There is certainly catch up logic in place. In the same night in almost back to back races I did a 2:03.4xx while far behind which would have been a record lap if another car did not push me onto the grass. A couple of races later I was taking excellent lines while I had a huge lead and could not get better than a 2:08. How else do you explain that?
A slow clock maybe?
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I dunno. Only joking, but I have noticed the reverse effect of what you are describing.
I'm not about to eat humble pie, but I noticed something earlier today whilst racing a three player race. As always, I was racing a tuned Elise (MT, no aids bar ABS of 1, and professional physics) against a Ferrari F430, and a Tuned Elise 111R.
Before the race started, I knew I had won, but the time I set stunned me - I was a whole 9 seconds faster than my 'par' within that race. Usually within a full 12 player race I draft my way to the finish line, and with speeds in excess of 200mph on the straights, corner entry speeds of around 195mph, and apex speeds of 178mph, I can only manage a finishing time around 4.19.xxx. That's a pretty fast time, and usually only achievable in race conditions with the help of some serious drafting.
So you can imagine my surprise when I started in first, pulled away from the pack, and finally managed to set a race time of 4.11.xxx! My maximum speed on any straight never went over 184mph, my corner entry speed was 184mph, and my corner apex speeds were a rock solid 178mph every time.
The car's engine never sounded like it was over or under revving, acceleration and top speed were precise, and at all times the Elise responded as it should of. Most importantly of all, the cars behind me never gained any time at all. All I can assume is that I was lapping VERY close to my online record of 48.xxx.
Could what has been described in this thread, be a bug rather than a feature? I (and others), have never noticed the
'catchup logic' that many here talk about. So something that is not present every time might point towards a bug of some sort? On another tangent, could this
'catchup logic' have anything to do with the physics settings the other drivers are using?