“Huge”. ok. Currently there is a 14 second gap between F1’s 2018 pole position and Indycar’s fastest test time. That’s about 15% slower. Your estimating that it will probably end up being 10-11 seconds, and perhaps that’s probably fair. So that’s a ~12% slower time.
For comparison, at the 2018 British GP the Formula 2 pole time (01:40.0) was 17.6% slower than F1 (01:25.9).
So it seems like Indycar could be pretty much bang-on between F1 and F2 quali times. Seems fair enough to me.
But why are we comparing the Indycar testing times to F1 qualifying times at all? I don’t think that’s a fair comparison at all. I’m sure they’d be closer to race trims for testing and, besides, the race is what actually matters, right?
2019 Indycar fastest test lap: 1:46.6
2018 F1 fastest race lap: 1:37.4 (-9.2)
2017 F1 fastest race lap: 1:37.8 (-8.8)
2016 F1 fastest race lap: 1:39.9 (-6.7)
Which tells me they are actually only 8-9% slower in race trim compared to the modern high-downforce spec F1, based on this single test, and 6-7% slower than the 2016 spec cars. The majority of the field in 2016 ran a fastest lap of around 1:44.0, so Indycar is already not far away from that at all.
Most importantly, in terms of apples and oranges, the Harding Steinbrenner Racing car that Colton Herta is running in 2019 is probably running on a budget less than 10% of the Mercedes car that we’re trying to compare it to. The gap doesn’t seem huge to me.