Vetteheadracer
Nigel S Dobbie's definitive book on Corvette racing

Oct
15

At the beginning of the 2015 season IMSA the Governing body of the TUDOR United Sportscar Championship set the Balance of Performance for all four Classes. I am only interested in what happened in the GTLM Class. So I have based my calculations on the following scenario:
I took all of the published IMSA Timing data available at http://www.imsatiming.com for the 2015 TUDOR United Sportscar Championship for all of the rounds involving the GTLM Class.
This year I did not filter out any of the laps except where there were zero data points I grouped the data by Brand and Car (I added two new columns to the data Circuit and Brand). I then wanted to find the fastest theoretical lap by Brand and to do this I looked at all of the sector times to calculate the best sector time for every sector regardless of the driver or the car i.e. Sector 1 for Corvette for example might be Antonio Garcia in the #3, then Sector 2 might be Oliver Gavin in the #4 and so on to get the Best Theoretical Lap Time.
For all of the charts below the bars represent the time in seconds for the cumulative theoretical best lap time by brand and is measured in seconds on the left hand axis (remember lower the bar = faster the car), the dark red line represent the average time for all the brands (6 at Daytona and Sebring and 5 for the rest of the rounds as Aston only competed at the first two rounds). The red line represents the top speed as measured by IMSA at their speed trap, this is the actual best time by brand and is measured in MPH and represented on the right hand axis of the chart.

Race 1 Daytona

Race won by Corvette #3, BMW #25 a close second with both cars completing 725 laps the #4 Corvette finished third on 718 laps. The Corvette was potentially the fastest car but only marginally from the Porsche and Ferrari who were both less than 1/10th of second slower the Corvette. Both factory Porsches collided with each other and therefore removed themselves from the chance of defending their Daytona 24 hours title, had they not they would have been right there at the pointy end of the race. IMSA did a great job of balancing the performance as all five brands were within just over 2/10th’s of a second and top speed was covered by less than 1 mile per hour through the speed trap. Now some would say that the BoP for Daytona is probably the easiest to set as so much of the lap is flat out.

Race 1
No Adjustments to Performance were applied to the GTLM Class before Sebring.
Race 2 Sebring
Race won by Corvette #3. IMSA again did a great job of balancing the performance as again all five brands within 4/10ths of a second over the best theoretical lap and Corvette was actually the slowest and significantly i.e. 2 of the 4/10ths spread of the field. The top speed was also covered by 2 miles per hour for every lap by every car within all five brands. Porsche was potentially the fastest car.
Race 2

8th of April and IMSA issued two separate Adjustment of Performance bulletins, BMW got a 10kgs weight reduction, they also received a 2 liter fuel tank increase. Corvette had their fuel capacity reduced by 3 liters, Ferrari received a 4 liter fuel tank increase but were penalized with an extra 15kgs of weight and a 0.3mm reduction in their air restrictor. Porsche received an extra 3 liters fuel tank capacity.

Race 3 Long Beach
Race won by #25 BMW. BMW potentially fastest, Porsche slowest but all four brands still covered by 4/10ths of a second the 10kgs adjustment definitely helped the BMW as they were more than 2/10ths of a second faster than the other three brands. I would conclude that the adjustment to the BMW’s weight was actually unnecessary and tipped the race in the direction of BMW.
Race 3
Race 4 Laguna Seca
1-2 finish for BMW and Porsche third. Ferrari was actually potentially the fastest car and Corvette the slowest. The Ferrari was potentially fastest by more than a 1/10th from the Porsche, the reason that Ferrari could only manage a 4th place finish in the race was that towards the end of the race the car slowed significantly compared to the top three finishers in the class despite having been fasted earlier in the race. Significantly all four brand were still covered by less than 4/10ths of a second.
Race 4
12th of June and IMSA announced another Adjustment of Performance and this time Corvette received a 10kgs weight reduction and also a 0.3mm engine air restrictor increase, both potentially good for the Corvette and in recognition of their poor performance particularly at Laguna Seca.

Race 5 Watkins Glen

Race won by the Falken shod #17 Porsche followed by one of the factory Porsches and then BMW. Corvette were potentially the fastest car and Ferrari the slowest. The overall gap between fastest and slowest had now stretched to over ½ second. The BMW and Corvettes were closely matched but nearly 3/10ths of a second faster than the Porsche. GTLM field still covered by about 1/2 second. However, this was a wet race so really the data is very inconclusive.
Race 5
Race 6 Canadian Tire Motorsport Park

Porsche wins the race from BMW and then Corvette. Porsche and Corvette both evenly matched for potential best lap time, BMW 2/10ths back and Ferrari a further 2/10ths back. GTLM field still covered by 1/2 second.

Race 6
Race 7 Road America

1-2 finish for Porsche and they had a significant advantage -more than ½ second in potential fastest lap – over Ferrari who finished third with Corvette another 2/10ths back and BMW more than a second further back. The field of four brands now spread over nearly 2 whole seconds!

Race 7
30th of July and IMSA announces the latest Adjustment to Performance and Ferrari and Porsche both get a 10kgs weight reduction and further more Porsche gets to reduce the drag of the Gurney flap on the back of the rear wing to just 10mm, this despite them just having been the fastest cars at Road America.

Race 8 VIR

Porsche 1-2 again with Ferrari again third. Porsche more than 3/10ths faster than the Ferrari and BMWs who were closely matched over a potential fastest lap with the Corvette lagging more than 6/10ths of a second further back. Almost 1 second between potentially fastest Porsche and slowest Corvette.Race 8

10th of September and IMSA announces another Adjustment to Performance which gives 20kgs extra weight to the Porsches.

Race 9 CotA

BMW win a fuel conservation race, finally the extra 3 liters of fuel capacity helped them whereas both factory Porsches and the #3 Corvette had to take on fuel just a couple of laps from the end of the race. Porsche were significantly fastest – despite the extra 20kgs of weight – with a potential best lap time of 2:03.000 whereas Ferrari were 1.65 seconds slower.

Race 9

Race 10 Petit Le Mans

Porsche won the race overall and therefore obviously the GTLM Class. The race was extremely wet and was actually shortened to less than 8 hours when IMSA decided to throw the checkered flag at 7hrs and 51 minutes. The reason that the Porsche and other GTLM class cars did so well has to be down to the Michelin wet weather tire being a significant advantage over the Continental wets being used by the other classes. Porsche was significantly faster – nearly 1.5 seconds – over the BMW who were 2/10ths faster than the Corvette and the Ferrari was slowest by a massive 2.4 seconds when compared with the Porsche. The wet weather and lack of aerodynamic grip of the Ferrari was a factor in their slower lap times.

Race 10

Conclusion

IMSA made a couple of mistakes in my opinion. The BMW weight reduction before Long Beach was one and not adding weight to the Porsche before VIR along with reducing their rear Gurney flap was the other.

Overall IMSA learnt from their mistakes in 2014 and didn’t make too many changes to the cars throughout the season. Personally I would like to see the cars all run with the same weight, same fuel filler restrictor size, fuel tank capacity size etc. I would like to see adjustments to performance being done with just the air restrictor on the cars. This adjusts the horsepower but doesn’t alter the other dynamics that weight adjustment does.

Michelin changed their tire during the season and this positively helped the Porsche and obviously that caused a performance change that IMSA cannot factor into their AoP. I would like to see the tire manufacturers provide a control tire that all teams use all season so that it is then up to the teams to get the best out of it. I know Corvette Racing did not have the time to really test the new Michelin and therefore they were playing catch up for a lot of the second half of the season. Porsche and Ferrari have a big advantage as brands over the other manufacturers as they have so many cars running in the FIA WEC that can be used for data comparision.

For 2016 Ford will be entering their new GT and this will cause an additional headache for IMSA given that the engine is a smaller capacity (3.5L) twin turbo. Porsche will no longer have the Falken shod #17 car as their third bullet as the Team Falken Tires announced they were withdrawing from the GTLM Class.

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Jan
14

C8 Zora vs Ford GT

With the announcement on the 12th of January at the North American International Auto Show of the new 2017 Ford GT, this raises a few interesting thoughts / questions in my mind today.As anyone with an ounce of petrol flowing through their veins will know the original Ford GT came about back in the 1960s as a revenge weapon against Ferrari. Enzo Ferrari famously courted The Ford Motor Company and then changed his mind, which led Ford to serve their revenge as a dish best served cold at the 1966 Le Mans 24 Hours race and just to push the knife in further again in 1967,68 and 69.
The Ford GT was then launched again in 2005 and a small number were raced at Le Mans in privateer hands and also in the FIA GT and GT1 World Championship, but not with factory support or as a factory team.
The plan for Ford in 2016 is to race again at Le Mans and this time the car will be backed by the Ford Motor Company but run by the (Target) Chip Ganassi organisation. Ganassi currently run the Ford 3.5 Twin Turbo Eco Boost engines in their Riley Daytona Prototypes in the Tudor United Sportscar Championship and therefore I would assume that for the 2016 season they will switch to the GTLM Class with the new Ford GT given it is the 60th anniversary of the 1966 Le Mans victory.
Given the international nature of Le Mans (it is in France after all) it doesn’t make sense to me that the team would be sponsored by Target – unless of course they are planning on launching a range of stores in France. The obvious and some would say iconic choice for a headline sponsor for the team would be the Gulf Oil Company, but this causes a problem as they currently sponsor one of the major GTLM / GTE PRO / GTE AM Class rivals Aston Martin.
What might you ask has this got to do with Corvette? Given this is a Corvette centric blog after all, well, GTLM features the current C7R Corvette and I would assume that in 2016 we can expect the Corvette Racing team to be given one instruction for the year. WIN LE MANS. Failing that beat the Fords everywhere they race.
For 2017 and the expected launch of the rear-engined Corvette C8 Zora I can see the rivalry intensifying as both will be competing with similar rear-engined machinery, again assuming Corvette Racing launch their C8R at the NAIAS in 2017….or will perhaps GM tell Corvette to ramp up the program and launch in 2016 to directly compete against the Ford with similar machinery…..only time will tell.
Just to throw a further manufacturer into mix, Ferrari is now owned by FCA or Fiat Chrysler Automotive, could this mean Ferrari running a factory backed Le Mans effort in GTLM with their Ferrari 458 Italia – a dish served 60 years colder – or resurrecting the factory backed Dodge Viper program to compete against Ford?
I am already thinking about booking for Le Mans in 2016,17 – possibly not a huge surprise to those that know me as I have attended every year that Corvette Racing have attended Le Mans going all the way back to 2000 – but given this potential new rivalry in the GTE Class I can see this being a new golden era for Le Mans so those “thinking” about attending should stop “thinking” and start attending.

Nigel S. Dobbie

Jan
12

Roar Before The 24 2015

IMG_3570

Christmas is over, New Year is done, time to get back to some racing! Okay so this isn’t strictly racing we all have to wait until the 24th of January for that to happen. The Roar Before The 24 is the three day test at Daytona International Speedway two weeks before the 24 Hours of Daytona which is the first race of the Tudor United Sportscar Championship and also the first leg of the North American Endurance Cup.

The 24 Hours of Daytona traditionally kicks of the Endurance Racing season in North America except usually there is a 3 week gap between the test and race weekends. Given that the Corvette Racing team are based in New Hudson, MI, an ice storm was being predicted for their route home Sunday / Monday, rain was forecast and duly arrived Sunday morning at the track and the team need to be back in Daytona on the Tuesday before the race they could be forgiven for packing up after the Saturday night practice session and heading home. It was also Doug Fehan’s birthday so maybe there was a massive party somewhere (that I wasn’t invited to I might add) and the team were all too hungover to return to the race track Sunday.

IMG_2025 IMG_2618 IMG_2619 IMG_2621 IMG_3365 IMG_3693 IMG_3980 IMG_4154 IMG_4169 IMG_4260 IMG_4263 IMG_4404

The Friday session started cold (45F) and overcast with conditions expected to warm up over the following 2 days. The GTLM Class of the Tudor United Sportscar Championship lost the factory Viper team at the end of the 2014 season but in compensation an extra Ferrari 458 Italia (#51) and the #98 Aston Martin brought the field back up to 10 entrants. Corvette Racing decided to bring the C7R 001 chassis as the #4 car which was the one the team finished the season with in 2014 plus the 003 chassis as the #3 car which had competed all of 2014. The only visible change to the cars was the change from the painted silver side stripe to a more black chrome side stripe.

The #98 Aston Martin topped the timings for the first session on Friday, the #911 Porsche the second session. Saturday session three and the Aston was back on top, session 4 it was the turn of the #25 BMW to record the fastest time. Session 5 again went to Porsche but this time the #912, the final session (the night practice) went to the Aston Martin with Corvette C7.R #4 second and #3 Corvette third.

Sunday as mentioned earlier was wet and a lot of the teams decided to head home rather than add meaningless laps to their cars while greatly increasing the risks of damage.

IMG_2401

Overall combined times for all the session saw the #912 Porsche take the honors with it’s session 5 time of 1:44.316 the slowest car was the #25 BMW with a time of 1:45.058. IMSA will be pleased that all 10 cars were covered by less than 9/10ths of a second over the 3.56 mile course which utilizes both the high banking of Turns 1-2 and 3-4 plus the infield horseshoe loop and the bus stop chicane on the back straight.

IMG_2420

In the Daytona Prototype Class Corvette DPs took the top honors for the weekend with Jordan Taylor recording a 1:39.181 on Saturday in session 3, second place went to the defending Daytona 24 Hours champions the #5 Action Express Corvette DP. The top 9 cars in the DP Class were covered by just 1 second and in addition to this the 10th / 11th place teams were testing brand new cars for the first time in public so I expect them and other teams in the top 10 to be aiming for a good finish on Sunday the 25th of January.

Testing is just that and therefore it is extremely difficult to get a feel for what programs each of the cars are running / tires / fuel loads etc. during each of the sessions. I know that Corvette were running with full tanks for at least some of the sessions. I also know they were trying different rear wing angles. Corvette Racing also welcomed a new driver for the test who will be racing at both Daytona and 12 Hours of Sebring in March and that is Frenchman Simon Pagenaud.

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Nigel S. Dobbie

Oct
16

2014 TUDOR Balance of Performance

TUDOR 2014 Balance of Performance

At the beginning of the 2014 season IMSA the Governing body of the TUDOR United Sportscar Championship set the Balance of Performance for all four Classes. I am only interested in what happened in the GTLM Class. So I have based my calculations on the following scenario:

I took all of the published IMSA Timing data available at www.imsatiming.com for the 2014 TUDOR United Sportscar Championship for all of the rounds involving the GTLM Class.

I then filtered it to Green Flag Racing Lap and grouped the data by Brand and Car (I added two new columns to the data Circuit and Brand). I then wanted to find the fastest theoretical lap by Brand and to do this I looked at all of the sector times to calculate the best sector time for every sector regardless of the driver or the car i.e. Sector 1 for Corvette for example might be Antonio Garcia in the #3, then Sector 2 might be Oliver Gavin in the #4 and so on to get the Best Theoretical Lap Time.

For all of the charts below the bars represent the time in seconds for the cumulative theoretical best lap time by brand and is measured in seconds on the left hand axis, the dark red line represent the average time for all the brands (6 at Daytona and 5 for the rest of the rounds as Aston only competed at Daytona). The red line represents the top speed as measured by IMSA at their speed trap, this is the actual best time by brand and is measured in MPH and represented on the right hand axis of the chart. For Daytona I actually added a further line which took out the Aston and the Ferrari and this line is in green.

Race 1 Daytona

Race 1

Race won by Porsche. Aston Martin considerably slower than the Average as was the Ferrari, however the Ferrari data is a little skewed by the fact that only Matteo Malucelli drove the #62 and the other Ferrari the #57 is the Krohn car. BMW, Corvette, Porsche, Viper all below the “average” so taking the Ferrari and Aston out of the equation I created an Adjusted Average of the other 4 manufacturers. This shows how well balanced all of those 4 manufacturers were at Daytona. Viper potentially fastest but less than 2/10th of a second covering all 4 manufacturers. The scale is lap time in seconds for all charts.

14th of February AoP adds 15kgs to the BMW, 15kgs to the Viper and reduces the Aston by -20kgs.

7th of March additional -30kgs for the Aston.

Race 2 Sebring

Race 2

Race won by Porsche. Aston Martin decided not to race so no data available so for the rest of this report there will be just 5 manufacturers shown. Ferrari again significantly slower than the average but again #62 crashed early and #57 the Krohn car more amateur than pro drivers. Potentially fastest car was the Corvette but both cars suffered late race problems so the next fastest car the Porsche won.

Race 3 Long Beach

Race 3

Race won by Corvette. BMW potentially fastest, Porsche right on the average and both the Ferrari and Viper more than 2/10ths slower than the average but also the two fastest cars through the speed trap.

Race 4 Laguna Seca

Race 4

Race won by Corvette. BMW significantly potentially fastest, Porsche also faster than the average by about 2/10ths of a second, Corvette the winners actually slower than the average but within 1/10th. Viper slowest and more than 3/10ths slower than the average. Ferrari also still slower than the Average. Viper fastest through the speed trap.

Race 5 Watkins Glen

Race 5

Race won by Corvette. BMW potentially fastest car, then Viper, Porsche and Ferrari both slower than the average. Viper now running -15kgs and with a bigger restrictor after 20th June AoP adjustment. Corvette running exactly on the Average. BMW lowest top speed but fastest lap time.

Race 6 Canadian Tire Motorsport Park

Race 6

Race won by Corvette. Corvette fastest car and faster than the average by more than 3/10ths of a second. Actually all cars faster than the average apart from the Ferrari which was massively slower than the average by more than ½ second. Corvette fastest through the speed trap.

IMSA makes Adjustment of Performance as follows: (Changes in BOLD)

BMW -15kgs
Corvette +25kgs
Ferrari -30kgs
Porsche +15kgs
Viper -15kgs

Race 7 Indianapolis

Race 7

Viper fastest car and it now appears that the cars are pretty well balanced as all four other manufacturers are all extremely close to the Average except for the Viper. However this is deceptive given the nature of the track when compared with the other tracks to follow and the amount of time under caution.

Race 8 Road America

Race 8

Race won by Ferrari. Porsche and Ferrari both significantly faster than the average. BMW and Corvette both slower than the average. BMW within 2/10th of the Average but Corvette now more than ½ second slower than the Average carrying the extra 25kgs and now 70kgs heavier than the Ferrari.

Porsche which has historically always liked Road America and had the potential fastest lap time, should have won the race.

Race 9 VIR

Race 9

Race won by Ferrari. Ferrari more than ½ second ahead of the Average, Corvette now more than ½ second slower than the Average. BMW about 2/10ths faster than the Average.

Race 10 COTA

BMW +25kgs 1255kgs
Corvette -15kgs 1255kgs
Ferrari -30kgs 1200kgs
Porsche +15kgs 1225kgs
Viper -15kgs 1250kgs

Race won by Viper. AoP applied before the race.

Race 10

Porsche was potentially the fastest borne out by their pole position and should have won the race and would have but for the failure of the driveshaft on the #911 car. Viper was the second fastest car and took full advantage taking the 1-2 in the race. Porsche finished 3rd, Ferrari 4th and Corvette ran to form i.e. last just behind both BMWs who were equally slow with the same weight as the Corvettes. The extra weight massively affected the BMW as it has the Corvette and the smaller restrictor on the Ferrari seems to have had the desired effect i.e. brought them back to the average. Porsche have a huge advantage of 0.7secs compared to the average. Corvette and BMW are both more than 0.5secs over the average. Spread of potential best times now a massive 1.2seconds from best to worst.

Race 11 Petit Le Mans

Race 11

Porsche significantly faster than all the other manufacturers and won the race. All the other four manufacturers were actually closely matched with the spread of potential best lap times covered by just over 0.3secs.

Weight / Wait!

My conclusion to all this is that given this was the first season of TUSC IMSA should have stuck to their guns i.e. left the Balance of Performance alone once it was set at the beginning of the season as they were pretty close to perfect at Daytona (except Aston Martin). Going forward into 2015 IMSA should set the class weight at 1245kgs for all cars AND NOT CHANGE IT EVER!

The fuel tanks for all cars should be the same (except for those running E85 as you need more fuel to get the same performance as E10). The fuel flow should be the same for all fuel rigs as a faster team in the pits shouldn’t be penalized for being better / faster.

If IMSA feel one car is making more power than another then sure they should change the restrictor(s) for the cars…..in other words lets’ go back to the days of GT1 where the best team with the fastest car won the races.

Mar
18

Sebring 2013

The right car won if for the wrong reasons.

The final season of the ALMS started with a Corvette victory yesterday but that doesn’t really tell the whole story. The #62 Risi Ferrari 458 took the pole position for the race but Oliver Gavin in the #4 Corvette took the lead at the first corner from second place on the grid and breezed off into the distance. All seemed to be set fair for the #4 car until the dashboard display for the gearbox and the gear shift lights decided to stop working. Two attempts to fix it dropped the car off of the lead lap but Tommy Milner managed to get around the #91 Viper that had taken the class lead. Then a full course caution closed the field up and with quicker pit work the #4 managed to move back to 4th place in the class and with Richard Westbrook storming around the car managed to re-take the class lead. Then after another full course caution Richard was assessed a 60 second penalty for avoidable contact with the Alex Job Racing Ferrari, leaving the vette again playing catch up. Olly Gavin took over the chase but when he handed the #4 Corvette back to Tommy Milner for the final time he was still over a minute behind the now class leading #62 Risi Ferrari. At the final pit stop Tommy took over 10 seconds out of Matteo Malucelli in the Ferrari and then set about the task of chasing down the Ferrari during the final hour of the race. Every lap Milner chipped away at the Ferraris lead and with 30 minutes left in the race it was down to 5 seconds. Eventually the pressure told and Malucelli made a mistake getting squeezed onto the grass by one of the Porsches and with that Milner was right on him, a few corners later on the same lap again the Ferrari ran wide and that was all the invite Tommy needed to take the GT Class lead. The final 13 minutes just needed a clean run to the chequered flag to take a well deserved 12 Hour victory for the #4 Corvette.
The result was the right result as the #4 Corvette was clearly the class of the field, twice shooting themselves in the foot cost them about 4 minutes more time in the pits than the #62 Ferrari so the right car won in the end. IF Bruni or Beretta had been in the #62 Ferrari for the final stint would they have lost the lead? A great debate for a night in the pub over a pint with friends.

The #3 Corvette had a troubled first race of the season with electrical problems, contact with another car and the resulting penalty then finally the gearbox decided to lunch itself. Worse still the car didn’t complete the required 70% of the winners laps meaning they scored no points.

Next race is Long Beach in April.

Nigel S. Dobbie

IBM Cognos Business Intelligence Expert during the week
Vette News Motorsport Journalist / Photographer on the weekend

Cell: 847-373-1608

Apr
26

Book Signing at National Corvette Museum 28/29 April 2012

Nigel S Dobbie will be signing copies of his definitive book, Corvette Racing: The GT1 Years, at the National Corvette Museum, on the following dates:

Friday 27th April (3pm-4pm)

Saturday 28th April (10am-11am)

He’ll be very pleased to meet you and to put some faces to names!