Rough Rebirth - 2003 Pagani Zonda GR

Back in 2003, Horacio Pagani gave his blessing to the very first official Pagani racecar. In a collaboration with famous Dutch racer Toine Hezemans, Pagani ventured out into the highly competitive world of GT racing. Sadly the project encountered problems early on when an engine deal with AMG unexpectedly fell through. Hezemans had been under the impression that he had food ties with AMG and Mercedes-Benz, but he was proven painfully wrong. The informal deal to secure the supply of AMG's mothballed LS600 V12-engines as used in the infamous CLK GTR failed to materialize, which sent Hezemans and his Carsport Modena organization back to square one.

Adding insult to injury, the car was tremendously overweight despite Horacio's promises. Thanks to this obesity and a hastily modified 6.0L V12 M120 road engine taken from a Mercedes-Benz S600, the car turned out to be a massive rolling disaster. After a dreadful experience in 2003, Hezemans tried to improve on the car's many foibles during the 2004 season after lending it to former F1-driver Philippe Alliot (FRA). A crash by driver Anthony Kumpen put a dent in his efforts however, and he decided to abandon the project after countless man-hours and dollars had been spent in vain.

The Zonda GR initially failed to live up to its promise.

The Zonda GR initially failed to live up to its promise.

After its horrible ordeal on the international GT-racing circuit, the Zonda GR was left to collect dust at Carsport Modena's Belgian workshop. The car laid dormant for a while, before it was put up for sale by its Belgian owner.

Since Pagani was still a relatively small name on the market, it seemed unlikely the car would fetch a high price. The relative obscurity of the project and its appalling results were also detrimental to the Zonda's chances of finding a new home.

 

Antonin Herbeck swooped in to give the Zonda a second lease of life.

Antonin Herbeck swooped in to give the Zonda a second lease of life.

Help was on the way however, as Czech media mogul Antonin Herbeck. Herbeck was the owner of Rock Media, a printing business handling the production of various well known magazines like Top Gear, Stuff, Cosmopolitan and Esquire. Aside from his lucrative business, Herbeck also enjoyed a second passion as a semi-professional racer. He started out in the Italian Ferrari Challenge driving a 360 Challenge in 2003. This experience lead to the purchase of a Ferrari 575 GTC GT1-machine shared with Andrea Montermini for the 2005 Italian GT Championship.

Upon learning of the disused Pagani, Antonin Herbeck decided to contact Carsport Modena with an offer. Eventually he settled on a price of €375,000-. Considering the car was in bad shape, this was a hefty price. Arrangements were made to ship the Italian stallion back with Herbeck to the Czech Republic, where his team of mechanics were set loose on the car to properly evaluate it. Upon arrival the car's Motec engine management system turned out to be faulty, which forced the team to completely change out the wiring loom and all associated comnponents.

The Zonda GR at the last major event of its original career, Le Mans 2004.

The Zonda GR at the last major event of its original career, Le Mans 2004.

When the car was originally built, Carpsort Modena had encountered a wide range of issues with its design. The high weight, unreliable transmission and lackluster road engine proved to be the bane of its existence, and now Antonin Herbeck's Team Rock Robots was left to pick up the pieces.

Thankfully the road car's sloppy chassis had already been stiffened up to racing standards by Carsport Modena. Carsport engineer Mike Gramke had modified the rear subframe by incorporating a second set of struts attached to the gearbox as well as the engine. Chassis-wise then, the car was in surprisingly good nick.

But as Team Rock Robots would soon find out, the Zonda still had a trick up its sleeve. When the engineers reviewed the engine, they found Carsport Modena had been using completely stock head gaskets, which were in no way strong enough to withstand the stresses of extended flat-out driving. To combat the issue the team ordered a set of improved multi-layered steel gaskets from American firm Cometic. 

The change did little to improve reliability however, as the big V12 kept true to its spirit by repeatedly exploding in a cloud of smoke. It was clear more adjustments were needed to get the unruly beast back in line. Rock Robots had been using improved pistons from British firm Perfect Bore to try and strengthen the engine, and retarded the ignition timing a bit to allow it to cool more efficiently.

 

The engine proved to be the car's Achilles' heel.

The engine proved to be the car's Achilles' heel.

Inexplicably though, the engine was now burning through its pistons at an alarming rate. Closer examination by the teams technical staff revealed the "improved" pistons to have a fatal flaw. Abandoning all common sense, Perfect Bore had designed the pistons with wafer thin sections directly under the hottest parts of the combustion chamber, right underneath the exhaust valves. With walls no thicker than a millimeter, the pistons would dissolve in a matter of minutes.

Exasperated. Antonin Herbeck and his team embarked on a long search to find a better replacement. In the end much stronger forced pistons from German specialists Mahle were selected for the car. With the new parts in stock, the team immediately grabbed the opportunity to invest in advanced dyno testing equipment to make them able to get a better understanding of the inner workings of their engine. As outsourcing engineering work to specialist firms had been a costly and nightmarish endeavor so far, Herbeck decided his team should take up developing parts of their own.

  

More testing followed, and it became apparent that the new Mahle pistons were working a little too well. The increased pressure inside the cylinders was starting to overwhelm the engine's relatively weak Alusil cylinder liners. Several failed attempts to plasma-coat the cylinders with Nicasil and experiments with wet liners followed, before the team settled on tougher grey steel cylinder liners.

At long last the engine was finally strong enough to last for more than a few laps. The fix came as a small consolation however, as the Zonda GR had been entered in rounds of the Italian GT Championship while the team was busy sorting out its many foibles. The constant breakdowns often occurred on the track, and ended a lot of days on a bad note. Too often the team had to pack up their equipment and head home as their competitors were enjoying a fine day of racing. 

 

 

The modified Zonda GR at the FIA GT Championship Test, Dijon 2006.

The modified Zonda GR at the FIA GT Championship Test, Dijon 2006.

To further increase strength, the team decided to revert the V12 to a 6L capacity. Shortly before the car was sold, Carsport Modena had taken the liberty of updating the Zonda's feeble engine to the 7L specification also found in the Mercedes-Benz SL70 AMG and the Zonda S.

Because the engine had simply been bored out, the spaces between the cylinders had been reduced to dangerous levels. In an ordinary road going supercar this was not really an issue, as very few Zonda owners would push their cars for one hundred percent of the time. For racing purposes however, the larger displacement motor had become far too weak and hard to keep cool.

FIA GT Championship Test, Monza 2007.

FIA GT Championship Test, Monza 2007.

Along with the decrease in displacement, the Zonda's powerplant received a plethora of performance enhancements. The intake and exhaust ports were carefully ported and redesigned Jenvey throttle bodies were fitted. The dry sump system also received an overhaul, with the addition of a 6-stage oil pump from Swedish manufacturer Autoverdi.

Additionally, the crankshaft was significantly lightened, and custom-made titanium conrods were fashioned courtesy of engineering firm Arrow Precision. The camshafts were re-profiled as well to provide higher lift on both the intake and exhaust side. Super light valves made by DelWest supplied the beefy V12 with its much-needed oxygen.

The numerous extensive changes totally transformed the lackluster engine into a fire-breathing maniac. The team took the wise decision to refrain from pushing the engine to its absolute limit, which left them with a very capable piece of machinery. Originally the engine had produced a relatively docile 580 horsepower.

With the new treatment however, this number skyrocketed to a scarcely believable 700 horsepower at 7500 rpm. The torque figure was even more impressive, as the big twelve cylinder was capable of generating a monumental 820 nm (604 ft lbs) at 6500 rpm. Through a very costly trial and error phase, Antonin Herbeck and his crew had finally created the engine of their dreams. 

We found out this engine does not like to be pushed to higher compression ratio’s and ignition advance. Once we backed away from wanting to have maximum horsepower and torque, we got reliability and very good performance.
— Antonin Herbeck.
Monza, 2008.

Monza, 2008.

Although the engine was now finally sorted, the extra power and torque came at a cost. The lightened crankshaft turned out to be too weak to handle the mountains of torque the Mercedes engine was belching out, which caused it to snap clean in half on two occasions. To make matters worse, the Xtrac gearbox seemed to be having a hard time coping with the extra strain as well. 

At the moment our weakest link is the crankshaft and the Xtrac gearbox. We’ve had two broken cranks and the gearbox looks very pained every time we are on track. Especially the 1st and 2nd gears do not handle the torque too well and we have to change the gears out quite a bit.
— Antonin Herbeck.
In 2009 the car's body underwent a drastic transformation.

In 2009 the car's body underwent a drastic transformation.

With the exasperating engine work finally over, the team could focus their attention on the rest of the car. Back when the Zonda GR originally competed it was subject to very stringent regulations governing aerodynamics, but the more open FIA Central European Zone championship there was more room for improvement. 

Contested over eleven rounds, the FIA CEZ series concentrated on smaller circuits in located in Hungary, Serbia, Austria, Croatia, Slovenia, Slovakia, Poland, the Czech Republic, and was open to anything from GT cars to bespoke prototypes. 

 

 

The large snorkel on the roof was one of the biggest changes to the Zonda's bodywork.

The large snorkel on the roof was one of the biggest changes to the Zonda's bodywork.

The Zonda was already fast enough to keep up with the much lighter and more advanced DTM cars which had also found a second home in the series, but it was clear much more work had to be done to enable the car to beat them outright.

    

The front end was also substantially reworked.

The front end was also substantially reworked.

With this in mind Antonin Herbeck contacted Nick Galbreith of Aurora Design to redesign the Pagani's aerodynamics package. Galbreith duly delivered by working with the team to introduce new rear wing mountings fixed directly to the gearbox rather than the bodywork, a new roof-mounted engine intake and a stiffened front subframe fitted with a much larger front splitter.      

The Zonda GR facing off against a Mercedes-Benz CLK DTM

The Zonda GR facing off against a Mercedes-Benz CLK DTM

The thorough updates finally made the Zonda a contendor, and soon enough it was frustrating the established front runners. All of a sudden, Herbeck had a car capable of overpowering even the fastest DTM-machines, which ruffled a few feathers along the way. This became apparent at the FIA CEZ race held at Most in the Czech Republic.

Audi A4 DTM-driver Tomáš Kostka had built up a comfortable lead in the event, but Antonin Herbeck and the Zonda were fast approaching. Record times saw the Pagani catch the DTM slowly but steadily, until Herbeck made the move on the penultimate lap. Kostka was not particularly happy about this. Apparently in a fit of rage, he battered the rear of the Italian machine going into the final corner on the last lap. As a result both cars were spun round into the pit wall, and both suffered massive amounts of damage.

Footage from Antonin Herbeck's crash after Kostka's hit.

Luckily the stricken machine could be rebuilt, but bad blood had been set between Antonin Herbeck and the Kostka outfit. The negative attitude towards Rock Robots and their swift Pagani seemed to spread among the other competitors, as Herbeck took the car to several wins.

After placing second in the FIA Central European Zone Championship in 2013, the team was slapped with a range of performance restrictions to appease the increasingly disgruntled opposition. With every good result by the Italian machine came more and more complaints, which lead the series' governing body to impose drastic weight penalties and the smallest intake restrictor allowable.

DMV GTC race at Hockenheim, 2014.

DMV GTC race at Hockenheim, 2014.

Unhappy with the officials' course of action, Antonin Herbeck elected to leave the Central European championship in favor of the German DMV GTC series. Contrary to the rather conservative FIA CE series, the DMV GTC featured a much more open character.A massive variety of open GT3, GT1 and prototype machinery occupied the grid, and the level of professionalism was markedly higher than in the Central European series.

Antonin Herbeck and his Zonda were right at home in the much more competitive field. Finally they had found some worthy adversaries. The venues were on a higher level as well, with rounds taking place at former Grand Prix tracks like Dijon-Prenois, Hockenheim, Zolder and the Nürburgring GP-Strecke, along with a current GP-circuit in the form of the beautiful Red Bull Ring. 

 

 

Due to increasingly stringent noise restrictions, the mighty V12 had to be silenced with four ungainly mufflers.

Due to increasingly stringent noise restrictions, the mighty V12 had to be silenced with four ungainly mufflers.

To try and assert themselves in the cutthroat world of DMV GTC, the team sent the Pagani to German suspension specialists KW in mid-2015. The car was brought over for a session on the shake rig to try and make some improvements.

In KW's expert opinion, the team had been using springs that were too hard in the front, and too soft in the back. Rock Robot's mechanics made the suggested changes, but once the car was back on the track it slowly but surely became apparent the switch was an utter disaster. 

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Quite frankly we listened to the experts and again and that threw us in the wrong direction with car setup. I think we started to lose about 1-2 seconds per lap with the softer setup. It took us a while to realize the experts were wrong again.
— Antonin Herbeck.

The team scrambled to get the setup back to the way it was, and recovered as much as 3 seconds a lap with a stiffer setup. Just like all the problems they had suffered before, Rock Robots rose above it. Sadly their battle still wasn't over, as newly installed Pagid brake pads gave up the ghost in the first race of the 2016 season, and the second race was marred by clutch failure.

 

Fourteen years on, the Pagani Zonda GR still holds it own against brand new machinery.

Fourteen years on, the Pagani Zonda GR still holds it own against brand new machinery.

Undeterred, Antonin Herbeck and his fanatical crew at Rock Robots are continuously working around the car to make it the ultimate racing machine. Throughout its life the car has been a temperamental and fickle mistress, but Herbeck's relationship with his prize possession is far from over. Back in 2004 he picked up a broken, uncompetitive GT1-reject for a hefty sum of money, and proceeded to try and turn it into a winner.

 

Through the blood, sweat and tears of countless men, the Zonda slowly but surely reached a winning level of performance, but never without a fight. Parts broke left and right as the car refused to stay together, but Antonin Herbeck and his team stayed determined to finish the job. This labor of love is seemingly never ending, but it's worth every single frustrating hour as soon as that glorious V12 starts up.

We love this car and are very thankful for the experience it has brought us. We have so many stories to tell our children about suppliers and engine tuners, whose answer to our problems with their products was a standard “We’ve never had this happen before”.

Stories about detonation, valve profiles, suspension settings, crashes caused by jealous opponents and lots of trophies on our shelves for our efforts.

But the biggest reward is the journey that our team and our car have taken so far.
— Antonin Herbeck.

Special thanks to Antonin Herbeck, Rock Robots founder and owner of this amazing machine, for providing all the information, images and videos needed to produce this article.