Seth Thomas

Chin Motorsports had an event at Road Atlanta this past weekend. We were testing the Next Level European IMSA Continental Tire Caymans during the event. I had the RS there where I had the chance to take the car out on the track in one of the afternoon sessions. The day was blazing hot with temps in the 95+ range all day. The alignment and specs on the RS are stock which I feel were limiting some of the speed the RS would have on the track. Enjoy the video.

siswati

Thanks for sharing Seth, great to ride along with you.

What I found so interesting to note was that the mid corner speeds were all slightly lower than our Spec Miata corner speeds.

Seth, as you know I respect your ability as a race car driver so please don't for a second think that this a reflection on your driving, but I was honestly expecting a car with splitter and wing and huge rubber to carry more mid corner speed. (I fully know you were nowhere near the limit, especially not with a passenger, no cage, no suit etc, it was a really hot day, and of course the setup is not dialled in), but still I was expecting more.

Seth Thomas

Good observation. Weight is the enemy. In this car with a full fuel load (filled up the 23 gallon tank that AM) and two passengers we have a car that is around 3700lbs. Your SpecMiata with driver is around 2400lbs. While the RS is good it isn't good enough to overcome 1300lbs of weight difference in the cars. Something has to give up slightly and the mid corner speed is part of it. In a 991 Cup Car for comparison the Vmin in Turn 1 is slightly over 100 MPH in a car with splitter, big rubber and rear wing but about 900lbs lighter than the RS. That would be my $.02 on the difference in speeds but well noted on your part.

siswati

Thanks Seth, yup that would account for it. 1300 lbs is significant for sure. 100 PLUS mph though T1 is hauling the mail - we are at 95mph with Hoosiers in the Miata.

Seth Thomas

Getting the car aligned today and found some interesting points that make it apparent why it wasn't handling up to snuff. Biggest was the rear was out of spec. The LR was toed in (don't remember the measurement but will get it when I pick the car up) and the RR was toed out. That will hurt in the handling department.

Kobalt

Are you getting a stock factory alignment?

Seth Thomas

No. Getting away from factory specs. I will have the specs on what we have it set at a little later but we lowered the front and the rear slightly, changed bar settings, and went more aggressive on the front camber. Driving it home it was a noticeable difference but I really won't be able to tell until I get the car to the track again

allans

Seth, Thanks for the video. I like the perspective with the helmet cam. What are you using for this set up? Best, Allan

robmypro

Nice driving! Love that track.

Seth Thomas

Allan, I will take a picture of the setup on my helmet when I get home today. Basically it is a GoPro Hero4 Session mounted on the front of the helmet high enough so I an open my visor. Then I used enough of the extensions to get it low enough to setup a good view out the front. The mistake I think I made with this one is I had it a little low so the focal point stayed low enough to create a washout of the stuff outside the car. Next time I am going to try to turn that off or aim the camera a little bit higher so the focal point stays outside the car.

awew911

Very nice! Thanks for sharing.

rm21

Seth - you're a braver soul than me. I was supposed to be there with some other folks but we decided to cancel at the last minute given the heat. We sat inside in the AC, drank wine, and drove the ring on Forza. Much more civilized.

Manifold

A car like a Miata with lower ratio of power/grip will optimally apex a bit earlier, with a higher apex speed, because it has less power to put down through corner exit. Conversely, a car like an RS, with plenty of power, will apex a bit later and slower in order to increase the average radius of the corner exit and put that power down.

As an example, compare the laps starting at 10:56 in this video:


The Viper has a substantially faster lap, but it has slower apex speeds in corners where the apex speed is under 68 mph; but it puts down power better than the Vette and accelerates past the apexes more quickly than the Vette. For corners with apex speeds above 68 mph, the Viper has higher apex speeds, likely because the mega aero enables that, plus cars have less acceleration as speeds increase, so the apex generally moves earlier/faster in faster corners. Here are the tabulated apex speeds: