Funny Miata track day story...
 

This occurred earlier this year at Nelson Ledges. Last week after a track day ended, I was talking to an owner of a 17 Mustang GT with 470 hp. He was telling me that at the previous track day he was out during the advanced group session. He looked in his mirror and saw a little white spec. Looked again and it was slightly bigger. By the 3rd look he realized it was a Miata. The Miata caught him in about 3 laps. The driver said he was giving it all he had and in disbelief he gave the Miata a point by. After coming in at the end of the session he saw the car parked in the paddock. The car was a 4 cylinder naturally aspirated NA, 1.8 with a wing on the back. I was there that day and the Miata owner told me he was turning 1 minute 15 second lap times on the two mile track. The owner of the Miata introduced himself to the Mustang owner, it was Tommy Byrne.

Sounds like Mr. Mustang didn't belong in the advanced group.

I'm not able to determine how good of a driver the Mustang owner is. But considering that the track record is 58 seconds set down by a formula type car( not sure of the exact specs) the 1.15 lap times by a Miata is impressive.

There's a lot of variables in the equation...

A while back, my wife's DD was a '17 Mustang GT PP, and I took it out for a session when we had both cars at the track... I was ~2 sec slower/ lap than in our NA (n/a VVT - 136hp) on a 2 mile track. Same track, same day, same driver. Miata was on Rivals, Mustang on Michelin all seasons (I know... it was it's first trip to the track). Data showed the Mustang had a 10-12mph advantage in terminal speeds on the straights, but the Miata consistently had 6-8mph in the corners.

And IMHO, being in the 'advanced' group is more about driver skill/experience than lap times anyway.

Auto Interests is more about skill development and improvement than laying down the fastest lap times.

IMO the most important variable, and I suspect the story of the OP is something like this. Similar driver skill and tires, the Mustang should be the much faster car. Taking nothing away from the Miata driver of course.

The Mustang was a Kenny Brown prepped Mustang and Tommy Byrne who owns the Miata is a former European Formula 4, 3, 2 champion from the late 80's. He raced a few races in F1 as well. He's also an instructor at Mid Ohio.

Agreed, it's primarily about the differences in passing rules, and thus driver awareness of traffic and ability to behave predictably when being passed are the most important.

Of course, it's also nice if he's not in the way. Three laps to go from "visible" to passing isn't a terrible margin though.

--Ian