Originally Posted by enigma
One we don't know its stock. You see in the video they are putting some diffrent tires on it. The term used is "cut slick" which may mean groved slick. Note: that is important because that would be a large upgrade over the tires on the M3 CSL. On a track as long as the ring that could mean 10-15s over a DOT-R whcih is already 10-15s over a street tire. So put street tires on the car and it might regress all the way to 8:00 or so.
If they did run a "slick" that also has other implications. That the stock suspension was able to run the tire without being overloaded means it must have a very, very good camber curve and a lot of roll stiffness, or the car has been upgraded from stock in some way. Possibly as an unanounced option package al-la the Exige Cup 240.
Statistics are great, but not when unknown factors can influence the times by far more than the accuracy of the statistics you are trying to use.
All we know is a GT-R like car did a specific time. We don't know any of the specs of the car in question. They clearly put special tires on it for the lap, were other things changed? Either as a straight mod or a performance option on the car, unkown.
OK some disagreement but I have much more simply thinking out loud to do. Bear with me. I think this reply get better as it goes...
Indeed a fully modified race car can place you some significant distance below the regression line - absolutely. This regression line is for street cars (and some exotics - but still steet cars). With the implication you make about the the vehicle being very far from stock, tires and suspension, maybe more, the entire point and impact of the video is called into question. The purpose of the video is marketing and despite the use of non street tires the ENTIRE POINT of the video is that Nissan has made a street car that is also a Porshe Turbo "killer". I trust we can agree on that? Surely if the vehicle is in a state of "tune" anywhere close to what you imply the entire exercise is a giant case of "apples to oranges" and all of the marketing advantages would be lost in a flurry of calls of fraud upon Nissan (and I'm assuming they would get found out somehow). So I contend that the car is likely stock except for two large variables: engine tune and or tires. One of these is easy to cover and to explain around ("it was just tires"...). Engine tune would certainly be a huge cheat as well but who knows. Again the most I can speculate on at this point is back to my points 1-4.
Not to split hairs on the tires but I will modify my possibilty #4. You clearly know more about tires than I do and I may have used incorrect terminology in that statement. I will revise my statement to:
4. The car had a tire of the grade track/competition and DOT legal or higher, potentially all the way to full race tire.
Considering the innovation of the car, as well as the marketing effort of Nissan focusing on the Ring time, I do think that the sole change of a tire could be enough to explain the distance from the regresson line. In other words tires could easily be worth 10+ seconds (this we know) and if the car was 10 seconds slower I would not consider it an outlier and consistent with the range of possibility based on the other data points. This is the way I am strongly leaning at this point.
Look how much more sense the GT-R point makes if you simply move it vertically up 10-15 seconds which is easily explainable by tires. However, to move it horizontally to imagine improving its power to weight ratio you have to move it by around 25% to get it to even reasonably cluster with other cars which are still well below the mean. Looking at things this way is simply another very valuable feature of looking at the data in this fashion. It shows very cleary how important tires are and how much power or weight it takes to match the effect of tires. I like!
In conclusion my guess is dead stock except tires, a great performing car well above almost all at this power to weight ratio.