How does leech cap work?

If I have 5600 life and have 1120 life leech rate per second. Will going to 120,000 life leech rate per second have any effect if i have no sources of leech cap or instant leech?

Leech cap is 20% of max life. To quote the wiki:

"

The #% of maximum Life per second to maximum Life Leech rate modifier raises a character's leech cap, calculated as (Maximum Life * (0.20 + #% of maximum Life per second to maximum Life Leech rate) ). Normally a character with 5,000 life can only leech health at a maximum rate of 1,000 per second (5000 * 0.20 = 1000) regardless of how many leech instances they have and what rate they individually regain life. If that character gains 5% of maximum Life per second to maximum Life Leech rate, such as from the notable Vitality Void, they will be able to leech up to 1,250 life per second. (5000 * (0.20 + 0.05) = 1250)

The short answer, in case you're asking what MIGHT be what I think is you're asking: no.



And for the long answer, just to make clear/review in case there's some confusion, (and hence, apologies if you get this all) "Life leech rate," contrary to what it might seem at first, is NOT based on your DPS.

It's (perhaps) easiest to think of leech as applying a "buff" to you each time, where it restores HP over time, and these buffs can stack; you get one buff stack per time you score a hit that leeches. There is also a cap on the number of stacks you may have.

By default, each stack of leech restores health at up to 2% of your max life per second. You have a default MAXIMUM leech rate of 20% of your max life per second, which works out to 10 stacks.

Raising the life leech rate increases the size of each stack, but NOT the total "mass" of stacks you can have. For example, if you have "Brutal Fervor" (100% increased life leeched per second) that will increase the size of your stacks to 4%/sec. However, the MAX cap of 20%/sec will remain, basically meaning you hit max at 5 stacks instead of 10.

To leech faster than your maximum life leech rate cap, you must increase it specifically. Currently, the ONLY source of improvements here are four passive nodes: Vitality Void, Hematophagy, and a minor node next to Hematophagy all grant +3% to that maximum cap, while Vaal Pact makes it "doubled" ("100% more", which outright doubles whatever it may be)

As mentioned above, the main advantage of increasing your individual leech rate (Rather than the maximum rate) is that it takes fewer hits in a row to "rev up" your life leech to maximum speed.