OK I threatened to do some testing, mindful of the old saying that "a man with an opinion and no data to support it just is a man with an opinion."
Objective:
To verify if there is any significant variance in the performace/durability/sensitivity of the tyre models used in the URD (Chevrolet Corvette) Mod and the iSI Vette.
Methodology:
From time to time I do a little bit of base setup testing at
Nazareth Speedway. I like it because it has 5 turns in a 27 sec lap and so I can test a 5 lap run on a setup change very quickly. You are pretty much turning all the time and you can immediately feel the cars response to setup changes. Its a very simple lap and personal performance doesnt vary much. Its a 1 mile skid pan in this sense. You can feel it and see for example a .5 sec improvement if its there without wondering too much "did I just drive better that lap?"
Its also brutal on the RHF tyre.
So I figured I can destroy 3 sets of tyres and get some consistent data without making a career out of it.
So I set up both cars for optimum lap time there. Loaded 50 litres of fuel and ran 40 laps as hard and fast as I could.
I used a Motec tool and wrote down lap times and tyre wear at 5 lap intervals.
If say that lap clearly had an error I used "data smoothing" and extrapolated from the laps surrounding it.
Results:
Best lap time: Nothing in it. The Endurance tyre is not noticeably slower.
URD Endurance 27.295
URD Sprint 27.464
ISI Vette 27.416.
Lap time delta across 40 laps.
URD Endurance 0.7 sec
URD Sprint 1.036 sec
ISI Vette 0.4 sec. (only ran to lap 28 as tyres were nuked, times would have dropped hugley by lap 40 if they lasted that long).
Tyre wear (RHS Front only) is markedly greater on the ISI Vette. At lap 30 its 29% left vs 62% and 63.5% for the URD tyres.
The URD End tyre keeps appr a 2% advantage in remaining wear over the URD Sprint tyre.
Tyre wear other: Its a brutal test so you ask would it hold true with less stress?The pattern stayed the same with the other 3 tyres.
Rears on URD car. 95% Sprint, 96% and 97% Endurance. after 40 laps.
Rears on ISI 82% and 91% (but only after 28 laps not 40.
Left front: URD 89%
ISI 89.52% (28 laps only).
Tyre Temps: behaved differently too. The URD tyres plateued more, whereas the ISI tyre temps kept rising. For example if we compare at lap 20 the the coolest temp achieved that lap for the hardest working part, the centre of the hardest working tyre the Front Right. The ISI tyre was 147 deg. The URD Endurance 126, Sprint 121. Peak temps were higher too.
Conclusions: The ISI car requires more tyre management. With 70% wear at 30 laps vs 36.5% (URD End) Its tyres wear out approx 80-90% faster. In a less brutal environment there may have been a bigger difference between the two URD tyres who knows. The rear tyre data does not suggest it.
Even on such simple track the cars feel quite different in personality. I wont go into it but when you are curious go and do 10 laps in each.
Thanks all for reading.
The data is available in XL format if you want to see it. see link below.
https://www.dropbox.com/s/l30qm1djsvzbs6g/Tyre Testing Corvette.xls