The R35 GT- R might be re­garded as one of the best cars to ever come out of Ja­pan, but that doesn’t mean you can’t im­prove on per­fec­tion. Cars are there to be mod­i­fied, af­ter all …

NZ Performance Car - - 2008 Nis­san Sky­line Gt- R( R35) - WORDS: MAR­CUS GIB­SON PHO­TOS: ADAM CROY, STEVE RITCHIE

Three hours is a long time to be do­ing any­thing, es­pe­cially when you start talk­ing about cir­cu­lat­ing a car non-stop at race pace around a rac­ing cir­cuit. Most sprint races last 10 to 20 laps, and when you crunch the num­bers for a three-hour en­duro on any New Zealand track, you can ex­pect that num­ber to to­tal be­tween 100 and 200 laps. This presents a spe­cial set of pa­ram­e­ters when build­ing a car, as no longer are you look­ing for out­right speed and stress­ing the car to achieve that per­for­mance, it’s about re­li­a­bil­ity and balanc­ing the power out­put to en­sure the car’s fast enough to run at the front of the field, but not so fast that you burn up tyres and fuel quicker than you need to. That old say­ing, to fin­ish first, first you must fin­ish, was surely penned with en­durance rac­ing in mind. If you watch the re­cently tele­vised High­lands 101 (ef­fec­tively High­lands Mo­tor­sport Park’s three-hour race) you will know ex­actly what we’re talk­ing about.

All this makes for a very chal­leng­ing build, and is per­haps why en­durance rac­ing is such a pop­u­lar sport here in New Zealand, at­tract­ing some of our big­gest fields — and prize purses. Auck­land’s In­ter­na­tional Mo­tor­sport is well versed in en­duro rac­ing, hav­ing built and run count­less ma­chines over the years, but this would be its first R35 GT-R.

The project be­gan when the own­ers, one of whom has a heav­ily mod­i­fied R35 street car, re­alised ev­ery­one was rac­ing a Porsche GT3, and no one had an R35. “The way the Sky­line is set up makes the car the per­fect op­tion for those week­end war­riors, as it’s a lit­tle eas­ier to drive. There’s a good amount of driver aids, good straight-line speed and four big wheels on it, with plenty of me­chan­i­cal grip,” ex­plained IMS fab­ri­ca­tor Ricky.

The GT-R was pur­chased as a fresh im­port from a friend, with only 5000km on the clock when it was rolled into the IMS work­shop and stripped to a near bare shell. Step­ping into the un­known was a chal­lenge for the team, as sur­pris­ingly not many peo­ple run R35s in en­durance rac­ing any­where in the world. Plenty com­pete in sprint race and week­end-war­rior track days, but not en­durance rac­ing. How­ever both IMS and the own­ers were con­fi­dent it could work, as Ricky ex­plained. “The good thing about this build was the bud­get. They didn’t want to mess around with do­ing any­thing half way, so the eas­i­est thing to do was over-en­gi­neer stuff. We knew the car was go­ing to be heavy, so we weren’t too wor­ried about weight, we wanted to make it re­li­able and safe for the en­duro stuff.”

With such a well-con­structed chas­sis to be­gin with, not too much was needed in the way of chas­sis stiff­en­ing. An ex­ten­sive roll cage was con­structed, and the rear al­loy brac­ing was re­placed with a tube struc­ture, which would also act as a bracket for the 120-litre spe­cial-or­der Fuel Safe fuel cell.

“The way the Sky­line is set up makes the car the per­fect op­tion for those week­end war­riors, as it’s a lit­tle eas­ier to drive. There’s a good amount of driver aids, good straight-line speed and four big wheels on it, with plenty of me­chan­i­cal grip,”

The VR38DET, which had barely been bro­ken in from fac­tory, re­ceived very lit­tle in the way of up­grades. The fac­tory tur­bos had new cores fit­ted lo­cally, and Amer­i­can com­pany AMS — which would end up sup­ply­ing plenty of pieces for the project — sent over its largest GT-R-spe­cific in­ter­cooler, along with its piping and a fuel rail kit, to house the ID1000 in­jec­tors. AMS also sup­plied the 3.5-inch turbo down­pipes, with IMS build­ing a five-inch side-exit ex­haust.

These few ba­sic up­grades are con­trolled by the MoTeC ECU, and see the 3.8-litre pro­duce more power than needed, some­where around 410kW (550hp), depend­ing on the ECU map cho­sen via the ad­just­ment on the dash.

The gear­box is the fac­tory-fit­ted item, al­though its ECU has had a lot of at­ten­tion to up­grade the way it func­tions, as Ricky ex­plained. “We are lucky to have have Lin­ney Tun­ing and EcuTek on board, they have ad­justed the way it shifts, hy­draulic line pres­sures and clutch-pack pres­sures. They do a

These few ba­sic up­grades are con­trolled by the MoTeC ECU, and see the 3.8-litre pro­duce more power than needed, some­where around 410kW (550hp), depend­ing on the ECU map cho­sen via the ad­just­ment on the dash

lot to take it away from how the road car ver­sion shifts, mak­ing it a lot harsher, which re­duces the heat.” In ad­di­tion, a large rear-mounted gear­box cooler ducts air up through the rear dif­fuser and out through the open­ing in the rear bumper. This and the cool­ers for both front and rear diffs all have their own pumps, and are tem­per­a­ture con­trolled by the MoTeC ECU. It’s fac­tors like this you just wouldn’t bother with for a sprint-race car, but banging out in ex­cess of 100 laps — as you do when en­durance rac­ing at some tracks — trans­lates to thou­sands of gear changes, and you don’t want to leave any­thing up to chance.

Other over-en­gi­neered ar­eas in­clude the brak­ing kit, one item they knew would need overkill — as R35s are known to be hard on brakes — but then again, any car weigh­ing over 1700kg will be hard on brakes. “Ev­ery­one with a GT-R com­plains that you can’t make the brakes last longer than six laps, you just cook them. So the owner went out and said “what’s the big­gest and bad­dest brake pack­age we can get”, and End­less came up with this — 400 by 36mm two-piece ro­tors up front and 387 by 37mm on the rear, with huge six-pot End­less rac­ing Mono6 calipers front and rear.

The brake duct­ing draws down through the bon­net to feed the ro­tors nice cold air, and it seems to be work­ing re­ally well. The spe­cial en­duro pads are get­ting 1mm of wear an hour. The boys are rav­ing about how well the brakes work, so we are rapt.” To put the size of the brake ro­tors in pro­por­tion, that’s just shy of 16 inches, add the caliper on top of that and you’re go­ing to need a big wheel, in this case a set of spe­cial-or­der 19x10.5-inch Wed­sports wrapped in 305/690R19 Pirelli slicks, the type nor­mally found on Fer­rari Chal­lenge cars.

The sus­pen­sion pack­age again comes from End­less and AMS, with a set of End­less Su­per Func­tion coilovers, and a full ti­ta­nium ad­justable-arm kit im­ported through AMS. This has seen the car find a good base tune rather quickly, but the IMS team has bat­tled the likes of front tyre wear and lack of front aero grip. The large Tuner Group rear wing and car­bon dif­fuser are work­ing well, but the front fell short. As a re­sult the car soon trans­formed into an even more ag­gres­sive look­ing ma­chine, with a new front bumper, front guards and side skirts, all aimed at in­creas­ing aero­dy­namic grip ahead of the full as­sault on both the North and the South Is­land En­durance se­ries next year. “It’s a com­pet­i­tive car — whether or not it’s a win­ning car is still to be found out, but it’s def­i­nitely com­pet­i­tive. Get­ting it to go fast over a long pe­riod of time is what it is all about.”

There is no deny­ing that the guys at Nis­san de­signed and built the R35 as one of the world’s great­est cars, and cer­tainly one of the great­est to ever leave Ja­pan, but just like the stock ver­sions of any of the cars fea­tured in this mag­a­zine, there is al­ways room to im­prove on what was once per­fec­tion in some­one’s eye. Mod­i­fy­ing a car like this is a brave move, but we have a sneak­ing sus­pi­cion that this com­ing sea­son we’ll be shown just how com­pet­i­tive the End­less/IMS R35 GT-R can be. Watch this space.

“It’s a com­pet­i­tive car, whether or not it’s a win­ning car is still to be found out, but it’s def­i­nitely com­pet­i­tive. Get­ting it to go fast over a long pe­riod of time is what it is all about.”

En­durance rac­ing means on-the-fly driver changes, so the har­ness is at­tached to this stretch cord sys­tem that pulls each belt out of the way, so the next driver jump­ing in does not need to hunt for ev­ery strap

With fuel sav­ing a must in en­durance rac­ing, this dial al­lows on-the-go power delivery changes by switch­ing the map in the MoTeC ECU.

There is a sur­pris­ing 200kW of ad­just­ment, but gen­er­ally the GT-R runs around the 410kW mark to all four wheels

Cool­ing is a se­ri­ous busi­ness, and the car has two en­gine-oil cool­ers, plus ra­di­a­tor, AMS in­ter­cooler, power steer­ing, front diff, large trans and rear diff cool­ers. Each cooler temp is logged, and has an elec­tric pump con­trolled by the MoTeC and PDM

Con­serv­ing fuel to work within pit stop strate­gies is a big part of race-day an­tics, as fuel stops are fit­ted into the manda­tory two driver changes. To run the dis­tance a spe­cial or­der 120-litre Fuel Safe blad­der sits in­side an al­loy case and feeds via a dry break fuel filler

The huge brak­ing pack­age sup­plied from End­less uses 400x36mm two-piece ro­tors

up front, 387x34mm two­piece ro­tors on the rear, and Mono6 calipers front and rear. This is a bolt-on kit, and works in con­junc­tion with the stock pedal box so as not to af­fect the in­built

driver aids

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