Running 4s 3400mah, geared 26/88 in a Blitz (tranny ratio of 2.6:1). That's pretty much HPI's recommended gearing for a 17.5 on 2s

The motor hit probably 160-170 the last time I ran it (in sensored mode with 2deg. of timing "boost"). Previously in Smart Sense mode it reached around 140-150, but of course had that cogging issue. These temps are determined by the touch of my hand, which has become pretty accurate over the years.
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz