousinvestmentintime,money,patience,andmanagingexpectations.I'veexperimentedwitha
T3(laggy),twodifferentK03/K04hybridsandaGT15/20hybrid(similartoK03/K04).Generallyspeaking,larger
turbosflowmoreairanddelivermoretopendpowerwhilesmallerturbosspoolfasteranddelivermorelowendtorque
(betterdrivability).Sofar,theK03/K04hybridismyfavoriteturbo.Itflowsslightlymoreairthanthestockunitand
providesamodestgainof~9whpand12lb/ftinthemiddleoftheband.I'mcurrentlyusingaoneofakindK03/K04
hybridwhichfeaturesaK04compressorinamodifiedK03housingaswellasaK04turbinestuffedintoamodifiedK03
exhausthousing("regular"K03/K04hybridusesaK03turbine).Itgivesupatinybitoftorqueinexchangeforsome
topendpower.Unfortunately,thetopendyieldisn'tenoughtomakethisturboaworthwhilereplacementforthe
K03/K04readilyavailableatBORAPARTS.ButIbelieveanunexpectedsideeffectofthelargerexhaustopeningis
improvedfueleconomywhendrivingsanely.TheK03/K04hybridisadirectreplacementforthestockturbo.
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PerformanceMods
I'mconsideringaGT2052wastegatedturbo.AbenefittostickingwithawastegatedturboisthatIcancontinuetouse
mycurrentprogrammingandboostcontrol.I'dneedtodosomepartsfabricationtomateittomyexhaustmanifoldas
wellastoconnectacustomdownpipe.That'sabitofholdup.ButI'vereadafewreportstosuggestit'sworththe
hassle.Anotheroptionisconversiontoavariablevaneturbo(VNT)similartothosefoundonnewerTDIs.TheVNT's
strengthisthatitspoolsquicklylikeasmallerturboyetflowswelllikealargerone.Adrawbackistheadditionalmoving
partswhichcanjamupwithsootifnotexercisedwithroutinefloggings.)ThereisabitmorelaborinvolvedwithaVNT
conversion.ReasonsIhavenotdoneitmyselfincludetheelectrical/mechanicalchangeswhichneedtobedoneand
thecarwillfailtheOBDIIcompliancetestatinspectiontime.Sure,I'mcurrentlyexemptfromemissionstesting,along
withmanyotherstates.Butit'sonlyamatteroftimebeforefulltestingisperformedonallcars1996andnewer,
includingdiesels.Iplantokeepmycarcompliantuntilaworkaroundisfound.IfIdomakeajumptoaVNT,it'lllikelybe
aVNT17/22HYBRIDoraGTB1756VK.However,Ireallylikethesimplicityofkeepingawastegatedsystem.
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PerformanceMods
"Mufflerecomy"
Themaingoalwithexhaustsystemupgradesistoreduceexhaustbackpressureandimproveexhaustflow.This
allowstheenginetoflowmoreairandimproveturboresponse.Manyownersgowithsomesortofcommercial2.5"cat
backexhaustsystem.Thisusuallycostsover$800!Instead,onecangetthesamebenefitbyreplacingthemufflerand
resonatorwithastraightpipe.Theturboandmy2.5inchdieselcatalyticconverterbyMagnaflow(#93006D)doa
prettygoodjobofmufflingenginenoise.TheimprovedaccelationandresponsewasmorethanIexpected.Eliminating
theoldcatlikelyremovedarestrictionandgavemesomeunexpectedlowendpowerandtorqueaswellasimproved
EGTs.Thenewcatkeepsmelegal!Ieventuallytookitjustastepfurtherandinstalledacustom2.5"stainlesssteel
downpipebyIDPARTS.Dynotestingofthelargerdownpipeandnewcatshowedamildpowerincreaseof~9whpand
10lb/ftbutthehorsepowerextendshigherintherpmband.Ihadalsoexperimentedwitharesonatorandeventually
optedtoputitinplaceofamufflertopassa"visualinspection."Oh,sinceIknowyou'rewondering,thenewexhaust
noteisprettyappealing.AnacquaintancewhofrequentsEuropesaysmycarsoundsliketheV6TDI.Here'sasmall
audiofile(rememberthatIhavealarge,openexhaust).:)
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"ChemicalIntercooling"(WaterInjection)
SomeMk3owners,gasanddieselalike,improvetheirintercoolingviafrontmountedintercooler(FMIC).However,
there'snotalotofspaceforinstallingoneonaMk3withoutcuttingtwothirdsofthebumperrebar.Cuttingtherebar
reducesframerigidityatthefrontend.Thisisundesirableandillegalontheautocrosscoursewhereframestiffnessis
paramount.Therefore,Iwentwith"chemicalintercooling"viawaterinjectionbySNOWPERFORMANCE.Iinjectabout
20%methanol(wateronlyinSCCAevents)andhavenotmeasuredanysignificantgains.Instead,I'mlikely
maintaininginitialpowerbyslowingtheriseofintakeairtemperature.Waterinjection'ssecondarybenefitisreduced
EGTs.IcanstillpegtheEGTgauge,butittakesalotlongertodoso.Imayalsomisttheintercoolersincetheplumbing
isalreadyinplace.:)AnotheralternativetoaFMICisanairtowaterintercooler(AWIC).Ihadresearchedsome
systemsbyFROZENBOOST.However,thereisnowaLARGERFMICavailablefortheMk3.Itsexactbenefitsare
unproven.ButI'msureitwilldelayheatsoaktothepointwhereitwouldbealmostimpossibleatjailfreespeeds.
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I'vemeasuredmostofmyprogressalongtheway.IchosetouseashopwithaDYNAPACKchassisdynomometer.
MeasurementsaretakendirectlyfromthehubandareVERYconsistentandrepeatable.Mybestdynopulltodateis
136whpand263lb/ft.UsingapopularMk3transmissionlossof17%,thatcalculatesto~163hpand316lb/ftatthe
crank...or~80%overadvertizedstockvalues.CheckoutmyMYDYNOVIDEO(6MB).Oh,fortherecord,IdoNOT
recommendtheuseoflightweightflywheelsinTDIs.TDIsnormallydonotrevhighenoughtomakethempractical
plus,TDIsrunmoresmoothlywiththestockflywheel.Myexperiencewithalightweightflywheelwasratherpainful.Feel
freetoreadMYREQUESTFORHELPatTDIClub.Inshort,mylightweightflywheeltookmeonanadventurewhich
sawthereplacementofprogramming,injectors,theinjectionpump,andeventheECUbeforetracingmyissuestothe
flywheel.ThegoodnewsisInowhavealotofsparepartsformyagingTDI.)
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PerformanceMods
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