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WOUGHER MIREGT Geftain turbocharged oil-burners arle pailicularly suitable for peilormanee tunirrg.., PeJer Bosenthal repotts.
o a greateror lesser extent,most peopleare familiarwith the various ways in which it's possibleto increasethe powerof a petrol-engined car. lndeed,there are a myriadof aftermarkettuning firmsto choosefrom, all dedicated to the questof extractingthe maximumperformanceout of the
petrolengine.Whichis allvery well, exceptfor the side-effects that extra horsepowerusually causes;namelyfar greaterfuel consumption.However,new developments in the tuningof dieselenginesmay changeall this and challengethe dominance of the petrolengine... One methodof tuninois to 're-
chip'the enginemanagement system;a tuningtechnique successfullyemployedin petrolenginedcarsfor a numberof years.There are now chips availablefor many diesel-engined vehicleswith electronicenginemanagementsystems,and in theoryyou shouldbe able to get significantincreasesin torqueand
UW Motoring May | 996 59
power,whilststill retainingthe all importantdieseleconomy.In the contextof turbochargedengines the improvementin performance i can be particularlydramatic. I was fascinatedwhen Peter Noad first broachedthe subjectof dieseltuning,in Pacenotesin the November'95issue,and I decided that I had to experiencea re-
HishFERFSRHIAH$H O lleftl: UW enthusiast Ghris Smith handled the Superchips conuersion. O (Belowl: The EPROM chipe installed by Superchips control the turbo's boost pressure lll, and the fuel injection system l2f.
chippeddieselfor myself! With four-starpetroltypically costingaroundt2.50 a gallon, and with increasingpressurefrom the governmentto conservefossil fuels,economicalhighperformanceturbo-dieselscould well representthe futureof sports cars.In the contextof a Golf TDl, for example,there alreadyexists a chipgivingVR6 levelsof torque, with only marginallyworse economy.Too good to be true? I took my Audi 80 TDl, whichhas the sameengineas the Golf TDI, down to Superchips,a specialist in performance chipping,to find out more. Superchips were originally foundedin 1976by PeterWales as'DetectionTechniques', a firmwho specialised in tuning MitsubishiStarionrace cars. Petersoon saw the possibilities of developinghis tuningtechniques to suit road cars,with the first chip producedbeingfor the Ford RS turboengine. Threeyears ago lan Sandford took over as ManagingDirector, changingthe company'snameto Superchips Limited.Theiroriginal cataloguecovered30 modelsof car; it now covers50 pages! Re-chipping is big business,and Superchipsare one of the market leaders,with over 7,800chipssold in '95.Theywere alsoone of the first companiesto introducechips suitablefor dieselengines. ChrisSmith,the Technical Managerat Superchips,is the man responsible for developing the chip for the TDl, and he'salso a keen VW Audi enthusiast. In the past he'soWneda Series2 Audi 80 Sport,and is currentlyrestoringa '71 Type 2 bay window- readyfor
t h e ' 9 6 R u nt o t h e S u n n o doubt!Chrishandledthe actual installation and set-upof the c h i pi n m y 8 0 T D l . The re-chippingprocess basicallyconsistsof removingthe factorymicrochips,which control the engine'soperatingparameters, from the enginemanagement's (ECU)printedcircuitboards(PCB) and pluggingin a re-programmed chip whichenablesthe engine's operatingcharacteristics to be varied,and hopefullyimproved! In the caseof the TDI engine, the first step is the removalof the completeenginemanagement system,whichis hiddenbehinda plastictrim panelin the passenger footwell.The ECU 'blackbox'can then be detachedas a complete unit,openedup and foldedout, revealingtwo PCBs containinga bewilderingarrayol minute electricalcomponents. The tube runningparallelto the circuitboardoriginatesfrom the turbocharger and enablesthe ECU to continually monitorand adjust the boostpressureas required.lf you look closelyat the photograph you can see that this grey boosttube is attachedto a blackplastic device,the pressuretransducer, which convertsthe analogueboost variationsintodigitalcode,which can be interpretedby the ECU's microprocessor. There are two microprocessors controlling the TDI engine's characteristics (see the arrows in the picture);one for the fuelinjectionsystem,and one for the turbo boost levels.The actual chips used are 26-pin Eraseable Programmable ReadOnly Memory (EPROM)items,whichcan be erased,priorto re-programming,
O TDI engine may look pretty boring, but is much more fun now that it develops an extra 2O bhp! by removingtheirlabeland subjecting themto ultra-violet light. However,in this case the factory chips are not re-programmed; insteadSuperchipsreplaceboth chipswith theirown modified EPROMunits. The othermicrochips and circuitryvisibleon the PCBs controlfail-safesystems;a diesel's ECU requiresadditionalsafety measurescomparedto a petrol engine'sECU.This is becausethe flow of dieselmust be extremely accurateas it directlydetermines the enginespeed;if a petrol enginedevelopsa faultthe ECU can shut off powerto the spark plugs- obviouslythis isn'tan optionfor a diesel! NormallySuperchips, or one of theirdealers,wouldsimply substitutemodifiedEPROM chipsin placeof the original factoryitems,checktheir function, and sendthe customeron their way. However,whilst I was at their factorythey went throughthe development sequencefor the B0 TDI chip,whichwas quite fascinating. Firstlythey connecta computer to the car's ECU,run the car on theirSun RAM12rollingroadand
UW Motoring May 1996 60
'read'all
the data off the factory chip.This information is fed into theirmaincomputer'emulator' programme,which storesall the data, illustratingit in the form of a blockof numericalcode. The car's boostand injection chips are then removedaltogether, and the car is run directlyoff the Superchips emulatorcomputer. Chriswillthen startto alterthe mappeddata fed to the ECU, via the PC screen,and study the effectson the car's performance.All these adjustments a r e m a d ei n ' r e a l - t i m e ' i . ew.h i l s t the car is actuallyrunning. The car's performanceis monitoredby plottingpower and torquecurves,which are obtained by revvingthe car up to its maximumspeedin the firstfour gears(fifthisn'tused as the higher speed overheatsthe rolling-road's bearingsl). Chriswill then increase the fuel supplyat highrevs,add a littlemore boostpressure,and observethe effectthis has on the powerand torquecurves. This processis repeateduntil the optimumsettingsare found; just the whicharen'tnecessarily most powerful.lt's quitefrightening to watch your belovedcar
HWFHmFSRHfifttreH SUPERGHIPSPOWERCURUES(Ar THE WHEETSI
roo 9(, 80 70 60 50 40 30 20 to o fo
t5
20
25
30
35
MAX POWER98bhp @ 4200 rpm
repeatedlyshriekingits way up to 100 mph, only a few feet away fromyou! Whenthe fuel supply and boostpressurewere increased the wail of the enginetook on a much hardernote and beganto soundquite meaty!An aggressivesoundingdieselengineseemed like a contradictionin terms,and was definitelya new experience to me! The originalpowerof the car was measuredas 78 bhp at the wheels,which equatesto about 92 bhp at the flywheel;pretty healthyas Audi quote 90 bhp at the flywheel!The torquewas initiallymeasuredas 134 lbf ft at the flywheel,at around2,100rpm. It is importantto point out that performancefigurescan vary, dependingon whichrollingroad is used,and shouldnot be used to quoteexactoutputs;they are best used comparatively, Initialtests managedto increase the torqueat the flywheelto 169 lbf ft, but this was subsequently reducedas it meantthat the engineproducedtoo much sooty exhaustsmoke,and would undoubtedlyhave failedthe MoT emissionstest.lt was reassuring to see that Superchipstook this responsibleattitude,and weren't just interestedin extractingthe maximumperformanceirrespective
of cost. After many more rolling road runs and even more adjustments,a torquefigureof 164 lbf ft at the flywheelwas achieved,givinga poweroutput of 110bhp at the flywheel,which equatesto 98 bhp at the wheels ('atthe wheels'figuresare usually around10 to 12 per cent lower than flywheelfiguresdue to transmission lossesthroughthe drivetrain).The exhaustsmoke was no more sootythan usual with this set-up. At this point,you're probably gettinga bit sick of technicalfacts, figuresand all the other electrical jargon- so was l! | was just itching to get my handson the car and give it some stick! However,Chris was the first to check it out on the road,and he returnedto ask if it usuallyhad so much torque-steer... When I drove away from prernisesI didn't Superchips' immediatelynoticeany difference, the car stillpulledin the sameway from low revs,and seemedas flexibleas usual.Then I put my foot down! A gratifyingscrabbling noisefrom the fronttyres accompaniedfirst gear,and then second,shortlyfollowedby a broadgrin!The acceleration.in first,and particularlyin second, was noticeablyfiercer,with the extratorquemakingfor smoolher
progress;less pedaltravelnow being requiredto get the car up to speed. Back at SuperchipsI askedthe obviousquestion;why don'tAudi engineerthe ECU likethis at the factory?Chrispointedout that rechippingdoes increasethe strain on the engineslightly,althoughthis is the case with any form of tuning. He also commented, though,that the dieselengineis a toughunit, and that severalof their test cars are still goingstrongwith over 100,000mileson them.He went on to point out that manufacturers are constrainedby massproduction,and tend to play safe with regardto forthcoming emissionstandards; this overcautiousapproachoften resultsin manufacturers producing cars that are itoo clean'. All this soundsa bit too good to be true;can a simpleplug-inchip, which only costs aroundf350,
UW Motorinj May | 996 6l
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providea considerable performanceimprovementwithout dramaticallyincreasingthe fuel consumption? Therewas only one way to find out... I testedthe 'Superchipped' car for almost4,000miles, and carefullymonitoredthe fuel consumption; this longtest distancekept the inaccuraciesto a minimum,and enableda realistic averagempg figureto be obtained. In standardform the TDI returnedan averageof 47.7 mpg over a 3,794 mile test distance, whilstin Superchipped form 41.2 mpg was achievedover a 3,807 miledistance. Over this extendedtest distance I have been highlydelightedwith the results;the car now pulls like a train al motorwaycruising speeds,whilstthe vaSt improvementin the 50 to 70 mph time speaksfor itself(see the performancetable).The only negativepointaboutthe chip is that it has introduceda slight jerkinessat around1,500rpm; Superchipsreckonthat a minor adjustmentwill eradicatethis. My next port of call was to an independent dieseltuningspecialist, to verifythe performancefigures obtainedfrom Superchips,and also to discoverif there were any adverseside effectsto this extra power. WarwickBanks Handling,based at Witham-on-the-Hill, are LandRoverspecialistsand expertsin the fieldof dieseltuning.They kindlyofferedto help us verifythe performancefigureson their rolling road. WBH'stechnicalexpert,Trevor Davey,commentedthat he would normallyrecommendcustomers to concentrateon intercooler improvementsas the initialstep in seekingextraperformancefrom a dieselengine.He reckonedthat just fittingan intercoolerto a previouslynon-intercooled engine wouldtypicallyprovidearounda 1 0 b h p p o w e rg a i n ;q u o t i n ga 1 2 bhp gain achievedon a Sierra dieselas an example.As such, he was a littlescepticalof the chip, viewingit as a somewhatcrude methodof hikingthe poweroutput. To ensureas high an accuracy
HeH
O lAbovef: Long-suffering fDl endured the Superchips rolling road... O (Rightlr ...and the rolling road at Warwick Banks Handling... O lBelowf: ...recording a maximum power of 98bhp at the wheels.
as possibleon the rollingroad, I had changedthe car's oil the week before,whilstthe tyre pressures were adjustedon the day of testing.The Claytonrollingroad used had only just been calibrated on the day before,which further ensuredaccuracy. The car was strappeddown securelyand a gaugewas attachedto measureboost pressureat the manifoldside of the turbocharger. A largecooling fan helpedto keep the engine temperaturereasonable,although it still rose to about 20 degrees higherthan usuallThe car was run up to maximumspeed in fourth gear and then subjectedto additionalrollingresistanceby poweringdown the rollerspeed. Quiteastonishingly the maximumpower outputat the wheelswas 98 bhp; exactlythe same figureas Superchipshad quoted!The power runs were repeatedseveraltimes,with the same result. The boostpressuregauge indicatedthat the turbochargerwas now runningat a maximumboost p r e s s u r eo f 1 . 1 b a r ( 1 6 p s i ) , whereasin standardform its maximumoperatingpressure
had been0.65 bar (9.4psi).This seemedto be quite a large increasein pressure,but Trevor allayedany concernI had; 'that'sa relativelylow boost pressure,some of the Discoveryswe tune operate at a boostof around 1.5 bar (22 psi);it'scertainlynot highenough to affectthe reliability'. All in all, Trevorconcludedthat the chip was providingworthwhile performancegains,without appearingto have any detrimental effectto the engine.However,he wasn't so impressedwith my averagefuel consumption of 41.2 mpg, and suggestedthat it should be higher. However,as the TDI engine often needsfull throttlewhen accelerating,perhapsthis higher fuel consumptionis a by-product of havingan additional20 bhp under my rightfoot. lt certainly costs a littlemore to run now, althoughI definitely thinkit'sworth it for the extra power.lf you look at the performancefiguresfor the B0 2.0E,it'sclearthat my TDI is quickerand morefrugal;a 2.O-litre petrolenginewill only average around29.5 mpg. One area of the all-important runningcosts I haven'ttouchedon
UW Motoring May 1996 62
is insurance. Of course,many peoplewith re-chippedcars take a chanceand'forget'tomentionthe modification, thus jeopardisingany claim they may make. Not wanting to take any risks,I contactedmy insurancecompany(Endsleigh, Tel:01132448111)and expected the worst. I was pleasantly surprisedwhen they merelyasked for an extra t10 to covertheir administration costs,and an engineer'sreport(easilysupplied by Superchips).For those of you readingthis with a guilty conscience, this will hopefully give you food for thought! With all thingsconsidered, the conversionhas provedto be a very cost-effectiveway of increasingperformance,well worth the 6 mpg loss in fuel consumption. Superchipshave re-chipped around1,000TDI models throughoutEurope,and look set to supplymany morewith the growthof their modem-linked dealers.Who needs a petrol engine?- long livethe dieseM
Useful Gontaets Superchips Ltd Buckingham Industrial Park B u c k i n g h a mM K 1 8 1 X J Tel: (01280)816781 Warwick Banks Handling Witham-on-the-Hill Bourne, Lincolnshire Tel: (01778)590500