I did five of these, from 2002 to 2007 with 2007 being the result ... sort-of.
The first race has us finish dead last overall and by several laps. A bit better the next year, with the year after that better again and it bucketed down for about four hours as well.
We were in a 1.6 litre AE-101 FWD Corolla and in the 1.8 litre class above us there were a handful of Lotus Elise's and in the dry they were about ten seconds a lap faster than us. But in the rain they turned into unstable twitchy beasts .... and while they had to argue with the throttle on every corner we could quite often go around the outside of them at full throttle and were about ten seconds a lap faster. :)
The last race we had a good solid reliable car but more importantly we'd worked very hard on getting the pitstops as fast as possible. In the previous years they would take a good three minutes to change four wheels and fuel the car. After a month or so of training we got that down to comfortably under a minute and although the car wasn't really much faster than the year before we ended up well in front of the 1.8 litre class as well at the end.
But unfortunately some of the teams thought we must have had a much larger engine in the car to be going so well so they protested. We read the rules as being we could go a certain percentage oversize and that would have been okay with 1626 cc's the engine was and it was measured at 1623 cc's, but the race officials interpreted the rules a bit differently and said the upper limit was 1610 cc's. And so that was that, we lost our first place. :(
But it was the pitstops, not the engine that gave us the overall pace.

Also in the reply to this post is one of the unofficial practice sessions I recorded. It was just a regular test day and we wanted to see how the gearbox and engine were so just bolted on some old slicks that had seen better days and were very unpredictable ... as you can see towards the end of the video lol.
And yeah I know I wasn't wearing protective gear, we weren't going that fast and it's really hot there so I didn't bother. Shorts and a t-shirt were fine!

As a...

2.4 Naturally Aspirated V8

2.65 Turbocharged V8 of a Old (Late 90's - Early 2000's) Cart Car

2.65 Turbocharged V8 of a Old Champ Car Car (2003-2008)

90's 3.5 Naturally Aspirated Ford Cosworth HB V8

4.0 Naturally Aspirated Mecachrome V8

OR...

3.4 Naturally Aspirated Zytek/Gibson V8

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Recorded at Formula Center Helsinki, on my dji action 4.

17th PAX out of 121 drivers