Question about AE86 braking and low speed behavior

[Raymi]

I was wondering if someone could explain what is going on in low speed corners (the hairpin in vallelunga club in particular) and under braking with the stock AE86 -

Under braking, the engine suddenly drops to idle or near idle (RS1600 did something similar on default set-up but it was easier to compensate for), and after releasing the brakes and a brief pause, revs swell back to normal.

Looking at my replays, some times the rear wheels appeared to be locking briefly, but many other times they did not. I also rarely if ever got a flatspotting warning during these events unless I way over did it or intentionally mashed the brakes.

As I was approaching that vallelunga hairpin in different ways, I noticed that even if I brake far in advance, mid turn the revs tanked as well. I also found myself compensating by heel toeing for the downshift, and then continuing to heel and toe once in gear, as that sometimes kept the revs from tanking and kept the car steady enough to carry more speed through the corner.

Is it something to do with the differential?

[CCCP BDA]

I've noticed this too. I don't know why it happens but my theory is that the car dives so hard under braking (due to light weight and soft springs) that it unloads the rear tires, hence the instant rev drop and sudden oversteer. Likewise the mid-corner rev drop could be due to lifting a rear wheel.

[Raymi]

I hadn't thought of that, I don't remember the wheels hopping or lifting in the replays but I'll check next time.