20 year-old vs new starter waveforms for curiosity

Hi Forum. My '04 original Denso starter began laboring with a bit more noise as of late. I decided to capture its voltage(blue line) and current(green line) waveforms before replacing with a Bosch starter (SR6437X) I bought on closeout in 2015. The new Bosch starter draws more current which explains the approximately 400A+ higher peak in its waveform (yellow line). In 2016 I used a handheld multimeter capable of capturing current waveforms to record the old starter and used the same handheld again just now to compare (third image below). Notice how much less noise in 2016 than 2024 . At that time it looks at least 150A greater than today (meter limited to 1500A) so it possible that new Denso draws same peak current as new Bosch. Brush wear, inadequate spring pressure from worn brushes, contaminated commutator or some combo main culprit. This noise is evident in more jagged lines of current and voltage waveforms of old starter (see second image which is zoomed-in). I would estimate15-17k start cycles on original starter . Others certainly have more miles on theirs and it seems that the Denso starter is worthy of brush replacement/service to keep as a spare as I'm confident Bosch won't last as long.

Sven #ad
#ad
#ad
x