Keen to find out how well tur­bocharged VXRs can cope with big power, Cal­lan Ack­er­man sub­jected this Ar­den Blue Astra to a wealth of up­grades in the pur­suit of 550bhp…

Performance Vauxhall - - CONTENTS - WORDS Dan Furr PHO­TOS Davy Lewis

Cal­lan Ack­er­man sub­jected his Astra VXR to a wealth of up­grades in pur­suit of 550bhp.

What is it that first drew you to Vaux­halls? For Astra owner, Cal­lan Ack­er­man, it was the noise! “I must ad­mit, I wasn’t overly im­pressed with the Mk5 VXR be­fore a mate took me out for a spin in his lightly tuned ex­am­ple. Up un­til that point in time, I’d been mod­i­fy­ing cars from the sta­bles of a va­ri­ety of dif­fer­ent man­u­fac­tur­ers. A Re­nault Me­gane R26, a Seat Leon Cupra R, a BMW E36 drop-top and even a 530D were just some of the cars I’d bought and tuned. I’d heard hor­ror sto­ries about the VXR’s en­gine and trans­mis­sion re­li­a­bil­ity when sub­jected to a sig­nif­i­cant hike in horse­power, but the pops and bangs my friend’s car was mak­ing, not to men­tion how quick it felt, con­vinced me I needed to find out how good or bad Astra VXRs are first-hand.”

“At the back of my mind, I liked the idea of fit­ting a tur­bocharger ca­pa­ble of pro­duc­ing more power,” says Cal­lan. “I tried to ex­er­cise re­straint by buy­ing a freshly built K06, but I was amazed at the claimed 620bhp be­ing de­liv­ered by the BorgWarner S257SX-E T3 twin­scroll tur­bocharger fit­ted to a

Mk4 Astra GSi I’d been read­ing about. When the owner of the car of­fered the part for sale, I couldn’t re­sist, al­though if any­thing was go­ing to test the dura­bil­ity of my car’s en­gine and gear­box, this was more than likely it!”


Pro­vid­ing the voice of rea­son, Dale stressed the need for Cal­lan to buy a stack of es­sen­tial sup­port­ing equip­ment if he stood any chance of be­ing able to make use of his new snail-shaped bhp booster be­fore the car’s en­gine blew it­self up. “I was sud­denly faced with a lot of unan­tic­i­pated spend,” sighs the scaf­folder from Bris­tol. “The block needed to be wedged, the cylin­der head needed to be over­hauled, I had to buy high-flow fuel kit, a new ex­haust, all new in­take equip­ment and a mass of other per­for­mance parts. The list was huge!” he gasps, al­though he’s the first to ad­mit Dale knows a thing or two about build­ing en­gines for VXRs chuck­ing out big bhp, as ev­i­denced by the high num­ber of re­li­able, supremely pow­er­ful As­tras which have rolled out of the Au­toworks Ser­vices work­shop doors of late.

De­pend­ing on which way you look at it, chas­ing ponies and buy­ing a big­ger turbo may have saved Cal­lan money in the long run. “Af­ter I gave the green light to Dale to start work on the en­gine, he con­tacted me with news the cylin­der head fea­tured a bent valve and one of the main bear­ings was se­verely worn. In short, I’d bought a tick­ing time bomb,” he groans. At least the prob­lem was dis­cov­ered be­fore ma­jor dam­age was done, al­low­ing Dale to con­tinue strip­ping the en­gine of its in­ter­nals be­fore deck­ing the block and re­build­ing with Omega over­sized forged pis­tons, PEC con­nect­ing rods, ARP fas­ten­ers, Mahle bear­ings, a bal­anced crankshaft and Vaux Pro wedges. The head was cleaned and re­built with new valves, Piper springs, fresh stem seal re­tain­ers and Regal Au­tosport RSS camshafts.


The de­mand for high fu­elling was met by In­jec­tor Dy­nam­ics 1050cc fuel in­jec­tors and an ASNU fuel pump, while the tur­bocharger ben­e­fits from a Nortech Per­for­mance tubu­lar ex­haust man­i­fold, twin Tur­bosmart waste­gates, a Tur­bosmart Race Port and large-bore air­flow pipework, in­clud­ing a Nortech down­pipe, a three-inch Co­bra dou­ble-de­cat ex­haust, an Airtec Gob­stop­per in­ter­cooler, an EDS in­let man­i­fold and a cus­tom in­take mated to an AEM open cone air fil­ter.

The stock M32 six-speed ‘choco­late box’ re­mains, al­beit bol­stered by a TTV Racing light­weight bil­let fly­wheel and a six-pad­dle clutch made specif­i­cally for Cal­lan’s car by the guys at He­lix. Vi­bra Tech­nics gear­box and en­gine mounts elim­i­nate any un­wanted move­ment from the driv­e­train, while a Quaife ATB lim­it­ed­slip dif­fer­en­tial will help the car to make use of the 550bhp he hopes to wit­ness the car pro­duce dur­ing a map­ping ses­sion at RnD Motorsport fol­low­ing the writ­ing of Rab­bid base map soft­ware cur­rently lim­it­ing power to a safe 365bhp.

“The diff went on not long af­ter I bought the car,” re­veals Cal­lan. “I’ve

now ex­pe­ri­enced seat time in a va­ri­ety of Mk5 Astra VXRs, and all of them like to spin their wheels, even on what you might con­sider to be a low out­put map. Stan­dard VXRs aren’t much bet­ter! I rea­soned Stage 3 with­out a lim­ited-slip dif­fer­en­tial would be un­drive­able. The Quaife unit has com­pletely trans­formed the way my car be­haves, en­abling me to get the power down with­out fear of los­ing trac­tion as soon as I hit the throt­tle,” he says.

De­ter­mined to drive a track- friendly week­ender, he re­placed the car’s Lo­tus-tuned fac­tory sus­pen­sion with Bil­stein B14 coilovers and a White­line ad­justable rear anti-roll bar. Solid sub­frame mounts will be fit­ted not long af­ter the car ar­rives at RnD’s York­shire head­quar­ters. The un­ap­peal­ing rims Cal­lan in­her­ited with the car are long gone, re­placed by su­per-light Team Dy­nam­ics Pro Race 1.2 eigh­teen-inch­ers with streetle­gal Yoko­hama track tyres. KS­port eight-pis­ton brakes can also be spot­ted at the nose end of the car. Fin­ished in pierc­ing yel­low, they’re dif­fi­cult to miss be­hind the gloss black spokes, but even gi­ant, brightly coloured brakes strug­gle to lay claim to be­ing this ace Astra’s defin­ing fea­ture. That hon­our must surely go to its rad­i­cally vented bon­net.


“A fel­low Astra VXR owner, Anthony Marsh, had the bon­net fit­ted to his car long be­fore the part was added to mine,” ad­mits Cal­lan. “I asked Anthony to let me know if he ever fancied sell­ing what is a unique panel based on an orig­i­nal VXR metal bon­net. Even­tu­ally, I com­mis­sioned a body shop to in­stall sim­i­larly big vents into a bon­net I bought specif­i­cally for the job. Just as the work was about to be­gin, how­ever, Anthony told me he was putting his VXR back to stan­dard spec­i­fi­ca­tion. Pleas­ingly, he gave me first re­fusal on his Astra’s cus­tom bon­net. I didn’t need to be asked twice!”

It’s cer­tainly an eye-catch­ing ad­di­tion to Cal­lan’s car, but he’s


KS­port eight-pots are dif­fi­cult to miss

An RnD Motorsport map­ping ses­sion should re­lease plenty of presently sti­fled ponies

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.