RUF YEL­LOW­BIRD CTR-4

Words: Johnny Ti­pler Pho­tog­ra­phy: Antony Fraser The lat­est Ruf Yel­low­bird CTR-4 is the most rad­i­cal of­fer­ing yet to fly the Pfaf­fen­hausen nest. We winged it on the Swabian black­top

911 Porsche World - - Contents -

It’s a Porsche, but not as we know it. Ruf’s new Yel­low­bird fea­tures a full car­bon tub, race sus­pen­sion and a full car­bon body, plus 700bhp

Yel­low plumage – and a cock­sure at­ti­tude: that’s about all that the lat­est Yel­low­bird has in com­mon with its trend-set­ting an­ces­tor. It is a true tech­ni­cal tour-de-force, be­cause al­though it presents it­self as some­thing ap­proach­ing a 964, ruf­fle those feath­ers and you’ll find it’s any­thing but. This freshly-hatched CTR em­ploys rac­ing car con­struc­tion tech­nol­ogy, mim­ing the same struc­ture as a DTM (Deutsche Tour­ing Meis­ter­schaft) sa­loon, for which the regs stip­u­late a com­mon-chas­sis con­struc­tion of car­bon-fi­bre mono­coque and steel rollcage, with front, rear and lat­eral crash el­e­ments, which also serve to lo­cate the sus­pen­sion com­po­nen­try.

Alois Ruf’s ve­hic­u­lar af­fec­tions proudly em­brace the im­agery of the clas­sic air-cooled 911s, and to that end the Yel­low­bird’s body shape emu­lates a 964 rather than a 991. Our run out into the Swabian coun­try­side with both ex­am­ples, old and new side by side, em­pha­sises the growth of the mod­ern car’s girth and stature. The new car is only 911-es­que, be­cause what you’re look­ing at is a car­bon-panel clad chas­sis. Whilst the cabin in­te­rior cor­re­sponds ex­actly with nor­mal 964 pro­por­tions, the ex­te­rior has swollen, very sub­tly, and it takes Alois’s guided tour to ap­pre­ci­ate the niceties.

Three decades sep­a­rate the two Yel­low­bird CTRS, one in­tro­duced in 1987, the lat­est in 2017. As Alois tells us, ‘the orig­i­nal idea was to make a mo­tor car that was not so large be­cause, re­mem­ber that in the same year, ’87, we had the 959 which was a very big car, rel­a­tively, and we wanted to fol­low the same prin­ci­ple with the new car, and make it smaller than the cur­rent 911. The en­tire mono­coque is car­bon, whereas the Ul­ti­mate that you saw last year only had a skin of car­bon, but here it’s the whole mono­coque. Most peo­ple think it’s based on a 964 or a 993, and it’s some kind of a back­date. But it’s based on a Ruf, and it’s com­ing from a clean sheet of pa­per.’

In fact, there’s a full-blown Le Mans race­car un­der­pin­ning this tra­di­tional look­ing car. ‘It could have a mod­ern body,’ Alois says, ‘but we wanted it to look as much as pos­si­ble like our orig­i­nal Yel­low­bird. This is why the car han­dles so nicely and feels so great, be­cause it’s a mod­ern, state-of-the-art race­car un­der­neath. The push-rod sus­pen­sion in­cludes up­per and lower wish­bones, and at the rear there are the hor­i­zon­tal cross-mounted shock ab­sorbers with coilover springs, while in the front they are lon­gi­tu­di­nally

mounted, and that’s pure race­car en­gi­neer­ing.’

Noth­ing is left to chance or done on a whim. ‘We needed to ac­com­mo­date these larger wheels and tyres to have an “ad­e­quate stance for the horse­power, be­cause out­put is 700bhp and it’s a light­weight chas­sis, so we made it wider, but the eye does not read it as a very wide car. To start with, we put 4cm more in the tail-lights, and when you com­pare that with the old one you’ll see the dif­fer­ence, that the tail-light and that sec­tion of body­work has broad­ened out.’ Typ­i­cally for a Ruf, the Yel­low­bird roof has no rain gut­ters. ‘The old one didn’t have gut­ters, and nei­ther does the new one. But what we’ve done here is to give the doors and the wings more shoul­der. When you open the door, you’ll see how much thicker it is than nor­mal. The size of the cabin in­side hasn’t changed, the glass area is still the same; we still have the same side-win­dow glass and the door frame that the old one has, as well as the wind­shield and the rear win­dow.’ How­ever, the glass in the rear-three-quar­ter win­dows has changed be­cause it’s acrylic and there’s a dis­creet air in­take ei­ther side for the com­bus­tion air. The two large ducts in the tops of the rear wings (fend­ers) pro­vide cool­ing air for the in­ter­cool­ers. ‘Take a few steps back and you will no­tice we have a 70mm longer wheel­base, and the eye doesn’t no­tice that, be­cause the over­all length of the car hasn’t changed. It is still the same length as the other one, but we have less over­hang, front and rear. The head­lights have been moved up by 20 mil­lime­tres, and no­body can tell that. The rear axle has moved by 50mm to­wards the back of the car and the front one by 20mm to­wards the front. We’ve length­ened the door by 25mm, and al­though it’s longer the piv­ot­ing points have not changed be­cause that would make it more dif­fi­cult get­ting in and out when you’re park­ing next to an­other car.’ Was it dif­fi­cult to ac­com­mo­date the front edge of the door

We made it wider, but the eye does not read it as a very wide car

within the struc­ture be­cause of its ex­tra length? ‘All the body parts are dif­fer­ent,’ says Alois. ‘There is noth­ing struc­tural that you could ex­change with a 911. You can carry over the wipers, the wind­screen, the side glass and the door frame, and that’s all; the rest is com­pletely new.’ The LED head­lights are spe­cially made for Ruf, and the door mir­rors are also to Ruf’s spe­cial de­sign, while the rear bumper cor­ners are slat­ted in the in­ter­ests of heat dis­per­sal. ‘We’ve just put it on Dun­lop tyres as part of the test­ing pro­gramme; we had been try­ing Miche­lin tyres, and now we’re try­ing the Dun­lops to see if there are any sig­nif­i­cant changes.’

To ac­cess the cabin, I first press the but­ton on the door lever and the lever swings out a lit­tle way in the fash­ion of a sim­i­lar Jaguar item, re­veal­ing a dis­crete Ruf logo. You only have to get into any Ruf and you’re sit­ting in some­thing rather spe­cial. In this case, the seat up­hol­stery is black-and­cream hound’s-tooth cloth, and the seat belt passes through an aper­ture in the side of the sports seat be­side your thigh. The steer­ing wheel is char­ac­ter­is­ti­cally black padded leather with­out any of the giz­mos that in­fest mod­ern wheels, so you’re look­ing through the aper­tures in the wheel arms rather than hav­ing switches to op­er­ate. Of the gauges, the rev counter is Ruf logo’d, the dig­its are in green against a black back­ground, and the whole car has been re-trimmed so that the panel gaps in the el­e­ments of the in­te­rior are all pretty well per­fectly aligned. There’s Kevlar cladding to the in­side sills and the outer skins of the footwells, and the cabin rear has been re­trimmed with flat sur­faces and stor­age bin where the rear seats would oth­er­wise be in a con­ven­tional 911. There’s a car­peted roof and Al­can­tara around the ‘A’ posts and ‘B’ posts, cladding the in­te­gral roll cage. The in­side door han­dle levers are very neatly con­cealed by the arm­rest and door-pull, and we have trade­mark Ruf alu­minium ped­als and a se­ri­ous footrest for the left foot. Over­all, the in­te­rior is de­lib­er­ately min­i­mal­is­tic be­cause it’s a CTR. There’s no glove com­part­ment and in­stead there are what re­sem­ble sponge bags in the lower door lin­ers, which pro­vide stor­age nooks.

I pull the engine lid re­lease knob and the lid lifts of its own ac­cord, re­veal­ing a very dif­fer­ent engine as far as the vis­i­ble an­cil­lar­ies are con­cerned. The oil filler in par­tic­u­lar is hand­ily placed, pro­ject­ing back­wards for easy fill­ing. Alois dis­abuses my col­league from tak­ing any photos of it as the mo­tor is still a work in progress and could even­tu­ally look some­what dif­fer­ent, cer­tainly more re­fined and less

race­car than it does cur­rently. ‘It’s func­tional the way it is now, but not pho­to­genic,’ he says. ‘To give it the feel­ing of the air-cooled engine we’ve put the al­ter­na­tor into the cen­tre, and we have re­lo­cated the air con­di­tion­ing com­pres­sor to the front with an elec­tric mo­tor, and the power steer­ing pump is also in the front with an elec­tric mo­tor, so we can af­ford to have a very clean engine here.’

Back in the day, we thought the 964’s sus­pen­sion was rad­i­cal when it shifted from tor­sion bars to wish­bones: the Yel­low­bird is in a dif­fer­ent league, tak­ing a leaf out of its mid-en­gined CTR-3 sib­ling’s set-up – and then some. Its coil-over spring-damper units, as­sis­tor shocks and ad­justers are mounted hor­i­zon­tally, front-to-back on ei­ther side un­der the front lid, rather than ver­ti­cally, and the sim­i­lar rear units are also mounted hor­i­zon­tally, but lat­er­ally, from side-to-side. Ac­cord­ing to Ruf PR Mar­cAn­dré Pfeifer, the ben­e­fit of hav­ing them hor­i­zon­tal rather than ver­ti­cal is that, ‘the car doesn’t bounce on bumps like it would with con­ven­tional ver­ti­cal springs and dampers, so it doesn’t lose con­tact with the road sur­face, and there­fore it doesn’t lose trac­tion.’ It also pro­vides greater space for “ac­com­mo­dat­ing wider tyres and big­ger brakes. The fuel tank oc­cu­pies a large pro­por­tion of the front boot area, but you fill it up via a race-style fun­nel ac­cessed through the cap in the front lid. This shorter filler pipe also en­ables a larger ca­pac­ity tank, cur­rently 8-litres more, and which will even­tu­ally be 105 litres.

Marc points out that this is, re­ally, ‘the pro­to­type, the first driv­ing car, where we can col­lect ex­pe­ri­ences and make notes as to how it’s work­ing, what we need to al­ter and ad­just.’ In which case, we’re priv­i­leged to be able to see how they’re get­ting on, and even at this stage this is a truly in­cred­i­ble car. I buckle up, fire up the deepthroated flat-six, and ease out of Pfaf­fen­hausen on the flat farm­land black­top to one of our photo lo­ca­tions, a won­der­ful sweep­ing B-road, which we have pretty much to our­selves. The quicker I go, the more the steer­ing light­ens up. It’s un­fail­ingly

The Yel­low­bird is in a dif­fer­ent league, tak­ing a leaf from the CTR-3

very pre­cise, and there’s no drama mov­ing the steer­ing wheel, partly be­cause the new sus­pen­sion al­lows the road wheels to turn more freely. Frankly, it’s kind of un­canny how smooth and di­rect it is, and how silky the ride. It’s all very acute, from the tur­bo­fused ac­cel­er­a­tion to the brak­ing punch and tight turn-in. Ev­ery­thing about the driv­ing ex­pe­ri­ence is ex­traor­di­nar­ily ex­act, there’s an un­canny smooth­ness to the steer­ing lock, and when I press the ac­cel­er­a­tor pedal there’s a dra­matic surge for­ward, ac­com­pa­nied by the whistling of the waste­gate with each shift. This is a dis­tinctly ma­cho car, re­quir­ing some 3000rpm to ac­tu­ally get it go­ing, and then ev­ery gearshift is a mi­nor work­out; it’s cer­tainly not a soft touch. I’m us­ing mostly 4000rpm be­fore each shift, and it has seven speeds, and though I’ve en­gaged 7th it’s not for long on this fast, ser­pen­tine B-road. Ac­tu­ally, there doesn’t seem to be much dif­fer­ence be­tween 6th and 7th, and I’m still ac­cel­er­at­ing hard in 7th. The rev counter is zing­ing round to 5-, 6000rpm, and the boost gauge is equally ag­i­tated, go­ing right round to 1.2-bar with each throt­tle thrust. Turn in is hyper-sen­si­tive and the steer­ing is ex­tremely sharp, and the surge of en­ergy it de­liv­ers when I ap­ply the ac­cel­er­a­tor lit­er­ally pins me against the back­rest. Con­versely, the stop­pers are so strong that, un­der brak­ing, my torso lunges for­wards into my belt.

This is a much more ma­cho car than its Pfaf­fen­hausen sib­lings, in­clud­ing even the mid-en­gined CTR-3. It’s quite dif­fer­ent in char­ac­ter to other Ruf mod­els, which could be de­scribed as rel­a­tively placid by com­par­i­son. This Yel­low­bird you can’t be soft with, you’ve got to grasp the con­trols and re­ally go with it. The para­dox is, its very light­ness and del­i­cacy of han­dling and steer­ing is at odds with the mas­sive power avail­able. ‘Sure,’ says Marc, ‘the more you get the feel of it the bet­ter you know how it’s go­ing to be­have. It has a huge per­son­al­ity, and it asks what you’d like to do with it, very di­rectly, and you are the driver, you de­cide what to do, and that means in a very tough way. A ma­jor fac­tor with most mod­ern sportscars is that you’re not afraid be­cause you have so many elec­tronic aids in­side that you know that, no mat­ter what I do, it will save me. But here we are in the realm where you can go over these lim­its, but it’s you that has to take care of it. Of course, we have stan­dards and safety reg­u­la­tions, but the limit of this car is so much higher in per­for­mance and cor­ner­ing that first you have to get used to it. Its light weight means you have much higher brak­ing ef­fi­ciency; you can brake later, you can ac­cel­er­ate ear­lier, you can go at higher speeds around the cor­ners, so ev­ery­thing is one or two steps above the lim­its that you’ve been used to be­fore.’

The per­son re­spon­si­ble for achiev­ing these stan­dards is Alois him­self. Whist Ste­fan Roser was the test pi­lot for the orig­i­nal Yel­low­bird, Alois has the most ex­pe­ri­ence in the be­hav­iour of rear-en­gined

cars, so it is he who has raised the bar and set the pa­ram­e­ters for the new Yel­low­bird. ‘We’ve tried to achieve a weight bal­ance that matches the be­hav­iour of the mi­dengined CTR-3,’ says Marc, ‘and this new push-rod sus­pen­sion, front and rear, pro­vides many more pos­si­bil­i­ties for us to achieve that goal. Then, of course, you just need a lot of test driv­ing, and you ei­ther hunt for per­for­mance lim­its like top speed or ac­cel­er­a­tion, or, what is more im­por­tant from our point of view, is that the car should give you as much fun as pos­si­ble when driv­ing it, be­cause that’s what it’s all about, the plea­sure of driv­ing. You can make a lot of cal­cu­la­tions and the­o­ret­i­cal con­cepts, but in the end it al­ways comes back to ex­pe­ri­ence, and this is our strength. Next year we cel­e­brate 80 years of Ruf, and that’s what we’ve tried to put into this car.’

Back at the Pfaf­fen­hausen show­room there’s a group of Brits en­joy­ing a guided tour – hi there, read­ers – and af­ter re­fresh­ments I head out again in the new Yel­low­bird, re­flect­ing that life just doesn’t get any bet­ter than this: it’s such a thrill. Its colos­sal power is in­stantly de­liv­ered, and the whole tac­tile ex­pe­ri­ence of the new CTR-4 is above and be­yond what you would nor­mally ex­pect, even in a Ruf. This is a very so­phis­ti­cated sportscar with rac­ing con­no­ta­tions as well, the way the power is de­liv­ered, a slight shud­der ac­com­pa­ny­ing each shift, al­most like a hint of torque steer with each gear change as the power comes in. And I don’t have to be try­ing very hard to make that hap­pen: squeeze the throt­tle pedal and we’re off! Let’s not talk about horse­power: this CTR de­ploys ele­phant power – and of course that’s partly down to its light­weight con­struc­tion, too. So, it’s a mus­cle car in the sense that it re­quires you to use your mus­cles to ac­tu­ally con­trol it when you’re ac­cel­er­at­ing hard. But as well as de­ploy­ing brute power it will poo­tle with the meek­est of them in an ur­ban con­text. Its ride is amaz­ing, too, and that’s mainly to do with the ori­en­ta­tion of the springs and dampers. As Alois puts it, ‘you feel the un­sprung weight is re­ally min­i­mal­is­tic, and you no­tice when you drive how nicely the wheels stick to the road; the sus­pen­sion still de­liv­ers very good ride com­fort, too. At the front we’ve gone lon­gi­tu­di­nal, so we have more space for the fuel cell and for lug­gage ca­pac­ity and the other an­cil­lar­ies we have

The CTR-4 is above and be­yond what you would nor­mally ex­pect

in there. We made a dif­fer­ent fuel cell that’s filled up from the aper­ture in the front lid, and by do­ing that we’ve gained 8-litres more fuel ca­pac­ity, be­cause you don’t have the fill­ing pipes of a nor­mal 911. Also, we wanted to have steer­ing that is very di­rect and very pre­cise, and it’s hy­drauli­cally as­sisted but with an elec­tric pump, which means we can keep the engine com­part­ment cleaner and bring weight to the front for bet­ter weight distri­bu­tion, and we gave up on the rear seats for that rea­son, too, so in­stead you’ve got a lug­gage box be­hind you.’

Alois takes us the few kilo­me­tres to the Ruf skunkw­erks where the chas­sis for Yel­low­bird CTR-4 num­ber two is in the process of be­ing cre­ated. The skele­ton of the chas­sis sits on a dais in the work­shop, look­ing for all the world like a rac­ing mod­ule. Two tech­ni­cians hold up a com­plete car­bon side of the car for Antony to shoot, demon­strat­ing the light­ness of it by us­ing just two fin­gers. Alois obliges by pick­ing up the en­tire roof panel by him­self. The front and rear sub­frames are crash struc­tures, made of light­weight steel, and bolted to the car­bon mono­coque. ‘The bond­ing hap­pens only be­tween the parts that are made in car­bon-fi­bre. The tub is made by a Ger­man firm, the same com­pany that makes all the DTM tubs for the race series.’ Some ar­eas are solid and ex­tremely rigid, while other box-sec­tions are voids. ‘You prob­a­bly felt when you drove the car how rigid it is; there is no squeak­ing, there is no flex, you don’t have the feel­ing that some­thing is mov­ing around, like in a steel body; it’s very solid. So, we are very proud that we have done some­thing with the tra­di­tional 911 shape that didn’t hurt it. Usu­ally what­ever peo­ple do to mod­ify a 911 only makes it worse, not bet­ter, and here we have put some­thing to­gether that could have been an evo­lu­tion of that iconic body.’

There is no doubt that the new Yel­low­bird CTR-4 is a mas­ter­piece, hints of which were man­i­fest in the air-cooled, car­bon-bod­ied “Ul­ti­mate” that we featured last year; but the Yel­low­bird is noth­ing less than a quan­tum leap in Ruf’s ever-evolv­ing take on the 911. Come home to roost? Far from it: these flights of fancy are still very much on the wing. PW

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